sap_pm_chap2

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Classifying plant

maintenance1 from a

business perspective

CHAPTER 2

DEFINITIONS

In bu sin ess adm inistration, plan t m ainten an ce is tradition ally classified as part of p

duction (Nolden 1996; Hartmann 1995). The following definitions are intendedillustrate th e m an y diverse ways of evaluatin g plant m aint enan ce, as well as the d if

en t objectives th ese en tail.

2.1.1 Plant maintenance to DIN 31051

Accordin g to th e Germ an stan dard DIN 31051, plan t m ainten an ce com prises all m e

ures for maintaining and restoring the target condition as well as determining a

assessing th e actual con dition of th e tech n ical equ ipm ent in a system . Th ese m easu

are subd ivided in to

Preventive m aintenan ce

2.1

5

1 We wish to express our th anks to Ms Renate Som m er (Business Adm inistration s Departm

University of Applied Scien ces Coburg) for advice on th e business adm inistration aspects of

chapter. In n um erous discussions, Ms Som m er established th e links between tradition al b

ness adm inistration and applied plant mainten ance.


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Inspection

Repairs

Preventive maint enan ce com prises all m easures for maintain ing th e target cond ition of

th e tech n ical equipm ent in a system . In addition to t h e maint enan ce task itself, this

includes creatin g main ten an ce plan s wh ich are used to carry out th e PM tasks at regu-

lar intervals.

Inspection comprises measures for assessing the actual condition of the technical

equipm ent in a system . Th is also in cludes creating a plan for determin ing th e actual

cond ition , with in form ation on th e in spection d ate, m etho d an d tasks, as well as on th e

use of technical equipment. An inspection is carried out on the basis of the plan; in

other words, specific characteristics are determined quantitatively. These results are

th en evaluated an d an y necessary PM tasks deduced.

Repairs com prise m easures for restorin g th e target con dition of th e techn ical equip-

m ent in a system . Th is process in cludes th e actual order, order docum entation , and

analysis of th e order conten t. During order plann ing, alternative solutions shou ld be

isolated and evaluated to enable the best possible solution to be found. Preparing to

execute tasks com prises costing, sch edulin g, provision of person n el, fun ds and m aterial,

as well as creating m ainten an ce task lists. After the t asks h ave been com pleted, a fun c-

t ional test , acceptance inspection, notification of completion, and evaluation

(including documentation, cost monitoring, and indication of suggested improve-

m ent s or preven tive measures) are carried ou t.

2.1.2 System-oriented plant maintenance

Wh ereas DIN 31051 ap plies to th e in dividual parts of a system an d associated m easures,

system -orien ted p lan t m ain tenan ce focuses on safeguardin g th e functionin g of a pro-

du ction system as a who le. Plan t m ainten an ce in th is sense belon gs to system logistics,

th e primary goals of which are plann ing, creating and m aintain ing system availability.

System availability is planned taking the maximality and minimality principles into

consideration.

The maximality principle aims at achieving the maximum possible yield from a

given resource (yield maximization). For further information on this principle, see

Schierenb eck (1995). Th e PM budget, for examp le, is a given qu an tity an d is inten ded

to ensure t h e h igh est possible level of system availability. By con trast, th e m inim ality

prin ciple aims at keepin g th e resource required to achieve a particular result as low as

possible (expen diture or cost m inim ization ). For exam ple, a particular system is to be

m aintain ed twice a year at as low a cost as possible. To en sure an o ptim um relation ship

between PM costs and system availability, th e extremu m prin ciple is used. This aim s at

achieving the most favourable relationship possible between yield and expenditure.

Yield and expenditure are optimized when the maintenance costs, as well as costs

incurred through loss of outp ut, are reduced to a m inimu m .

SAP R/ 3 PLAN T M AIN TEN AN CE6


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disposal of materials. The purpose of plant maintenance is to ensure the avail-

ability of operation al facilities at a m inim al cost. (Ind ex entry plan t m aint en an ce

in Sokiano s (1998))

2.1.4 Malfunction and breakdown

Whereas inspection and preventive maintenance are carried out on a functioning

system, repairs presuppose a malfunction or breakdown.

A m alfunction (or defect) is an un wanted in terruption to or imp airmen t of th e cor-

rect fun ctionin g of a un it; th is defin ition does no t take the cause of th e malfunction

into accoun t. A m alfun ction can take th e form of a brief interruption . Th e terms

m alfun ction an d breakdown are often defin ed in such a way that a breakdown is

caused by factors in th e actual un it in question. In th e even t of a malfun ction , a

un it can con tinue t o carry out its required function (a ventilator filled with dust

or leaves is an exam ple of a malfun ction , no t a breakdown ). A breakdown always

impl ies a malfun ct ion, n ot vice versa . (Hubert Becker: Grundbegri ffe .

http://home.t-online.de/home/becker2/log3_1_1.htm)

Th e criteria according t o wh ich breakdown s can be classified include

The life cycle of th e system

Th e particular form breakdown s take

Th e logical sequen ce of breakdown s

In th e life cycle of a system, th ere are th ree breakdown ph ases:

1. Early breakdown ph ase; for exam ple, due to incorrect operation or m aterial weak-

nesses

2. Random breakdown ph ase during consolidation; for example, due to vibration or

fluctu ation s in pressure, temp erature, load, or voltage

3. Late breakdown ph ase; for example, due to aging, wear and tear, or fat igue

Depending on the particular form they take, breakdowns are classified either as

tot al or partial. For examp le, if on e mo tor breaks down in a system com prisin g a total

of th ree mot ors, th is is con sidered a partial breakdown .

