x e d n I

AA air gapDescription of back�ow prevention device S15.2 6.10

AB air gapDescription of back�ow prevention device S15.2 6.10

Abbreviations vi

AC air gapDescription of back�ow prevention device S15.2 6.10

Access coverRequirements for 1,000 litre plus cistern G16.13 7.11

Access to �oat operated valvesCold water storage cistern G16.14 7.14

Access to operational valves G10.2 4.12

AccessibilityCold water storage cistern G16.14 7.14Stopvalve, servicing and drain taps G10.1 4.12To operate stopvalves etc. G10.2 4.12

Accessibility of water �ttings G7.1 3.17

AD air gapDescription of back�ow prevention device S15.2 6.10

Adhesive jointsProhibition below ground G7.10 3.24

AF air gapDescription of back�ow prevention device S15.2 6.10

AG air gapDescription of back�ow prevention device S15.2 6.10

AgeingE�ect of, in selection of �ttings G2.5 2.13

Agricultural water troughsWater troughs to comply with BS 3445 G30.4 12.6

Air gapAA, with unrestricted discharge S15.2 6.10AB, weir o ver�ow S15.2 6.10AC, vented submerged inlet S15.2 6.10AD, with injector S15.2 6.10AF, circular over�ow S15.2 6.10AG, with minimum circular over�ow S15.2 6.10AUK1, with interposed cistern S15.2 6.10De�nition S15.1 6.10

Air pressure vessel �re sprinklersFluid category G15.28 6.49

Alarms Audible warning device for storage cisterns G16.5 7.6

Allowed back�o w G15.1 6.24

Animal drinking troughsBack�ow prevention R30.3 12.5General R30.1 12.4Location of servicing valve R30.2 12.4Speci�cation to BS 3445 G30.4 12.6

Anti vacuum valve DADescription of back�ow prevention device S15.3 6.11

Anti vacuum valve with single check valve DUK1

Description of back�ow prevention device S15.3 6.11Application of Byelaws

Water Byelaws 2000, Scotland 11Application of RegulationsWater Supply (Water Fittings) Regulations 4

Approval of method of installation by the undertakerWater Byelaws 2000, Scotland Byelaw 12 15Water Supply (Water Fittings) Regulations Reg.12(3) 7

Approval of speci�cation by the Regulator Water Supply (Water Fittings) Regulations Reg. 12

(1) – (2) 7Approved materials

Circumstances where not required G2.6 2.14Compliance with Regulators’Speci�cation 16

ArrestorsFor prevention of water hammer G5.4 3.14

Ascending spray bidetsBack�ow protection for G15.9 6.28

AUK1 air gapWith interposed cistern, description of S15.2 6.10

AUK2 domestic tap gapDescription of back�ow prevention device S15.2 6.10

AUK3 higher risk tap gapDe�nition of back�ow prevention device S15.2 6.11

BA reduced pressure zone valv eDescription of back�ow prevention device S15.3 6.11Relief outlet requirements G15.7f 6.27

Back�o wDe�nition of R15.4 6.26

o l f k c a B w allowed in hot water supply pipes G15.1 6.24Back�ow device

Accessibility G15.7a 6.27Burial in the ground G15.7c 6.27Inspection of G15.7a 6.27Line strainers servicing valve, need for G15.7e 6.27Line strainers, requirement for G15.7e 6.27Location outside premises G15.7b 6.27Maintenance G15.7a 6.27Operation G15.7a 6.27Renewal of G15.7a 6.27RPZ relief outlet requirements G15.7f 6.27Suitability for backpressure or

backsiphonage G15.7 6.27Suitability for risk G15.3 6.25Vented & veri�able, not in ground G15.7d 6.27

Back�ow preventionAccessibility of back�ow prevention

devices and arrangements G15.7 6.27Air gaps at taps or other terminal �ttings R15.13.1 6.36Animal drinking bowls G30.3 12.5Animal drinking bowls, from supply pipe G30.3c 12.5Animal drinking troughs with AA air gap G30.3b 12.5Animal drinking troughs, interlinked G30.3a 12.5Back�ow device adequate for purpose Schedule 2,

15(5) 6.8Back�ow prevention arrangements

and devices G15.4 6.25Bidets supplied o ver the rim R15.11 6.32Bidets with �exible hoses, installation of G15.10 6.29 Bidets with hoses and/or inlets belo w

spillover level R15.9 6.283 / 1 . 0 1 . 5 1 R 6.30

Class of back�ow device Schedule 2, 15(3) 6.8

Combination tap assemblies R15.13.2 6.37

I n d e x

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Back�ow prevention (continued)Commercial, industrial and

laboratory applications R15.30 6.50Devices for application of fertilisers or

domestic detergents R15.22 6.43Diagrams of back�ow prevention

arrangements 6.13 – 6.21Direction of �ow R15.3 6.25Drinking water fountains G15.15 6.41Examples of �uid categories – Tables . 6 2/4

R15.2 6.25Exceptions to back�ow requirements R15.1 6.24

Schedule 2 15(2) 6.8

Existing hose taps, house garden use R15.21 6.43Fire protection systems R15.27 6.48General interpretations of back�o w

prevention devices S15.3 6.11General interpretations of terms relating

to back�ow prevention S15.1 6.10Hose pipes for house gardens and

other applications R15.17 6.41Hose taps adjacent to WCs R15.12.2 6.35Hose taps, house garden use R15.20 6.42Industrial and commercial G15.18 6.41Interpretations of back�ow prevention

arrangements S15.2 6.10Mini irrigation systems in house gardens R15.23 6.44Miscellaneous commercial and

industrial applications R15.30 6.50Non-mechanical back�ow prevention

arrangements R15.5 6.26Ponds, pools and fountains G31.2 12.6Porous hose irrigation systems R15.19 6.42Precautions where pumped appliances

are installed R15.8 6.28Pressure �ushing valves for WCs

and urinals R15.12.1 6.33Protection appropriate to highest risk

downstream Schedule 2 15 (3) 6.8

Requirement to notify installation to water supplier Reg. 5 5

Secondary back�ow protection – Common supply pipes R15.24.3 6.46

Secondary back�ow protection – Distributing pipes R15.24.4 6.46

Secondary back�ow protection – General R15.24.2 6.46Secondary back�ow protection –

