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Site Supervisor Course for Labour-Based

and Community-Managed Upgrading of

Urban Low-Income Settlements

International Labour Organization

ASIST, Advisory Support, Information

Services and Training

KEWIRepublic of Kenya, Ministry of

Environment & Natural Resources

Kenya Water Institute

Republic of Kenya,

Ministry of Roads and Public Works

Kisii Training Centre

Andreas Beush and Marie Winsvold

Site Supervisor Course forLabour-Based and Community-Managed Upgrading

of Urban Low-Income Settlements

Supervisor’s SiteReference Handbook

Andreas Beusch (Intech Beusch & Co.)

and Marie Winsvold (ILO)

Republic of Kenya, Ministry of Roads and Public WorksKisii Training Centre

KEWIRepublic of Kenya, Ministry of Environment & Natural Resources

Kenya Water Institute

International Labour OrganizationASIST, Advisory Support, Information Services and Training

Copyright © International Labour Organization 2002

Publications of the International Labour Office enjoy copyright under Protocol 2 of the UniversalCopyright Convention. Nevertheless, short excerpts from them may be reproduced withoutauthorization, on condition that the source is indicated. For rights of reproduction or translation,application should be made to the Publications Bureau (Rights and Permissions), InternationalLabour Office, CH-1211 Geneva 22, Switzerland. The International Labour Office welcomes suchapplications.

Libraries, institutions and other users registered in the United Kingdom with the CopyrightLicensing Agency, 90 Tottenham Court Road, London W1T 4LP [Fax: (+44) (0)20 7631 5500;email: [email protected]], in the United States with the Copyright Clearance Center, 222 RosewoodDrive, Danvers, MA 01923 [Fax: (+1) (978) 750 4470; email: [email protected]] or in othercountries with associated Reproduction Rights Organizations, may make photocopies in accordancewith the licences issued to them for this purpose.

ILO ASIST Africa Regional Progamme

Andreas Beusch, Marie Winsvold

Site Supervisor Course for Labour-Based and Community-Managed Upgradingof Urban Low-Income Settlements – Supervisor’s Site Reference Handbook

Geneva, International Labour Office, 2002

ISBN 92-2-112813-X

The designations employed in ILO publications, which are in conformity with United Nationspractice, and the presentation of material therein do not imply the expression of any opinionwhatsoever on the part of the International Labour Office concerning the legal status of anycountry, area or territory or of its authorities, or concerning the delimitation of its frontiers.

The responsibility for opinions expressed in signed articles, studies and other contributions restssolely with their authors, and publication does not constitute an endorsement by the InternationalLabour Office of the opinions expressed in them.

Reference to names of firms and commercial products and processes does not imply theirendorsement by the International Labour Office, and any failure to mention a particular firm,commercial product or process is not a sign of disapproval.

ILO publications can be obtained through major booksellers or through ILO ASIST Informationservices, PO Box 210, Harare, Zimbabwe (e-mail: [email protected] , website: www.ilo.org/asist) ,ILO local offices in many countries, or direct from ILO Publications, International Labour Office,CH-1211 Geneva 22, Switzerland. Catalogues or lists of new publications are available free ofcharge from the above address, or by email: [email protected].

Visit our website: www.ilo.org/publns.

Illustrations: Dan AmayoDesigned by MDP, International Training Centre of the ILO, Turin, ItalyPrinted in Italy by the International Training Centre of the ILO

Preface

The ILO has promoted the concept of people’s participation since themid-seventies. Participation of local communities in developmentdecisions affecting their lives is indeed a precondition to economic,social and political changes required to achieve better working andliving conditions for the low-income groups in society. During the1990s, efforts to materialise “participation” were undertaken in anumber of grassroots programmes, resulting in the development of“community-contracting” as a policy tool to define roles, rights andobligations of each party concerned – e.g. local government and acommunity-based organisation – and to introduce the principles oforganisation and negotiation in the weakly organised and informalurban or rural areas.

Experience in the field projects, particularly with community-managedlabour-based upgrading schemes in urban low-income areas, revealedthat, for local government to effectively deliver its part of the contract, the municipal staff needed and actually requested support to improveand update their qualifications. Consequently, in 1999, a trainingneeds assessment was carried out by ASIST1 in Tanzania and Kenya,with a view to evaluating the needs for training of municipal engineers, technicians and foremen. The training material developed on the basisof this assessment consists of two parts:

a training course for engineers and town planners, “Sustainablecommunity-managed and labour-based upgrading of urbanlow-income settlements”; it has three components: i) Trainer’sNotes; ii) Workbook; and iii) Handbook; and

a Site Supervisor Course for Labour-Based andCommunity-Managed Upgrading of Urban and Low-IncomeSettlements; this course consists of i) Training Manual: BasicCourse; ii) Training Manual: Skills Course; and iii) Handbook.(This site supervisor course addresses the needs of both foremen andtechnicians).

Obviously, the present training material must be completed by similartraining material addressing the needs of the communities themselves, i.e. their technical and managerial capacity, and their organisationaland bargaining capacity2.

iii

1 ASIST: Advisory Support Information Services and Training, is the regional supportprogramme of the ILO’s Employment-Intensive Investment Programme.

2 Ref.: “Community Contracts In Urban Infrastructure Works, Practical lessons fromexperience” by Jane Tournee and Wilma Van Esch. 2001.

It is hoped that this package will enable local communities and localgovernment to improve their ability to effectively cooperate andsucceed in their efforts to upgrade the economic and social conditionsof those who so often lack access not only to economic opportunitiesand basic social services, but also to the so much needed technicalsupport.

The present Handbook for the Site Supervisor Course for Labour-Based and Community-Managed Upgrading Of Urban and Low-IncomeSettlements has been prepared by Andreas Beusch and MarieWinsvold.

I would like to thank the authors for this useful material, and expressmy gratitude to DANIDA for their financial assistance.

Jean MajeresHead,

Employment-Intensive Investment Branch

iv

Acknowledgement

This handbook has been prepared for the Advisory SupportInformation Services and Training Programme, under theEmployment-Intensive Investment Programme of the InternationalLabour Organisation, by Intech Beusch & Co., Consulting Engineers,in co-operation with the International Labour Organisation and withfinancial assistance from Danida.

Gratitude is expressed to the Kisii Training Centre of the KenyaInstitute of Highways and Building Technology and Kenya WaterInstitute for piloting the training courses from which this handbook isan extract. Acknowledgement is given to Wilma van Esch (Solid Waste) and Bjorn Rydtun (Water Supply) who assisted with very valuablecontributions to the development of this handbook. Special thanks toKelley Toole ILO/ASIST, Harare for her valuable contribution with therevision of the material and to Thomas Stenstrom and the rest of theASIST team for assisting and commenting on the development of thetraining material and the pilot courses.

This Handbook

This handbook is aimed primarily at Site Supervisors for labour-basedand community-managed infrastructure works for urban low-incomesettlements. It will also be useful for planners and contractors whendealing with site planning and supervision.

The handbook provides practical tables, guidelines andrecommendations in a concentrated format for use on site and iswritten in an easy understandable language. It is, however, is not atraining manual and has been prepared with the assumption that users have previously attended adequate training in urban infrastructureworks.

December 2001Marie Winsvold

Andreas Beusch

v

Table of Contents

Chapter A: Construction Measurementsand Calculations A-1

A.1 Unit Conversion A-2A.2. Lengths A-3A.3 Areas A-3A.4 Volumes A-4A.5 Weight A-4A.6 Density A-5A.7 Slopes A-5A.8 Pressure A-6

Chapter B: Tools, Equipment andProcurement B-1

B.1 Construction Handtools B-2B.2 Compaction Equipment for Labour-Based

Works B-5B.3 Procurement B-6

Chapter C: Setting Out C-1

C.1 Tools for Setting Out C-2C.2 Setting Out a Straight Line C-6C.3 Setting Out Angles C-7C.4 Setting Out Gradients and Levels C-8

Chapter D: Concrete Work D-1

D.1 Concrete Types D-2D.2 Batching for Concrete Mixing D-3D.3 Mixing Concrete D-4D.4 Water-Cement Ratio D-4D.5 Transporting Concrete D-5D.6 Placing Concrete D-5D.7 Curing Concrete D-7D.8 Quality Control for Concrete Work D-8

vii

Chapter E: Masonry Work E-1

E.1 Material for Masonry Work E-2E.2 Mortar E-3E.3 Quantities E-4E.4 Stone Masonry Work E-5E.5 Brick and Block Masonry Work E-6E.6 Quality Control for Mortar E-9

Chapter F: Solid Waste Management F-1

F.1 Solid Waste Types and Quantity F-2F.2 Storage of Solid Waste F-3F.3 Collection, Transportation and Disposal of

Solid Waste F-5F.4 Minimising generation and Maximising

Recycling of Waste F-6F.5 Safety related to Solid Waste Handling F-7F.6 Stakeholders in Solid Waste Management F-8

Chapter G: Road Work G-1

G.1 Road Work Terminology G-2G.2 Planning G-3G.3 Road Construction G-4G.4 Quality Control for Road Work G-14

Chapter H: Drainage Work H-1

H.1 Drainage Work Terminology H-2H.2 Planning H-3H.3 Drain Types and Options H-4H.4 Drain Construction H-6H.5 Quality Control for Drainage and Sanitation

Work H-16

Chapter I: Water Work I-1

I.1 Water Work Terminology I-2I.2 Planning I-2I.3 Construction Work I-3I.4 Quality Control for Water Works I-17

viii

Chapter J: Sanitation Work J-1

J.1 Sanitation Work Terminology J-2J.2 Planning J-2J.3 Types and Options J-4J.4 Sanitation Construction J-7J.5 Quality Control for Sanitation and Drainage

Work J-18

Chapter K: Work Management K-1

K.1 Site Work Planning K-2K.2 Site Organisation K-6K.3 Work Implementation K-9K.4 Site Planning, Reporting and Monitoring K-10

Chapter L: Community Contracting L-1

L.1 Contract Types and Contract Parties L-2L.2 Contract Documents L-4L.3 Contract Procedures L-5

Chapter M: Labour Issues M-1

M.1 Labour Laws and Regulations M-2M.2 Labour Recruitment and Remuneration M-4M.3 Safety and Health on Site M-7

ix

Chapter A: ConstructionMeasurements and Calculations

A-1

A.1 Unit ConversionsUnit System Metric Imperial + US

Length

Meter(m)

Kilometre(km)

Inch(in)

Foot(ft)

Yard Mile

1 0.001 39.3701 3.28084 1.09361 0.00062

1000 1 39370.1 3280.84 1093.61 0.62137

0.0254 0.00003 1 0.08333 0.02778 0.00002

0.3048 0.00030 12 1 0.33333 0.00019

0.9144 0.00091 36 3 1 0.00057

1609.34 1.60934 63360 5280 1760 1

Unit System Metric Imperial + US

Area

Square meter(m2)

Are(a)

Hectare(h)

Squarekilometre

(km2)Square yard Acre

1 0.01 0.0001 0.000001 1.19599 0.00025

100 1 0.01 0.0001 119.599 0.02471

10,000 100 1 0.01 11,960 2.47105

1,000,000 10,000 100 1 1,196,000 247.105

0.83613 0.00836 0.00004 1 0.00021

4046.86 40.4686 0.40469 0.00405 4840 1


Volume

Cubic meter(m3)

Litre(lt.)

U.S. gallon Cubic inch Cubic feetImperialgallon

1 1,000 264.171 6,1023.7 35.3147 219.978

0.001 1 0.26418 61.0255 0.03532 0.21998

0.00379 3.78532 1 231.001 0.13368 0.83270

0.00002 0.01639 0.00433 1 0.00058 0.00360

0.02832 28.316 7.48048 1728 1 6.22883

0.00455 4.54596 1.20095 277.42 0.16054 1


Weight

Gram(g)

Kilogram(kg)

Ton(t)

CaratOunce(oz)

Pound(lb)

1 0.001 5 0.03527 0.00220

1,000 1 0.001 5000 35.274 2.20462

1,000,000 1,000 1 5,000,000 35274 2204.62

0.2 0.0002 1 0.00705 0.00044

28.3495 0.02835 0.00003 141.748 1 0.06250

453.592 0.4359 0.00045 2,267.95 16 1

Do not mix the measurement systems and units.Before you make any calculations you have to make sure

that you use one system and one unit only.

Chapter A: Construction Measurements and Calculations

A-2

A.2 Lengthmm cm m km

1 mm 1 0.1 0.001 0.000001

1 cm 10 1 0.01 0.00001

1 m 1,000 100 1 0.001

1 km 1,000,000 10,000 1,000 1

Length: for construction work the most common andpractical units are metres and centimetres.

A.3 AreaRelationship between units or areas:

mm2 cm2 m2 hectare km2

1 mm2 1 0.01 0.0000001

1 cm2 100 1 0.0001

1 m2 1,000,000 10,000 1 0.0001 0.000001

hectare 10,000 1 0.10

1 km2 1,000,000 100 1

Calculations for areas of common shapes:

square: a x a rectangle: a x b

triangle: a x h 2

trapezoid: a + b x h 2

rhombus: a x h

circle:

area = d2 x 4

circumference = d x

Area: when working out areasalways make sure that all the units are the same!


A-3

a

a

a

b

h

d

a

b

h

a

a

h

A.4 VolumeRelationship between units of volume:

cm3 dm3

(1 litre)m3

1 cm3 1 0.001 0.000001

1 m3 1,000,000 1,000 1

If you have to change a volume from one unit to the next loweror higher one, you have to multiply or divide the quantity by

1,000 respectively, as shown in the table.

Calculations for volumes of common shapes:

rectangular prism:a x b x c = v

triangular prism:a x b x c = v

2

quadrilateral prism:a + b x h x c = v

2

cylinder: area x hd2 x x h = v

4

Volume: for construction works the most important units arecm3 and m3. For practical reasons use metres.

A.5 WeightRelationship between the various units of weight:

gram kilogram tonne

1g 1 0.001 0.000001

1Kg 1,000 1 0.001

1t 1,000,000 1000 1

Weight: for construction works the most importantunits are kilograms and tonnes.


A-4

h

area

d

b

ac

a

bc

a

b

hc

A.6 Densitykg/m3 kg/m3

Steel and iron 7,800 Stone for masonry work (dense) 2,500-3,000

Aluminium 2,700 Stone for masonry work (porous) 2,200-2,500

Copper 8,900 Building sand (natural moisture) 1,900-2,100

Lead 11,340 Building sand (dry) 1,800-2,000

Wood 400-800 Gravel (clean, without fines) 1,500-1,800

Hardwood 700-1,000 Cohesive soil 1,800-2,000

Asphalt 1,600-2,000 Heavy clay 1,800-2,000

Bitumen 1,100 Cement or lime mortar 1,900-2,100

Cement stone wall (with mortar) 1,800-2,000 Cement (loose) 1,200-1,400

Lime stone wall (with mortar) 1,600-2,000 Lime (loose) 900-1,300

Brick wall (with mortar) 1,300-1,500 Concrete with reinforcement 2,300-2,500

Masonry wall (with mortar) 2,000-2,200 Water 1,000

A.7 SlopesDefinition: the slope shows the steepness of an ascent or descent.

Slope calculation: slopes can be expressed asa ratio or in percentage.

Example Ratio:


A-5

Example Percentage:

A.8 Pressure

Volume:

Height x Length x Width 1 m x 1 m x 1 m = 1 m3

Weight:

1 m3 water weight = 1,000 kg

1 cm3 water weight = 1 gram

Pressure:

Pressure is defined as a distributed force (F)acting on an area (A).

P = Force (F) = F Area (A) A

F is measured in Newtons (N)

A is usually measured in m2 or in cm2

However, force measured in Newton is not a value we easily recognisein daily life. To simplify when dealing with water we use the fact that1.000 cm3 of water weighs 1 kg (1.000 cm3 = 1 kg). Hence a watercolumn, whatever shape (following a pipeline or the depth of a lake),produces a force of 1 kg per 1 cm2 or every 10 m of vertical height.


A-6

Conversions for Pressure:

1 bar = 100,000 Pa1 atm = 101,330 Pa1 kp/cm2 = 98,067 Pa1 mm Hg = 133,32 Pa1 mm WS = 9,8067 Pa1 lbt/in (psi) = 6894,8 Pa1 lbt/ft2 = 47,88 Pa

Example:At 60 m vertical height the pressurein a water pile is:

D = 60 = 6 kg/cm 2

10 10


A-7


A-8

Chapter B: Tools, Equipment andProcurement

B-1

B.1 Construction Handtools

The number of handtools depends on the number of labourersand type of job to be carried out.

Tools and Equipment for Road, Drainage and Sanitation WorksRequirements for a 50 Worker Gang

Tools Number Required

Hoes 40

Shovels 30 – 40

Mattocks 20 – 35

Pick-axes 20 – 35

16 lb hammers 4 – 6

4 lb hammers 2

Claw hammers 2

Sledge hammers 6

Crow bars 4 – 6

Grass slashers 2

Pangas (bush knife) 4

Hand axes 2

Felling axe 1

Rakes 6 – 10

Spreaders (for gravel) 4 – 6

Steel buckets 6 – 10

Wheelbarrows 10 – 15

Hand files 2

5 m tape 1

30 m tape 2 – 3

Line levels 3

1 m spirit levels 4

60 cm spirit levels 1 – 2

Chapter B: Tools, Equipment and Procurement

B-2

Tools and Equipment for Road, Drainage and Sanitation WorksRequirements for a 50 Worker Gang

Tools Number Required

Bow saws 2

Carpenter saws 2

Mason trowels 4 – 6

Mason hammers 4

Plumb bobs 2

Squares (metal) 2

Ranging rods 9

Straight-edges 2

Camber boards 2

Boning rods, sets 2

First-aid kits 2

Hard brooms 2

Balls of twine 8

Hand rammers 8

Fishing line 1 roll x 20 m

Drain templates (according to required size) 2

Water drums, 210 lt 1

Pedestrian roller/tamper (compaction) 1 – 2

Road sign posts 3


B-3

Tools and Equipment for Water Supply Works

Workbenches (permanent and portable type)

Holding devices

Bench vice (used when cutting with hacksaw, dismantling and assemblingvalves

Pipe vice (used when cutting reaming and threading pipes)

Chain vice (support bigger sizes of pipes)

Cutting tools

Pipe cutter

Hacksaw

Threading tools

External thread stock and die (used for cutting external threads on pipeconduits and steel bars

Internal thread taps (used for cutting internal threads, extending andre-cutting slightly damaged threads in bottom holes and nuts)

Measuring tools

Tape measure

Folding rule

Steel scale

Trysquare

Spirit level

Venier capliers

Assembling/disassembling tools

Pipe wrenches (for screwing and unscrewing pipes and pipefittingtogether)

Chain wrench (for bigger pipes)

Adjustable spanner (used on hexagonal shaped items only)

Open end spanner

Ring spanner

Water pump pliers

Screw drivers

Allen key

Miscellaneous tools

Hammer

Chisels

Bow lamp


B-4

Tools and Equipment for Water Supply Works

Soldering iron

Steel brushes

Clamps

Machinery

Threading machine (used for threading, cutting and reaming)

Bending machine (for bending pipes)

Drilling machine

Bench grinder

B.2 Compaction Equipment for Labour-BasedWorks1. pedestrian tandem

vibrating rollerssuitability: light, clayey andwell-graded soils

2. pedestrian vibratingrollerssuitability: clayey soils

1. 2.

operational weight

roller width

working speed

thickness loose layer

approx. passes

t

cm

km/hr

cm

No.