The logical sequence of breakdowns can be used to distinguish primary and sec-

ondary breakdowns, as well as breakdowns with a common cause. A primary

breakdown is the breakdown of a unit due to a failure in the unit itself. In the case of

a secondary breakdown, th e un it eith er breaks down due to th e failure of an u pstream

unit or has to be deactivated for safety reasons. A breakdown with a common cause

invo lves several un its breaking do wn sim ultan eously.



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Documenting and analysing breakdowns is one important task of pl

m aint en an ce. In th is con text, th e techn ical breakdown (failure) rate in VDI (Associat

of Germ an En gineers) Guideline 289 3 is particularly sign ifican t.

Th e techn ical downt ime com prises all th e down times attributable to t ech n ical m

functions. According to VDI Guidelin e 3423, the target run n ing time is the run n

tim e of a mach ine (accordin g to capital in vestmen t plan n ing, for examp le). Th e agof a unit can be deduced from the characteristic of the technical breakdown rate

oth er words, if th e techn ical breakdown rate increases, scrappin g a un it could, in c

tain circumstances, entail lower costs than maintaining it.

TRADI TIO N AL FORM S OF ORGAN IZ ATI ON IN PLANTMAINTENANCE

2.2.1 Plant maintenance in line organization

Line organization is the oldest and most basic form of organization (Steinbuch 19

172ff). The characteristic features of line organization are:

Cent ralization of tasks

Simp le subordin ation

Full auth ority on ly

In line organization , each job is allocated on ly one m anager, and each m anager has s

eral subordin ate mem bers of staff. Th is is a form of organization in wh ich th e man a

plays an auth oritarian role and each m em ber of staff is answerable to on ly one leve

auth ority. In oth er words, every PM techn ician is an swerable to th e PM m an ager. Lorganization is the most common organizational form in small and medium-siz

comp anies, in which all decisions are made by on e person .

The advantages of this form of organization include unambiguous relationsh

between superiors and subordinates, uniform chan n els for comm un ication and rep

ing, as well as clear demarcation of tasks, authority and responsibility. T

respon sibility of th e m an ager for th e decision process ensures th at all process steps

be int erpreted easily, and facilitates con trol an d sup ervision of m em bers of staff.

One of the disadvantages of line organization is the excessive load it puts

m anagemen t. Th e emph asis on h ierarchical thin kin g hind ers cooperation betw

m em bers of staff and also run s the risk of increasin g bureaucracy. With lin e orga

zation , a limited n um ber of in termediate auth orities results in a broad organizatio

plan an d, th erefore, large span s of con trol. A large nu m ber of int erm ediate auth

ties in l ine organization, however, results in long communication and report

paths.

Figure 2.1 illustrates plant m ainten an ce in lin e organization as a subarea of prod

tion. The PM manager is subordinate to the production manager here. Figure

2.2

CLASSIFYIN G PLANT M AIN TEN AN CE FROM A BUSIN ESS PERSPECTIVE 9


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illustrates plant maintenance as a separate area on a par with production. The PM

m anager here shares the same h ierarchical level as the produ ction m anager, and both

are subordinate to the corporate m anagemen t.

2.2.2 Plant maintenance in the line-staff organization structure

To relieve the excessive load on management staff, which is a disadvantage of line

organization, this organization structure assigns authority to staff units (Steinbuch

1997: 173ff). These staff units do not usually have competence to issue instructions;

their tasks are, rather, in the areas of decision preparation, planning and support, as

well as m on itoring. A ch aracteristic feature o f th e line-staff organ ization al structure is

its separation of decision-m akin g powers (for exam ple, of th e produ ction m an ager) an d

the expert knowledge of the staff (for example, of the PM manager and his staff).

Furth er characteristic features of th is organ ization al form are:

Cen tralization o f tasks

Simp le subordin ation

Full and p artial auth ority

In ad dition to relievin g man agemen t staff, th e advant ages of the line-staff organization

structure include improved decision quality by incorporating specialists, the uniform


Plant Maintenance Production

Management

Workshops

Planning

Part Production

Assembly (Process)

Plant maintenance in line organization as a separate area ( SAP AG)FIGURE 2.2

Production Sales

Management

Plant Maintenance

Part Production

Assembly (Process)

Procurement Administration

Plant maintenance in line organization as a subarea of production

( SAPAG)

FIGURE 2.1


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line of command and communication channel, as well as the clear demarcation

responsibility.

The disadvantages of this organizational form include the potential for confl

between th e lin e position and th e staff un it assigned t o it (for examp le, between

produ ction m an ager and th e PM m an ager), the dan ger of staff un its becomin g too la

for th e lin e position , as well as th e possibility of th e staff un it usin g its specialist knoedge m an ipulatively.

As a rule, th e staff un its in plant m aintenan ce are entrusted with long-term plan

n ing tasks, such as drawing up m aint enan ce strategies for in dividual produ ction

plants, creating budgets, determinin g personn el capacity, elaborating m ainte

n ance task lists, and adm inisterin g and m ain taining th e plan t m ain tenan ce data

(Grobholz 1988: 84ff)

The plan n ed PM tasks can actually be carried ou t eith er by th e specialists of th e PM s

unit, or by production staff. External processing (outsourcing) managed by the sun it is also con ceivable. Figure 2.3 represent s plant m aint en an ce as a staff un it assign

to th e lin e position Produ ction .