Requirements for R15.24.1 6.46Secondary back�ow protection in

two storey premises R15.6 6.27Separately occupied properties Schedule 2

15.4(a) 6.8Separation of domestic and �r e

protection supplies R15.29 6.49r e m b u S ged outlets to washbasins or baths R15.14 6.38

Washing machines, washer – driers and dishwashers R15.16 6.41

Whole site and zone protection R15.26 6.47Backpressur e

Description of R15.4a 6.26BacksyphonageDescription of R15.4b 6.26

Bath inlet abo ve spillo verBack�ow protection G15.13 6.36

Bath inlet below spillo verBack�ow protection G15.14 6.38

BathsBath taps G15.13 6.36Combined over�ow/warning pipe discharge R16.9 7.9Noti�cation of large volume 4(b), Table

Reg. 5 5Submerged inlets G15.14 6.38Waste outlets G28.1 10.6Ascending spray G15.9 6.28

BidetsBack�ow protection – over the rim supply G15.11 6.32Back�ow protection - submerged inlet

or �exible hose G15.9 6.28Over the rim type, back�ow prevention for G15.11 6.32

Bidets inlet abo ve spillo verBack�ow protection G15.13 6.36

Bidets inlet below spillo verBack�ow protection G15.9 6.28

Bidets with ascending sprayBack�ow prevention, alternative methods G15.10 6.29

BoatsBack�ow prevention R15.30 6.51

Booster pumpsNeed for written approval for installation of G6.1 3.15

British StandardsReference to, in selection of �ttings G2.4 2.13

Building Regulation G3Installation of unvented hot water storage G19.1 8.10

Buried cisternsDesign and installation R16.13.1 7.12

CA non-veri�able disconnectorDescription of back�ow prevention device S15.3 6.11

Capillary �ttingsUse of R2.1.4 2.8

Cathodic protection Protection of copper cylinders by G3.4 3.5Access cover, cistern over 1,000 litres G16.13 7.11

Cisterns Accessibility G16.14 7.14 Bottom outlets from cisterns G16.6 7.7Coatings G16.13 7.11Common warning or over�ow pipes from

two or more cisterns R16.15 7.15Common warning pipes, need for G16.12 7.11Condensate on lid, contamination of G16.13 7.11Discharge points of warning and

over�ow pipes R16.9 7.9Domestic, protection against freezing G4.2/.3 3.6Exclusion of insects G16.13 7.11Filling rate, per slab width, urinals G25.12b 9.13Filling rates, automatic urinal G25.12a 9.13Fixing of �oat control devices R16.5 7.6Fixing of inlet valves G16.5 7.6Inlets to cisterns R16.4 7.6Lid speci�cation G16.13 7.11Linking together G16.15 7.15Maintaining water temperature in

storage combination units R16.13.4 7.13

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Cisterns (continued)Minimum headroom G16.14 7.14Minimum size of warning pipe R16.10 7.10Outlets from cisterns serving

primary circuits R16.7 7.7Provision of adequate support to cisterns R16.14 7.15Reduced requirements for cisterns

serving primary circuits R16.13.5 7.13Reduction of microbiological growth

in cisterns R16.13.3 7.13Supplying hot water systems G20.4 8.15 Support of G16.14 7.14Vermin screens to warning and

over�ow pipes R16.11 7.10Warning & over�ow provisions G16.13 7.11Warning and over�ow pipes G16.8 7.8Warning level relative to over�ow G16.5 7.6Water tight construction, requirements for G16.13 7.11

Citation, commencement and interpr n o i t a t eWater Byelaws 2000, Scotland 11 Water Supply (Water Fittings) Regulations 3

Coal tar productsProhibition of the use of G2.1 2.4

CoatingsCistern, cold water G16.13 7.11

Cold water temperaturesMaximum distribution temperature G9.1 4.10

Colour coding of pipesTo prevent cross connection G14.1 5.4

Combi boiler �ow rates G8.4 4.9

Combination hot water storage unitsTemperature of distributed water G18.2/4 8.9

Combination tapsAppropriate for �ow and pressure G2.9 2.15Back�ow prevention R15.13.2 6.37Standards for high and low pressur e G2.10 2.15

Combined temperature and pressur erelief valvesNeed for HW Storage abo ve 15lts capacity G17.1b 8.4Requirements for operation G22.1 8.21Requirements for the provision of G23.1 8.22

Common connection Domestic & �re supplies,

back�ow protection G15.29 6.49Common supply pipes

Secondary back�ow protection G15.24 6.45Common warning pipesDischarge from over�ow in one

cistern to another G16.9/12 7.9 Compatibility of di�erent materials

Selection of �ttings G2.5 2.13Concealed �ttings

Accessibility G7.1 3.17Gunmetal G7.4 3.21In solid �oors G7.3 3.21Requirement for dezinci�cation resistance G7.5 3.21

CondensateCistern lid, contamination due to G16.13 7.11

Connection for �llingClosed circuits for heating systems G24.1/.2 8.24

Connection for warning pipeRequirement for, in WC cisterns G25.6 9.6

Conspicuous dischargeR r i u q e ement for, from cistern warning pipe G16.12 7.11

Consumption of waterDish-washer, domestic G29.3 11.4Washer-drier, domestic G29.2 11.4Washing machine, domestic G29.1 11.4

Contaminated groundInstallation of pipes or �ttings in G4.16 3.12

Contamination of materialsMaterials and substances in contact

with water G2.1 2.4Contamination of water

Ban on substances which may cause – G2.1 2.4By permeation of �uids G4.14/15 3.11Location of cistern in contaminated locations R8.6 4.10Restriction on �ttings in contaminated

environment R8.5 4.9Contractor’s certi�cate

Water Byelaws 2000, Scotland 14Water Supply (Water Fittings) Regulations 6

Contravention of byelaws and defences Water Byelaws 2000, Scotland 14

Contravention of regulations and defences Water Supply (Water Fittings) Regulations 6

Control of �ushingUrinals, automatic or manual G25.10 9.10

Control of water entering a building G10.5 4.14

Control of water to premises G10.3 4.12

Convenient drinking tapRequirement for G26.1 10.4

Copper cylindersCathodic protection for G3.4 3.5E�ect of local water on G3.4 3.5Thickness of G3.4 3.5