1 to 1.5

90

1 to 2

15 to 20

4 to 6

0.5 to 1.0

70 to 80

1 to 2

15

4 to 6

1. vibro tamperssuitability: for light, clayeyand well-graded soils

2. dropping weightcompactorssuitability: all soils

1.

note: for compaction of backfills only

2.

note: for compaction of backfills only

operational weight

compacting area

blows/min

thickness loose layer

approx. passes

kg

cm2

No.

cm

No.

100

1000 to 1600

500

20 to 30

2 to 4

50 to 100

890 to 530

60 to 80

20

2 to 4

Compaction equipment for urban works is usually used to compactthe various road layers and backfills for trenches and structures.There is no need to hire big compaction plant as most of the work

can be done with fairly small and versatile compactors.


B-5

B.3 Procurement


B-6

Tools andEquipment

Materials

Check whether a BQis available

Agree withCommunity

to prepare a BQ

No

Decide on clearspecifications

Community to agreewith BQ = Signature

Yes

Get written approvalto go ahead with

procurement

On the basis of thesize and nature of

the job as well as thenumber of potentiallabourers, decide on

the tools andequipment required

Check withCommunity what

is already availableand what needsto be procuredand/or hired

Decide on clearspecifications

Community to agreelist of required toolsand equipment with

specifications =Signature

Get at least 3 quotations fromsuppliers in sealed envelopes.

Provide them with clear quality andquantity specifications for each item

Ask the Community to open thequotations at the same time and ask

them to sign the quotations

Check together with the Communitythe correctness of the quotations andmake a decision where to buy if funds

are sufficiently available

Ask the Community to give you asigned order for the procurement or

to procure the items for you

Procure goods, have them checkedby Community and

let them sign for delivery

Store goods well and guard them

Chapter C:Setting Out

C-1

C.1 Tools for Setting Out

Pegs:

Pegs are used for survey purposes and for setting out all the activities. Onlabour-based sites wooden sticks ofapproximately 50 cm in length are usually used. They are pointed at one end so that they can easily be hammered into theground. Survey pegs, for examplechainage pegs, are cut at the edge tomake a flat surface so that a clearmarking can be made.

Tape measure:

A great variety of tape measures exist.The most common length of tape measure used for setting out is 30 metres. Thetapes are made of steel or linen. Although the former is stronger, the numbers/marking on the tape become unreadableafter a period of use.

Note: The zero point is not always located in the same place on different tapemeasures.

Ranging rods:

Ranging rods are used for surveyingpurposes and for setting out all theactivities. They are round sticks, usually2 m long, with a diameter ofapproximately 2.5 cm. They are made ofvarious materials (metal, hard plastic,wood) and are usually provided with apointed metal end. They are paintedalternatively red and white with blackmarking at the 1 meter points. The length of the red/white sections is 50 cm.

As a cheaper alternative, a hardwood lath(must be straight), which is pointed atone end, can also be used as a rangingrod. At the same time it can be used as avertical part of the profile board (seebelow).

Chapter C: Setting Out

C-2

Metal Point

Pointed HardWood Lath

Boning rods(also called travellers):

Boning rods are used to controlgradients and are T-shaped and of auniform height. They can easily bemanufactured by nailing a woodenplank of 80 cm length and 10 cmheight onto another plank of 130 cmlength and 10 cm width so that theend result looks like a ¨T¨. Thehorizontal plank should be painted in clearly visible colours. Boning rodshave to be used in a set of three.

Profile board:

Profile boards are used for the samepurposes as boning rods and are designed in such a way that they can be attachedto a ranging rod. They have a screwmechanism that enables the profile boardto slide up and down on the ranging rodand be fixed at any desired point simplyby tightening the screw. A long lastingprofile board is one made from thin steelplate (40 cm x 10 cm) welded to a shortlength of metal tubing that can slide upand down and can be clamped to themetal rod.

Alternatively, wooden profile boards canbe attached to a hardwood rod and fixedwith a wedge pushed into the woodenclamp.

Spirit level:

Spirit levels are used to make an evenlevel and are available in all differentsizes. For construction work, robust andlong spirit levels are ideal. The longer thespirit level the more exact themeasurement will be. Always ensure thatthe spirit level is properly adjusted beforeyou buy it.


C-3

Straight-edge with spirit level:

If the spirit level is not long enough, thena straight-edge of 2.50 to 3.50 m, usually made out of wood, can be used. Alwaysensure that your straight-edges arestraight on both sides.

Line level:

A line level is a small spirit level of about80–120 mm in length. It has a hook oneach end of the level which is used forhanging the level onto a smooth line. Thelevel is used together with a line, rangingrods (or profile boards) and a tapemeasure. The line level requires twopeople to operate it.

The line level can be used to:

transfer levels over a max. of 20 m,

check existing gradients,

set out gradients.

Always check:

that the line is smooth, preferablymade of nylon,that the line is tight,

that the level is in the middle of thetwo ranging rods,

regularly the accuracy of the level.

Check accuracy of level:

place two ranging rods 20 m apart,

fix a line at the 1 m mark on one rodand transfer the level to the other rod; mark this level,

keep the line in place and turn thelevel around,

adjust the line again and mark the new level and measure the differencebetween the two levels: if thedifference is less than 10 cm, thecorrect level is exactly in the middle ofthe two marks; if the difference ismore than 10 cm the level should bechanged.

Plumb Bob:

The plumb bob is used to check thevertical alignment of walls, posts, pillars,etc. The distance plate is slightly wider(about 1 mm) than the plumb bob itselfand can be freely moved along the stringline. In this way the plate can be heldagainst the top of the wall while theplumb bob hangs on the lower end. If theplumb bob nearly touches the wall, thenthe top and bottom point of the wall are in a vertical line. The alignment of the wallcan then be checked by sighting the string line with the wall line. If they are parallelto each other then the wall is straight too.


C-4

Templates:

Templates are used to control certain shapes of the road and drain excavations. Forexample, to control the correct shape of a storm drain, and for the labourers tocontinuously check whether the correct shape is dug, a template of the standarddrain size can be used. Templates are very useful control aids as any labourer cansee the exact size and shape of the work she/he is required to carry out. They areusually made of wood and tailor-made for each particular project in accordance withthe standard measurements (see specifications).


C-5

C.2 Setting Out a Straight Line

The two end points of the straight line to be established are eachmarked with a ranging rod. The intermediate points can be found by sighting from one end rod to the other and moving a third rod untilit is aligned with the two end rods (see picture above).

The same procedure can be used to extend a straight line. Place two ranging rods at a certain distance, e.g. 10 metres, along the lineyou would like to establish. Walk with the third rod to the next point of the line, e.g. another 10 metres ahead. Sight the first two rodsand shift the third rod until all three rods are in a straight line. Markthis point with a peg and repeat the same procedure every 10metres until you have reached the end of your straight line. Checkthe entire line again.


C-6

C.3 Setting Out Angles

Setting out of a right angle(90°):

The right angle is established bymeasuring a triangle with side lengths of3, 4 and 5 metres.

Measure the length AB of 4 metresalong the centre line of the road. Setpegs exactly at points A and B.

Hold the zero point of the tapemeasure on the peg A.A second person holds the 8.00 metremark of the tape measure on peg B.

A third person holds the tape measureat the 5.00 metre mark which will leadto point C when the tape measure ispulled tight.

Setting out of a 45° angle:

First establish a right angle as shownabove.

Set out the same distance on both ofthe two lines (L) starting from theintersection point B, e.g. 3.00 metres,and fix pegs A and C.

Span a string line between points Aand C and measure this length A to C.

Divide the length A to C by two and set peg D exactly in the middle of thislength.

Establish the new line B to D with astring line and extend beyond peg D ifnecessary.

Setting out of 30° and 60° angles:

First establish a right angle as shownabove.Set out the same distance on both ofthe two lines (L) starting from theintersection point B, e.g. 3.00 metres,and fix pegs A and C.

Span a string line between points Aand C and measure this length A to C.

Divide the length A to C by three andset pegs D (for 30°) after one third ofthe length A to C, or E (for 60°) aftertwo thirds of the length A to C.

Establish the new lines B to D or B to E with a string line and extend beyondpeg D or E if necessary.


C-7

C.4 Setting Out Gradients and LevelsIn order to check existing gradients or to set out new ones overrelatively short distances (up to 20m), the line and level method issimple and sufficiently accurate (± 0.5 cm). Where more accuratelevels are required a levelling instrument or a transparent water hoseshould be used.

Checking (finding) an existing gradient

1. Fix ranging rods vertically at the two end points of the slope firmly intothe ground.

2. Tie the string line at the 1 metre mark of the ranging rod at the higherpoint of the slope.

3. Fix the string line at the lower ranging rod, hook the line level at themiddle point between the two ranging rods and move the string line atthe lower point ranging rod up or down until the level bubble is exactlyin the middle. Mark this level at the lower ranging rod, turn the line levelaround and mark the level again. Measure the middle of the differenceof the two marks. This is the exact horizontal level transferred from thehigher to the lower ranging rod.

4. Now measure the difference between your horizontal level mark and theone metre mark at the ranging rod (= D).

5. Measure the exact distance (length) between the two ranging rods (= L).

6. Calculate the percentage of the slope. The distance between the tworanging rods represents 100%. The calculation is therefore as follows:“D” divided by “L” multiplied by 100 perc ent = the percentageof the slope. Use centimetres for all measurements.


C-8

Setting out a given gradient

1. Define D: = divide L by 100% and multiply by given % (e.g. 3% as inexample below).

2. Fix the line level to the lower ranging rod so that the line is horizontaland mark the point on the other ranging rod.

3. Now add D to 1 m and measure from the level-mark downwards.You will see that in order to be able to measure this new height, youneed to dig a small slot next to the ranging rod. Dig the slot in smallsteps until you can measure the exact height (D + 1 m). The bottom ofthis slot is now at the required level.

4. In order to transfer the gradient uniformly you have to use boning rodsor profile boards. Set a boning rod at each end point, every few metresdig a small slot, set the third boning rod at the bottom of the slot anddeepen the slot until all three boning rods are in line with one another.


C-9

Checking the uniformity of a gradient

In order to achieve a reasonably smooth and aligned surface (horizontal orgradient) without unnecessary depressions or humps it is necessary tocontrol the levels. The simplest method is to use a set of boning rods ortravellers.

Procedure:

1. Fix boning rods/profile boards at the two ends of the straight you wantto check assuming that those two points have the level you need tomaintain. If you use profile boards make sure the two end boards arefixed at the identical measure on the rod, e.g. 1.30 metres from theground.

2. While sighting from one end to the other, let an assistant place the thirdboning rod/profile board at any point you want to check in between thetwo end rods, e.g. the first rod is at the culvert inlet, the second at theend of the outlet drain and third is used to check whether the outlet ofthe culvert at any point in between is in line with the two end pointswhich would indicate that the entire culvert drain has the same gradient.


C-10

Chapter D:Concrete Work

D-1

D.1 Concrete Types

The proportion of the mix is always = Cement : Sand : Stones

Type UseMix

(by volume)Condition

Leanconcrete

blinding of foundationexcavation and liningculvert beds

culvert haunching

other minor works wherelittle strength is required

1 : 4 : 8 Meagre mix with little cementcontent, stiff and not too wet

Massconcrete(grade 15)

gravity, non reinforcedstructuresculvert haunching

kerb stone placing

concrete building blocks

etc.

1 : 3 : 6 Medium mixture with morecement than lean concrete andwith coarse aggregates up to50 mm in size. The gradeindicates the required strengthof 15 N/mm2 after 28 days.

Structuralconcrete(grade 20or 25)

reinforced structures, e.g.slabs for access to buildings

reinforced and unreinforcedculverts

haunching of culverts where a bearing capacity isrequiredunderwater concrete,reinforced or unreinforced

1 : 2 : 4 “Fat” mixture with a highamount of cement and amaximum aggregate size of20 mm to allow for culvertproduction and to easily passaround reinforcement bars. The grade indicates the requiredstrength of 20 or 25 N/mm2

after 28 days.

Always check in the contract specifications for therequired concrete grade or mix. Consult the engineer or atechnical advisor when you are in doubt or where it is notspecified and ask for advice. Ask for written instructions!

Chapter D: Concrete Work

D-2

D.2 Batching for Concrete MixingConcrete on site is usually mixed by hand or, where available, with aconcrete mixer. In order to achieve the required mix proportions gauge boxes are used to batch the dry aggregates. The box, made out ofwood or metal, has the same volume as a 50 kg bag of cement(36 litres) when filled level with the top.

Inside measurements:

length = 40 cm

width = 30 cm

height = 30 cm

volume = 0.036 m3 = 36 litres

Batching by volume:

Concrete

Type(Grade)

Mix by volume:

Cement-Sand-Stones

(Max. stone size)

Batch with 1 bagof cement

Material required for 1 cubicmetre finished concrete

(approximate)

No. of boxes ofaggregates

Approx.yield per

batch

No ofcement

bags (kg)Sand (m3)

Stones(m3)

Sand Stones

Lean1 : 4 : 8(40 mm)

4 8 0.30 m3 3.3(166 kg)

0.47 0.94

Mass(15)

1 : 3 : 6(50 mm)

3 6 0.24 m3 4.3(215 kg)

0.46 0.92

Structural(20)l

1 : 2 : 4(20 mm)

2 4 0.16 m3 6(300 kg)

0.42 0.84

Structural(25)

1 : 1.5 : 3(20 mm)

1.5 3 0.14 m3 7.3(365 kg)

0.38 0.76


D-3

H

L

W

D.3 Mixing ConcreteHand-mixed batches should not exceed 0.5 m3. The mixing shouldnever be done on the bare ground, as this results in contamination ofthe mix. A platform of about 4 m by 4 m has to be built with timberboards, metal sheets or lean concrete.

Procedure for mixing by hand:

1. Measure the amount of sand and stones with the gauge box and putthem in alternating layers on the platform.

2. Spread the cement over the top.

3. The dry materials should be mixed at least three times. Two persons,one on each side of the heap, shovel the heap to one side, turning thematerial in the process. This operation is repeated, the heap beingthrown back to its original position and then back again until the colourof the dry mix is uniform.

4. Water is then added by a third person while turning the mix the fourthtime using a watering can or a bucket (use your hand to sprinkle fromthe bucket) so that the water is spread evenly while the material ismixed again. Only the correct amount of water should be added (seeguideline below). The mixing must be continued (to be turned at leastthree times) until the concrete is uniformly wet and has reached therequired consistency.

5. Another, often applied method is to spread the dry mix, make a hollowin the middle and then add the water into this hollow. Afterwards themixing is done very carefully avoid that any of the water from the middlegets lost.

D.4 Water-Cement RatioThe strength of concrete depends to a great extent on the amount ofclean water used in mixing. The amount used should be the minimumnecessary to give sufficient workability for efficient consolidation of the concrete. The amount of water is specified by weight and stated as afraction of the cement used or: weight of water divided by weight ofcement = water/cement factor.


D-4

As an approximate rule the water/cement ratio equals 0.5. Thismeans that the water content is usually 25 kg (or litres) to 50 kg or(one bag) of cement.

Depending on the type of aggregate, the proportion of the mix andthe natural moisture content of the sand, the water content canvary from:

24 to 28 litres per bag of cement for concrete mixed by hand

22 to 26 litres per bag for concrete mixed by plant

D.5 Transporting ConcreteConcrete should be mixed as near as possible to the site ofplacement to avoid segregation during transport and to shorten thetime between mixing and placing. On site, concrete is usuallytransported in wheelbarrows or Karais.

D.6 Placing ConcreteConcrete should be placed in position as soon as possible and beforesetting has begun. This allows a maximum of 15 minutes aftermixing to transport and place the concrete.

The formwork, or shuttering, must be clean, secure from movement or leakage and should be wetted before the concrete is filled in. Steel and wooden formwork should be oiled (old engine oil mixed with diesel willdo) to allow it to be removed easily later on.

For walls, concrete has to be placed in layers of a thickness notexceeding 30 cm when hand ramming. This may be increased to50 cm when a vibrator is used. Each layer must be rammed orvibrated before the next is spread. As a rule of thumb, sufficientcompaction is achieved when water appears on the surface and/ordrips through the joints of the formwork, provided the water/cementratio is correct and the formwork has been constructed with tightjoints.

Hand ramming should be carried out using a round steelreinforcement bar (do not use a rammer). Poke the bar in smalldistances deep into the concrete layer, twist the bar and move at it upand down at same time. Repeat this procedure at every 10 to 15 cm.


D-5

Too much compaction of concrete causes disintegration of the mix. Thisis particularly risky when using the vibrating poker. The bigger stonessink to the ground and the water with the cement appears at the top.

Adequate compaction for slabscan only be achieved with a vibrator!!


D-6

D.7 Curing ConcreteIt takes at least 28 days for concrete to gain the full strength. Thistime span is called the curing period, and special care must beprovided during this time. Concrete can only strengthen properly ifkept wet.

Concrete slabs must be kept constantly wet. This can be achievedby:

covering the slab with damp sand (needs to be watered from time to time);

covering the slab with wet canvas (needs to be kept wet);

covering the slab with polyethylene sheets (additional water mustbe added from time to time); or

continuously watering the slab.

Concrete walls should also be protected from direct sunshine and the crown should be covered with wet canvas, polyethylene sheet orleaves. Water should be added to the crown at least during the first7 days.

Formwork for slabs cannot be removed before the 28 days ofcuring are over.

Wall shuttering can be removed after 2 days. This has to be done verycarefully, as by this time the concrete is still relatively “soft”.


D-7

D.8 Quality Control for Concrete Work

CONCRETE TESTS

(i) Type of tests:Check on the suitability of the material for concrete making and the strength of the curedconcrete. Unlike most other tests, the client carries out these tests in the laboratory.However, the Site Supervisor has to ensure on site that he/she achieves the requiredspecifications. Continuous control mechanisms and simple site tests ensure good qualitywork.