2.2.3 Plant maintenance in matrix organization

With m atrix organization , specific fun ctions are no t assigned to th e business areas

are carried ou t cent rally for th e entire com pan y (Steinb uch 1997: 185ff). Cen tral dep

ments are set up for this purpose and carry out their tasks for all business areas. A

secon d level, a ho rizon tal fun ctional organization is com bined with t h is vertical org

ization o f business areas, th ereby creatin g a mat rix. Th e characteristic features of m a

organization are:

Cent ralization of objects

Multiple subordination

Full auth ority, or partial and full auth ority


ManagementOrganization

staff unit

Plant maintenance

staff unit

Production

Plant maintenance in the line-staff organization structure ( SAP AG)FIGURE 2.3


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This organizational form is primarily used by large companies which have diverse

produ ct groups, a marketin g orien tation an d h igh m anagemen t poten tial.

Som e of th e advan tages of m atrix organ ization are th at it safeguards corporate un ity,

generally confers th e advan tages of specialization , relieves th e strain on m an agemen t,

an d p rovides a large variety of respon se option s.

Th e disadvantages of matrix organ ization , ho wever, in clude th e risk of con flict dueto m ultiple subordin ation, th e danger of ent erin g in to un satisfactory com prom ises, the

ten den cy towards greater bureaucracy, as well as high costs due t o th e large nu m ber of

managers required.

Within m atrix organization th e PM un it th at carries out th e m ain tenan ce tasks is

assign ed to th e (horizont al) central Mainten an ce division , as well as to th e vertical divi-

sion of the relevant product group (Grobholz 1988: 35ff). In general, strategic PM

planning is located in the central division, while the vertical divisions carry out PM

plan n ing for th eir prod uct d ivision an d also perform th e PM tasks. Figure 2.4 sho ws an

example of th e cen tral Production and Plant Mainten ance division s for th ree product

divisions.

2.2.4 Classification of external plant maintenance

Generally speakin g, in ternal plant m ain tenan ce can be combin ed with external plant

m ain tenan ce (outsourcin g) in all of the t h ree tradition al form s of organization . In th is

case, th e maint enan ce departmen t is respon sible for plann ing and m on itorin g the PM

measures but not for carrying them out. Of course, it is also possible to transfer

plann ing, con trol and execution o f m ainten ance tasks ent irely to th e external provider.


Management

Product Division 1 Product Division 2 Product Division 3

Production

Central Division

Plant Maintenance

Central Division

Plant maintenance in matrix organization ( SAP AG)FIGURE 2.4


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In all th ree organization al form s, external plant m ainten an ce can result in lean er str

tures. Figure 2.5 illustrates th e structu re of in tegrated fixed-asset man agemen t an d

inclusion of internal and external plant m ain tenan ce.

If m ainten ance is placed at th e core of this type of fixed-asset m an agem ent , it i

clear that choosing between internal and external maintenance has conse-quences not only for the area of maintenance, but for al l of the remaining

activities in fixed-asset management. Depending on the particular tasks carried

out by fixed-asset management, these consequences can affect the planning

execution, and control of the various activit ies in fixed-asset management

(Grobholz 1988: 54)

The evaluation technique used in decision making can be applied as a basis

deciding for or against external plant m ainten an ce. Th is techn ique centres on cre

ing a value profile which comprises the variables criterion, weighting, degree

fulfilment, and evaluation. Specific criteria are assigned a weighting from 110, example. In addition to this, the degree of fulfilment is specified; in other wor

wh ich m ainten an ce provider fulfils which criterion , and to wh at extent. The exter

maintenance provider is then evaluated on the basis of the criteria, weighting, a

degree of fulfilm en t. Multip lying th e values in th e Weigh tin g an d Degree of fu

ment columns yields values per line, the sum of which constitutes the final val

Comparing the final values for the various external maintenance providers with

final value for internal plant maintenance provides a basis for deciding whet

external plant maintenance is a viable option and, if so, which external provi

should be com m ission ed.

Th e following criteria can be used for decision m aking (Grobh olz 1988: 66ff):


Asset provision

Internal plant

maintenance

External plant

maintenance

Asset

usage

Asset

modernization

Asset decommissioning and replacement

Asset accounting and management

Asset planning and design

Integrated fixed-asset management (from Grobholz 1988: 55) ( SAP FIGURE 2.5


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Quality

Deployment of well-trained specialists; use of precision tools; experience with

similar cases; selection of repairs, spare part s, repairable spares and op eratin g sup -

plies appro priate to th e specific dem an ds involved; procedure in accordan ce with

state-of-th e-art techn ology.

TimeTime savings du ring execution of m easures by m eans of dep loying specialists in

parallel; use of plann ed down times in prod uction.

Capacity

Imp roved utilization of in tern al plant m ainten an ce capacities; intern al PM capac-

ities relieved of routine tasks; short-term and cost-saving satisfaction of peak

dem an d for PM activities.

Elasticity

External PM provider adapts to m eet fluctuation s in dem and and chan ges in type

of PM requirement.

Planning

Plan n ing o n th e basis of data provided by system user (wear-an d-tear profiles, life-

tim e statistics and o peratin g efficien cy analyses); determ ination of optim um PM

strategy for th e system user.

Information processing

Developm en t an d/ or m ainten an ce of specific software for IT-assisted p lant m ain-

ten an ce; ent ry of existin g PM data.

Provision and storage

Provision of spare parts, repair materials, repairable spares and repair operating

supplies; knowledge of input /procuremen t m arket for spare parts, and so on .Finance

Funds required remain constant due to long-term service contracts.

Safety, environm ental protection and industrial safety

Elim ination of risks to p erson n el, such as risk of intern al specialists being u n avail-

able due to illness or accident; warranty confirmations and good-will services;

improved industrial safety and accident prevention by adopting tried-and-tested

concepts; transfer of waste disposal issues.

