Www.arrowvalves.co.uk copyright 20061 Primarily Focusing on Backflow Prevention Presentation By...

www.arrowvalves.co.uk copyright 20061

Primarily Focusing on Backflow Prevention

Presentation By

Steve Grace B-Eng FIPHE

Technical Director - Arrow Valves Ltd

March 2006

References to the Water Regulations Guide with practical solutions


Objectives

Fluid Categories – risk classification - New UK standards Regulations 2 – 6 – requirements and solutionsBackflow – how it occurs, back siphonage vs back pressureBackflow prevention devices - Fluid Categories 2 – 5RPZ valves – use, installation & testingSealed heating – regulations and devicesWater Fittings Approval Standards – Kiwa, WRASWater conservation – requirements and devicesHose Union Taps - requirements and devicesTemperature – limit and controlSummary


The legal UK Water Regulations include -

Regulations & Guidance Available Information

The Water Supply (Water Fittings) Regulations – Statutory Instruments 1148

Schedule 1 – Fluid Categories

Schedule 2 – Requirements for Water Fittings

The “Water Regulations Guide” contains all the Regulations and Guidance(Replaces Water Supply Byelaws Guide)

Guidance is produced by DETR (DEFRA) and WRAS “Water Regulations Advisory Scheme”

http://www.arrowvalves.co.uk/waterregulations/waterregsorderform.doc


Schedule 1 – Fluid Category Risk Comparison

European Fluid Category 5



EuropeanFluid Category 2

EuropeanFluid Category 1

Class 1Schedule A Risk

Class 2Schedule B Risk

Class 3Schedule C Risk

Previous UKClassification

European/New UKClassification

WholesomeWater

Air Gap – AA AB Pipe Interrupter - DC

RPZ – BAPipe Interrupter - DB

Double Check – ED

Single Check – EB

No Protection Required(Except Secondary, at times)

Backflow Prevention Examples(Used in Building Services)


2. - (1) Subject to the following provisions of this regulation, these Regulations apply to any water fitting installed or used, or to be installed or used, in premises to which water is or is to be supplied by a water undertaker. (4) Nothing in these Regulations shall require any person to remove, replace, alter, disconnect or cease to use any water fitting which was lawfully installed or used, or capable of being used, before 1st July 1999.

Regulation 2 Application of Regulations

“lawfully” means conformance to the Water Byelaws


Example of New Water Regulations applying to existing installations

R15.21“While the Regulations are not retrospective appropriate measures must be taken against any known situation where there is a potential backflow risk from hoses.

The offence will be deemed to have been committed when the hose was attached and not when the tap was first installed.”

Regulation 2 Retrospective Clause

The same applies to filling loops etc.


3. - (1) No person shall - (a) instal a water fitting to convey or receive water supplied by a water undertaker, or alter, disconnect or use such a water fitting; or (b) cause or permit such a water fitting to be installed, altered, disconnected or used in such a manner that it causes or is likely to cause - (i) waste, misuse, undue consumption or contamination of water supplied by a water undertaker; or (ii) the erroneous measurement of water supplied by a water undertaker.

Regulation 3 Restriction on installation etc. of water fittings


Back Siphonage

Courtesy of WRAS

This tap is sucking up water due to a vacuum in the supply pipeand an inadequate air gap.


What is Backflow?

Back Siphonage (Vacuum on supply)

Back Pressure (Downstream pressure higher than supply)

Some devices are suitable for Back Siphonage only - e.g. DC Pipe Interrupter. Others e.g. BA (RPZ Valve) are suitable for both.

“Backflow” means flow upstream, that is in a direction contrary to the intended normal direction of flow, within or from a water fitting.


Backflow Example – Hotel Baths

Supply pressure lost –

mains or booster failure Tap turned on –

Negative pressure – could suck fluid

out of bath via shower hose

Contaminated!

Solution -Point of Use Protection

Shower Hose Double Check Valve

Model ED235

Solution – Secondary Protection

Branch ValveDouble Check Valve

Model BRV


Secondary Backflow Protection

Servicing Valves, Double Check and Drain Taps should be fitted to

every branch(G11.3, G11.4, G11.5,

G15.24, R15.24.1)


Branch ValveServicing Valve, Double Check and Drain Tap should be fitted to every branch

(G11.3, G11.4, G11.5, G15.24, R15.24.1)

Model BRVServicing, Double Check & Drain Tap

with Solder Unions

Model BRPRVServicing, Pressure Reducing,

Double Check & Drain Tap


Point of Use Protection - The LawBackflow prevention devices MUST be fitted at POINTS OF USE - paragraph 15 (1) of the Statutory Instruments (Water Regulations).