(ii) Methods used:(see table below)

(iii) Rectification measures:Adjustment of batching volumes and mixing water for every major concrete operation.

Test item Method Location When? Tolerance

M1.) Sand purity and grading visualquarrysupplier

beforeprocurement

–

M2.) Aggregate purity + grading visualquarrysupplier

beforeprocurement

–

M3.) Water purityvisual,

if req., lab.site if required –

M4.) Cement age and conditionproduction

date + visualinspection

at supplier’sand at site

when buyingand using

–

P1.) Mixing (batching) placevisual

identificationsite

beforeproject

–

P2.) Identification of concrete typecheck

specificationscontr. docs.

and drawingsfor every

concrete job–

P3.) Weather conditions visual site - ditto - –

F1.) Batching volumesbox

40x30x30 cmsite

startof project

–

F2.) Mixing arrangementscounting

batches andwater

site always –

F3.) Mixing time (3’ dry, 3’ wet) count site always –

F4.) Mixture (consistency andplasticity)

handmoulding,slump test

sitefor every

concrete job –

F5.) Casting time limit 1 hour site always –

F6.) Compaction (vibration)

- fill layers ofmax. 30 cm

height

- cement milkpassing joints

site always –

F7.) Curing keep wet site always formin. 15 days

–

Legend: M = Material Tests, P = Preparation Tests, F = Fabrication Tests


D-8

Chapter E:Masonry Work

E-1

E.1 Material for Masonry Work

Sand:

Clean building sand, the same as for concrete. Check cleanlinesswith bottle test.

Cement:

(The same as for concrete.)

Water:

(The same as for concrete.)

Stones:

It is important to choose only good stones to build foundations,walls and for linings. The following can not be used:

– weathered stones;

– cracked stones;

– small stones (minimum length of sides = 20 cm);

– coral.

Stones must be free of dust and dirt. It is therefore advisable towash them and, if necessary, clean them with a brush.

Bricks:

Only use good quality bricks for infrastructure works. Preferably,they should be from the same kiln. The differences of themeasurements should be kept to a minimum (toleranceplus/minus 1 mm per brick). Bricks must be watered before use. Bricks with cracks must be rejected.

Blocks:

For infrastructure objects only cement bound blocks should be used. They should be of high strength and equal size (toleranceplus/minus 2 mm per block).

Chapter E: Masonry Work

E-2

E.2 MortarMixing proportions:

Construction typeMixture

(cement : sand)

Note: always check in the contract specifications forthe required mortar grade or mix. Ask for advice ifnot specified.

Non bearing walls:stone lining, minor walls

1 : 7

Small retaining walls:head- and wingwalls,retaining walls up to 1 mheight

1 : 6

Bearing walls: walls forstructures, retaining walls higher than 1 m,foundations

1 : 4

Rules of thumb for masonry mortar:

The consistency should be such that it does not flow off the trowel.

The mortar can be kneaded in the hand and retains its form (like “Ugali”).

The quantity of mortar to be mixed should not be more than a mason canuse within one hour.


E-3

E.3 Quantities

Masonry typeApproximate

width ofjoints

Requirementsfor 1 m3

finished wall

Rubble stonemasonry:The stones are notspecifically cut orshaped. To build awall with properbonding usingrubble stonesrequires well-developed skillsfrom a mason.

1 cmto 4 cm

Stones:approx. 1.3to 1.5 m3

(includeswaste)

Mortar:300 to 400

lt/m3

Shaped stonemasonry:The stones areshaped to arectangular prism.By using thesestones it is easierto produce a wallwith properbonding anduniform surface.

1 cmto 2.5 cm

Stones:approx. 1.2 m3

(includeswaste)

Mortar:200 to 300

lt/m3

Brick masonry:Bricks can be ofvarious sizes andcan be laid inmany differentbonds.

1.2 cmto 1.5 cm

Bricks:approx. 1.1 m3

(includeswaste)

Mortar:250 to 270

lt/m3

Block masonry:Blocks can be ofvarious sizes.Blocks may be ofdifferent material,e.g. burned clay,concrete, sandcement, etc.

1.2 cmto 2 cm

Blocks:approx. 1.1 m3

(includeswaste)

Mortar:200 to 250

lt./m3

(depending onthe size of the

blocks)


E-4

E.4 Stone Masonry Works

Foundations:

Foundations for bearing walls are usually made of reinforcedconcrete and need to be appropriately designed and specified inthe contract specifications and drawings.

For minor walls up to 150 cm in height which do not support aheavy weight, no special concrete foundation is required. However,some principle guidelines should be followed when buildingfoundations:

– depth underground = minimum 40 cm, on firm uniform ground:

– 5 cm lean concrete (1 : 4 : 8) as a base;

– the first course (footing course) should be laid with the largest and straightest stones since the stability of the wall depends largely on the bearing of the stones on the ground.

Joints:

– for rubble stone masonry = 1 cm to 4 cm;

– for shaped stone masonry = 1 cm to 2.5 cm.

Bond:

The bond should allow for a minimum overlap of 1/4 length ofthe smaller stone (see drawing below). Most of the stones are laidas stretchers. Headers, or “through stones”, should be laid atregular intervals to bond the two faces of the wall together. Theseheader stones should cover at least two-thirds of the wall thicknessand their overlap should not be less than 10 cm.


E-5

Weep holes:

For retaining walls it is important to add at regular intervals(approximately every 150 cm) weep holes which allow water thatcollects behind the wall to drain off. The weep holes should beplaced about 20 to 30 cm above the existing ground level. Weepholes can be made of short plastic pipes or simply by constructingsmall holes, e.g. a banana stem can be easily removed once themortar has cured.

E.5 Brick and Block Masonry Work

Foundations:

Foundations for bearing walls are usually made of reinforcedconcrete and need to be appropriately designed and specified inthe contract specifications and drawings.

For minor walls, which do not support a heavy weight, foundations (footings) can also be made with bricks or blocks and serve thesame purpose as concrete foundations.

– depth underground = minimum 40 cm, on firm uniform ground;

– 5 cm lean concrete (1 : 4 : 8) as a base.

As a rule of thumb brick or block foundations should be twice aswide as the actual wall thickness on the lowest wall course.Each course of the foundation is reduced in regular 1/4 offsets oneach side until the actual wall thickness is reached:


E-6

Joints:

– for brick masonry = 1.2 cm to 1.5 cm;

– for shaped stone masonry = 1.2 cm to 2.0 cm.

Bond:

Bricks can be laid in very many different bonds. However, for thepurpose of urban infrastructure works the bond must be practicaland easy to construct. Therefore, only two different bonds arerecommended, specifically the “Stretcher Bond” and the “FlemishBond”.

STRETCHER BOND

Stretcher .....

1 Header, Stretcher .....

Stretcher .....

FLEMISH BOND

Header .....

3/4 / Header / Stretcher /Header .....

Header .....

Common Masonry Tools:

Tape measure

Square

Plum bob with string

Mason string

Spirit level

Line level and/or horse pipe (for transferring levels)

Straight-edge

Trowels, various shapes and sizes depending on the work

Masonry hammer, various sizes and shapes depending on the work

Chisels, various sizes and shapes, e.g. flat and pointed

Wheelbarrow and/or mortar basin

Floats, wooden and steel, various sizes depending on the work

Protection goggles, helmet and protective gloves (mainly for stonemasonry)


E-7

Rules for quality brick and block masonry construction:

Construct a proper foundation.

Use only bricks which are not cracked and from the same supplier.

Bricks need to be moistened before.

Use mortar of the correct mixture and consistency.

Before you start building the wall always lay the first two courses “dry”(without mortar) to find out the correct bonding.

Ensure proper bonding and joints.

For every course check for plumbness of the corners and levels.

Keep close watch on the size of the joints.

Finish the joints and clean the brickwork as you go along.

For urban infrastructure work only flush joints are required (pointed,concave, recessed, racked, etc. joints are only used for buildings asdecorative measure costly, have no particular structural purpose)

Keep the wall crown wet (use wet sacks or sand) and protect the wallfrom direct sun impact for at least one week to ensure proper curing


E-8

E.6 Quality Control for Mortar

MORTAR TESTS

(i) Type of tests:Checks on the suitability of the material for mortar making and the strength of the curedmortar. Unlike most other tests, the client carries out these tests in the laboratory.However, the Site Supervisor has to ensure on site that he/she achieves the requiredspecifications. Continuous control mechanisms and simple site tests ensure good qualitywork.

(ii) Methods used:(see table below)

(iii) Rectification measures:Adjustment of batching volumes and mixing water for every major concrete operation.

Test item Method Location When? Tolerance

M1.) Sand purity and grading visualquarrysupplier

beforeprocurement

–

M3.) Water purityvisual, if req.,

laboratorysite if required –

M4.) Cement age and conditionproduction

date + visualinsp

at supplierand at site

when buyingand using

–

P1.) Mixing (batching) placevisual

identificationsite

beforeproject

–

P2.) Identification of mortar typecheck

specifications

Contractdocument and

drawings

for everymasonry job

–

P3.) Weather conditions visual site - ditto - –

F1.) Batching volumesbox

40x30x30cmsite

startof project

–

F2.) Mixing

countingbatches – mix

3x dry ,3x wet

site always –

F3.) Mixture (consistency andplasticity)

- handmoulding

- grove “V”test withtrowel

sitefor every

masonry job–

F5.) Usage time limit set time limits = 30 minutes

site always –

F6.) Curing keep wet sitealways for

min. 7 days–

Legend: M = Material Tests, P = Preparation Tests, F = Fabrication Tests


E-9


E-10

Chapter F:Solid Waste Management

F-1

F.1 Solid Waste Types and QuantityClassification and sources of solid waste:

Household waste

Commercial waste

Industrial waste

Medical wastes

Street waste and litter

Garden/agricultural waste

Dead animals

It is not the responsibility of normal waste collectorsto handle hazardous waste. Such waste are to be handled by

specialised, well-trained and well-equipped people. Industries orproducers of hazardous waste are responsible for their own waste.

Waste generation rates and composition:

The composition of waste determines the density which is the amount ofwaste in kilos per cubic meters.

Waste generation rate means the weight and volume of waste producedper unit household, or per person, or per business entity, or per a knownarea, in a certain amount of time.

Example (from Lusaka – Zambia):

Solid wasteparticulars

Households Business

Amount ofkilograms/day

0.6 per person 1.7 per stall

Density (kg/m3) 395 207

Composition Mixed soil 66%Vegetables, fruits, garden, leftovers 25%Paper and cardboard 3%Plastics 3%Others 2%

Mixed soil 50%Vegetables, fruits, garden, leftovers 23%Paper and cardboard 12%Plastics 7%Others 4%

Chapter F: Solid Waste Management

F-2

F.2 Storage of Solid WasteStorage at the source:

For individual households, shops, industries and offices: in containers, bags, plastic or galvanised bins with lid. Any other container can do if emptied frequently.

Communal storage:

The cheapest form is the open dumping places called collection points.The waste is dumped somewhere on the street, square or in an openarea. The environment is not protected against the waste. Opendumping places are sometimes improved by fencing them off with a wallmade of concrete, masonry, timber or iron sheets. The dumping place isstill easily accessible.

Another form of permanent dumping places are little buildings/constructions. These buildings can look like a box and sometimes havespecial facilities for easy dumping and collection for further transport by atruck.

Handling waste:

It is best to reduce the handling of waste to a minimum andtherefore storage points should be well designed (easy disposaland storage) and the waste should be transferred fromhouseholds to legal transfer or landfill sites as directly as possible.

Workers have to be protected against the dust, smell and dangersof hazardous waste.

Designing storage points:

Consider:

the required storage volume (based on waste generation, density andfrequency of emptying);

how people are going to dump the waste (wheelbarrow, handcart, inbuckets, etc.);

how the communal storage point is going to be emptied. For example, if a city council truck is going to empty the storage point, the height of thestorage point should correspond with the height of the truck to facilitateeasy collection of the waste (see drawing below).


F-3

JOB SHEET

SOLID WASTE MANAGEMENT OPEN DUMPING PLACE

WORK METHOD:

Note: An open dumping place (container) is a relatively simple construction. It has the shapeof an open box where waste can be temporarily stored. The size depends on the numberof users, waste generation rate, and the frequency of clearing the box.

The box can be constructed using locally available materials like bricks or stones.Also, cement/concrete blocks or cast concrete can be used, but these are moreexpensive. In areas where there is a lot of rain a simple roof made of corrugated ironsheets could be added.

The capacity of a communal container:

C = N x R x I

C = capacity in litres

N = number of usersR = waste generation rate (litres per day)I = emptying interval (days)

CONSTRUCTION:

Calculate the required size as shown above.

Set out the trenches for the foundation. Usepegs and strings to mark the edges andcorners.

Excavate the foundation trenches.

Construct the foundation.Build the walls and plaster with cementmortar. Use mortar with a mix of 1 : 7

for details check Module B5.

If funds are available construct a slab insidethe container (either concrete or plasteredstones).

For rainy places add a simple roof add post at all four corners, with front posts higherthan rear posts. Connect the corner postswith wooden trusses (e.g. 8/12cm) addgrid for roofing sheets add roofing sheets(e.g. corrugated iron sheets).

Cure walls and slab for 14 days before use.

LABOUR:

1 Gang Leader1 Mason

Labourers

TOOLS AND EQUIPMENT:

Tape measurePlumb bob

Masonry tools

Shovels

Watering can

MATERIAL:

SandCement

Bricks, stones or cementblocks

(Posts, trusses and ironsheets)

ASSUMED PRODUCTIVITY:

Day work =

ACTUAL PRODUCTIVITY:

Day work =

F-4

F.3 Collection, Transportation and Disposalof Solid WasteStreet sweeping:

Tools for manual street sweeping:

Brooms

Shovel

Collection carts (wheelbarrows or hand carts)

Collection and transport of stored waste:

Primary collection refers to the collection and transport of waste withinthe community.

Secondary collection refers to the collection and transport of waste fromthe community to the municipal disposal site, usually the legal landfill.

Waste collection methods:

Collection of waste at household level and transportation to transfer site.

Collection of waste from communal collection point and transportation totransfer site.

Transport equipment:

When selecting the vehicles (motorised and non-motorised) one needs toconsider the following:

There should be enough spare parts in the compound as well as enoughexperienced mechanics to maintain the vehicles.

The vehicles' reliability and cost.

Use of the same kind of vehicles in similar situations.

If the vehicle is loaded by manual labour the height should not exceed 1.5 metres.

Making sure that the vehicle is easy to unload.

Even for the most simple handcart, use of appropriate (rubber) tyres asthere may be sharp objects on the roads.

Possible transport vehicles: handcarts, wheelbarrows,animal-drawn carts, engine driven vehicles.

F-5


Organising primary waste collection:

The waste collector may be a small enterprise or community-basedorganisation that gets paid by the individual households for collecting thewaste. The waste collector needs to get a community contract orauthorisation from the council that allows him/her to collect the waste andto be paid for this.

It is important that agreements are drawn up clarifying who collects the waste and who gets paid for the waste collection.

The agreement should include issues such as:

what service will be delivered;

the organisation or person who will deliver the service;

how often the waste will be collected;

the equipment necessary;

the fee the residents need to pay for waste collection;

who will construct and maintain collection points;

arrangements made for secondary collection.

F.4 Minimising Generation and MaximisingRecycling of WasteMinimising waste generation:

Produce less waste, e.g. avoid buying goods wrapped in paper, in plasticbags or in a tins. Residents should be made aware on how to avoidgenerating unnecessary waste.

Make compost out of kitchen, market and garden leftovers. Compost is agood fertiliser and at the same time bad smells and the hygiene risk ofwaste is eliminated.

Utilise some of the leftovers for new and useful purposes. For example,bags, bottles and tins can be cleaned and reused. Some may even bedecorated to add further value.

Separate those leftovers, which can be used by others, e.g. glass, tins,papers, plastic bottles or bags etc. These recycables can be given away or sold to scavengers.


F-6

Recycling and composting:

Materials with a high potential for recycling are:

Waste paper, like newspapers, magazines, cardboard, books, letters and others. These can be used to produce new paper products.

Metal, for example scrap metal, aluminium (beverage) cans, iron, copper, etc. These can be use to produce new metal products.

Textile cut-offs can be used for the production of door mats, cushions,mattresses, kid’s underwear, home-made caps and duster coats, stuffingdolls and others.

Plastic, such as broken buckets, containers, etc., can be re-melted andformed into new products.

Organic materials, such as vegetable leftovers, can be used forcomposting.

Recycling and composting are usefuland can generate income.

F.5 Safety Related to Solid Waste Handling

The main dangers in solid waste management are:

cuts and wounds from sharp objects;

contamination from hazardous waste such as hospital waste, chemicalwaste or handling dead animals;

air pollution: respiration problems from the fumes that are generated by waste as well as dust created by sweeping;

diseases transmitted through solid waste and through direct contact with exposed skin;

muscle and back strains due to wrong posture or having to lift heavywaste;

road accidents, particularly for road sweepers.

Educate workers about specific occupational hazards.

Ensure use of protective gear such as gloves, boots, dust masks, goggles, etc.

Ensure availability of first-aid kit within reasonable reach of the work site.

Use reliable equipment and maintain it in good condition.

No alcoholic drinks or drugs during work.

Undergo medical check-ups regularly.

Do not eat or drink anything while working.

Wash hands and face before leaving the place of work.


F-7

F.6 Stakeholders in Solid Waste Management

Stakeholder Possible roleYour remarks onappropriateness

The CityCouncil

1. Issuing contracts

2. Supervision

3. Monitoring

4. Making regulations5. Enforcement of regulations

6. Fee collection

7. Payment of services

8. Secondary transport

9. Landfill management

10. Managing special waste

11. Other:

TheEnvironmentalCouncil

1. Making regulations

2. Enforcement of regulations

3. Issuing licences

4. Managing the landfill5. Other:

CommunityDevelopmentCommittee

1. Issuing contracts

2. Supervision

3. Monitoring

4. Awareness raising

5. Enforcement of regulations

6. Fee collection


8. Provide waste collectionservices


10. Primary transport

11. Other:

Waste serviceprovider

1. Provide waste collectionservices

2. Awareness raising

3. Monitoring4. Enforcement of regulations

5. Fee collection

6. Primary transport


8. Cleaning of roads

9. Cleaning of drains

10. Other:


F-8

Stakeholder Possible roleYour remarks onappropriateness

Communitymembers


2. Handing waste to serviceprovider

3. Bringing waste to collectionpoints

4. Awareness creation

5. Cleaning of paths and smalldrains

6. Minimising waste produced

7. Separating recyclables:

Truck owners 1. Secondary transport

2. Other:

Recyclingenterprises

1. Buy materials for recycling

2. Other:

Community involvement:

Communities can be involved:

in decision making (for example in deciding that waste should becollected and that residents have to pay a fee);

in planning and design (for example in discussions on where thetransfer station should be located);

in implementing the work (in constructing the transfer station,collection of waste, recycling);

in operation and maintenance (by repairing the transfer station, orimproving the path to the transfer station);

by contributing money (by paying the waste collection fee),

by contributing labour (by supporting a cleaning campaign onSaturdays, or attending meetings without being paid).