Hum an resources

Reduction in staffing requirements; reduction in internal training measures.

Organization

Improved process structure in plant maintenance; centralization of decision-

m akin g auth ority.

Costs

Avoidance of overtime; elimination of reworking costs by means of warranty

claims; falling fixed costs; cost-saving execution via plant-scale/quantity reductions.

12

11

10

9

8

7

6

5

4

3

2

1



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PLAN N IN G IN PLAN T M AINTENAN CE

2.3.1 Planning and control

Planning in plant maintenance comprises all activities, tasks and actions, proc

flows, tech n ical data, econ om ic criteria an d costs, wh ich affect th e labour prod uctiv

of the plant m aintenan ce departmen t and th e adjoining enterprise areas or the en

prise as a whole (Grobholz 1988: 38).

2.3


Your company operates an ice-cream production plant. You are planning external mainte

nance for the cooling systems in this plant, since these require highly specialize

maintenance and sophisticated precision tools. You now have the task of creating a valu

profile for selecting the most suitable external maintenance provider.

You choose quality, time, elasticity, planning, corporate finance, safety/environmental protection/ industrial safety, human resources, and costs as criteria with a high weight ing. Sinc

you consider support during PM planning and saving training costs to be less important, yo

assign these criteria a weighting of 5 on a scale of 110. You consider environmental pro

tection to be very important for the cooling system, since you also intend to transfer dispos

of the coolant to the external maintenance provider. You consider it equally important t

conclude a long-term service contract with favourable conditions, and therefore assig

these criteria a weighting of 10. You assign all the remaining criteria a weighting of 8. Tab

2.1 illustrates the resulting value profile with entries for an external maintenance compan

X. In this way, you can evaluate the potential external maintenance providers, and decide o

the company with the highest final value.

EXAMPLE

Value profile for an external maintenance providerTABLE 2.1

Criterion Weighting Degree of Evaluation of

fulfilment company X

(from 2 to +2)

Quality 8 +1 +8

Time 8 1 8

Elasticity 8 1 8

Planning 5 +1 +5

Finance 10 +2 +20

Environmental protection 10 +1 +10

Human resources 5 1 5

Costs 8 +1 +8

Final val.: +30


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Con trol in plant m ain tenan ce comprises order-related sch edulin g and capacity

determination, as well as monitoring the execution of PM tasks. Whereas planning is

inten ded for th e m edium or long term, con trol is always short-term in n ature. Figure

2.6 sh ows how p lann ing an d con trol in teract in th e order processing cycle.


Strategy

Budget

Provision of

personnel and material

Process flow

Planning

Analysis of results in

conjunction with

Construction

Procurement

Quality assurance

Production

Planning

Control

Control

Execution

Scheduling

Capacity requirements

a planning

Task monitoring

Variance analysis

Order placement

Planning and control ( SAP AG)FIGURE 2.6

PM plan

Materials plan Personnel plan Staff plan

Inspection

plan

Maintenance

plan

Repair

plan

Cost/activity

plan (budget)

Plan for

expenditure on plant

replacements

Strategy

plan

Monetary

plans

Quantity

schedules

Operational

plan

Strategy plans (from Grobholz 1988: 40) ( SAP AG)FIGURE 2.7


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2.3.2 Strategy plans and maintenance task lists

On th e basis of Recom m end ation No. 10 of the Deutscher Kom itee fr Instandh altu

(DKIN: German Com m ittee for Mainten ance), a distin ction is drawn in plant m ain

n ance between strategic plann ing an d work scheduling using m ain tenan ce task li

Strategy plans are always created for the medium term or long term, and apply t

cycle or a period of time. By con trast, main ten an ce task lists are sh ort-term in n atu

an d app ly to a specific date.

Strategic plan n ing in cludes creating th e operation al plans (activities: prevent ive

m aintenan ce, inspection, repair), th e quan tity schedules (th e person n el plan a

well as the materials plan including the machine and equipment plan), the

cost/performan ce plans, an d th e strategic overall plan . (Grobh olz 1988: 40)

Figure 2.7 shows th e strategy plan s in con text.

The maintenance task list is the instrument for controlling the PM tasks and

based on the operational plans. For example, a maintenance task l ist based o

repair plan con tains detailed in structions on repair tasks as well as in formation c

cerning the execution date. After the repair tasks have been executed,

m ainten an ce task list is return ed to t h e preparation stage to allow an an alysis to

carried out during planning. Figure 2.8 shows the work scheduling cycle in pl

maintenance.


Execution

Control

Maintenance task list

Material slipWork slip

Work scheduling

Operational plan, personnel plan, materials plan

Work scheduling (from Grobholz 1988: 41) ( SAP AG)FIGURE 2.8


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PLANT M AIN TEN ANCE M ETHOD S

2.4.1 Damage-based plant maintenance

Th e dam age-based m ethod of plant m ain tenan ce (in extreme cases, also known as the

breakdown or run-to-failure method) is characterized by the fact that no preventive

m ainten an ce is carried out . System com pon en ts are in stalled with n o PM ou tlay, worn

out, an d replaced comp letely in th e event of a malfun ction .

The damage-based plant maintenance method is financially viable, therefore, only

un der the following conditions:

If th e system com pon ent s in volved cost con siderably less to acquire than to m aintain.

If system comp on ents involved present n o dan ger to either prod uction o r safety in

the event of a breakdown, and can be repaired without significant outlay (for

example, with out shu tting down th e system).

If th e system com po n ent s in volved h ave a limited service life that it is neith er fea-

sible nor desirable to extend (n o refurbishm en t).