Covering operational valves G10.2 4.12

Critical water levelDe�nition R15.1 6.10

Cross connectionsTo unwholesome water, prevention of G14.2 5.5

DA anti-vacuum valveDescription of back�ow prevention device S15.3 6.11

Damage to water �ttingsProtection for the prevention of G4.17 3.12

DB pipe interrupterDescription of back�ow prevention device S15.3 6.11

DC pipe interrupterDescription of back�ow prevention device S15.3 6.11

Dead legsRemoval of G11.7 4.16

Default pressuresFittings to withstand G4.1 3.6

Depth of coverFor underground pipes G7.7 3.22

Design of water systemsFlow rates and pipesizing R8.3 4.8Flow rates with instantaneous boilers R8.4 4.9General considerations R8.1 4.4Types of distribution systems R8.2 4.7

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Detergent dispensing by garden hoseBack�ow protection G15.22 6.43

Deterioration of materialsGalvanic action R3.2 3.4

Dezinci�cationConcealed �ttings, safety devices and

back�ow prevention devices R7.5 3.21Marking of �ttings G7.6 3.21Resistant �ttings below ground G7.9 3.24Thickness of protection G7.6 3.21Use of DZR �ttings G7.4 3.21

Discharge from warning pipesNeed for conspicuous discharge G16.12 7.11Requirements for G16.8 7.8

Discharge pipeExpansion & temperature relief valves G19.1/3 8.10

Disconnection of disused �ttings and branch pipesRedundant �ttings and dead legs R11.7 4.16

DishwashersDomestic use, back�ow protection G15.16 6.41Non-domestic use, back�ow protection G15.16 6.41

DisinfectionDisposal of disinfection �uid R13.3.5 4.21Following suspected contamination G13.2d 4.19For systems not regularly used G13.2e 4.19Introduction of disinfection �uid to

the water system R13.3.2 4.20Major extensions and alternations G13.2b 4.19New installations G13.2a 4.19Procedure R13.3.1 4.20Underground pipework G13.2c 4.19Using chlorine R13.3.3 4.20Using other than chlorine R13.3.4 4.21

Disputes Water Byelaws 2000, Scotland 15Water Supply (Water Fittings) Regulations 8

Distinguishing types of pipesColour coding of pipelines R14.1 5.4

Distributing pipesDe�nition R1.1.3 1.6Provision of drain taps for G11.4 4.15

Distribution systemsTypes of G8.2 4.5

Distribution temperatur eCold water, maximum recommended R9.1 4.10

Diverter with automatic returnHC back�ow prevention device,

description of S15.3 6.12Domestic hose

Back�ow protection G15.20 6.42Domestic hose, existing

Back�ow protection G15.21 6.43Double check valves

Location of, on domestic hoses G15.20 6.42Downstream back�ow riskRelated to �uid categories G15.3 6.25

Drain downTo prevent freezing G4.3 3.6

Drain tapsBuried G11.6 4.15Frost-free location G11.5 4.15Labelling G4.10 3.8Operating requirements of G2.7 2.14Provision of G11.4 4.15Spherical type G11.5 4.15Standards for G11.5 4.15Submerged G11.6 4.15Thermostatically controlled for

prevention of freezing G4.5 3.7Types of drain taps G11.5 4.15

Draining supply and distribution pipes G11.4 4.15

Drinking waterAlternative sources of drinking

water supplies R27.2 10.4Drinking water points in houses R26.2 10.4Labelling of drinking water taps R27.4 10.5Provision of wholesome supply R27.1 10.4Standards for installation of supply to pigs G30.5 12.6Water softened on the premises R27.3 10.5

Drinking water fountainBack�ow protection G15.15 6.41Outlet plug not required G28.1e 10.6

Drinking water tapRequirement for tap o� supply pipe R26.1 10.4

Dual and single �ushReplacement of existing WCs G25.15 9.15

Dual �ush operationInstructions for use of G25.5 9.6

Dual �ush WCsLimit for lesser �ush volume G25.3 9.5

Ductile iron pipesSpeci�cation and installation r s t n e m er i u q e R2.1.3 2.5

DuctsRemoval of pipes from G7.3 3.21Requirement for pipes in G7.2 3.20Sealing of G7.2 3.20

DUK1 anti vacuum valveDescription of back�ow prevention device S15.3 6.11

DurabilityE�ect of, in selection of �ttings G2.5 2.13

EA veri�able single check valv eDescription of back�ow prevention device S15.3 6.11

EB non-veri�able single check valv eDescription of back�ow prevention device S15.3 6.11

EC veri�able double check valv eDescription of back�ow prevention device S15.3 6.11

ED non-veri�able double check valv eDescription of back�ow prevention device S15.3 6.12

E�ect of water on copper cylinders G3.4 3.5

Embedding of pipesAccessibility G7.1 3.17

Energy conser vationMaximum hot water pipe length G18.7 8.10

Enforcement Water Supply (Water Fittings) Regulations 7

Exceptional freezing conditions Precautions against, G4.3 3.6

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I n d e x

Exclusion of insectsCold water storage cistern G16.13 7.11

Existing �ushing cisternReplacement by cistern of similar volume G25.15 9.15

Expansion cisternCapacity and water level G21.1 8.21

Expansion relief valves Discharge pipe speci�cation G19.4 8.13

Expansion system Integral expansion system G17.1d 8.4

Expansion system malfunctionSafe discharge expansion relief valv e G17.2 8.7

Expansion valvesExpansion valve speci�cation G22.2 8.22R r i u q e ement for, if HW storage over 15 litr s e G17.2 8.7Requirements for – G22.1 8.21Speci�cation to BS6283(1) G22.2 8.22

Expansion waterAccepted into cold water storage cistern G20.4 8.15Expansion vessel �ow through type G17.3 8.8Maintaining cold water temperature G20.5 8.18Primary feed and expansion cisterns G21.1 8.21Returned to the supply pipe G17.1d 8.4Water level in feed and expansion cisterns G21.1 8.21