F-9

Experience shows that important strategies for low-income/high-densityareas include:

creating awareness on the hazards of waste;

educating residents on how waste can be properly stored, how best toreduce waste generation and/or recycle waste.

applying user charges – waste services should be paid for to reflect the marginal cost of providing the service;

separating primary and secondary waste collection and agreeing ona partnership between the municipality (responsible for secondarycollection) and communities (responsible for primary collection).


F-10

Chapter G:Road Work

G-1

G.1 Road Work Terminology

Formation WidthFull width of road (can includedrains as well).

RoadwayWidth of road available fortraffic, including shoulders.

CarriagewayPaved width of the road.

ShouldersPaved or unpaved width of road next to the edge of thecarriageway adjacent to theditch or embankment slope.

Camber or CrossfallA cambered road has a cross-section like a “roof” to drain the rainwater away from thecarriageway to the side drains.

Gravel CourseA layer of compacted gravelwhich can form the surface (orpavement) of the carriageway

Base/FormationUpper layer of the soil (naturalmaterial) supporting theroadway. For paved roads thislayer is often constructed fromgravel.

Sub-baseThis is the lowest layer of the road. In labour-based road construction this is oftencalled “excavation to level”, which means that a horizontal platform is created as abasis (or foundation) for all other layers. The sub-base is constructed from the naturaloccurring material. Preferably this layer should be compacted.

Side DrainSide drains run along the road and collect the water from the carriageway andadjoining land and transport it to a convenient point of disposal.

CrownPeak or highest point of the camber.

Road Centre LineLine running along the centre of the road (important in surveying and setting out theroad alignment). Longitudinal sections usually run along the road centreline.

Chainageis a term frequently used for describing distances measured along the centreline of aroad and shown written on pegs or boards which are fixed in the road reserve.

Chapter G: Road Work

G-2

G.2 PlanningPlanning elements to consider are:

Requirements of the community (people): Access to houses,business centres and social infrastructure.

Requirements for vehicles: Conventional motor vehicles do notneed to reach every house. Main links have to be motorable forsmall buses and service vehicles; pedestrians and small vehicles(bicycles, wheelbarrows and carts) are dominant traffic that needsto reach houses.

Requirements for services: Services like water supply, seweragepipes, open drainage channels and power lines require space. Theseare usually located within the road area (integrated). This makesthe construction of the road very complex.

Required pavement width: The extent of the paved widthdepends on the total width of the access way and the volume andtype of traffic to be accommodated. For access up to 5 m in width, it will usually be advisable to pave the whole width. For wider accessways it may not be necessary to pave the whole width (see tablebelow):

Minimum Paved Width Standards

Type of Traffic Paved Width

Pedestrian and bicycles 1.5 metres

Light local traffic (mainly bicycles, carts + limitednumber of cars)

3.5 metres

Minibus routes, service vehicles 6 metres

Routes for commercial/public transport 7.2 metres


G-3

G.3 Road ConstructionConstruction operations and activities:

OPERATION ACTIVITY

Support setting out alignment

work at camp (e.g. stores, tools, etc.)

water supply

Site Clearing andPreparation

setting out of centre line

waste removal

removal of vegetation, if any

cleaning of existing drains

locating and marking of service lines, e.g.power, water, sewerage

Sub-base(earth works)

detailed setting out

excavation to level sub-base formation

1st compaction

Base (earth works) formation: use of drain excavation material orborrow, e.g. gravel for higher class roads

spreading of fill material for formation crossfall

2nd compaction

Road Drainage culvert laying (for cross water drainage)

water-crossing construction, e.g. foot bridges,box culvert, etc.

soil conservation measures, where necessary

Note: storm water/side drains are separatelydealt with in the next section

Pavement, Seal depending on the pavement structure and type, e.g. gravel course, block or brick pavement,stone pavement, bitumen seal, etc.


G-4

JOB SHEET

ROAD CONSTRUCTION SETTING OUT (centre line and road edges)

WORK METHOD:

Establish the centre of the road at the start of a section of the road (either in the centre of theavailable space between the buildings or along the agreed alignment – could be off-centrealong one side of the road reserve, or along an existing drain).

Establish the centre of the road at the end of the road section, which is either a straight line ora curve.

Establish the centre line and mark it with centre pegs at 10 metre intervals between the twoend points; for a straight section set out a straight line ( see drawing below); for curves useone of the setting out methods shown on the job sheet “Setting out curves”.

When the centre line is identified the edge pegs can be established (roadway width = totalwidth of the road structure including drains, if they are part of the road). Set out a right angle(use the 3 : 4 : 5 method) to the centre line and measure from the centre half of the roadwaywidth to establish the edge peg. Repeat the same procedure for the other side of the road.

Mark all established centre points with pegs or steel rods, which are driven firmly into theground. It is advisable to mark reference points on permanent structures in case centre pegsare removed.

LABOUR:

1 Site Supervisor and/or one trained Gang Leader

2 Labourers


3 ranging rods

Tape measures, long andshort

1 big hammer

Brush for marking

MATERIAL:

Pegs or steel rods

String lines

Paint for marking referencepoints


Metres / Day / Gang =



G-5

JOB SHEET

ROAD CONSTRUCTION SETTING OUT CURVES

WORK METHOD:

Most standard geometric methods to set out curves require space, which in urban areas is rarelyavailable. This job sheet explains a practical alternative method, which is suitable for places withrestricted space and where there is already an existing alignment.

Establish the centre line pegs at each end of the curve (A and B).

Set intermediate pegs at 5 metre intervals along the approximate centre line.

Tie a string along all centre pegs.

Adjust pegs which do no appear to be on a smooth curved line until the entire curve appearsto be a uniform round.

LABOUR:

1 Site Supervisor and/or one trained Gang Leader

2 Labourers


3 ranging rods


1 big hammer

Brush for marking

MATERIAL:

Pegs or steel rods

String linesPaint for marking referencepoints





G-6

A

B5 m

Adjust these two pegs tothe right until the curveappears uniform

Tie string along all centre pegs

JOB SHEET

ROAD CONSTRUCTIONREMOVING OF WASTE, SILT

AND VEGETATION

WORK METHOD:

Set out with pegs the width of the area to be cleaned from waste and silt (usually the entirearea between houses and premises).

In the case of vegetation determine the plants which need to be cleared, e.g. trees at theroadside may not have to be cut.

Define quantities and allocate gangs for cleaning and clearing.

Clear and load onto transport.Deposit waste at approved dump ground.

LABOUR:

1 Gang Leader

Labourers

TOOLS AND EQUIPMENT: MATERIAL:

Pegs or steel rods

String linesTape measure

1 big hammer

Shovels

Rakes

Hoes

Pangas (and axe)

Slashers

Wheelbarrows

Hauling equipment


Waste removal: m3/day/labourer =

Vegetation removal: m2/day/labourer =




G-7

JOB SHEET

ROAD CONSTRUCTION CLEANING OF EXISTING DRAINS

WORK METHOD:

Identify the drains which need to be cleaned and calculate the volume of silt and waste inthem.

Allocate labourers.

Clear and load onto transport.Deposit waste at approved dumping ground.

LABOUR:

1 Gang Leader

Labourers


Tape measure

Shovels

HoesPick-axes or forked hoes

Wheelbarrows

Hauling equipment

MATERIAL:


Waste/silt removal: m3/day/labourer =



G-8

JOB SHEET

ROAD CONSTRUCTION MARKING SERVICE LINES

WORK METHOD:

Identify all service lines which are within the perimeters of the road.

Identify their exact location, e.g. by means of digging investigation trenches.

Measure the exact location and mark on permanent structures, e.g. house walls, posts, drainlinings, etc.Enter the location of the service lines with measurements onto the site sketch.

LABOUR:

1 Site Supervisor1 Labourer


3 ranging rodsTape measures, long andshort

1 big hammer

Brush for marking

MATERIAL:

Pegs or steel rodsString lines



Day work


Day work

G-9

EL = Electric Line

S = Sewerage Line

W = Water Line

WP = Water Collection Point

JOB SHEET

ROAD CONSTRUCTION SUB-BASE CONSTRUCTION

WORK METHOD:

For this activity, it is assumed that the road follows an existing track and that major earthwork isnot required. Sub-base construction is also referred to as “excavation to level” when applying l.b.methods.

From the established centreline set out the formation width. Where the drains are part of theroad the formation width includes the drains. Where the drains are not directly adjacent to the road, the formation width ends with the actual road edge (end of shoulder).

Establish the longitudinal profile for the sub-base; identify the actual level of the sub-base inthe centre. Repeat the same for the end of every straight line and/or curve.

Balance the levels in between the end points by using boning rods or profile boards at 10 mintervals.Dig slots where the sub-base has to be lowered and set pegs at the correct levels where it has to be lifted. Balance where necessary to avoid big fills or cuts.

Calculate the volume of earthwork required and allocate labour gangs.

Level the sub-base by borrowing material where cuts have to be made, and fill it into areaswhere the sub-base has to be lifted until a uniform terrace is formed.

Compact sub-base, if possible using a pedestrian vibrating roller or dead weight roller.Minimum 6 passes.

LABOUR:

1 Site Supervisor

1 to 2 Gang Leaders

Labourers


Pegs or steel rods

String lines3 ranging rods

Tape measures

Straight edge andspirit level

Hoes and shovels

Boning rods orprofile boards

Pick-axes and/orforked hoes

Rakes

Wheelbarrows

Compactor


Setting out = Day work

Excavation to level: m3/day/labourer =



Excavation to level: m3/day/labourer =

G-10

JOB SHEET

ROAD CONSTRUCTION BASE CONSTRUCTION

WORK METHOD:

The base course is constructed by using in-situ material as much as possible. In the casewhere side drains are constructed the material from the drain excavation can be used to formthe camber.

In the case where drains are already in place, material for the camber has to be borrowed.

Note: The same construction principle can also be adopted for a road with a middle drain as shown in Module B5.3.1

LABOUR:

1 Site Supervisor

1 to 2 Gang Leaders

Labourers


Pegs or steel rods

String linesRanging rods

Boning rods

Tape measures

Camber board andspirit level

Hoes and shovels

Pick-axes and/orforked hoesRakes

Wheelbarrows

Compactor



Excavation: m3/day/labourer =

Spreading: m3/day/labourer =




Spreading: m3/day/labourer =

G-11

Paving:

HAND-PACKED STONE

Description: Natural stones of 15 – 30 cm dimension laid on a 5-cmsand/gravel bed with the top surface set to the final cross fall.The large stones are packed together with smaller stoneshammered into place and the surface is blinded with agravel/sand/clay mixture. The finished paving is compacted byroller.

CLAY BRICK OR CONCRETE BLOCK PAVING

Description: Burnt clay bricks or concrete blocks (typically 200 x 100 x 80mm) laid on a layer of clean sand (30 to 50mm) on a normalroad base. This pavement has a load carrying capacity, isdurable and can be upgraded to asphalt standard.

SURFACE DRESSING

Description: A thin film of bitumen applied mechanically or by hand onto the road surface (well compacted gravel base course) and coveredwith a layer of stone chipping, then lightly rolled. Used as aninitial surface for a road pavement. Multiple coats may beapplied.

This method can also be applied to upgrade stone, brick andblock pavements.

GRAVEL SURFACE

Description: A gravel layer of 12 to 15 cm compacted thickness is addedonto the base course. The gravel has to be of approvedmaterial.

Gravel is not the best alternative for urban areas but is oftenthe only affordable option if available within the vicinity of thesite. A gravel surface is more maintenance intensive then theother pavement options.

G-12

JOB SHEET

ROAD CONSTRUCTION STONE, BRICK OR BLOCK PAVING

WORK METHOD:

The basic work method is more or less the same for all three options.

Before paving work can start ensure that the base course is well compacted, smooth and hasthe correct cross fall.

Set out the centre line and the edges of the pavement. Fix steel rods every 3 to 5 metresalong these lines. Fix strings along the rods at the correct level of the finished surface.

Lay the edge stones in concrete along thepavement edges. Ensure they are in a straightline and to the correct level. They may beslightly higher than the surface itself.

Add a layer of clean sand (3 to 4 cm) andcompact with a hand rammer. Lay stones andensure good bonding. Various patterns arepossible for Bricks and Blocks. Commonlyused are running bond and herringbone bond.

Fill shoulder with gravel and compact.Brush and wash sharp sand into the joints.Compact carefully with a pedestrian ordead weight roller.

LABOUR:

1 Site Supervisor

1 Gang Leader

Labourers


Steel rods

String linesRanging rods

Tape measures

Straight edge andspirit level

Boning rods orprofile boards

Shovels

Rakes

Wheelbarrows

Hand rammers

Mason hammersBrooms

Compactor



Setting edge stone: m/day/labourer =

Laying sand bed: m2/day/labourer =

Laying stones/bricks/blocks: m2/day/labourer =



Setting edge stone: m/day/labourer =

Laying sand bed: m2/day/labourer =

Laying stones/bricks/blocks: m2/day/labourer =

G-13

G.4 Quality Control for Road Works

ROAD DIMENSION TESTS

(i) Type of tests:Simple checks on the dimensional accuracy of the construction works.

(ii) Methods used:Tapes or templates are used to measure the completed works.

Test Method LocationTest interval(every ...)

Tolerance(mm)

Width of carriage way surface course tape field 100 m +/- 25

Width of base course tape field 100 m +/- 50

ROAD PROFILE TESTS

(i) Type of tests:Checks on the camber and longitudinal profile of the carriageway.

(ii) Methods used:Camber boards, boning rods and/or levelling instrument are used to measure the completedbase and surface layer.


Tolerance

Camber template field 20 m +/- 10 mm

Longitudinal profile boning rods field 20 m +/- 30 mm


G-14

GRAVEL SOURCE TESTS (FOR BASE LAYER)

(i) Type of tests:Check on the suitability of a gravel source for base layer or surface layer.Unlike most other tests, the client can only carry out these tests in the laboratory beforeconstruction commences. However, if you are doubtful about the quality of the material youmay use a simple field test to identify the suitability of the chosen gravel. If the testdescribed below shows doubtful results, then the client should be consulted for furtherinstructions.

(ii) Methods used:• “Bottle” test to identify the grading.• Moulding and drying test to identify plasticity and strength.

Test Method Location When? Tolerance

Grading bottle fieldwhen

necessary–

Plasticity moulding fieldwhen

necessary –

Strength drying field whennecessary

–

GRAVEL LAYER TESTS (FOR BASE OR SURFACE LAYER)

(i) Type of tests:Tests on the thickness and degree of compaction of the finished base layer.

(ii) Methods used:• Tapes are used to measure the gravel thickness.• Special laboratory tests are used by the client to measure the degree of compaction.

A simple way of ensuring the compaction is achieved is by ensuring that the requiredminimum number of compaction passes, at optimum moisture content, are actually made.This method does not provide the contractor with the actual result but ensures that thedesired compaction is achieved in most cases.


Tolerance

Thickness of gravel layer tape field 50 m +/- 10 mm

Degree of compactioncounting

compactionpasses

field always 0


G-15


G-16

Chapter H:Drainage Work

H-1

H.1 Drainage Work Terminology

Alignment: The horizontal direction of a drain (or road).

Backfill: The earthfill surrounding the drainage channel.

Catchment area: The total surface area from which any given point in acertain area receives runoff water.

Culvert: A culvert is a transverse drain built under the road and itsfunction is to lead water from the higher side of the road to the lower.

Deposition: Accumulation of soil and/or debris deposited by a waterstream into a drain.

Depression: A basin, dip or otherwise low-lying area to where the runoffwater flows.

Ditch: An unlined drain.

Drain: All natural or man-made arrangements to carry water, sewage and other unwanted liquids. They may take the form of natural ditches, pipes,channels, trenches, dips, etc.

Drainage: Structures and facilities for collecting and carrying away water.

Drained area: The total surface area serviced by the drainage system.

Erosion: Removal of soil by the action of water and wind.

Flow velocity: Speed and runoff water in meters per second.

Gradient: Amount of slope, inclination to the horizontal.

Ground water level: The elevation to which the water surface will rise in a well.

Retention capacity: The amount of water a low-lying area (depression)can hold.

Runoff ratio or coefficient: The part of the total quantity of rainwaterthat does not evaporate or soak into the ground but runs off to lowerareas. Expressed as a number between zero and one.

Scouring: The washing away of soil around and beneath a structure or on a drain bottom (and on earth or gravel road surfaces).

Sewage: All waste water from washing, food preparation, wasted tapwater and from water-flushed toilets.

Sewer: The pipe that carries away the waste water.

Sewerage: The system which carries away the waste water.

Slope: Difference in level between two ends of a drain, road or otherproject (also refer to gradient).

Soakage point: A place where water can penetrate ground which isotherwise impervious in order to reach the groundwater level.

Subdrain or underdrain: A structure beneath the ground surface forcollection underground water and carrying it to an outlet.

Sullage: Waste water from washing, food preparation and wasted tapwater. It does not contain excreta.

Surface drainage: Collection and removal of water from surface of roadand ground.

Chapter H: Drainage Work

H-2

H.2 PlanningTwo principal objectives for urban drainage:

Drainage of sullage; and

Drainage of surface water.

The purpose of urban drainage is to control storm and waste waterso that it:

does not damage roads and houses;

reduces the frequency, duration and extent of flooding; and

reduces health risks.

Understanding the drainage system:

The primary system: This is the ultimate “recipient” of the waste andrainwater the river, lake or sea. Usually this primary system has awater level that is below the average water level of the urban area.However, there are cases where this is not guaranteed.

The secondary system: This is also called the collector and leads thewater from the various urban areas to the primary system. In most cases, these are man-made drains.

The tertiary system: This is the system of the local area and is the basic system which leads the water from the households to the secondarysystem. It can consist of:– natural runoff from buildings, paved areas and vegetation covers;– natural runoff through permeable soil layers;– open drains (ditches, channels, trenches, and gutters);– closed drains (pipes, conduits, culverts).

When starting the planning process for a tertiary drainage system someimportant questions have to be answered:

What are the main drainage routes?

Where is the next secondary drainage line where the water from thetertiary system can be offloaded?

Does the existing secondary drainage have the capacity to takethe additional waste water?