Th e busin ess process for this meth od begins with th e not ification th at a m alfun ction

has occurred. The second step involves specifying the nature of the malfunction. The

PM plann er respon sible can either ask the n otification creator for m ore details or in ves-

tigate the malfunction himself. If the notification creator is a PM technician, he can

also specify the nature of the malfunction himself in the second step. As soon as the

details have been established, plann ing an d con trol of the repair task can be carried ou t.

Th e amou n t of time available for plann ing and control varies depen ding on th e sever-

ity of the m alfun ction an d its effects on prod uction . If sufficien t tim e is available, th ePM plann er can specify repairable spares, workflows, or th e too ls to be u sed. If little

time is available, the PM planner provides a PM technician with a roughly specified

work order.

In t h e event o f serious m alfun ctions, th is sequen ce can also be reversed. In t h is case,

th e repair is perform ed first, and o fficial no tification an d specification of th e m alfun c-

tion are carried out o n ly afterwards.

2.4


The service life of a seal is used up completely until a malfunction occurs. A damage-based

plant maintenance task is then carried out to install a new seal. In this case, the damage-

based plant maintenance method is worthwhile, since regularly inspecting and maintaining

a seal would cost more than the seal itself. The situation is rather different, however, if the

seal is classified as a system component presenting a danger to production or safety. In this

case, the method would not only be foolish, but would also give rise to high downt ime and

follow-up costs.

EXAM PLE


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After the malfunction has been corrected (repaired) by an internal or external

techn ician , th e PM plan n er (as the ord erin g party) signs off th e service perform ed

th e concludin g step, the ord er is settled by accoun ting. Figure 2.9 presents an overv

of th is business process.

2.4.2 Time-based plant maintenance

With t ime-based (or periodic) plan t m aint enan ce, prevent ive m ainten an ce of a syst

com pon en t is carried ou t regularly after a specific period of use. One advan tage of

method is that regular preventive maintenance increases the service life of a syst

com pon en t. In som e cases, statuto ry or safety regulation s requ ire proof of regular p

ventive maintenance (for example, fire extinguishers and automobiles are subject

inspection at regular intervals). On e disadvant age of tim e-based m ainten ance is that

service life of a system com pon en t always depend s on its level of usage.

The business process for time-based plant maintenance begins with notificat

(gen erally outpu t by a comp uter system ) that th e specified date has been reached . T

specified date is the finish date of a particular maintenance cycle. Follow


Malfunction reportDescription of

malfunction

Planning and

control

Service

acceptanceSettlement

Malfunction

correction

Business process for damage-based plant maintenance ( SAP AG)FIGURE 2.9

A pump in an ice-cream production plant has to be replaced after every 10,000 litres at th

latest. From a statistical point of view, this limit is reached every two months. As a result ,

maintenance cycle of two months is specified by time-based plant maintenance. In March

this pump is replaced after 9000 lit res; in May, after 4000 litres; and in July, after 9200 litre

In May, the utilization level was considerably lower than in the other months, which mean

that the pump only really needed to be replaced in June. However, time-based plant main

tenance takes only the maintenance cycle of two months into account, and not the actua

wear and tear. As a result of replacing a pump that was still functioning in May, the compan

incurred additional costs.

EXAMPLE


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notification, the planning and control of the maintenance task is carried out on the

basis of a mainten ance plan. Since th e m aintenan ce tasks are known in advan ce, this

m ainten an ce plan can also be outpu t by a com pu ter system . An in ternal or extern al PM

technician carries out the maintenance on the specified date, and the PM planner

signs off th e service perform ed. As in d am age-based m ainten an ce, this step is followed

by settlemen t. Figure 2.10 sh ows an overview of th is business process.

2.4.3 Condition-based plant maintenance

Of the three traditional plant maintenance methods, condition-based plant mainte-

nance is the one that enables the service life to be leveraged optimally and

econ om ically. In con dition-based m aintenan ce, a m ain tenan ce task is required on ly if

a specific level of wear an d t ear h as been reach ed (for exam ple, if an d o n ly if th e value

for the p um p h as actually reached 99 00 litres).

To en able con dition-based plan t m ainten an ce to be carried out, th e actual cond ition

of th e system comp on ent m ust be m easured precisely by m eans of regular in spections.

For example, the pu m p can be fitted with a m eter that m easures the flow in litres and

is read regularly.


Notification of

cyclical

requirement

Planning and

control

SettlementServiceacceptance

Maintenance

Business process for t ime-based maintenance ( SAP AG)FIGURE 2.10

Notification

of maintenance

requirement

Planning and

control

Service

acceptanceSettlement

Condition

measurement

Maintenance

Business process for condition-based plant maintenance ( SAP AG)FIGURE 2.11


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Th e busin ess process for th is m eth od begins with regular m easurem en ts of th e c

dition. When this measurement determines that a specific value has been reach

n otification o f the m aintenan ce requirem ent is issued. Th e PM plann er plan s and c

trols th e main tenan ce tasks on th e basis of a mainten ance plan. As in th e oth er busin

processes, m ainten an ce is th en carried o ut, sign ed off and settled. Figure 2.11 sho ws

overview o f th is business process.A comp any can use all three of the above meth ods in p arallel, or combine th em

required. Th e particular meth od u sed often d epends on th e type and value of the m

rial in question . Damage-based p lant m aintenan ce can be used as a meth od for p

subject to wear an d tear, wh ereas tim e-based or con dition-based plan t m ainten an ce

be used for system components with a long service life. It can also be expedient

combin e tim e-based an d cond ition -based plant m aintenan ce.