External corrosionE�ect of, in selection of �ttings G2.5 2.13

External temperaturesE�ect of, in selection of �ttings G2.5 2.13

Fatigue of materialsE�ect of, in selection of �ttings G2.5 2.13

Fertiliser dispensing by garden hoseBack�ow protection G15.22 6.43

Fire sprinklers and hose reelsBack�ow protection G15.27 6.48

Fittings appr ovalUse of appr oved test house G2.3 2.13

Fixing of water �ttingsRecommended spacing of pipe supports G4.17/.18 3.12

Float operated valvesAnimal drinking troughs or bowls G30.1 12.4Flow control for cisterns using G16.1 7.4For use with hot water G16.3 7.6Requirements for R16.2 7.4

Flow rateCombination boilers, hot water

temperatures G18.4 8.9Flow reduction

Insect screen on o ver�ow causing G16.11 7.10Fluid categories

o l f k c a B w device related to do r t s n w eam risk G15.3 6.25De�nitions and examples of Section 6 .1 6.2

Flushing of water servicesRecommendation to follow BS6700 R13.1 4.19

Flushing urinals Flushing rate, complies with BS 1876 G25.12 9.13

Flushing valve, manualFor urinal or WC �ushing G15.12 6.33

Foreword vii

Fountain, drinking waterBack�ow protection G15.15 6.41

Clause

Section Number and Page

FreezingExtreme conditions G4.3 3.6

G4.11b 3.9Factors in the prevention of G4.4 3.7In unoccupied properties, prevention of G4.3 3.6Normal conditions, protection for G4.11 a 3.8Protection of �ttings outside

thermal envelope G4.2 3.6Shut o� & drain down G4.3 3.6

Frost protection Distinction between normal and

extreme conditions G4.11 3.8E�ectiveness of insulation G4.4/.8 3.7Exceptionally cold circumstances G4.5 3.7For expansion & temperature relief pipes G19.2 8.11General provisions G4.1/.13 3.6Insulation materials G4.6/.7 3.8Insulation of cisterns G4.13 3.10Insulation to hot water pipes G4.9 3.8Location of pipes R4.3 3.6Thermal envelope R4.2 3.6Trace heating R4.12 3.10

Frost statsFor prevention of freezing G4.5 3.7

Galvanic actionE�ect of mixed materials G3.2 3.4Protection against G2.11 2.15With lead and other materials G2.11 2.15

Garden hosesBack�ow protection – domestic G15.20 6.42

Gas permeationPlastics and permeable materials R4.16 3.12

Gate valvesRequirements of G2.8 2.14

Grey waterColour-coded pipes to distinguish G14.1 5.4

GuidanceGeneral, Regulations/Byelaws 2000 16

Gunmetal �ttingsRequirement for concealed �ttings G7.3 3.21

HA hose union back�ow preventerDescription of back�ow prevention device S15.3 6.12

HC diverter with automatic returnDescription of back�ow prevention device S15.3 6.12

Health care premisesTemperature of hot water pipes and outlets G18.6 8.10

Hose pipe for house gardenHand held hoses with self closing mechanism G15.17 6.41

Hose pipe materialsUse with washing machines etc. G2.6 2.14

Hose union back�ow preventerHA back�ow prevention device S15.3 6.12

Hose union tap incorporating double check HUK1 back�ow prevention device S15.3 6.12

Hot water �oat valvesRequirements for G16.3 7.6

Hot water pipesMaximum un-insulated lengths G18.7 8.10

Hot water systemsClosed primary circuits – �uid category R24.2 8.24Closed primary circuits – general R24.1 8.24

I n d e x

Hot Water Systems (continued)Discharge pipes from expansion valves R19.4 8.13Discharge pipes from safety devices R19.1 8.10Expansion and safety devices R22.1 8.21Expansion valves – Requirements R22.2 8.22Expansion vessels – Use of R17.3 8.8Expansion water, e�ect on stored

water temperature R20.5 8.18Hot water distribution temperature R18.2 8.9Independent water heaters R17.1.1c 8.6Indirectly heated HWS using high

temperature primary heater R20.7 8.20Maximum lengths of un-insulated pipe R18.7 8.10Methods of accommodating expansion water R17.1.3 8.6Minimum air gap at termination of vent pipe R20.3 8.14Non-mechanical safety devices R23.2 8.23Purpose of expansion valve R17.2 8.7

z i S e of primary feed and expansion cisterns R21.1 8.21Temperature and combined temperature

and pressure relief valves R23.1 8.22Temperature of hot water at terminal

�ttings and on pipe surfaces R18.4 8.9Temperature of water within a hot water

storage system R18.1 8.8Thermostatic valves for safe use of R18.5 8.9Unvented hot water system with

vented primary circuit R17.1.2 8.6Unvented hot water systems R17.1.1 8.5Vent pipe above warning pipe in cistern R20.1 8.13Vented hot water systems requiring

dedicated cold water cisterns R20.6 8.18HUK1 hose union tap

Description of back�ow prevention device S15.3 6.12Impervious liningFountains, ponds and pools G31.1 12.6

Independent cold water distributing pipeAscending spray bidets installation G15.10 6.29

Inlet servicing valv eAnimal drinking bowls G30.2 12.4Inlet to cistern, requirement for G16.4 7.6

Insecticide dispensing by garden hoseBack�ow protection G15.22 6.43

Inspections, measurements and tests Water Byelaws 2000, Scotland 14Water Supply (Water Fittings) Regulations 7

Instantaneous water heater �ow rates G8.4 4.9

InstructionsDisplay of, for dual �ush WC operation G25.5 9.6

InsulationConditions a�ecting the e�ciency of G4.4 3.7Hot water �ttings outside thermal envelope G4.9 3.8Roof space, protection of �ttings b y G4.13 3.10Storage cisterns G4.13 3.10

Insulation materialsClose cell type G4.6 3.8Essential installation requirements G4.8 3.8Protection against damage G4.8 3.8Protection against moisture G4.8 3.8Thermal conductivity G4.7 3.8