What will be the system in question include: will it comprise sullageand runoff water, or will it be for runoff water only?

How are existing drainage channels maintained?

Where does flooding occur at present and what are the reasons for it?

What can local upgrading do and what can it not do?

Should new drains be covered or not?


H-3

H.3 Drain Types and Options“V” and “U” drains:

“V” Drain When little water flows through the drain, onlythe narrow bottom of the drain is used. This isparticularly suitable for sullage discharge. When the water rises higher, e.g. during rains, alarger section of the drain is used. Theadvantage is that the water will have a steadyflow speed and will keep the channel cleanwhether the water level in the drain is low orhigh. Water in this section flows most evenly,reducing deposits of dirt to a minimum.However, the parabolic shape at the bottom isrelatively expensive to construct.

“U” Drain This section is often used for drains in narrowroads and next to houses. The vertical sidesallow drains to occupy less than half the surface that “V” drains use. It is also much easier toprovide “U” drains with a cover or to buildapproaches to houses as the span is reduced.

Instead of brick walls drains can also beconstructed with in-situ cast concrete.

In cases where sullage has to be carried by the“U” drains it is advantageous to provide thedrain with a semi-circular invert, for the samereason as the V-section.

Unlined, partially lined and lined drains:

Unlined drains can be constructed manuallywith the help of hoes, picks and shovels. Theymust be built on land with gentle slopesotherwise they may be damaged by scouring ifthe gradient exceeds 1%. Stepping the bottomof the ditch will decrease the slope. The sideslopes have to be constructed in accordancewith the natural soil angle and have to beprotected by planting grass.


H-4

Partial lining of drains is necessary whereslopes range from 1% to 5%, to preventscouring. Between these slopes the watervelocity is between 1 to 5 m/sec. A partial lining may also be necessary for the most vulnerablesections of unlined drains, like culvert inlets and outlets, drain junctions, sharp bends andsteeper sections.

Fully lined drains are expensive and need to be provided only when the threat of erosion fromhigh water velocity is real. When slopes exceed3% water velocity exceed 2 m/sec. This willcause erosion.

Drains can be lined using several methods:

stabilisation with bitumen, cement or lime;

paving with stones or bricks;

paving with concrete drain elements, either prefabricated or cast on site.

Open or covered drains:

Wherever they are used, open channel drains take up space and pose ahazard to road users and residents, especially if the drain is very wide ordeep or passes through a busy area. If this situation can be avoided andresources are available, then drains should be constructed covered withremovable slabs, allowing access for the rainwater and sullage.


H-5

Steep slope drains:

Options for leading water down gradually and in manageable quantitiesinclude:

Diverting the water horizontally through sideway drains, thus reducingwater speed.

Stepping the drains to form a series of almost horizontal sections.

Leading the water in a controlled zigzag manner through baffles built intodrains.

Combining stepping and zigzag construction so that the soil settles behind the baffles and gradually builds a steped drain.

H.4 Drain ConstructionDrain construction can be subdivided into the following main activities:

Setting out

Removal of waste and vegetation

Cleaning of existing drains (sections of drains)

Locating and marking of existing service lines

Excavation

Shaping and slopping (for unlined and lined drains)

Lying of prefabricated drain elements (drain bottoms, fullsections)

Lining: masonry, concrete slabs, etc.

Construction of pedestrian crossings

In cases where drains are constructed as part of theroad some of the activities will be integrated into the road

construction process, e.g. setting out, removal of waste andvegetation, cleaning of existing drains, locating and

marking service lines and excavation of drains.


H-6

JOB SHEET

DRAIN CONSTRUCTION SETTING OUT (alignment and levels)

WORK METHOD:

Determine drain sections: a section is a straight or curved stretch of the drain which has thesame gradient. Wherever the gradient, curve or direction of the drain changes, a new sectionstarts.

Set out the centre line of these sections. Establish first the straight lines by fixing pegs at theend points of the sections. For curves set centre point pegs at closer intervals, e.g. 1 metre.

Determine the inlet and outlet levels of drain sections. Place a profile board at the two endpoints (marked by the centreline pegs), with top of profile board 150 cm or 200 cm above thecompleted drain bottom level.

Mark the boards clearly with the measurements to be used to find the levels, e.g. +150 or+200. These will be your reference levels for all other intermediate levels.

These profile boards can then also be used to set out all the following construction activities. A wire stretched from one profile board to the next one assists in ensuring a straight drain lineat any point. All important measurements (cross-sectional) can be marked on the profile board and the wire used to set out all intermediate points, e.g. edges of excavation, placing of drainelements, etc.

Place reference points for the centre line pegs as well as for the levels at the section ends onpermanent structures since the centre pegs will eventually be removed during excavation.

LABOUR:

1 Site Supervisorand/or one trainedGang Leader2 Labourers


Pegs or steel rodsfor centre pegs

Poles, boards andsteel wire for profile

Paint for marking

3 ranging rods

Tape measures

Tools for diggingholes ( posts)

1 sledge hammer

1 carpenter hammer

Brush for marking


Metres/Day/Gang =


Metres/Day/Gang =

H-7

JOB SHEET

DRAIN CONSTRUCTION REMOVING OF WASTE AND VEGETATION

WORK METHOD:

Set out with pegs the width of the area to be cleaned from waste and vegetation. Use theprofile boards with the wire as your reference line.



LABOUR:

1 Gang Leader

Labourers


Pegs or steel rods


1 hammer

Shovels + hoesRakes

Pangas (and axe)

Slashers

WheelbarrowsHauling equipment







H-8

JOB SHEET

DRAIN CONSTRUCTION CLEANING OF EXISTING DRAINS

WORK METHOD:

Identify the drains which need to be cleaned and calculate the volume of silt and waste in it.

Allocate labourers. Make sure necessary protective clothing is available and used.

Clear and load onto transport.

Deposit waste at approved dump ground.

LABOUR:

1 Gang Leader

Labourers


Tape measure

Shovels

Hoes

Pick-axes or forkedhoes

Wheelbarrows

Hauling equipment

Protective clothing





H-9

JOB SHEET

ROAD CONSTRUCTION MARKING SERVICE LINES

WORK METHOD:

Identify all service lines which are within the perimeters of the drains (and road).



LABOUR:

1 Site Supervisor

1 Labourer


3 ranging rods


1 big hammer

Brush for marking

MATERIAL:

Pegs or steel rods

String lines



Day work


Day work

H-10

EL = Electric Line

S = Sewerage Line

W = Water Line


JOB SHEET

DRAIN CONSTRUCTION EXCAVATION

WORK METHOD:

Set out the edge lines for excavation using the profile boards as reference points. Use a plumb bob to transfer the edge line from the wire to the ground. Mark the edges with pegs and string lines.

Use the level reference points from the profile boards to find the correct excavation levels atthe two end points. Dig a slot next to each profile board. Dig slots at 10 m intervals todetermine the levels and quantities for excavation. Use boning rods to transfer the levels tothese slotsAllocate labourers.

Excavate and deposit the excavated material well away from the drain.

LABOUR:

1 Gang Leader

Labourers


Pegs and stringsTape measure

Plumb-bob

Boning rods

Shovels and hoes



Slots: number/day/labourer



Slots: number/day/labourer


H-11

JOB SHEET

ROAD CONSTRUCTION SHAPING AND SLOPING

WORK METHOD:

Depending on the drain type, the exact profile has to be shaped after the excavation has been completed.

Use templates to determine the exact shape and boning rods to check the levels of theexcavation. Use the profile board with the wire to check the alignment.

Pay attention to the slopes; they have to be uniform and to the correct slope gradient. This isparticularly important for drains which will be lined. In cases where too much material was excavated (e.g. holes in slope) backfill carefully andcompact with an earth rammer until the wanted shape is achieved.

LABOUR:

1 Gang Leader

Labourers


Pegs or steel rods


Plumb-bob

Boning rods andtemplates

Shovels and hoes



Shaping: m2/day/labourer =


Shaping: m2/day/labourer =

H-12

JOB SHEET

ROAD CONSTRUCTIONLAYING OF PREFABRICATED

DRAIN ELEMENTS

WORK METHOD:

Prefabricated drain elements:

drain bottom consisting of semicircular full drain profileconcrete segments

Drain elements must be laid ontocompacted in-situ soil. A sandbed is required where the soil isstony and where the exact levels cannot be easily cut out of thesoil, e.g. in-situ gravel.

Each element must be in fullcontact with the ground (nohollow spots).

Place each element at the exactlevel(check with the boning rod andprofile board)

Align (plum bob on profile boardwire).

Seal joints with cement mortar.

Backfill, where necessary andcompact.

LABOUR:

1 Gang Leader

1 MasonLabourers


Wooden wedges

(Sand)Tape measure

Boning rods

Plum-bob

2 crow bars

Shovels and hoes

Hand rammer


Laying: m/day/labourer =


Laying: m/day/labourer =

H-13

JOB SHEET

ROAD CONSTRUCTION LINING

WORK METHOD:

Type: most drains are lined either using rubble stones or prefabricated concrete slabs (tiles).

Preparation: the slopes to be lined have to be uniformly shaped with the correct slopegradient. There should be no loose soil on the slopes compact and fill possible pockets andholes.

Base layer: for high quality lining a layer of approximately 5 cm lean concrete (1 : 4 : 8) isadded. Compact well using a hand rammer. Where lower quality lining (cheaper) is used thelean concrete layer is not required. However, the base has to be very well compacted andshaped.

Lining with rubble stones: First place some shovels of mortar (1 : 6) loosely onto theground and spread evenly (do not compact). Place moistened rubble stones close to eachother onto the mortar bed and “waggle” the stones into position. Ensure that there aregood joints between the stones (1 cm to 4 cm) and that there is some good bonding. Ensure that the surface of the lining is as uniform as possible. Fill joints with mortar. Cover lined area with old sacks or leaves. Keep wet for 7 days.Lining with concrete slabs: Place slabs directly onto the prepared ground. Ensure thatthe slabs interlock. Ensure proper bonding. Slabs without interlocking joints have to beplaced to allow for mortar joints of approximately 1 cm to 2 cm.

LABOUR:

1 Gang Leader

1 Mason

Labourers


Cement

Sand

Ballast (if leanconcrete)

Shovels

Wheelbarrows

Mason hammers

Mason trawl

Brush


Lining: m2/day/labourer =


Lining: m2/day/labourer =

H-14

Construction of pedestrian crossings (Examples):

For unlined or partial lined drains which have a semicircular bottom,culverts are better suited. Such approaches, however, requireheadwalls.

H-15


H.5 Quality Control for Drainage andSanitation Work

PROFILE TESTS

(i) Type of tests:Checks on the longitudinal and cross-sectional profile.

(ii) Methods used:Line-levels and boning rods are used to control the levels. Straight-edges and slopetemplates are used to control drain slopes (see module B5.1).

(iii) Rectification measures:Works that are found to be out of tolerance should be dismantled and re-laid.

Test item Method Location Test interval Tolerance

1.) Excavation levels Line-level siteslots,

minimumevery 10m

+/- 1-2 cm

2.) Excavation slopes

Straight edge,slope template

with spiritlevel

siteslots,

minimumevery 10m

+/- 5°

3.) Blinding surface levelsLine-level andboning rods

siteslots,

minimumevery 10m

- 1-2 cm

4.) Manhole/box culvert bottomslab levels

Line-level andboning rods

siteslots,

minimumevery 10m

+/- 0 cm

5.) Pipeline levelsLine-level andboning rods

sitein/outlet ofeach pipe

+/- 0 cm

6.) Manhole cover levelsLine-level andboning rods site

everymanhole +/- 1-2 cm


H-16

DIMENSION TESTS (drains, manholes, other structures)



(iii) Rectification measures:Correct dimensions of formwork before casting concrete. For masonry works lay first brickcourse and then confirm the dimensions.


1.) Width of excavation base tape siteevery slot,min. 10 m + 5 cm

2.) Width of concrete blinding tape site every slot,min. 10 m

+ 5 cm

3.) Structure’s cross-sectionaldimensions

tape,formwork

before castingsite every 3 m +/- 5 cm

4.) Manhole dimensions tape siteeach

manhole +/- 0.5 cm

5.) In/outlet dimensions tape siteeach

manhole+/- 2-3 cm

6.) Construction lengths(expansion/construction joints)

tape site every joint +/- 1 cm

7.) Verticality of constructionelements

spirit leveland/or

plumb bobsite every 3 m +/- 1 cm

Note: Concrete and mortar tests are shown in Chapters D and E respectively.


H-17


H-18

Chapter I:Water Work

I-1

I.1 Water Work Terminology

Air valve: Valve which allows entrained air to escape the distributionsystem.

Flow velocity: Speed of water in metres per second.

Gradient: Amount of slope, inclination to the horizontal see alsoModule B2.


Interruption chambers or break-pressure tanks: Chamber with acontrol valve which limits the total pressure in a pipeline downstream ofthe same tank.

Pipe fitting: Bend, socket, branch piece, reducer, etc. fitted onto a pipelength.

Vacuum valve: Valve which allows air to be sucked into the pipedistribution system if suction pressure is experienced.

Wash out: Point of full pipe opening were the water may be drained outof a pipeline.

I.2 Planning

It is important to note that the planning process of awater supply system has to be done in combination with

planning the sewage and possible electrical cables systems.

Planning tasks:

CBO to inform local government and water authorities of the project,establishing the geographical and administrative situation, populationcount, infrastructure and plans for further development, economicalaspects.

Searching out water sources.

Water quantity and quality at source.

Water quantity needed.

Survey pipe routing and trench lines.

Occurrence and quality of local building materials: sand, gravel, stonesand wood.

Technical Report: estimate.

Organisation of community work.

Implementation of project.

Planning and organisation of maintenance.

Chapter I: Water Work

I-2

I.3 Construction WorkThe pipeline construction work can be subdivided into the followingactivities:

Setting out pipeline trenches



Trench excavation

Trench bed preparation

Pipe laying on trench beds

Pressure testing of sections

Trench backfilling

Pipeline marking

Disinfection of pipelines


I-3

JOB SHEET

WATER SUPPLY SETTING OUT (pipe lines)

WORK METHOD:

Determine the pipe route as agreed with the community. The pipe should be laid along thestraightest route possible. Road crossings should be done at a right angle to the roadwhenever possible.

Place pegs to mark along the pipe route.

Place sighting boards or level sticks along the pipe trench and set out the depth to beexcavated at short intervals (5-10 m). Mark clearly on the boards or sticks the correct depthmeasurement.

Establish a reference level at every section such that checks on each level stick can be made.

Check all measurements. Call the Community Representative or the technician in charge toconfirm the measurements before you start with the excavation work.

LABOUR:

1 Site Supervisor

2 Labourers


Pegs or steel rods forcentre p.

Poles and boards forprofile

Steel wirePaint or markers formarking reference points

Ranging rods

Tape measures,long + short

Tools for digging holes ( posts)

1 sledgehammer

1 carpenterhammer

Brush formarking


Day work


Day work

I-4

JOB SHEET

WATER SUPPLY REMOVING WASTE AND VEGETATION

WORK METHOD:

Set out with pegs the width of the area to be cleaned from waste and vegetation.


Clear and load onto transport.

Deposit waste at approved dump ground.

LABOUR:

1 Gang Leader

Labourers


Pegs or steel rods


1 hammer

Shovels + hoes

Rakes

Pangas (and axe)

Slashers

Wheelbarrows

Hauling equipment







I-5

JOB SHEET

WATER SUPPLY MARKING COINCIDING SERVICE LINES

WORK METHOD:

Identify all service lines which are crossing or following the pipe route.



LABOUR:

1 Site Supervisor

1 Labourer


Pegs or steel rods

String lines


3 ranging rods


1 big hammer

Brush for marking


Day work


Day work

I-6

EL = Electric Line

S = Sewerage Line

W = Water Line


JOB SHEET

WATER SUPPLY TRENCH DIGGING

WORK METHOD:

Identify the soil conditions or any impassable sections such that eventual re-routing can bemade.

Make use of a measuring board or stick to check the actual depth to be excavated at eachlocation.

Excavate step by step. Normally the excavated material can be used for backfilling and mustbe deposited next to the trench but at a sufficient distance to prevent it from falling back andresulting in unnecessary cleaning of trenches.

The recommended width of a trench is at least 60 cm.

The trench depth will protect the pipe against damage from traffic and weather conditions. Aminimum 60 cm should be provided to protect the pipe against great variations intemperature, root growth into flexible joints, etc. Trenches of more than 1,5 m depth willrequire some investigations on pipe strength to withstand earth pressure. In weaker soilsstrutting might be necessary.Road crossings may be done at a depth of 1,2 m, or laid into a sand bed and covered with atleast 20 cm sand at a depth of 1 m. At less depth the pipe should be covered with 20 cm sand and a concrete slab on top as a protection before backfilling.

LABOUR:

1 Gang Leader

Labourers



Plumb-bobShovels and hoes

Pick-axes or forked hoes





I-7

JOB SHEET

WATER SUPPLY LAYING OF PIPES

WORK METHOD:

The pipes should be laid on firm ground or foundations in order to prevent uneven settlement,which may damage the pipe. In rocky soils rocks and stones should be cleared away from thebottom of the trenches for 15 cm beyond the pipes and should be replaced by plain earth,sand or concrete.

Pipelines to be laid in straight lines between changes in gradient. The slopes of mains shallpreferably be 0.5% for diameters <200 mm and 0.2% for bigger pipes. When the topographymakes this impossible air valves at appropriate points have to be included. Pipes have to be laid with a cover of 0.6 to 3 m with no local high points where air pocketscannot be released.

Where motor traffic may occur, pipes must be protected by a minimum 0.9m cover. Whenever possible the pipelines should be located 1.5 m from the edge of the road reserve.

When a pipeline is first constructed, or later drained for maintenance purposes, it is filled withair at atmospheric pressure. When water enters, air may be trapped in certain sections. Aswater is filled the pressure builds up and the air pockets will be compressed. Compressingthese air pockets and therefore reducing the amount of energy available to move waterabsorbs hydrostatic pressure. If too much energy is absorbed by compressing no flow willreach the desired discharge point.

Possible air blocks near to the static level are the more critical ones and should be minimisedfirst by use of tee connections to water points or automatic air valves.

Before lowering the pipe into thetrench the pipes should be inspectedfor cracks, punctures or otherdamages. The pipe inside should beinspected for foreign bodies (snakes,mice, sand, etc.) The pipes and theirjoining ends should be wiped andcleaned.

A small depression should be dug outunder the coupling or socket so as toallow an adequate support for thepipe over its entire length.