BEN CHM ARKIN G I N PLANT M AIN TEN ANCE BASED O NKEY PERFORM ANCE IN DICATORS

Bench m arkin g involves using specific criteria to d efine various subareas of plant m a

tenance, an d th en com parin g these wi thin on es own com pany or wi th otcomp anies. To enable plant m ain tenan ce man agem ent to be improved, the particu

dem an ds th at h ave to be satisfied are specified for th e criteria. Two of th ese sub areas

for example, corporate m anagemen t and asset m anagemen t.

In the corporate management subarea, the following criteria must be evaluated

regards their level of maturity and th e results ach ieved in com parison with th e ben

marking partner (Biedermann 1998: 34):

Written version of the plant m aintenan ce ph ilosoph y

Target-based form ulation of cont inuou s imp rovem ent

Cross-departmen tal team s with target achievemen t m on itorin g

Cross-departmental controlling with PM contribution as regards

Quality (key performan ce indicators)

Productivity (key perform ance indicators)

Utilization o f system capacity (key performan ce ind icators)

Safety (internal area) an d en vironm ent (external area)

4

3

2

1

2.5


The pump should always be replaced after 10,000 litres, but only after a minimum usag

time of two months. Or the pump should be replaced by an external company every twmonths; if the value of 9900 litres is reached, however, the pump can also be replace

within the two-month cycle.

EXAMPLE


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Stan dardization (stan dards, guidelin es, instruction s)

Staff commitment and delegation

Risk profile for organ ization (division) of work between system op erator an d m ain-

tenan ce provider

Catalogue of criteria for transferring tasks to p rodu ction

An alytical evaluation of th e opt imu m level of decen tralization

Strategic orien tation in assign ing external services

Con trolling fun ction s

In t h e asset m an agem ent subarea, th e followin g criteria mu st be evaluated as regards

th eir level of maturity and th e results ach ieved in com parison with th e bench m arking

partn er (Biederman n 1 998: 35):

Docum ent ation of critical system s/assem blies and d escription o f relevan t m ainte-

nance strategy

Systematic p rocess of weak-poin t elim inat ion

Tech n ical assessm ents

Busin ess assessment s

Assessm ent s with regard t o o ccupation al an d o peration al safety, as well as envi-

ronm ental protection , with associated docum entation

Classification of systems with regard to their significance and place in the pro-

duction process, with associated documentation (key performance indicators)

Definition of targets in th e areas of reliability an d availability

Use of meth ods and tools or tech n iques to increase actual produ ction time

Rou tin e evaluation for reliability engin eerin g

Use of information technologies for supporting reliability management

Visualization by m eans of reports, graph ics an d d iagram s as m eans of organizing

information in accordan ce with deman ds

Inclusion of plant m ain tenan ce concepts in t h e drafting and con struction of new

systems

Use of meth ods to com pare th e econom ic efficiency of asset in vestm ent as regards

plant m ain tenan ce or replacemen t

In th is con text, som e of the PM key performan ce in dicators in VDI Guideline 2893 are

significan t. You can use key performan ce ind icators 14, for exam ple, to an alyse PM

costs. Key performan ce indicator 1 is th e PM cost rate; in oth er words, th e total costs

(costs for person n el, labou r, materials an d ext ernal services) for PM tasks to DIN 31051

divided by the indexed acquisition value, the asset value in the year of procurement

11

10

9

8

7

6

5

4

3

2

1

11

10

9

8

7

6

5



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m ultiplied by t h e price ind ex (index figures of th e Federal Statistical Office Germ a

for the year in question.

Key performan ce in dicators 24 provide a furth er breakdown of th e total cost.

performance indicator 2 is the PM cost portion for personnel; in other words,

labour and salary costs for PM personnel, including the total cost divided by the to

PM costs in accordance with key performan ce in dicator 1.Key perform an ce in dicator 3 is th e PM cost portion for materials; in ot h er words,

costs for material used for plant m ainten ance (spare parts, operatin g supplies and c

sum ables) divided by th e total PM costs in accordan ce with key performan ce in dicato

Key performan ce in dicator 4 is the PM portion for external services; in o th er wo

th e costs for PM tasks carried ou t by extern al com pan ies divided by th e total PM co

in accordan ce with key perform an ce in dicator 1. It is advisable h ere to list separat

th e labou r and m aterial costs for the extern al service in accordance with key perfo

ance indicators 2 and 3.

Th e PM person n el cost rate (key perform an ce in dicator 17) and PM m aterial cost r

(key performan ce in dicator 18) can also be calculated in accordance with key perforance indicator 1. With the PM personnel cost rate, the personnel costs in accorda

with key performan ce in dicator 2 are divided by th e indexed acquisition value in acc

dan ce with key performan ce in dicator 1. With th e plant m ainten ance m aterial cost r

the material costs in accordance with key performance indicator 3 are divided by

acquisition value in accordan ce with key perform an ce in dicator 1. (For furth er PM

performan ce in dicators, refer to VDI Guideline 2893. On PM key performan ce in d

tors, see Gamweger 1998: 101112.)

M OD ERN PLANT M AIN TEN ANCE M ANAGEM EN T

2.6.1 Total Productive Maintenance (TPM)

The TPM concept was developed in Japan in the 1970s, but only became more wi

spread during the 1990s. The main characteristic of TPM is that the tasks forme

plann ed an d carried ou t by cent ral PM departm ents are transferred gradually to

machinist.

In con trast to tradition al plant m ain tenan ce, which is regarded as an auxiliary

plan t or service fun ction o f prod uction , TPM pu rsues con siderably mo re exten sive

objectives, since all members of staff are included in the improvement process.