Internal corrosionE�ect of, in selection of �ttings G2.5 2.13

Internal temperaturesE�ect of, in selection of �ttings G2.5 2.13

InterpretationsBack�ow prevention arrangements

and devices R1.1.2 1.4Back�ow prevention arrangements Table

S15.2 6.10Back�ow prevention devices Table

S15.3 6.11Chemical water conditioner R1.1.3 1.7Cisterns R1.1.3 1.6Communication pipes R1.1.3 1.6Contamination of water supplied by

an undertaker R1.1.2 1.4Critical water level S15.1 6.10Distributing pipe R1.1.3 1.6Erroneous measurement R1.1.2 1.4General interpretations relating to

back�ow requirements S15.1 6.10Misuse R1.1.2 1.4Physical water conditioner R1.1.3 1.7Service pipe R1.1.3 1.5Spillover level S15.1 6.10Supply pipe R1.1.3 1.5Undue consumption R1.1.2 1.4Waste R1.1.2 1.4Water �ttings R1.1.3 1.5Water softener R1.1.3 1.7Wholesome water R1.1.3 1.5

Irrigation systemsBack�ow protection G15.19 6.42

Joints on pipes and �ttingsAdhesives and underground pipes R7.10 3.24Joining of di�erent types of materials R2.11 2.15Jointing compounds R2.15 2.16Pipes, pipe �ttings and joints R2.1 2.4PTFE tape R2.16 2.16Silver solder or brazing material R2.13 2.16Soft solders R2.12 2.16Soft solders and stainless steel pipes R2.14 2.16

JoistsNotching for pipe installation G7.1 3.17

Key to symbols vi

LA pressurised air inlet valv eDescription of back�ow prevention device S15.3 6.12

LabellingServicing valves G4.10 3.8Stopvalves G4.10 3.8Taps in non domestic premises G27.4 10.5

LB pressurised air inlet v v l a e, with check v v l a e

Description of back�ow prevention device S15.3 6.12Lead, lead alloys or coal tar products

Prohibition of the use of G2.1 2.4Lengths of hot distribution pipes

Maximum un-insulated G18.7 8.10Lid speci�cation

Cold water storage cistern G16.13 7.11Linking together cisterns

Preventing short circuiting G16.15 7.15

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I n d e x

Location of operational �ttings G10.2 4.12

Location of servicing valves G11.2 4.14

Location of stopvalves G10.5 4.14

Location of water �ttingsConcealed �ttings R7.3 3.21Pipes entering premises below ground lev l e R7.2 3.20Requirements for R7.1 3.17

MaintenanceStopvalves, servicing valves and drain

taps, access for G10.1 4.12Use of servicing valves to facilitate G11.1 4.14

Maximum �ush volumeWC, single and dual �ush G25.3 9.5

Maximum operating pressur e G5.1 3.14

Mini-irrigation systemsBack�ow protection G15.23 6.44

Minimum depthFor underground pipes G7.7 3.22

Minimum headroomCold water storage cistern G16.14 7.14

Mixing tapsBack�ow protection R15.13.2 6.37

Modi�cation Water Industry Act Section 73 Reg. 8, 6

Movement below groundAllowance for G7.9 3.24

Movement of �ttingsAllowance for thermal or other cause G4.18 3.12

Night pressures G5.2 3.14

Non-mechanical safety deviceFusible plug thermal relief valves G23.2 8.23

Non-mechanical back�ow devicesPreference for protection by G15.5 6.26

Non-metallic materialsCompliance with BS6920 G2.2 2.13

Non-veri�able disconnectorCA device for back�ow protection S15.3 6.11

Non-veri�able double check valv eED device, for back�ow protection S15.3 6.12

Non-veri�able single check valv eEB device for back�ow protection S15.3 6.11

Notching joistsFor pipe installation G7.1 3.17

Noti�cationBooster pumps G6.1 3.15Byelaw 5, Scotland 13General commentary 16Regulation 5, England and Wales 5

Operating pressur eMaximum design pressure G5.1 3.14

Operational �ttingsAccessibility R10.1 4.12Concealed or decorative material covering R10.2 4.12Examples R10.1 4.12Location of servicing valves R11.2 4.14Location of stopvalves in buildings R10.5 4.14Provision of draining taps R11.4 4.15Stopvalves – controlling more than

single premises R10.4 4.14

Stopvalves – provision to premises R10.3 4.12Types of servicing valves R11.3 4.14Water supplies in common to two or

more premises R10.4 4.14Outlets, cisterns

Requirement for servicing valve G16.7 7.7Outlets, waste

Plugs, requirements and exemptions R28.1 10.6Outside �ttings

Protection against freezing G4.2 3.6Over the rim bidet

Back�ow prevention for G15.11 6.32Over�ow and warning pipes

For water storage R16.8 7.8For WC R25.6/8 9.6

Over�ow inlet & outlet G16.8 7.8

Over�ow pipesCapacity reduction due to screen G16.11 7.10Capacity related to inlet valve failur e G16.10 7.10Discharge arrangement, linked cisterns 2 1 / 9 . 6 1 G 7.9 Flexible hose attached to G16.8 7.8Required fall in installation G16.8 7.8Requirement for G16.10 7.10Requirement for, with ‘no less e�ectiv e’

warning device G16.8 7.8Permanently vented distribution pipes

As back�ow prevention devices G15.6 6.27Permeable hoses

For irrigation, back�ow protection G15.19 6.42Permeable materials

Location to avoid contamination G4.14 3.11Petrol or oil contamination

In contact with plastic pipes G4.16 3.12Pipe interrupter, moving element

DB device for back�ow prevention S15.3 6.11Pipe interrupter, permanent atmospheric

DC device for back�ow prevention S15.3 6.11Pipe location

To avoid contaminating �uids G4.15 3.11Pipe suppor t G4.18 3.12

PipesEntering premises underground G7.2 3.20In cavity walls or through joists G7.1 3.17

Pipes undergroundMinimum depth G7.7 3.22

Pipes, mixed metalsE�ect on corrosion G3.2 3.4

Pipes, pipe �ttings and jointsCopper tubes R2.1.4 2.8Ductile iron pipes R2.1.3 2.5Iron pipes R2.1.3 2.5Lead pipes prohibited R3.2 3.4Plastics pipes for hot and cold water use R2.1.7 2.12Polyethylene pipes R2.1.6 2.11Stainless steel pipes R2.1.8 2.12Steel pipes R2.1.2 2.4Unplasticised pvc pipes R2.1.5 2.10

PipesizingDesign �ow rates and pipesizing R8.3 4.8

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Plastic materialsPermeation of G4.14 3.11