LABOUR:

1 Gang Leader

1 Pipe Fitter

6 Labourers


Pegs and strings

Pipes

Fittings and valves

Pipe tools

Thread tape

Wire brush

Cloths for cleaning pipe





I-8

JOB SHEET

WATER SUPPLY THRUST BLOCKS, ANCHORING

WORK METHOD:

Thrust blocks are necessary at bends, tees, valves and tapers and also branch take-off ifflanged joints are not used. These blocks are often large and must be well keyed into firmground.

A pipe laid on sloping ground should have anchor blocks cast around it and the weight of theblock is to withstand the occurring forces.

The size of the thrust block has to be decided in accordance with the external forces and hasto be calculated by the design engineer.

In soft soils it is important not to firmly attach the thrust block to the pipeline as this mayendanger the line safety if the line bends unevenly.

Construction:

Investigate the soil for its compactness at the point where the thrust block willbe built.

Excavate and construct formwork forthe thrust block.

Cast concrete.

Fix anchors into the block in order toconnect the pipe for cases where theblock does not cover the pipe (seediagram).

LABOUR:

1 Gang Leader

1 Mason

1 Pipe Fitter

Labourers


Aggregate and sand

Cement

Wire mesh

Timber for formwork

Nails and wire

Tape measure

Plumb-bob

Masonry tools

Shovels

Watering can

Pipe tools


Day work =


Day work =

I-9

JOB SHEET

WATER SUPPLY BACKFILLING

WORK METHOD:

The material for backfilling must not contain lumps, rocks or large stones. The pipe must firstbe covered with 20 cm of sand or similar soft material before bulk filling of the remainingtrench can be permitted.

The initial backfilling (20 cm above pipe) should be done as soon as possible to protect thepipe.

Soil or sand shall be placed up to a height of 1/2 ofthe external diameter.

The soil under the pipe and between the pipeline andtrench wall shall be tamped.

Backfill by hand to a height of 20 cm over the pipeand tamp every 10 cm layer.

Bulk-backfill of the rest of the trench in layers not exceeding 20 cm. If large stones have been excavatedit is not advisable to use them for bulk backfilling thetrench. Each layer has to be compacted.

LABOUR:

1 Gang Leader

2 Labourers


Sand (if no fine soilavailable)

Shovels

Hoes

Sieve

Trench compactor or earthrammers


Backfilling + compaction: m3/day/labourer =


Backfilling + compaction: m3/day/labourer =

I-10

JOB SHEET

WATER SUPPLY MARKING OF PIPELINE

WORK METHOD:

If the line of the pipe has not been marked during construction it will later be difficult andsometimes very costly to find the pipe. It is important that immediately after backfilling thepipe should be marked by permanent signs to be able to follow the pipe if need arises (e.g.repairs, building of new houses or roads).

A concrete sign which contains the following information may be the best way to mark the pipetrace permanently:

Pipe material and diameter laid into the ground

The direction of the pipe

Continuous numeration in sequence of all concrete signs

LABOUR:

1 Gangleader

2 Labourers


Sand, ballast and cement

Timber (for shuttering)Shovels

Watering can

Concrete mixer (if available)


Day work =


Day work =

I-11

JOB SHEET

WATER SUPPLY DISINFECTING PIPELINES

WORK METHOD:

The disinfection of new or repaired pipelines can be expedited and greatly simplified if specialcare is exercised in the handling and laying of pipes. Trenches should be kept dry and a tight,. Fitting plugs should be provided at the end of the line clean. Lengths of pipe that have soiledinteriors should be cleansed and disinfected before connecting them. Each continuous lengthof main pipe should be separately disinfected with a heavy chlorine dose or other effectivedisinfecting agent. This can be done by using a hand pump to inject the chlorine at thebeginning of the section through to a wash point, temporary valve connection or tank.

First the section is flushed thoroughly by ensuring sufficient pressure and draining through ahydrant, flush or drain point until the water flow is clear.

Chlorine is then injected into the line at a rate according to the water flow giving a residual ofminimum 50 mg/l.

After this the line should again be flushed thoroughly.

LABOUR:

1 Gang Leader

2 Labourers


Water supply

Chlorine solutionChemical tank with chlorine

Hand pump


Day work =


Day work =

I-12

JOB SHEET

WATER SUPPLY PUBLIC STANDPIPE

WORK METHOD:

Use the profile boards with wires and plumb bob to establish the 4 corners of the slab for thetap stand.

Establish the bottom level of the slab; use reference points from the profile board.

Excavate the slab and a drainage channel if the terrain does not allow for natural drainage.Excavate the soak away pit if no other drainage is naturally available.

Compact the ground at the tap stand, place some aggregate and compact well if soil is weak.

Install the pipe work.

Install some stone pitching around the tap stand slab to allow for support and stability of thesurrounding ground and allow for drainage.

Cast bottom slab (add crack reinforcement, e.g. weld mesh), trowel slab top smooth. Allow for a valve box with a water meter to be located behind the tap stand.

Construct the concrete wall of the tap stand.

LABOUR:


Labourers


Aggregate, sand, cementCement blocks

Weld mesh, rods

GI pipes ¾”, sockets andelbowsTap ¾” or ½”

PVC pipe 50mm

Timber for formwork

Nails and wire

Tape measure

Plumb-bob

Masonry tools

Shovels

Watering can

Pipefitting tools


Day work =


Day work =

I-13

JOB SHEET

WATER SUPPLY VALVE CHAMBERS

WORK METHOD:

It is necessary to have valves at intervals along the pipeline to control the flow of water.These valves are preferably situated in a chamber built of concrete or cement blocks forprotection and access.

The chamber must allow opening and closing of the valve using a suitable spanner.

The valve is backfilled around the body to just below the top body flange and the brickchamber is set around the upper part and covered with a hinged cover so that an operatingtee key or spanner can be lowered on to the valve cap when it is necessary to operate thevalve.

Construction:

Valve chambers should be at least 60 x 60 cm internally.

UPVC pipes shall not be used within the chamber.

LABOUR:

1 Gang Leader

1 Mason

Labourers


Sand

Cement

Bricks or cement blocks

Tape measurePlumb-bob

Masonry tools

Shovels

Watering can


Day work =


Day work =

I-14

JOB SHEET

WATER SUPPLY STORAGE TANK CONSTRUCTION

WORK METHOD:

Reservoir tanks are provided to store water during lower consumption periods to be availableduring consumption peaks. The maximum hourly consumption can amount to 3 times theaverage consumption.

Storage tanks may also serve as pressure holding tanks and should preferably be located close to the area of peak consumption in the system. However, normally the tanks are locatedaccording to the local topography. The tank can be supplied directly from the water source orthrough the distribution system.Use the profile boards with wires and plumb bob to set out the storage tank.

Establish the bottom level of the slab; use reference points from the profile board.

Place a hardcore layer of approximately 15 to 20 cm depth, compact well.

Add lean concrete layer of approximately 5 cm thickness.

Cast bottom slab (add crack reinforcement, e.g. weld-mesh), trowel slab top smooth.

Construct outside walls, preferably using cement blocks. Plaster walls inside if not made ofconcrete.

Construct formwork for slab. Add reinforcement. Provide openings (manholes) for access,min. Ø 60 cm.Cast concrete, trowel top smooth and cure for 28 days. Remove the formwork from the slab.

LABOUR:

1 Gang Leader

1 Mason

Labourers


Hardcore, ballast, sand,cement and cement blocks

Weld mesh, RE bars

In-/outlet “T” pipes

Timber for formwork

Nails and wire

Tape measure

Plumb-bobMasonry tools

Shovels

Watering can


Day work =


Day work =

I-15

JOB SHEET

WATER SUPPLYPIPE CONNECTIONS AND CONNECTIONS

TO BUILDING AND TANKS

WORK METHOD:

If an existing main or branch-line is the main source of water supply and the new systems arean extension of this supply, a connection has to be made.

Tank connections must be water tight if taken through a wall.

(1) To connect a steel or plastic pipe intoa tank a seal must be installed, e.g. a rubber seal or a flange and gasketwhich is fitted at the wall centre.

Flexible connection for pipelines which are laid intoground and must be connected into a tank.

(2) Plastic pipe connection: If a tee hasto be inserted into an existing pipethe length cut out of the latter mustbe slightly greater than the overalllength of the tee. The socket end ofthe tee is pushed up to fit one end ofthe cut pipe and the resulting gap atthe other end is joined by using acollar inserted into the other cut pipeend, leaving sufficient length forinstallation of the tee. Upon the collar is inserted the tee still covering theexisting pipe.

(3) Steel pipe connection: A connectionto existing pipes can be made byclamping a split collar onto the steelpipe. The collar has a flanged branchwith a valve. A cutter opens a hole inthe pipe and is withdrawn as thevalve is closed.

To make sure there will be no leaks where the pipesenter into the tank a single flange fitting with one flangein the middle of the wall is very useful.

(4) For concrete pipes a service pipe canbe installed by using a ferrule and asaddle strap.

Service pipe connection to a main pipe of cement or steel.

I-16

teecollar

existing pipe

tee collar

I.4 Quality Control for Water Works

PRESSURE TESTS (for water lines)

Testing is best to be made before backfilling to easily discover leaks and damages on thepipes.

Some initial backfilling can be made before testing to assure minimum pipe movements anddamage from objects falling into the trench. The straight pipe sections can first be filled with20 cm of sand or similar soft material and joints and fittings should be left open beforepressure testing.

A section of 500 m should be isolated and tested by a pumping device or use of natural slopeand a transparent hose. The air at high points must be removed during filling.

An end cap or section valve shall isolate the section and a pump or plastic pipe connected theother end. A pressure gauge can be used for the pumping or an elevation measure given forthe plastic pipe connected.

Plastic and steel pipes should have no loss of water, cement pipes will absorb some waterduring the first 24 hr and thereafter the loss shall not exceed 0,05 l/m2 of the inner surface per hr.The pressure test shall last for a minimum of 15 min/100 m.

I-17



I-18

Chapter J:Sanitation Work

J-1

J.1 Sanitation Work Terminology

Excreta: Human waste eliminated from the human body.

Flow velocity: Speed and runoff water in meters per second.

Gradient: Amount of slope, inclination to the horizontal see alsoModule B2: Mensuration.


Pit latrine: A hole in the ground where excreta and cleansing materialsare deposited, usually with a superstructure on top to provide privacy tothe user.

Septic tank: An underground tank that acts as a settlement unit in which solids settle out by gravity.

Sewage: All waste water from washing, food preparation, wasted tapwater and from water toilets.

Sewer: The pipe that carries away the waste water.

Sewerage: The system which carries away the waste water.

Sullage: Waste water from washing, food preparation and wasted tapwater. It does not contain excreta.

Superstructure: A small cubicle (house) on top of the latrine to ensureprivacy of the user.

J.2 Planning

For the planning process of sanitation systemsit is important to note that this has to be done

in combination with planning the water systems.

When planning a community-managed sanitation projectthe degree of participation achieved will depend on three main factors:

1. Motivation, 2. Education, 3. Training

Chapter J: Sanitation Work

J-2

Investigating the existing situation:

Are there existing sanitation systems in place? What kind? What condition are they in? Where are they? Who has access to these systems? Whodoes not? Can they be extended or adapted for a wider use?

Are present defecating practices in danger of directly polluting watersources or the food chain?

What is the cultural behaviour of the future users?

What is the population density of the area in question?

Is there space available on each plot?

What is the level of the ground water table?

What is the depth and permeability of the soil? Can it be dug easily byhand?

Are there any people familiar with the construction of latrines?

Is there a potential use of stabilised waste material as fertiliser?

Is there municipal capacity available for emptying pits and septic tanks?

What trade, skills and materials are available locally?

What is the location and capacity of local trunk sewers and sewagetreatment plant?

Selection of sanitation system:

The selection of the most appropriate sanitation system is influenced bytechnical, cultural, institutional and financial factors. The following twopoints are of basic technical importance:

The quantity of water available for use in the sanitation system:Water requirements of different systems vary from zero to 80 litres perperson per day. Hence the level of service for water supply is important.

The material used for anal cleansing after defecation: This dependsupon the cultural and religious practices of the society. Materials usedinclude water, paper, leaves, sand and stones.

J-3


J.3 Types and OptionsTypes of on-site sanitation systems:

Pit Latrines

The principle of all types of pit latrine isthat excreta and anal cleansing materialsare deposited in a hole in the ground. Inits simplest form the pit latrine consists of a superstructure, which affords privacy tothe user, a hole (or seat) set into a slab,which covers the pit beneath the slab intowhich excreta are deposited.

Simple pit latrines should have a lid tocover the hole to reduce smells and flies.

Ventilated Improved Pit Latrines(VIPs)

In the case of VIPs, the pit is ventilatedby means of a vertical pipe. The action ofwind blowing over the top of the vent pipe creates an up-draught of air, which flowsup the pipe. Air is drawn down throughthe hole in the cover slab and circulates in the pipe. Any unpleasant odour passes up the pipe rather than out of the hole in thecover slab into the superstructure. Fliesare attracted to the top of the vent pipe,but the presence of a fly screen made outof fine gauge mesh prevents many fliesfrom entering. Flies which do breed in thepit tend to head towards light, but thescreen blocks their exit. The interior of the latrine superstructure needs to bedarkened to prevent flies from entering,which requires the latrine to have apermanent superstructure with a roof.


J-4

Pour Flush Pit Latrines

In regions where water is used foranal cleansing as opposed to solidmaterial such as paper, leaves,stones or sand, it is possible toadapt the simple pit latrine byinserting a pour flush bowl into thehole in the pit cover slab. Whenfilled with water, this bowl forms an effective seal, which isolates the pitfrom the user; this is a mosteffective way of eliminating smellsand fly nuisance.

The bowl is designed so that itrequires only a small volume ofwater to flush excreta into the pit.Depending upon the detaileddesign, 1-6 litres of water arerequired for each flush, which ismuch less than the 10-20 litres forconventional cistern flush toilets.Pour flush latrines are only suitablein areas where a reliable andappropriate water source isavailable.

Septic Tanks

A septic tank comprises a sealedtank that has both an inlet and anoutlet into which excreta areflushed from a conventional cisternflush toilet using typically between10-20 litres of water for each flush.The tank is connected to the toiletby a sewer pipe. Partially treatedeffluent flows out of the tank. Thismarks an important difference fromthe pit latrine, in which any waterentering the pit leaves bypercolation into the surroundingground. Septic tanks may receiveeither toilet waste alone, or bothtoilet wastes and sullage from sinks, showers and baths.

The septic tank acts as a settlement unit in which solids settle out by gravity; thesolids undergo a process of anaerobic decomposition. The effluent which flows out ofthe septic tank constitutes a potential health hazard. A common disposal method isby absorption into the ground using a soakage pit or trench. The settled sludge has to be periodically removed by a suction tanker.

Septic tanks may be built to combine several households or plots. Regularmaintenance (removal of sludge) is essential and relatively expensive.

J-5


Double Pit Latrines

Pit latrines should always be downhill from a well and as far away as possible. Areasof high housing density have potentially high densities of pit latrines and there is realdanger of wells and pits being too close together. Problems encountered with groundconditions, high water table and groundwater pollution usually lead to the pit beingvery shallow. Unfortunately this means that the pit fills rapidly and rapid emptying isrequired.

These difficulties can be overcome by using the double pit latrine system in whichboth pits are shallow, but not less than 1.2 metres deep. Additional capacity can beobtained by increasing the plan areas or raising the pit (higher costs).

This first pit is used until it is full, and the second pit is then put in use. When thesecond pit is full, the first can be emptied safely because the contents will have beendigesting for at least one year.

Double Pit Ventilated Improved Latrine:

Pour Flush Double Pit Latrine:

Source: WEDC, Loughborough University of Technology


J-6

J.4 Sanitation ConstructionDrain construction can be subdivided into the following main activities:

Setting out



Excavation (for pit latrines and septic tanks)

Pit lining

Pit slab construction

Superstructure

Septic tank construction

J-7


JOB SHEET

SANITATION SETTING OUT (pit latrines, septic tanks)

WORK METHOD:

Determine the exact location of the pit latrine or septic tank in accordance with the plan or the agreed location as agreed with the community. Place pegs to mark all corners.

Place profile boards outside the working area and transfer the corner points to the profileboards. Mark clearly on the profile boards the various measurements.

Establish reference levels (for septic tanks only) and secure them on profile boards orpermanent structures, like house walls. Check again all measurements. Call the Community Representative or the technician in charge to confirm the measurements before you start with the excavation work.

LABOUR:

1 Site Supervisor

2 Labourers


Pegs or steel rods for centrep.

Poles and boards for profile

Steel wire

Paint or markers for marking reference points

Ranging rodsTape measures, long + short

Tools for digging holes ( posts)

1 sledge hammer1 carpenter hammer

Brush for marking


Day work


Day work

J-8

JOB SHEET

SANITATION REMOVING OF WASTE AND VEGETATION

WORK METHOD:

Set out with pegs the width of the area to be cleaned from waste and vegetation. Use theprofile boards with the wire as your reference line.



LABOUR:

1 Gang Leader

Labourers


Pegs or steel rods


1 hammer

Shovels + hoesRakes

Pangas (and axe)

Slashers

WheelbarrowsHauling equipment







J-9

JOB SHEET

SANITATION MARKING SERVICE LINES

WORK METHOD:

Identify all service lines which are within the perimeters of the area where the sanitationfacility will be built.


Measure the exact location and mark on permanent structures, e.g. house walls, posts, drainlinings, etc.

Enter the location of the service lines with measurements onto the site sketch.

LABOUR:

1 Site Supervisor

1 Labourer


Pegs or steel rods

String lines


3 ranging rods

Tape measures, long andshort1 big hammer

Brush for marking


Day work


Day work

J-10

EL = Electric Line

S = Sewerage Line

W = Water Line


JOB SHEET

SANITATION EXCAVATION FOR PIT LATRINES

WORK METHOD for Pit Latrines:

Identify the soil conditions(if conditions are poor likesandy or stony soils the pit has to be lined).

Set out the edge lines forexcavation using theprofile boards. If lining isrequired add the thickness of the pit walls to theexcavation width. Typicaldiameters are:– unlined pit in stable ground = 100 cm– lined pit in soft ground = 140 cm

Excavate step by step. The excavated material has tobe hauled to the top withbuckets. A tripod or asimple winch is useful tohaul the material safelyfrom deep pits.

Ensure that the internaldimensions and form ofthe pit is uniform from top to bottom. Shape pit walls.

Deposit the excavatedmaterial safely away fromthe pit (at least 5 metredistance).

Haul the excavatedmaterial to an approveddump place or use forother construction work ifrequired.

LABOUR:

1 Gang Leader

Labourers



Plumb-bob

Tripod (if available)

Rope and buckets

Shovels and hoes






J-11

JOB SHEET

SANITATION EXCAVATION FOR SEPTIC TANKS

WORK METHOD for Septic Tanks:

Set out the edge lines for excavation using the profile boards as reference points. Use a plumb bob to transfer the edge line from the wire to the ground. Mark the edges with pegs and string lines or sawdust.