(Matyas 1999: 31)

Train ing th e operatin g person n el is an impo rtant prerequisite h ere for overcom ing

traditional organizational separation of machin e operation and m ach ine m ain tenan

According to Matyas, the objective of TPM is autonomous operator maintenanc

2.6



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This is evident, for example, in the Japan Technology Groups mission statement for

TPM:

Total Productive Mainten ance m eans th at op erators are em powered to m ain tain

continuous production on total ly efficient l ines. (Japan Technology Group,

Nipp on Lever BV, Japan . h ttp ://w ww.bekkoam e.or.jp/ ~axeichi/ n _lever)

With in t h e scope of TPM, th e actual PM departm en t an alyses the PM tasks carried out

by the operating personnel. The PM department also carries out strategic planning,

adm inistration of main tenan ce task lists and m ainten ance plans, as well as cost con trol.

2.6.2 Reliability Centred Maintenance (RCM)

RCM, also known as Reliability Based Maintenance (RBM), is concerned specifically

with system breakdowns, the associated follow-up costs, and how to avoid them. The

aim o f this meth od is to use a risk an alysis an d risk evaluation (as a separate m eth od,

Risk Based Maintenance) to decide whether preventive PM tasks could incur higher

costs than a system breakdown and its con sequen ces.

The question of whether preventive measures are expedient arises especially

where redun dan t (bypass) or m ultiply redun dan t system s are used. This is because

th e bypass is in tend ed to take effect if th e comp on ent breaks down. Wh at is th e

use of prevention wh ere a safeguard is already installed? Th is sho uld be taken int o

con sideration particularly in th e case of systems with a h igh level of redun dan cy

determin ed by techn ology or legal stipu lation s (for exam ple, in systems involving

n uclear tech n ology). (Sten der 1999: 43)

The m ost imp ortan t prerequisites for RCM are calculation an d evaluation of a system

breakdown.

2.6.3 Life Cycle Costing

Life Cycle Costing is a tool used in cost m an agemen t for a prod uct or a system.

Life Cycle Costing is not a separate method; it is based on a number of well-

known methods from capital budgeting (for example, system evaluation

methods, cost forecasting procedures, and methods for taking risk and inflation

into accoun t). (Gn th er 1997: 900)

When a system is procured, for example, Life Cycle Costing facilitates the decision

between alternative produ cts offered by rival providers. Th is meth od is used to com pare

not only the procurement and init ial costs, but also (and more importantly) the



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operating an d follow-up costs in th e life cycle of a system . Th e operating an d follow

costs essen tially con tain th e costs for preven tive m ain tenan ce and p lant m aintenan

as well as the o perating an d d isposal costs. Even after a system h as been p rocured, L

Cycle Costing contributes to optimizing costs and performance throughout the l

cycle of th e system :

In con trast to capital bud getin g, Life Cycle Costing do es n ot en d wh en t h e analy

sis of life cycle revenues and costs is complete. To achieve its goal as regards

design, Life Cycle Costing employs a continuous process for optimizing the

design of the p articular product o r system th roughou t its entire life cycle (. . .)

(Gn th er 1997: 912)

Life Cycle Costing is particularly worthwhile for systems involving high cap

investm ent an d with a lon g service life, as well as where th e follow-up costs accrued

th e system are h igh in com parison t o th e initial costs. Life Cycle Costing is, th erefo

an important method for classifying and planning the scope of plant maintenastrategically.

2.6.4 Decentralized Equipment and Process Responsibility (DAPV)

DAPV was developed by the Fraunhofer Institute for Production Engineering a

Autom ation (German y). Th e m ethod focuses prim arily on th e organizational struct

of th e PM departmen t; in oth er words, on creating decentralized structures and tra

ferring respon sibility to work group s and t eam s.

With a cen tralized form o f organization, p erson n el and organ ization in th e four

elem ent s of plann ing, con trol, execution , an d m on itoring are separate. In fact, it

can even be said that t h e greater the separation of th ese elem ent s with regard to

persons and departments, the higher the level of centralization. By contrast, the

characteristic feature of a decent ralized organization is th at th ese four elemen ts or

tasks are performed by a group or team (and possibly even by only one person)

(Stender 1999: 51)

Former m embers of th e PM departmen t can be int egrated in th e production te

that performs plant maintenance tasks. The team calls in external maintenan

providers only in th e event of more extensive and com plex plan t m ain tenan ce ta

These providers come either from an internal plant maintenance service centre

from an external compan y.

The obvious thing to do, then, is to eliminate function-oriented departments

such as production (quantity), plant maintenance (system), logistics (time), and

qu ality, in o rder to establish process-orient ed dep artm en ts (fractals), in wh ich part



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tasks of th e original logistics, plant , main ten an ce an d qu ality fun ction s are carried

out, as well as production. The former logistics, plant maintenance, and quality

departments are retained in cases where specific tasks requiring a high level of

fun ction-specific kno w-how h ave to be carried o ut. If they are retained, h owever,

these departments give up personnel, since the overall scope of their tasks is

reduced. In addition to this, the role of persons responsible changes, since theyare now only engaged by the production fractals as service providers within a

clearly defined custom er/ven dor relationsh ip. (Sten der 1999: 56)

As with TPM, the o rgan izational role of th e PM departm ent with in t h e comp any is

chan ged, wh ile th e actual PM tasks are now carried out as a role in a prod uction team .

2.6.5 Other trends

System engineers as service providers

In addition to th e PM man agem ent con cepts outlin ed above, a n um ber of oth er trends

for modern izing tradition al plan t m aintenan ce are currently developing. Som e m anu -

facturin g com pan ies are n ow carrying out n ot on ly tradition al system en gin eerin g, but

also production o ptimization and system m aintenan ce.