Plastic pipesIn contact with oil, petrol etc. G4.16 3.12

Plastic pipes and �ttingsCompliance with BS6920 G2.2 2.13

Plug cockSpeci�cation for G2.8 2.14

Plugs – waste outletRequirement for and exemptions G28.1 10.6

Pneumatic pressure vessel �re sprinklersBack�ow protection G15.28 6.49

Ponds, fountains and poolsBack�ow protection for water supply to R31.2 12.6Construction and lining R31.1 12.6Noti�cation of construction of Table Reg. 5 5

Porous hosesIrrigation, back�ow protection of G15.23 6.44

Position of servicing valv eAnimal drinking bowls and troughs G30.2 12.4

Pressure �ushing valvesFor WC �ushing in non-domestic premises G25.2 9.4

Pressure requirementsDesign for operating pressur e G5.1/.4 3.14Pressure testing G12.1/.3 4.17

Pr essure surgeAttenuation devices G5.4 3.14

Pr essure testing Metallic water systems G12.2 4.17Plastic water systems G12.3 4.18

Pressurised air inlet valv eLA device for back�ow prevention S15.3 6.12

Pressurised air inlet valve & check valv eLB device for back�ow prevention S15.3 6.12

Prevention of freezingr e S vicing v v l a es and drain taps for isolation G4.10 3.8

Primary circuit ventRequirement for discharge size & point G20.1 8.13

Primary circuitsExpansion of water in R21.1 8.21

Primary feed cisternWholesome water not required for G2.6 2.14

Primary system cisterns outletsRequirement for servicing valve G16.7 7.7

Primatic cylindersBack�ow prevention G20.11 8.20

Pr ohibited materialsUse of coal tar products, lead or lead allo s y G2.1 2.4

Protection against damageWater �ttings G4.17 3.12

Protection of insulation G4.8 3.8

Protector rodsIn copper cylinders G3.4 3.5

Provision of servicing valvesRequirements for G11.1 4.14

PTFE tapeSpeci�cation for G2.16 2.16

PumpsApproval for installation of sho wer R6.3 3.16E�ect on distribution pipes G15.8 6.28

E�ect on system operating pressur e G5.2 3.14Limitation on discharge of pumped showers R6.2 3.16Location a�ecting back�ow risks G15.8 6.28Need for written approval for installation of G6.1 3.15

Rain waterColour-coded pipes to distinguish G14.1 5.4

Recycled waterColour-coded pipes to distinguish G14.1 5.4

Reduced pressure zone valve (RPZ)BA device, description of, for

back�ow prevention S15.3 6.11Redundant �ttings and dead legs

Requirement for permanent removal R11.7 4.16Relaxation of requirements Water Byelaws 2000, Scotland 15Water Supply (Water Fittings) Regulations 7

Removal of dead legs G11.7 4.16

Repair of �ttings or appliancesExemption from Regulations/Byelaws 16

Replacement of WCs G25.15 9.15

Requirement for back�ow protection Schedule 215(1) 6.8

Requirements for water �ttingsWater Byelaws 2000, Scotland 12Water Supply (Water Fittings) Regulations 4

Restriction on installation etc. of water �ttings Water Byelaws 2000, Scotland 12Water Supply (Water Fittings) Regulations 4

Retrospective back�ow protection Garden hoses G15.21 6.43

Reverberation in pipesSigni�cance of surge pressur e R5.4 3.14

Revocation of byelaws Water Byelaws 2000, Scotland 15Water Supply (Water Fittings) Regulations 8

Risk categories for back�o wprevention devicesMechanical devices Table S15.3 6.12Non-mechanical devices Table S15.2 6.11

Routing of pipesMaintenance of hot water temperatures G18.3 8.9

Safety devicesControl of water temperature by G18.1 8.8Requirement to withstand

operational temperatures G3.3 3.5Unvented hot water systems G17.1 8.4Vented hot water storage, requirement for G20.6 8.18

Safety valvesDischarge arrangements for

expansion & thermal relief G19.1 8.10Requirements for discharge point G19.4 8.13

Sanitary appliancesAutomatic urinal cistern �ushing rates R25.12 9.13Dual �ush operating instructions R25.5 9.6Marking of maximum volume in

WC �ushing cistern R25.4 9.5Maximum volume for �ushing WC pans R25.3 9.5Pressure �ushing valves for WC pans R25.2 9.4Regulation of �ushing periods for urinals R25.11 9.11Renewal of existing WC cisterns R25.15 9.15

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Sanitary appliances (continued)Requirements for WC pans and

WC �ushing devices R25.11 9.11Urinal �ushing devices R25.9 9.8Urinals, maximum �ush volume using

pressure �ushing valves R25.13 9.14Visibility of discharge from warning pipe R25.7 9.8Warning pipe discharging over

WC pan or urinal R25.8 9.8Warning pipes from WC cisterns R25.6 9.6WC �ushing capacity and method

to Jan 2001 R25.14 9.15WC �ushing – single or dual �ush R25.1 9.4

Schedule 1 – Fluid Categories Regulations/Byelaws 2000 20

Schedule 2 – R r i u q e ements for water �ttingsRegulations/Byelaws 2000

1.3, 2.3, 3.3, 4.3, 5.3, 6.8, 7.3, 8.3, 9.2, 10.3, 11.3, 12.3

Scottish Water ByelawsFull text 11–15General Guidance 16–17Summary 10

Screwed jointsJointing compounds for G2.15 2.16Secondary use of permanently vented

distribution pipes G15.6 6.27Secondary back�ow protection

Distributing pipes R15.24.4 6.46In two storey premises R15.6 6.27Industrial and commercial applications G15.18 6.41Requirement for R15.24.1 6.46Supply pipes R15.24.3 6.46Vented distribution pipes G15.6 6.27Whole site and zone protection 6 2 / 4 2 . 5 1 R 6.45

Secondary circulation systemsThermal insulation of G18.7 8.10

Secondary vent pipesMinimum internal diameter G20.2 8.14

Selection of �ttingsFactors having an e�ect on G2.5 2.13Fittings down stream of terminal �ttings G2.6 2.14