Use the level reference points from the profile boards to find the correct excavation levels. Use boning rods to transfer the levels within the excavation pit.

Allocate labourers.Excavate and deposit the excavation material well away from the pit.

LABOUR:

1 Gang Leader

Labourers



Plumb-bob

Boning rods

Shovels and hoes


Wheelbarrows +buckets





J-12

JOB SHEET

SANITATION PIT LINING (for pit latrines)

WORK METHOD:

Note: In soft ground conditions or where the soil is not stable the pit has to be lined. The thickness of the walls have to be considered for the excavation.

1. Foundation:

At the bottom of the pit set out thetrenches for the foundation andexcavate.

Cast the foundation with concrete orbuild with bricks/blocks.

Add a layer of hardcore to the pitbottom.

2a. Lining with bricks or cement blocks:

Construct walls using bricks or cementblocks.

Do not fill the vertical joints with mortar so that liquid from the pit can seep intothe surrounding soil. Ensure goodbonding. Ensure vertical alignment ofthe walls!!

For circular pits use a template (halfthe circle) to check the shape.

After every course backfill the wallswith sand or gravel.

Fill all joints for the top 50 cm.

2b. Lining with porous concrete rings(culverts):

Lower porous concrete rings (min. Ø90cm) carefully into the pit using ropesor a tripod.

Mortar the joints.

Ensure vertical alignment of the rings!!Backfill with sand or gravel after everyring is placed.

LABOUR:

1 Gang Leader

1 Mason

Labourers


Sand and cement

Ballast

Hardcore

Bricks or cementblocks, or porousconcrete rings

Tape measure

Plumb-bobMasonry tools

Template, semicircular

Shovels, hoes,pick-axe

Buckets and ropes

Tripod


Day work =


Day work =

J-13

Sand or Gravel Fill

Concrete or Brick /BlockFoundation

Hardco re

Open jo in tedBrick/blockworkbelow 50 cm

All jo in ts fi lledwith mortar to adepth of 50 cm

Sand or Gravel Fil l

Concrete Foundation

Hardco re

PourousConcrete Rings

• Prepare a f lat and horizontal platform• Spread a PC sheet onto the ground• Construct a t imber shuttering, square or round• Place reinforcement (weldmesh or steel bars = Ø12mm

with a dis tance of 15 cm• Place wooden forms for squat and vent ilation pipe holes• Cas t concrete and trowel top. Ensure slope towards the

squat hole

thickness: 8 - 10 cm

• Prepare a f lat and horizontal platform• Spread a PC sheet onto the ground• Construct t imber shuttering, square, as shown above• Place reinforcement bars ( = 3 pieces Ø12mm per beam)• Place wooden forms for squat and vent ilation pipe holes• Cas t concrete and trowel top. Ensure s lope towards the

squat hole

ledge to form groove, 4cm/4cm

~ 35cm8cm

• Construct a t imber shuttering, as shown• Place reinforcement (weldmesh or s teel bars = Ø12mm

with a dis tance of 15 cm• Place wooden forms for squat and vent ilation pipe holes• Cas t concrete and trowel top. Ensure slope towards the

squat hole• The shuttering remains underneath the slab

t imber trusses .e.g. 7.5 x 12 cm

timber boards

Concrete Crownas Foundat ion

JOB SHEET

SANITATION PIT SLAB CONSTRUCTION

WORK METHOD for Septic Tanks:

Note: Although the latrine slab can be made of local material such as treated timber, reinforced (or unreinforced) concrete is better suited as it lasts longer, is safer and is easier to

clean. Where funds are available concrete slabs should be used.

Reinforced concrete slabs:

Alternative 1: Cast theslab close to the pit on ahorizontal platform cure slab shift slab to the top of the pit. Be careful, theslab is very heavy, forexample a 65 mm thickcircular slab with Ø 1500mm weighs approximately275 kg.

Alternative 2: Castreinforced concreteelements of 30 cm width(beams) cure placeover pit. This system isalso practical for biggerslabs, e.g. for double VIPs.

Alternative 3: Construct“lost shuttering” and castslab in situ (circular orrectangular). Curebefore use for 7 days.

Unreinforced domed concrete slabs:

Because of the slab shape noreinforcement is needed, so domedslabs are cheaper to construct. Thearrangements for forming the slabhave to be made accurately.

see detailed productionarrangements on the next page.

LABOUR:


Labourers


Sand, ballast and cementPVC plastic sheets

Timber (for shuttering)

Nails and wire

Masonry tools

Carpentry tools(for shuttering)

Shovels, watering can(f. mixing)

Concrete mixer (if available)

Concrete vibrator(if available)


Day work =


Day work =

J-14

CONSTRUCTION OF UNREINFORCED DOMED SLABS

CASTING: ARRANGEMENTS:

Source: Engineering in Emergencies, IT Publications.

J-15

JOB SHEET

SANITATION SUPERSTRUCTURE

WORK METHOD:

Note: Superstructures are required for pit latrines to ensure the privacy of the users. The construction standard depends on the funds available. In an urban setting, where latrines are extensively visited, it is advisable to construct permanent structures of good quality which can be easily cleaned and maintained. This job sheet describes a permanent structures built with bricks or cement blocks.

Construction:

Build walls with bricks or cement blocks along the edge of the slab (can be used as foundation).

Leave openings near the top inall 4 walls for ventilation andlight.

Add timber frame and door.

Plaster inside of cubicle wallswith cement mortar and trowelsmooth (for easy cleaning). Incase you need to economise,plaster only 100 cm from thebottom.

Point the joints outside andabove the plastered section of100 cm.

Fix ventilation pipe with flyscreen on top. Seal with Bondexaround the pipe on the roof andwith cement on the floor slab.

Provide a cover for the squathole (can be made from timber).

Paint walls and door if funds areavailable.

LABOUR:

1 Gang Leader

1 Mason

Labourers

TOOLS ANDEQUIPMENT:

MATERIAL:

Sand

Cement

Bricks or cementblocks

PVC pipe, Ø 12 cm

Wire mesh

Timber trusses

Corrugated ironsheets

Nails and wire

Timber door andframe

Tape measure

Plumb-bob

Masonry tools

Shovels

Watering can


Day work =


Day work =

J-16

Corrugated iron sheetroofon timber trusses

Fly screen

Ventilation pipe

Brick or cement blocks,inside plastered, min100cmhigh

Cross ventilationon all 4 walls

Concrete platforminfront ofdoor

JOB SHEET

SANITATION SEPTIC TANK CONSTRUCTION

WORK METHOD:

Note: There are various types of septic tanks that can be constructed. This job sheet describes the details of a common type. The size depends on the number of toilets which are connected to the septic tank, and the number of people using these toilets.

Construction:

Use the profile boards with wires and plumb bob to establish the 4 corners of the septic tank.

Establish the bottom level of the slab; use reference point from profile board.

Place hardcore layer of approximately 15 to 20 cm, compact well.

Add lean concrete layer of approximately 5 cm thickness.

Cast bottom slab (add crack reinforcement, e.g. weldmesh), trowel slab top smooth.

Construct lower concrete dividing wall; ensure that the wall can be tight into outside walls.

Construct outside walls, preferably using cement blocks. Leave grooves for the 2 baffles anddividing wall. Plaster walls inside if not made of concrete.

Construct the formwork for the 2 reinforced concrete baffles and the dividing wall and castconcrete.

Construct formwork for slab. Add reinforcement. Provide openings (manholes) for access, min. Ø 60 cm.Cast concrete, trowel top smooth and cure for 28 days. Remove the formwork from the slaband baffles.

LABOUR:

1 Gang Leader

1 Mason

Labourers


Hardcore, ballast, sand,cement and cement blocksWeld mesh, RE bars

In-/outlet “T” pipes

Timber for formwork

Nails and wire

Tape measure

Plumb-bob

Masonry toolsShovels

Watering can


Day work =


Day work =

J-17

J.5 Quality Control for Sanitation andDrainage Work

PROFILE TESTS

(i) Type of tests:Checks on the longitudinal and cross-sectional profile.

(ii) Methods used:Line-Levels and boning rods are used to control the levels. Straight edges and slopetemplates are used to control drain slopes (see module B5.1).

(iii) Rectification measures:Works that are found to be out of tolerance should be dismantled and re-laid.


1.) Excavation levels Line level siteslots,

minimumevery 10 m

+/- 1-2 cm

2.) Excavation slopes

Straight-edge,slope template

with spiritlevel

siteslots,

minimumevery 10 m

+/- 5°

3.) Blinding surface levelsLine level andboning rods

siteslots,

minimumevery 10 m

- 1-2c m

4.) Manhole/box culvert bottomslab levels

Line level andboning rods

siteslots,

minimumevery 10 m

+/- 0 cm

5.) Pipeline levelsLine level andboning rods

sitein/outlet ofeach pipe

+/- 0 cm

6.) Manhole cover levelsLine level andboning rods site

everymanhole +/- 1-2 cm


J-18

DIMENSION TESTS (drains, manholes, other structures)



(iii) Rectification measures:Correct dimensions of formwork before casting concrete. For masonry works lay first brickcourse and then confirm the dimensions.


1.) Width of excavation base tape siteevery slot,min. 10 m + 5 cm

2.) Width of concrete blinding tape site every slot,min. 10 m

+ 5 cm

3.) Structure’s cross-sectionaldimensions

tape,formwork

before castingsite every 3m +/- 5 cm

4.) Manhole dimensions tape siteeach

manhole +/- 0.5 cm

5.) In/outlet dimensions tape siteeach

manhole+/- 2-3 cm

6.) Construction lengths(expansion/construction joints)

tape site every joint +/- 1 cm

7.) Verticality of constructionelements

spirit leveland/or

plumb bobsite every 3 m +/- 1 cm

Note: Concrete and Mortar tests are shown in Chapters D and E respectively.

J-19



J-20

Chapter K:Work Management

K-1

K.1 Site Work PlanningIssues of consideration:

What are the activities to be done?

What quantities of work are to be carried out in each of these activities?

What productivity (guidelines) should be used?

What is the sequence (order) of carrying out these activities?

What is the amount of time available?

Overall, can resources be planned and utilised to the optimum?

Activities and sequence:

ItemType of

InfrastructureOperation Activities

1 All Supporting Setting out

Water carrying

MaintenanceCollecting rock

Collecting sand

Camp work

Tools repair

2 Clearing, stumping Removal of vegetation

Waste clearing

Grubbing

Stumping

3 Earthworks Excavation

Hauling

Spreading and compacting

4 Sppecific RoadActivities

Drainage Ditching and slopingSpreading

Camber formation

Mitre and catch water drains

Culvert outlet

5 Road structures Culverts

Drifts

Vented fords

Bridges

7 Road gravelling Excavation and loading

Hauling

Spreading and compacting

Road paving Bitumen sealing

Block & brick paving

Stone paving

Chapter K: Work Management

K-2

ItemType of

InfrastructureOperation Activities

8 Specific PipeLaying Activities

Pressure testing Pressure gauge

9 Pipe laying Pipe laying

10 Storm DrainWorks

Finishing Finishing drain bottom

Lining drain bottom andsides

Replacing top soil

11 Structures Constructing debris trap

Constructing sand trap

Constructing slabs overdrain

12 Sanitation Structures(Pit latrine)

Foundation works

Floor slab

Walling

Roofing

K-3


TASK RATES/PRODUCTIVITY RANGE

ACTIVITY TASK RATE REMARKS

Bush clearing Light bush200 – 250 m2/wd

Considering there is bush all over theclearing width.

Tree & stump removal daily paid Roughly 1 wd for every 20 cm Ø of tree.

Grubbing Light ground coverup to 5 cm thick 150 – 300 m2/wd

Considering grubbing the entire clearingarea.

Boulder removal daily paid From experience.

Slotting (for road base) 2 – 4 slots/wdCheck according to the volume ofearthwork.

Excavation only

Soft/loose soil 3 – 4 m3/wd

Maximum throwing distance of 4.0 m.Hard soil 2 – 3 m3/wd

Very hard soil 1 – 1.5 m3/wd

Excavation &loading

Soft/loose soil 3 – 3.5 m3/wd

Hard soil 1.75 – 2.5 m3/wd


Sloping

Soft/loose soil 3 – 4 m3/wd

Sloping includes shaping the slope to theright gradient, e.g. for drains.

Hard soil 2 – 3 m3/wd


Formation ofcamber (for roads)

First spreading 90 m2/wdSpread material from ditching or fromimported material.

Gravel excavationincluding loading

Normal weatheredmaterial

1.5 –2.5 m3/wd

Very hard materialwith boulders

1 - 1.5 m3/wd

Gravel spreading 0.20 m thick 50 – 70 m2/wd

Stone collection and loading 2.5 – 3 m3/wd

Sand collection and loading 3 – 4 m3/wd

Stone masonry 2 -2.5 m3/wdThis includes hand laying of the stonesonly. Mixing of mortar and preparation ofstones is not included.

Brick laying for walls8 – 10 m2/wd

This includes hand laying of the bricks only. Mixing of mortar and preparation of bricksis not included.

wd = worker day


K-4

Establishing Task Rates

Important factors to set task rates:

The difficulty of the work, e.g. soil hardness/wetness, bush thickness,throwing distances.

The condition of the tools.

The temperature/weather conditions.

The fitness/health of the labourers and their experience of work.

To decide a task rate for an activity follow this procedure:

Step 1 Set aside one day for a trial on the activity. Organise thelabourers on a day-work basis for this activity.

Step 2 Supervise the labourers closely, making sure that they all workhard for an eight-hour period.

Step 3 Stop works after eight hours and measure the quantity of workcompleted. Divide the quantity by the number of labourers onthe activity. This gives an average task rate for the activity.

Task rate = Total work completed in 8 hours Number of labourers on activity

Repeat this exercise frequently and adjust the task rate so that all labourers work on site for at least six hours a day.

Task rates are important – keep them fair!!

K-5


K.2 Site OrganisationCommon Organisational Structure:

Location of Site Office:

The site office for the Site Supervisor should include a store for materialsand tools, and provisions for a toilet.

There should be a source of clean water nearby.

It should be accessible to supervision and service vehicles.

It should be sited on high, well-drained ground.

It should be within walking distance of all the workers.

It should be sited away from known trouble spots.


K-6

Site Supervisor

Setting-outand Quality

Control

• Gang Leader• Labourers• Tools

Preparationand

Earthworks

• Gang Leader• Labourers• Tools

Structuresor

Pipe Layingor

Plumbing

• Gang Leader• Artisans• Labourers• Tools

Labour Recruitment:

A ballot system should be used to recruit the labour forcewhere more labourers apply for jobs than the number required.

The recruitment process should follow this procedure:

The recruitment of casual labourers for each site should be carried outat a public meeting, a week or two before the start of the actual sitework.

Casual labour force must be recruited from the population living inthe locality of the project.

Men and women should be equally eligible for employment and thepublic must be informed accordingly.

Secret ballot should be used for the recruitment exercise if the turn-outis greater than that required.

Each recruit should sign a casual employment contract form wherethe conditions of employment are clearly stated.

The recruitment has to be witnessed by the responsiblecommunity-based organisation and, if possible, the local authority,e.g. representative of the municipality.

When recruiting casual labourers, make it clear that they are beingemployed on a temporary basis and will be made redundant whenimprovement work on the road is complete.

Balloting:

Step 1: The number of workers needed is determined (A).

Step 2: The number of job seekers present is counted (B).Ballot papers are prepared as follows: “yes” papers equal to thenumber of jobs (A) and “no” papers equal to (B-A). These papersare folded and placed in a container.

Step 3: Each person who wants a job draws a ballot.

Step 4: Note down the names of people who draw ballot papers marked“yes”. These people will be recruited for the job. Draw up areserve list from those who draw ballot papers marked “no”.Tell each group when they are to report for work.

The conditions for employment must be made clear before theemployees are made to participate in the recruitment exercise.

Thereafter they have to sign a Casual Employment Form. An exampleis shown on the next page.


K-7

CASUAL EMPLOYMENT FORM

Name of Project Employment No:

Ref. No: Place and Date:

Name: Mr/Mrs/Ms

1. You are hereby offered employment with casual conditions as

..............................................................................................................................

with effect from .......................................................................................................

2. The terms and conditions of employment are as follows:

a. You will be paid Kshs .................. per day for an eight-hour working day or anequivalent task rate

You will not be paid for public holidays or any day not worked regardless of the reasoni.e. heavy rains, sickness, etc.

b. You will be paid at the end of each month for the days worked.

c. You are not entitled to annual leave, housing, transport or any allowances.

d. Your employment will be terminated by any of the following:

- at the end of the three-month period starting on the date mentioned above,

- at the completion of this project,

- when you absent yourself from work without permission from your supervisors,

- when you do not follow the instructions of your supervisors,

- when you behave in a disorderly manner.

e. You are responsible for any loss or damage of tools issued to you by your supervisors.

3. By signing this acceptance form you have agreed to the terms and conditions ofemployment set out above.

CBO/Company Name:

Site Supervisor: ............................................................ Date: ...............................

I have read (it has been read to me) and understood the above terms and I hereby accept thecasual employment on the terms and conditions of this form.

Signature of Employee: ................................................................................................


K-8

K.3 Work ImplementationStarting up a site:

The following points are important to remember when starting up asite:

Most labourers will have had no previous experience of infrastructureworks, so it is important that they are split into smaller groups so thatthey can be trained. Each group is to be led by a competent Gang Leader.

The site labour force should be increased gradually so that each group oflabourers can be trained individually and Gang Leaders selected. EachGang Leader should be trained to do one operation and be responsible forthat operation throughout the job.

At all times during improvement work the number of labourers working on each operation must be balanced with the difficulty and quantity of workfor each operation. If this balance is not correct, some operations willeither pull ahead or fall behind the others.

The site will be more difficult to supervise if the operations are spread outover a wide distance.

KEEP ALL OPERATIONS CLOSE TOGETHER AND SEQUENCE THEMIN THE LOGICAL ORDER!

Incentive schemes:

Day work: Labourers work for a fixed wage per day.

Piece work: Labourers work for a fixed amount per unit of work done.

Task work: Labourers are given a measured amount of work to do.They are then allowed to leave the site when the workhas been done to the satisfaction of the supervisor.

Bonus schemes: Labourers are paid extra reward for efficient work done.

The task-work system, if used fairly, is a very useful system because:

Each labourer has to do the same amount of work.

The labourers know that if they work hard they can leave the site earlier.

But, for the task-work system to work properly you must:

Measure the quantity of work to be done.

Choose a fair task rate of work to be done.