15. (1) “Subject to the following provisions of this paragraph, every water system shall contain an adequate device or devices for preventing backflow of fluid from any appliance, fitting or process from occurring”.

(3) “The device used to prevent backflow shall be appropriate to the highest applicable fluid category to which the fitting is subject downstream before the next such device”.

G15.25 “The provision of zone or whole-site backflow protection should be in addition to individual requirements at points of use and within the system”.

3) The device used to prevent backflow shall be appropriate to the highest applicable fluid category to which the fitting is subject downstream before the next such device.


Whole Site Protection

Example of “Whole Site Protection” - Florida USA(Frost Protection unnecessary!)


Point of Use ProtectionWhere the appliances are of different types, e.g. a Washing Machine and

Dishwasher (commercial use), each appliance must have its own Backflow Protection - RPZ Valve Assembly - (Water Regulations Schedule 2, Paragraph 15)

Point of UseProtection

Prevents Cross Contamination

Point of UseProtection

Built-in Category 3 protection – too low

Built-in Category 3 protection – too low


Zone ProtectionWhere several appliances of the same type and same Fluid Category are used within a commercial building, Water Suppliers may accept a single RPZ Valve to protect multiple appliances.

Zone Protection

Cross Contamination

Possible


Backflow Example

Problem -Steel Pipe

is Fluid Category

2 Risk

E.g. Fire Sprinkler Cistern

(with AA / AB air gap)

Solution -Single Check

Valve at Branch

“Wholesome” Water Fluid Category 1

Fluid Category 5

Model EB402


Single Check ValveEB Single Check ValveCategory 2 protection

EB is “non-verifiable” meaning there are no test

points provided. EA is verifiable but none is approved and since

protection is still category 2, there is no benefit.

Applications –

Single Check Valve above DN50 are described as “Non-

Return” but are currently acceptable for backflow

protection.

For double check valves, ensure upstream check valve

cannot open downstream valve!

Single Check Valve. To provide backflow protection from flexible

hoses. Washing machine version pictured -(Model EB20FM235)

No Tools Required

Connections to steel pipe

Prevent mixing of hot & cold (e.g. TMV)

Fire sprinklers (no additives)


Double Check ValveED Double Check Valve

Category 3 protection

ED is “non-verifiable” meaning there are no test

points provided. EC is verifiable but none is approved and since

protection is still Fluid Category 3, there is no

benefit.

Applications –

Exceptionally low head-loss ED Device (with optional Drain Tap - Model ED132)

Stainless Steel - exceptionally low head-loss – Model ED316

Double Check Valve - model ED235. For fluid category 3 protection on

shower hoses. Flow limiter option

No Tools Required

Supply to flats (whole site)

Separate floors (secondary)

Numerous others


Double Check Valve – Low Loss

E.g. Model ED132 - size 15 mm - has 1 m head loss compared with 4.5 m for conventional Double Check Valve at 3 m/s.

Head Loss / Flow Chart 15 mm DCV

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Velocity (m/s)

Del

ta P

ress

ure

(m H

2O)

Conventional DN15

Arrow Valves ED132


Pipe Interrupters

DB Pipe InterrupterCategory 4 protection

There are many restrictions on its use -

No control valves downstream

300 mm min. above spillover level or free discharge point

Applications –

Model – DB20IL15with quick release hose connector

Porous hoses for house only(Hose Union tap also requires a separate Double Check Valve)


Pipe Interrupters

DC Pipe InterrupterCategory 5 protection

There are many restrictions on its use -

Minimal restriction downstream

300 mm min. above spillover level or free discharge point

150 mm above sparge outlet

Applications –

PZ

R

Model DC257Urinals

(fed directly from supply pipe)


RPZ Valves – Category 4 Protection

DN15 - DN20 DN25 - DN32

DN40 - DN50

DN65 - DN100


RPZ (BA) Assembly in Cabinet

A large capacity fine strainer should be used for high

volume applications

Small cabinet (300 mm square) to house a 15 mm

RPZ. E.g. for dishwashers etc.