Self-closing mechanismDomestic hoses G15.17 6.41

Service pipeDe�nition R1.1.3 1.5

Servicing valvesAnimal drinking troughs or bowls G30.2 12.4For �oat valves, back�ow prevention

devices & appliances, G11.1 4.14Labelling G4.10 3.8Location adjacent to appliance R11.2 4.14Location of G7.1 3.17

G11.2 4.14On inlets to storage cisterns G16.4 7.6Operating requirement of G2.7 2.14Outlets to cisterns G16.6 7.7Prohibition of loose washer plate G2.7 2.14Types of G11.3 4.14Use with line strainers G15.7e 6.27

Shallow pipesNeed for written approval G7.8 3.22

Shower bath trayUnplugged waste outlets G28.1d 10.6

Shower heads, discharge abo ve spillo verBack�ow protection G15.13 6.36

Showers – pumped Need for written approval for installation of G6.2 3.16

Showers – Regulators’speci�edNeed for written approval for installation of G6.3 3.16

Silver solderUse for stainless steel capillary joints G2.13 2.16

Simultaneous discharge ratesHot and cold water, combi systems G8.4 4.9

Single check valve veri�ableEA back�ow pr v e ention device, description S15.2 6.11

Single feed indirect cylindersRequirement to be vented G20.11 8.20

Single supply pipe For domestic and �re purposes G15.29 6.49

Siphonic �ushingVolume of WC �ush prior to Jan 2001 G25.14 9.15

Softened waterRequirement to be wholesome for drinking G27.3 10.5

Soil watering systemsBack�ow protection G15.19 6.42

Solder For stainless steel G2.14 2.16Lead-free for capillary joints of copper G2.12 2.16

Solid �oorsPipes in G7.1 3.17

Speci�cationExpansion relief valves discharge pipe G19.4 8.13Regulators’, for WC pans & �ushing devices G25.11 9.11

Speci�cation for PT FETape for thread sealing applications G2.16 2.16

S pherical type servicing valves G11.3 4.14

Spillo ver levelDe�nition S15.1 6.10

Stagnant waterPreventing, in cold water storage cisterns G16.15 7.15

Stainless steelSolder for capillary jointing of G2.14 2.16

StandardsFloat operated valves G16.2 7.4

StopvalvesControlling more than single premises G10.4 4.13Inside buildings G10.4/.5 4.13Labelling G4.10 3.8Location in buildings R10.5 4.14Location on common supply pipe G10.4 4.13Occupiers’access to G10.4 4.13On distribution pipes G10.3 4.12On supply pipes G10.3 4.12Operating requirements of G2.7 2.14Outside buildings G10.4 4.13Point of entry G10.5 4.14Prohibition of loose washer plate G2.7 2.14Requirement for control of water supply G10.3 4.12Speci�cation below ground G2.8 2.14To premises G10.3 4.12

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Storage cisternsInsulation of G4.13 3.10Use for supply for domestic purposes G16.13 7.11

Storage vesselHot water, single feed indirectly heated R20.4.3 8.17

Submerged drain tapsProhibition of G11.6 4.15

Suitability of �ttingsAdequate for purpose G3.1 3.4Factors to be considered G2.5 2.13Need to withstand operational temper r u t a e G3.3 3.5

Summar yWater Byelaws 2000 for Scotland 10(Water Supply) Regulations 1999 2

Supply pipeDe�nition R1.1.3 1.5Provision of drain tap G11.4 4.15

Supply to animals Flow control, drinking bowls G30.1 12.4

Support of cisternsRequirement for G16.14 7.14

Support of pipesRequirement for G4.18 3.12

Surface temperatures Pipes in health care premises G18.6 8.10

Surge pressur eE�ect on test pressure requirements G5.3 3.14Signi�cance of R5.4 3.14

Suspended �oorsPipes under G7.1 3.17

Tap gapDe�nition S15.1 6.10

Tap gap domestic AUK2Description for S15.2 6.10

Tap gap high riskAUK3 back�ow prevention device S15.2 6.11

Tap inlets abo ve spillo verBack�ow protection G15.13 6.36

Tap inlets discharging below spillo verBack�ow protection G15.14 6.38

TemperatureHot water distribution G18.2 8.9Hot water temperatures,

combination boilers G18.2 8.9Wholesome water, maximum for G20.5 8.18

Temperature – operationalPipes to be capable of withstanding G3.3 3.5

Temperature at hot outlets Health care premises G18.6 8.10

Temperature control deviceProvision for, in HW storage o ver 15lts G17.1a 8.4

Temperature of cold waterMaximum for distributed water G9.1 4.10

Temperature relief valvesAutomatic closing expansion &

temperature valves G22.1 8.21Discharge over tundish G19.3 8.11Requirement for, with non-mechanical

safety devices G23.2 8.23Speci�cation for discharge pipes from, G19.3 8.11Speci�cation to BS6283(2) G23.1 8.22Vented hot water system, solid fuel heated G20.6 8.18

Temporary connectionFountains, ponds and pools G31.2 12.6

Terminal �ttingsDraw-o� taps R2.10 2.15Exclusion from requirement for

dezinci�cation resistance G7.5 3.21Suitability for pressure and �o w

requirements R2.9 2.15Test house

Use of appr oved, for materials and �ttings G2.3 2.13Test pressuresRequirements for G12.1 4.17

TestingPressure testing of rigid pipe systems R12.2/3 4.17Pressure testing plastics pipes R12.3 4.18Requirement for pressure testing R12.1 4.17

Thermal conductivityOf insulation materials G4.7 3.8

Thermal envelopeProtection of hot water �ttings outside of , G4.9 3.8

Thermal insulation materialsStandards for G4.6 3.8

Thermal movement in pipesAllowance for, in installation G4.18 3.12

Thermal safety devices Requirements for G20.6/7 8.18

Thermostatic controlAutomatic and manual re-setting G20.6/7 8.18

r t n o C ol of temper r u t a e at hot outlets using G18.5 8.9Terminal �ttings, hot water in

public buildings G18.5 8.9Time and temperatureHot water temp / time speci�cation G18.4 8.9Instantaneous water heaters hot

water temper s er u t a 4 . 8 1 G 9 . 8Temperatures of hot water at

terminal �ttings G18.4 8.9Trace heating

Self regulating for frost protection G4.12 3.10Trains

Back�ow prevention for �lling R15.30 6.50Transient pressuresOccurrence and consequences G5.4 3.14