Peg out the tasks so that each labourer knows exactly what he must do.

Check the work of each labourer several times during the day and makesure it is being done properly.

K-9


K.4 Site Planning, Reporting and Monitoring

DAILY SITE OPERATION PLANNING & REPORTING FORM

Site Name: Date:

ActivityNo.

Activity description

Planned Actual Progress

Exp.output

Taskrate

Workerdays

Actualoutput

Workerdays

BeforeTo

date

1 Setting out

2 Preparation activities

2.1 Clearing + refuse removal

2.2 Grubbing

2.3 Top soil removal

2.4 Tree/stump removal

2.5 Boulder removal

Sub-total

3 Earthwork activities

3.1 Excavation (mass, e.g. road)

3.2 Excavation (drains and trenches)

3.3 Excavation (pits)

3.4 Sloping/backsloping

3.5 Shaping trench bed

3.6 Spreading material (camber etc.)

Sub-total

4 Drainage works

4.1 Placing prefabricated elements

4.2 Constructing drains (masonry)

4.3 Placing and filling gabions

4.4 Building scour checks

Sub-total

5 Structures

5.1 Constructing/casting foundations

5.2 Constructing walls (masonry)

5.3 Constructing concrete shuttering

5.4 Placing reinforcement

5.5 Casting concrete slaps and walls

5.6 Plastering walls, etc.

5.7 Installing culverts

5.8 Backfilling and compaction

Sub-total


K-10

DAILY SITE OPERATION PLANNING & REPORTING FORM (cont.d)

ActivityNo.

Activity description

Planned Actual Progress

Exp.output

Taskrate

Workerdays

Actualoutput

Workerdays

BeforeTo

date

6 Support activities

6.1 Support work

6.2 Repairs

Sub-total

7 Others

7.1

7.2

7.3

Sub-total

TOTAL

Site Supervisor’s Name Signed:

K-11


WEEKLY SITE RESOURCE PLAN AND REPORT

Project Name: Month:

Name of Site Supervisor: Date:

Itemno.

Resource Description Plan ActualWorking

DaysTotalActual

Remarks

1 Casual labourer

Men

Women

Gang Leader

Sub-total

2 Skilled Labour

Mason

Carpenter

Plumber

Operator

Blacksmith

Sub-total

3 Staff

Site Supervisor

Foreman

Sub-total

4 Equipment

Tractor

Truck

Trailer

Water bowser

Roller

Vibrator

Sub-total

5 POL Diesel Petrol Oil

Tractor

Truck

Roller

Vibrator

Sub-total

6 Material Unit Actual

Cement Bags

Steel No.

Pipes No.

Timber FT


K-12

MONTHLY PRODUCTIVITY SUMMARY FORM

Project Name: Month Ending:

Name of Site Supervisor: Date:

Operation

Input Output Productivity

RemarksResource Worker

daysUnit Target Achieved Unit Target Achieved

K-13



K-14

Chapter L:Community Contracting

L-1

L.1 Contract Types and Contracting PartiesConventional contracts:

The Client, either an authority or private, organisation/individual, makes anagreement with an Engineer (consultant)or Contract Manager to design a projectand to manage the contract. The clientfunds the project and retains the overallcontrol.

The Engineer/Contract Manager isusually a consultant and is in charge ofdesigning and supervising the project onbehalf of the client. For large projects,design and supervision is carried out bydifferent consultants.

An established Contractor, who isusually selected through a normaltendering process, carries out the work.The contractor is responsible for theexecution of the work.

The contractor hires labourers for thelabour activities. Very often labourers areemployed on casual terms, which meansthey can be hired and fired as required.

Chapter L: Community Contracting

L-2

Client

EstablishedContractor

Labourer

Engineer /Contract Manager

Community contracts:

The Funder is an agency thatprovides funds for the work to beundertaken.This can be a donor agency(bilateral, multilateral or NGO), agovernment department, aprivate company(eg. water company) or acombination of these. Thecommunities themselves can also contribute, either in terms oflabour and tools, or also withfunds.

The Contracting Authority is an agency that issues contracts tothe committee or grouprepresenting the community. This can be a governmentdepartment, an NGO or a projectteam. Communities can also berepresented in the contractingauthority.

The Contractor is responsible for the execution of the works. Incommunity contracting,preference is given to contractors from within the community suchas construction committees,youth groups, women's groups,etc.

The Contractor engageslabourers to carry out theworks. Labourers in communitycontracting are usually membersof the community in the projectarea to ensure that they benefitfrom the employmentopportunity.

L-3


Funder (Client)

Construction by Communitye.g. Community Construction, or

Local Project Committee

Labourer

Contracting Authoritye.g. government department,

NGO or project team

Contractor

Types of community contracts:

Depending on the skills and organisational capabilities of thecommunity, the availability of outside assistance, and the type ofconstruction work envisaged, the following contracts can be used:

Labour-only contracts: The community is only responsible for theprovision and organisation of the labour input. The client or externalassistance group is responsible for the timely provision of materials andequipment in sufficient quantity and quality.

Labour and material contracts: The community is responsible for boththe labour and material input for a certain construction activity. To keepthe contracts simple, the work is divided into well-defined tasks andcommunity contracts are issued for each task.

Full contract: Under a full contract the community provides the labour,material and the necessary equipment, and is also responsible for overallmanagement, subcontracts, etc.

L.2 Contract DocumentsThe structure of the documents for labour-based community works isthe same as for any other construction contract and usually consists of the following documents:

Documents Parts of Contract

1. Instructions to tenderers

Legal part of contract

2. Forms of tender, qualificationinformation, letter of acceptance,agreement

3. Conditions of contract

4. Contract data and schedules

5. Security forms

6. SpecificationsTechnical part of contract

7. Drawings

8. Bill of Quantities Financial part of contract

Contract documents for community contracting are kept as simple aspossible. Because there is usually no tendering process involved, acontract may only consist of the essential parts which describe thework, namely:

1. Specifications 3. Bill of Quantities

2. Drawings 4. Conditions of contract


L-4

L.3 Contract ProceduresStandard procedures for conventional contracts:

Step Explanation

1. Prequalification This is an invitation, usually in the press, for contractors to bid for a contract. Contractors may be shortlisted foran invitation depending on their past record or anyother specific conditions/criteria which the client mayprefer, e.g. contractor must be from a certain location,or have a certain size, etc. Interested contractors haveto submit records of past experience, previous clients,present staff, present plant and equipment fleet,current and future commitments, financial strength, etc.

2. Notice of Tender The contractors who meet the pre-qualification criteriaare identified and listed. The successful contractorsreceive the notice to collect tender documents againstpayment or a tender deposit. The deposit will not bereturned to contractors who fail to submit their tender.

3. Instructions toTenderers

Instructions are given together with the tenderdocuments and may consist of: instructions on how tocomplete the tender; address and time for submission;procedures on how to submit alternative tender;amount of security (as a bank guarantee); declarationof tenderer’s obligation of a site visit; information onsupplementary documents available; etc.

4. Tender Period The tender period is usually three months although forsmaller jobs the period may be shorter. Clarification oftender can be sought during the tender meeting whenthe bidding documents are issued or in writing at anytime during the tender period.

5. Tender Opening Tenders have to be submitted in sealed envelopes andon the date and time specified in the instructions totenderers. The submitted tenders are usually openedimmediately in the presence of the tenderers who wishto participate. The total sum of each tender is read,including the statement that the tender bond is in order(or not).

6. Tender Evaluation The appointed Engineer or the client scrutinises thetenders and prepares an evaluation report. Thefollowing evaluations are made: arithmetical checking of BQ; checking for any unacceptable reservations orconditions; evaluating alternative tenders (if any);evaluating foreign currency requirements; evaluatingthe work programme and construction methods;evaluating the proposed equipment to be used;checking the degree of subcontracting and qualifications of subcontractors; checking for unbalanced tender;comparison of tender sum with Engineer’s estimates.


L-5

Step Explanation

7. Winning Tender Award of Contract

Usually the lowest tenderer is selected. A letter ofacceptance is issued to the winning tenderer after theclient has accepted the evaluation report. Thecontractor must produce a bank guarantee (usually 5%of tender sum) when signing the contract. After thecontract is signed, the Engineer issues an order to startwork.

8. ContractImplementation

The contractor carries out the work under thesupervision of the Engineer. The supervisory procedures are specified in the contract and include, among others: quality control, progress control, cost control, taking ofmeasurements, preparation of payment certificates,reporting.

9. Completion ofContract

After a specified guarantee period there is a finalinspection, and the maintenance certificate is issued, ifthere are no shortcomings that can be blamed on thecontractor. The last half of the retention money and the performance bond can now be released.


L-6

Checklist: Procedures for community operated contracts:

Steps Outputs/Results

Step 1 Legally registered representative committee from the communitywith an operating bank account.

Step 1a Community has agreed priorities for improvements to their livingenvironment.

Step 1b General agreement signed for assistance with survey and designwork.

Step 2 Community priorities confirmed or re-defined.Community action plan developed.

Step 3 Initial inspection carried out, and the types of assistance requiredagreed upon.

Step 4 Outline of appropriate levels and position of services agreed.

Step 5 Plans, designs, quantities, costing and workplan all prepared in anaccessible format, including proposals for cost sharing between thefunder and the community.The wider community informed of proposals.

Step 5a Maintenance plan prepared, discussed and agreed.

Step 5b Plans thoroughly discussed and understood by the community.

Step 6 Funding agreed upon.

Step 7 Training needs assessment carried out.

Step 8 Workplan prepared with areas for assistance clearly marked.

Step 9 Community contracts understood.

Step 9a Approval for scheme given by relevant authority.

Step 10 Construction Committee (CC) formed.

Step 11 A signed Community Contract Agreement.

Step 12 First subcontracts prepared.

Step 13 Workers fairly recruited.

Step 14 Storekeeper recruited and trained.Appropriate tools and materials purchased.Equipment hired or purchased as appropriate.

Step 15 Construction work started.On-the-job training carried out.

Step 16 First subcontract or measured section of work completed and paidfor.

Step 17 Payment of subcontract sum including profit.

Step 18 Infrastructure completed.

Step 19 Funds used for agreed community purpose.

Step 20 Operation and maintenance implemented.

Step 21 Community well informed about the infrastructure improvements.

Step 21a Monitoring and evaluation of the process and achievements carriedout.

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L-8

Chapter M:Labour Issues

M-1

M.1 Labour Laws and RegulationsSome important labour standards relevant to labour-based technologyare such as those dealing with:

Equality

Freedom from forced labour

Freedom of association

Minimum age

Minimum wages

Protection of wages

Safety and health

Other employment conditions

Equality:

Men and women should receive equal pay for work of equal value.

Persons should be given equality of opportunity and treatment inemployment and occupation. There should be no discrimination againstpersons in their employment and occupation on the basis of their race,colour, sex, religion, political opinion, national extraction or social origin, oron any other basis set out in national legislation.

Freedom from forced labour:

Work or service should not be exacted from any person under the menaceof penalty or under circumstances where the person has not offered himselfor herself voluntarily.

Work or service should not be exacted from any person:

as a means of political coercion;

as a method of mobilizing and using labour for purposes of economicdevelopment;

as a means of labour discipline;

as a punishment for having participated in strikes;

as a means of racial, social, national or religious discrimination.

Chapter M: Labour Issues

M-2

Freedom of association:

What steps can be taken to protect, respect and promote workers',employers' and the community’s rights of association?

The following have to be considered:

national laws on rights of association;

international obligations on rights of association;

relevant associations;

prevailing attitudes towards rights of association;

practical impediments to the exercise of these rights;

benefits derived by various groups if they form organizations.

Minimum age:

No person under the age of 15 should be employed or work.No person under the age of 18 should be employed or work in hazardouscircumstances.

Minimum wages:

Minimum wages should be established for groups of wage earners where, in consultation with employers' and workers' organizations, the competentnational authority finds it appropriate. Minimum wages, where they exist,should have the force of law and should not be subjected to abatement.Failure to pay minimum wages should be subject to penal or othersanctions.

Protection of wages:

Wages should be paid in cash. Where wages are paid partially in the form of allowances in kind, such allowances should be appropriate for the personaluse and benefit for the worker and his or her family, and fair value shouldbe attributed to such allowances. Employers should not limit in any way theworkers` freedom in using wages. Workers should be informed of anydeduction made from wages, and national regulation should set downcondition for deductions from wages. Wages should be paid regularly at ornear the place of work.

Safety and health:

All appropriate precautions shall be taken to ensure that all work places aresafe and without risk of injury to the safety and health of workers. Workersshall have the right and the duty at any work place to participate inensuring safe working conditions to the extend of their control over theequipment and the methods of work and to express views on the workingprocedures adopted as they may affect safety and health.

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Other employment conditions:

As a matter of principle, the forty-hour work week is approved, and is tobe applied to prescribed classes of employment.

Employed persons should receive a holiday with pay of at least threeweeks duration for one year of service. A country may set a minimumqualification period of employment for entitlement to the holiday (andrules of its calculation), but it shall be no more than six months.

Women employed should be given special attention during pregnancy andafter confinement. They should not be dismissed during absence relatedto confinement and maternity.

Working hours should not ordinarily exceed eight hours in a day and 48 in a week. Workers should ordinarily have at least 24 consecutive hours restevery seven working days.

To ensure that contractors and/or CBOs respect labour regulations,construction contracts include contract clauses that requirecontractors/CBOs to apply the conditions of employment whichprevail in the country where the work is being done.

Penalties are often imposed where this provision is not respected.

M.2 Labour Recruitment & RemunerationRecruitment for jobs should be conducted in a manner thatensures:

Impartial and transparent methods e.g. lottery system/ secret ballotmethod.

No distinctions such as gender, political opinion, ethnic or social origins orany other criteria not related to the ability to do the job.

No force or threat of any nature.

Enough open publicity about impending recruitment.

Before an actual recruitment exercise is conducted, publicityabout recruitment for jobs should be made. This publicityshould:

Be made well in advance of recruitment.

Be aimed at all segments of communities.

Give full information about the jobs and terms of employment.

State that all male and female workers above the minimum age arewelcome to apply/participate.


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Principles of fair working conditions:

The recruitment and employment procedures that will be adopted have tobe first discussed and agreed on with the community-based organisationand/or the small contractor.

Conditions of employment have to be worked out beforehand and agreedon with all parties concerned. This requires awareness of internationallabour laws and regulations to be applied.

In principle, the people to benefit from project employment should be thepeople living within the project area. Specialised personnel, like craftsmen and technicians, may be hired from elsewhere if they cannot be found inthe project area.

The lottery system:

The opening of recruitment is widely advertised by signs, word of mouth,etc. A date and place is set for the recruitment.

All persons who would like to have a job during the project place theirname on a piece of paper. All names are collected in a container. Aneutral person selects the names out of the container one at a time andthe names are written down in the order in which they are drawn. Persons are then offered a job in the order in which their names were selected.

Adaptations that can be made:

Limitations of those who can participate can be based on: where they live(close to the project); previous unemployment; households with singleadult heads; etc. Household names are used instead of individuals.

Payment:3

1. Time-based

The worker is paid on the basis of how much time he or she is present atthe place of work. This can be the “daily-paid” system.

2. Productivity-based

The worker is paid on the basis of how much he or she produces. This can be the “piece-work” or the “task-work” system.

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3 In works clearly defined as community works, e.g. with a direct benefit to thecommunity, it is possible that the community contribution to a project is provided inkind (e.g. in labour days). See training module B-3 on community resources.

Daily paid (time-based):

The worker is paid a fixed sum each day in return for working a fixednumber of hours during that day. The number of hours, number ofbreaks, start and finish time are established.

Production is assured by supervision and by disciplinary measures forworkers who do not produce.

One day’s worth; no assurance of quantity.

Easy book-keeping, simple to organize.

High amount of supervision required to maintain reasonable output. Rateof progress can be extremely variable.

Piece work (productivity-based):

The worker is paid on the basis of small quantities or pieces of output.There is no reference made to the amount of time it takes to accomplishone piece.

Production is assured as payment is made only upon production.

Many pieces, usually unlimited.

Pay relates to output and output can be maximized each day.

Tendency to self-exploitation as no limit is placed on the amount of worka worker can do. Difficult to control by government administration.

Task work (productivity-based):

The worker is paid a fixed wage in return for a fixed quantity of work ortask. The size of the task is usually set to be accomplished in eight hours.The size of a task may be smaller and more tasks may be given in asingle day; the smaller the task the more like piece work. The size of thetask may be large, set to be accomplished over several working days andperhaps with several other workers.

Production is assured as payment is made only upon production.Adaptations are common.

Usually one task. Where the task is small, usually 2 or 3 per day; wherethe task is larger, a fraction of one task a day. A rule may limit thenumber of tasks which may be done in one working day.

Where a task is set properly, it allows typical worker to finish the task and go home.

Requires close supervision and monitoring in the daily laying out of workand overall setting of task size. When deviations are made from the usualmodel, particularly as regard the amount of work (number of tasks andportions of tasks) which can be done every day, there is a possibility ofexploitation.


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What is payment in kind?

Most workers like to be paid in cash money. However, for a number ofreasons:

They may be offered things of value other than cash money, or

they may actually prefer to receive things other than cash money for their work – for example food, particularly where it is scarce.

Why is it important for workers to be paid correctly in time andamount?

Correct and timely wage payments keep labour-based infrastructureprogrammes working. Without them:

Project progress can be seriously slowed or stopped because of labourproblems and strikes

Project costs go up because of delayed production

The quality of the final infrastructure can go down because workers andsupervisors lose motivation to produce high quality work

The social objective of providing gainful employment is weakened or lost,and

The continued use of labour-based methods is threatened.

M.3 Safety and Health on SiteEssential safety measures:

First-aid kit to be on site!

Protective goggles for stone cutting, chiselling, grinding, andwelding.

Gloves and other protective clothing such as boots for handlingchemicals, waste and other hazardous material.

Face masks when working in dust and smouldering waste.

Helmets when working on sites where there is a danger of fallingobjects, e.g. in deep drains, digging pit latrines, work in quarries,etc.

The Site Supervisor should also know where the nearest hospital/clinic is and where an ambulance or quick transport can be found.

It is also advisable that the Site Supervisor has first-aidknowledge.

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Special safety measures are required when deep trenches have to bedug, for example for water or sanitation pipes. In an urban environment the space is often restricted and it is not possible to dig trenches with safeslopes. Depending on the material (natural soil slope) and the depth of thetrench strutting will be required to avoid collapsing trench sides. Theconstruction of strutting has to be done carefully and required anexperienced builder.

Essential health measures:

Sufficient and clean drinking water to be on site.

Latrines on or near site to be available for the workers.

No alcoholic drinks or drugs during work.


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