Waterless Traps are ideal -conventional traps can dry out(check approved for application)

RPZ

Compact

High performance


Initial Connection

RPZ (BA) How it Works

With no pressure in the system, both Check Valves (1) and (2) are closed and the Relief Valve (3) is open.

Once the upstream pressure (A) reaches about 0.3 bar, sufficient pressure exists above the Diaphragm (5) to compress the Spring (6) and close the Relief Valve (3).

At approximately 0.5 bar, Check Valve (1) opens allowing water to flow into Zone (B). (Look at Check Valve (1))

A further 0.1 bar is required to open Check Valve (2) and thereafter flow is maintained through the Valve.

Closed


Initial Connection


With no pressure in the system, both Check Valves (1) and (2) are closed and the Relief Valve (3) is open.

Once the upstream pressure (A) reaches about 0.3 bar, sufficient pressure exists above the Diaphragm (5) to compress the Spring (6) and close the Relief Valve (3).

At approximately 0.5 bar, Check Valve (1) opens allowing water to flow into Zone (B).

A further 0.1 bar is required to open Check Valve (2) and thereafter flow is maintained through the Valve.


Downstream Pressure Increase


If Check Valve (2) fails to seal whilst the downstream pressure (C) is higher than (B), the Relief Valve (3) will open before (B) gets to within 0.14 bar of the Supply Pressure (A). The Relief Valve (3) orifice is substantially larger than the open area of a leaking Check Valve and therefore prevents fluid reaching the base of Check Valve (1).

Backflow - due to an increase in downstream pressure - is prevented by Check Valve (2).

Failsafe (Positive Action)


Installation Diagram

Ground / Floor / Cabinet

Access Height0.3 m min1.5 m max

Upstream Isolating

Valve

Downstream Isolating

Valve

Strainer

RPZ Valve

Air Gap

Discharge Pipe

IGN 9-03-02 Issue 3 requires RPZ installations to feature -

AdequateRear

Clearance

RPZ Valves must be annually

tested

Tamperproof environment – Plant Room or

use Cabinet


RPZ Typical Applications

· Sealed Heating Systems – Non house (Filling loops with Double Check Valve prohibited)

· Hose Union Taps - Commercial - (where Fluid Category 4)· Clothes Washing Machines - Commercial use · Dishwashers - Commercial use· Cooling Coils - Commercial· Under Floor Heating - Commercial· Dyeing Equipment· Printing and Photographic Equipment · Pressurised Fire Fighting Systems· Water Treatment Plant· Vehicle Washing Plant· Water Softening - not Salt

The Following MUST be protected with either an appropriate air gap or an RPZ assembly


RPZ (BA) Guidance

· On the inlet to a pump - fit to outlet· On gravity systems - unless at least 10 m head · On elevated mains systems - e.g. second floor and above

RPZ’s have a pressure drop of about 0.6/0.7 bar inherent in their design. The supply pressure must be more than 0.7 bar. (The increase in

pressure drop after 0.7 bar is small)

Do not use an RPZ -

RPZ Valves (BA device) need to be tested by an Accredited Tester after installation and annually thereafter .


Break Tank – with AB Air Gap

AB Air GapCategory 5 protection

Either gravity supply from storage cistern or

Boost with pumps

Applications –“Non-Domestic” Hose Union taps

e.g. Waste Bin WashingWash-down

IrrigationLaboratoriesRain water

Baths/Showers - HealthcareBed pan washers

Air Gap AB

“Boost-A-Break” Fixed speedBreak tank and Booster - model

BTABV

“Boost-A-Break”Variable speed


Break Tank – with AF Air Gap

AF Air GapCategory 4 protection

Applications –

“Pent-A-Boost” Fixed speedCompact Domestic Booster - model

BTAFV

“Pent-A-Boost”Variable speed

Boosts pressure for high buildings where the mains

supply is inadequate

e.g. penthouse suites


Break Tank Accessories

RPZ Valves, Break Tanks and other fittings must be protected from freezing

Outdoor GRP Kiosk with thermostatically controlled heater for break tank (model

BTABV). Note - low level screened Type AB slot

Applications –

Wall coverNote – brackets required

Wash-down

Irrigation

Drip Tray


Filling Heating Systems – Category 3

Unlike BA (RPZ) valves, CA devices do not need to be tested. A

discharge pipe is required to be connected to the tundish.

A CA device (with pressure control) can be used to automatically fill house and non-house heating systems less than 45 KW output.