Th is mean s th at erstwhile produ cers are increasingly becomin g providers of holistic

product solutions extending from system planning and construction through to

system support du ring operation . Th is establishes a con trol loop th at also sets imp or-

tant new trends for maintenance. The total asset history costs of a machine or

system from con struction th rough t o system o peration are no w relevan t for system

engin eers. Th is m eans th at th ey not o n ly h ave to take th e costs of the first phase ofth e produ ct life cycle in to con sideration , but also have to allow for th e subsequ ent

costs of ensuring the availability of their system. This involves giving particular

consideration to influences on system behaviour arising from the construction of

assemblies and operational methods, the use of basic materials, and the quality of

intern ally pro du ced as well as externally purch ased p arts. (Proksch 1999: 14)

Remote diagnosis and virtual service groups

Virtual service groups are specialist teams for High Intelligence Maintenance (HIM),

wh ich work togeth er on p rojects and are organized via virtual m arkets.

Virtual service groups will be created, in which companies (particularly PM serv-

ice providers an d com pon ent suppliers, but also system m an ufacturers) cooperate

to provide services. The global options for accessing system data enable highly

qualified specialist plant maintenance teams to be assembled internationally as

and when required. This is especially useful in the case of more complex



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malfunctions, system optimizations, modifications, or other large-scale meas

ures. (Slender an d Proksch 1999: 14)

This scenario offers following rem ote d iagn osis opt ion s:

Process supervision an d weak-poin t an alysis

Process m anagemen t and con trol

Business reengin eerin g, process opt imization

Remot e programm ing and con trol of machines

Rem ote con trol an d fault correction for con trol software

Teleservice with sensors, video/audio monitoring (on teleservice, see Stoll 1999

Intern et techn ologies can be used to create a virtual marketplace (or po rtal) opera

by providers of software for PM planning and control systems, for example. In t

portal, providers of PM services, suppliers of spare parts, and systems engineers c

advertise th eir prod ucts an d services un der th e h eadin g Sell; com pan ies seeking to pchase plan t m ain tenan ce services in th e short-term or m id-term can advertise un

Buy. Th is m arketplace can be used n ot on ly to level out supp ly and dem an d, h owe

but also to exchange information (for example, on benchmarking results, key p

formance indicators, and PM strategies, as well as experience with modern P

m an agem ent con cepts or tech n ical inn ovations). Som e of th e above option s for rem

diagno sis cou ld also be im plem ent ed directly via a marketplace of this type.

Facility management

Building m ainten an ce is a subarea of facility or buildin g man agemen t. Th e greater level of autom ation via buildin g control systems, th e m ore importan t it is to int egr

th e PM processes sm ooth ly. If comp uters are used to support p lant m aintenan ce op

ations, an interface m ust exist between th e m ain tenan ce plann ing and control syst

(MPC) and th e buildin g control system so th at a m alfunction report is generated au

m atically in th e MPC as soon as th e building cont rol system detects a malfun ction

Graphical user interfaces for MPC

Tradition al MPC system s can be m ade easier for PM plann ers or techn ician s to oper

by m eans of intu itive user in terfaces. Malfun ctions in a system can be localized m

easily if th e MPC system is equ ipped with a user int erface sup port ing CAD drawin

three-dimensional images, construction plans, or process and instrumentation d

grams. Drawin gs or images of this kin d can b e mad e available throu ghou t th e comp

on the internet/intranet and accessed via a browser. This means that users do

require a techn ical key for the system comp on ent affected in order to en ter data a

trigger even ts in an MPC system (for exam ple, to initiate a malfun ction repo rt).



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Solution databases

Analysis procedures, such as Safety through organizational learning (SOL), are cen-

tered on th e con cept of learnin g from experience. (On SOL, see Geipel-Kern (1999).)

Breakdowns, malfunctions, accidents and near-accidents are evaluated systematically to

enable processes to be im proved an d similar malfun ctions to b e corrected m ore quickly.

Tried-and -tested solution s can be stored in solution /task datab ases. By m eans of Case-

Based Reasoning systems (CBR), the system can link the description of a particular

problem to d escription s of sim ilar problem s. Th ese description s are con n ected, in turn ,

to a tried-an d-tested solution th at h as already been u sed successfully an d linked to th e

description s of problems via SOL, for exam ple. Th is en ables com pan y-int ernal kn owl-

edge relating to plant maintenance processes to be stored in a knowledge base. Some

system engineers or manufacturers of spare parts supply product-specific knowledge

bases with th eir produ cts. Th e PM techn ician (as custom er) can th en call up th e m an-

ufacturers kno wledge base directly or via th e int ernet sh ould problem s arise.

Simulation programs

Simulation program s can be used, for examp le, to sho w h ow th e breakdown of a sub-

system will affect th e system as a wh ole.

In th e simu lation system itself, the beh aviour of the system is m apped via events,

which are triggered at th e appropriate tim es by means of th e determined ch arac-

teristics. These cause changes in the system condition, which trigger further

event s (discrete event simu lation ). This not o n ly en ables th e behaviou r of real sys-

tem s/system com pon ent s to be described, but also allows supplem ent ary levels of

analysis to be integrated in the simulation model in parallel with the actualprocess flows. (Feldman n 1999: 54)

Wh en used as part of a prelim inary econ om ic evaluation of the sim ulated m alfun ction,

th is procedure en ables th e costs for PM personn el to be calculated d irectly according to

th e duration of the malfun ction and th e hou rly rate, for example.


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