Filling Valve - CA device with PRV, strainer and servicing valves

Model – CA296PRV


Filling Heating Systems – Category 4

Quick-fill loops (with Double Check valve) are prohibited for “other than house” applications.

Fill and pressurise with Autofillsupply from -

Mains – ground (& first floor)

Boosted CWS

R24.2 “The type of backflow protection device required should be suitable for Fluid Category 3 in the case of a house or for Fluid Category 4 risk for

installations in premises other than a house”.

Autofill is a Fluid Category 4 device for filling and pressurising

(Water Industry now accept systems less than 45 KW output as Fluid Category 3)

Wall mounting brackets available


Heating System AccessoriesUnvented heating systems require a correctly sized & rated

Expansion Vessel

Model EVCP (4 bar)Vessels must be correctly

pre-charged

Model EVUP (10 bar)Approved for heating & domestic water

Model BVEVProper vessel valve – lock shield,

wired, drain tap and union


Heating System AccessoriesCommon accessories for commercial unvented systems include -

Model WMV3Water Meter – establish

system volume and leaksVolumetric & readable to 1 litre

Model ADRAir and Dirt Removers

(separators) DN20 – DN250Model DP5Dosing Pots (3.5 – 25 litres) to add

inhibitors – water meter helps determine system volume

With anti-blowback and anti-scald


4. - (1) Every water fitting shall - (a) be of an appropriate quality and standard; and (b) be suitable for the circumstances in which it is used. (2) For the purposes of this regulation, a water fitting is of an appropriate quality or standard only if -(a) it bears an appropriate CE marking in accordance with the Directive;(b) it conforms to an appropriate harmonized standard or European technical approval;(c) it conforms to an appropriate British Standard or some other national specification of an EEA State which provides an equivalent level of protection and performance; or(d) it conforms to a specification approved by the regulator.

Regulation 4 Requirements for water fittings etc.

It is necessary to prove conformance – only use Water Regulations approved fittings. There are several organisations now -


Regulation 4 Approval Organisations

Remember – to comply with Regulations, all fittings in contact with (wholesome) water supplied by the water company must be approved.

Available free on Internetwww.kiwa.co.uk

Also available free on Internetwww.wras.co.uk

http://www.bre.co.uk/index.jsp


Regulation 4 - Compliance www.kiwa.co.uk

All fittings KIWA UK approved assure

compliance with Regulation 4 – see their web site for

approved products –www.kiwa.co.uk


5. - (1) Subject to paragraph (2), any person who proposes to install a water fitting in connection with any of the operations listed in the Table below - (a) shall give notice to the water undertaker that he proposes to begin work; (b) shall not begin that work without the consent of that undertaker which shall not be withheld unreasonably; and

(c) shall comply with any conditions to which the undertaker's consent is subject.

Regulation 5Notification

Water Companies are permitted to make “reasonable” terms and conditions

“Unreasonably” means 10 working days from receipt of application


1. The erection of a building or other structure, not being a pond or swimming pool. 2. The extension or alteration of a water system on any premises other than a house. 3. A material change of use of any premises.

Regulation 5 continuedNotification

Notification is required for the following -

(2) This regulation does not apply to the installation by an approved contractor of a water fitting falling within paragraph 2, 4(b) or 4(g) in the Table. Commercial alterations, bidet, RPZ Valve.

There are others but these are for house installations. Everything requires notification in a “non-house” structure – see above


Regulation 6Contractor's Certificate

6. - (1) Where a water fitting is installed, altered, connected or disconnected by an approved contractor, the contractor shall upon completion of the work furnish a signed certificate stating whether the water fitting complies with the requirements of these Regulations to the person who commissioned the work. (2) In the case of a fitting for which notice is required under regulation 5 (1), the contractor shall send a copy of the certificate to the water undertaker.


Water Conservation

Automatic Flow Limiting Valve

Combined Servicing Valve and Automatic Flow Limiting cartridge. Constant flow between 1 – 10 bar.

Applications –

Cartridges can be changed though side port with pliers

8 Colour-coded cartridges available - with matching colour on disc that

snaps into plug

Automatic Flow Limiting Cartridges

0.07 – 0.43 Lt/s

Every appliance 15 or 22 mm


New “Features & Benefits” sheet

available

Water Conservation

“Equi-Flow” - Shower Flow Limiter

Ensures even distribution of water in a controlled and balanced

manner.

Model AFLE

Applications –

WITHOUT

WITH

Showers in multiple occupancy buildings e.g. flats, hotels and student

accommodation.

1 bar

5 bar

10 bar

Excessive flow

Insufficient flow

– Even distribution


Standpipe – Category 3

ED Double Check Valveis required for Hose Union Tapsused for “domestic purposes”

Taps with integral check valves (HUK1) are no longer acceptable

Applications –

Above ground garden wateringOffices, Schools, Recreation Ground

Standpipe - Model SPED

Miniature Standpipe – model SPTB.

Only 250 mm high


Standpipe – Category 4

“Non Domestic” Hose Union Taps may be risk assessed as Fluid Category 4

(G15.18) & a BA device could be used

Applications –

Standpipe - Model SPBA

Hose and medium duty washdown

gun

“Hand held hoses should be fitted with a self –closing mechanism at

the outlet of the hose.” G15.17

Car Washing & Degreasing Plants

Mini Irrigation Systems


Standpipe – Installation

750 mm

MDPE Pile

Standpipe

Insulation


“Conceal-A-Tap”

Flush Hose Union Tap – vandal resistant, frost proof

Model - HUC

New “Features & Benefits” sheet

available


“Conceal-A-Tap”Suits any wall thickness – cut copper tube to suit

Model - HUC

1. PARTIALLY INSERT SPECIAL KEY, ROTATE KEY ONLY 1/4 TURN, PULL DISC OUT.

2. CONNECT HOSE WITH "HOZELOCK" OR "INTER-LOCK" COUPLING (PULL BACK RING).3. PUSH KEY IN FULLY, TURN ON (1/4 TURN).

KIWA UK APPROVED A030526ARROW VALVES

T. 01442 823123 www.arrowvalves.co.uk

CONCEAL-A-TAP


Tap Box

To prevent unauthorised use and prevent waste – use a lockable Tap Box.Available in rear entry or bottom entry.

G11.5 warns against using spherical valves in frost prone areas. The Tap Box

features a right angle pattern spherical valve, which does not have a trapped cavity and is therefore frost resistant.

Applications –

Tap Box - Model HUTB

Tap Box (surface entry)- Model HUTBS

Shown with optional hose guard and pipe cover

Wall mounted Hose Union Tap(Backflow prevention provided

separately)


Hose Union Tap Below GroundBelow ground hose

union tap

All irrigation outlets less than 150 mm

above the ground are considered a Fluid Category 5 risk and

must be fed via an AB or AUK1 air gap.

E.g. “Boost-A-Break”

model BTABV

Model HUBG


Temperature Control

Supplied with AFL Servicing Valves fitted (including strainer)

Copes with unbalanced pressures

Applications –

G18.5 “Terminal fittings or communal showers in schools or public buildings, and other facilities used by the public, should be supplied

with water through thermostatic mixing valves so that the temperature of water discharged at the outlets does not exceed 43O C”.

Model TMV5213 Kit with AFL valves

TMV Servicing Valve model

BVTMV

Wash basins

Showers

Baths

Sinks

Bidet


Pressure Control

Model PRV535

With Solder Unions to allow secure and neat connection to copper tube

Model PRV536

With Solder Unions and Servicing Valves

Model PRVNGE

Pilot Operated. Range of other controls - solenoid

Model PRV1300

Exceptionally Low head loss


Regulations 7 - 14

• 7 Penalty for contravening Regulations• 8 Modification of section 73 of the Act• 9 Inspections, measurements and tests• 10 Enforcement• 11 Relaxation of requirements • 12 Approval by the regulator or the water undertaker• 13 Disputes• 14 Revocation of the Byelaws


Resources – Specification Clauses

Available at -

www.arrowvalves.co.uk

Simply copy & paste into any

project specification


Summary

The salient points of this presentation are –

• The Water Regulations Guide is the single most useful source of information• The local water company has the authority to enforce, inspect and risk assess• The Regulations apply to the whole building (if supplied by the water company) • “Point of use” backflow protection is required – not whole site• Communal bin washing – where a hose can be submerged – is Fluid Category

5• Irrigation outlets less than 150 mm above the ground are Fluid Category 5• The Fluid Category is dependant on the risk – not the fluid per sé• Non House heating systems above 45 kW are Fluid Category 4• It is an offence to waste water – even if metered• Water fittings must be approved – e.g. KIWA, WRAS, BSI


The End

Thank You

To view datasheets

[email protected]

Tel. 01442 823123Fax. 01442 823234

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