Triggers, self closingRequirement for domestic hose G15.17 6.41

TundishDischarge from expansion relief valv e G19.4a 8.13WC warning pipe discharge to G25.7 9.8

Type B upstandDe�nition S15.1 6.10

Types of distribution systemMethods of supplying G8.2a 4.5

Underground �ttingsDezinci�cation resistant G7.9 3.24Exceptions to minimum depth of cover R7.8 3.22Minimum depth for G7.7 3.22Prohibition on use of adhesives G7.10 3.24Protection from damage or frost G7.8 3.22

Unoccupied propertiesProtection against freezing G4.3 3.6

Unvented hot water systemsRequirements for safety of G17.1 8.4

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Unvented primary circuitDescription R17.1.2 8.6

Unwholesome waterColour-coded pipes to distinguish G14.1 5.4

Urinal �ush volumeWith pressure �ushing valves G25.13 9.14

Urinal �ushingRequirement for �ush time control G25.10 9.10

Urinal �ushing devicesSpeci�cation for urinal �ushing devices G25.9 9.8

Urinal manual �ushing valv eBack�ow protection for G15.12 6.33

UrinalsFilling rates for automatic �ushing of G25.12 9.13Flushing devices for R25.9 9.8

Use of GuideNotes on, viii

Vent pipesDischarge from primary not to

wholesome water G20.9 8.20Discharge from secondary not to

primary cistern G20.10 8.20Discharge not to primary feed cistern G20.10 8.20Discharge point, primary circuits G20.1 8.13Height of G20.3 8.14Minimum size to protect from

freezing, secondary G20.2 8.14Vent siz e

Primary hot water circuits G20.1 8.13Vented distribution pipes

For back�ow protection of cistern fed systems G15.6 6.27

Vented hot water storageTemperature relief G20.6 8.18

Vented primary circuitNo discharge in normal operation R20.3 8.14

Vented system Mechanical safety devices G20.6 8.18

Veri�able back�ow deviceDe�nition of S15.1 6.10

Veri�able double check valv eEC back�ow pr v e ention device, description S15.2 6.11

Visual alarmsStorage cisterns G16.5 7.6

Warning & o ver�ow pipeCold water storage cistern, requirements G16.13 7.11

Warning devices R r i u q e ement for ov o l f r e w and warning pipe G16.8 7.8Storage cisterns G16.5 7.6Common pipe, identi�able,

conspicuous discharge G16.12 7.11Equally e�ective alternative devices, G25.6 9.6Flexible hose attached to, prohibition of G16.8 7.8Required fall in installation G16.8 7.8Requirement for G16.8 7.8

Washbasin inlets Above spillover, back�ow protection G15.13 6.36Below spillover, back�ow protection G15.14 6.38

Washbasin or troughSelf-closing taps, plug not required G28.1c 10.6

Washing machineBack�ow protection G15.16 6.41Limitation on water consumption R29.1 11.4

Waste outletsApplications where plug not required G28.1 10.6

Water Byelaws in ScotlandText of 11

Water closetsRequirements for WC pans and

�ushing devices R25.11 9.11Water connection

Ponds, fountains and pools G31.2 12.6Water consumption

Domestic appliances G29.1/3 11.4Water draw-o� – kitchen sink

Location of drinking water point G26.2 10.4Water �ttings

Adequate for purpose G3.1 3.4Capable of withstanding

operational temperatures G3.3 3.5Underground, minimum depth for G7.7 3.22

Water Fittings and Materials Director ySelection of �ttings G2.3 2.13

Water Fittings RegulationsGeneral Guidance 16Summary 2Text 3–8

Water for non-domestic applicationsBack�ow protection G15.18 6.41

Water for outside useBack�ow protection, hose pipes for

house gardens G15.20 6.42Self-closing trigger, hose pipes for

house garden and other applications R15.17 6.41Water supplies for house garden use

in existing premises R15.21 6.43Water hammer

Cause and attenuation of G5.4 3.14E�ect on system operating pressur e G5.3 3.14

Water levelIn cisterns with alternative warning devices G16.5 7.6

Water Regulations in England and Wales 3

Water softenersDescription of types of R1.1.3 1.7For domestic use, �uid category 2 Table

G6.1b 6.26.5

Water suppliesCode of practice for supply to pigs G30.5 12.6

Water system design factorsContaminated environment G8.1 4.4

Water systemsFlushing for cleaning of G13.1 4.19

Water tightness Cold water storage cistern G16.13 7.11Suitability of �ttings R4.1 3.6

WC �ushingRequirement to clear pan contents G25.1 9.4

WC �ushing cisternsRequirement for marked water line G25.4 9.5

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WC manual �ushing valv eBack�ow prevention, pressur e

�ushing valve G15.12 6.33WC warning pipe

Discharge into WC pan G25.8 9.8Wet sprinkler systems

Back�ow protection G15.27 6.48Whole installation

Hydraulic testing of systems G12.1/.3 4.17 Whole site back�ow protection G15.24 6.45

G15.26 6.47Wholesome water Applications not requiring, G2.6 2.14Drinking water from storage cistern G27.2 10.4Requirement for tap supplying

drinking water G27.1 10.4R r i u q e ement of softened water for drinking G7.3 10.5

Working pressur ePressure testing G12.1 4.17

Written appr ovalCommentary 16Pumped showers G6.2 3.16Water supplier’s, before installation starts Byelaw 5 13

Reg. 5 5Zone back�ow protection G15.24 6.45

G15.26 6.47Zone protection

Industrial and commercial applications G15.18 6.41

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GL Ground level

WC Water closet

WB Washbasin

SL Spill-over level

WP Warning/over�ow pipe

SV Stopvalve

SgV Servicing valv e

CV Appliance control valve or tap

DT Drain tap

T Tundish with air gap

SCV Single check valv e

DCV Double check valve

FC Siphonic or non-siphonic �ushing cistern

PFC Pressure �ushing cistern

FV Pressure �ushing valv e

PRV Pressure reducing valv e

TRV Temperature relief valv e

TPRV Combined temperature and pressure relief valv e

EV Expansion valv e

ExVl Expansion vessel

S Strainer

AVV Anti-vacuum valve

PIDC Pipe interrupter with permanent atmospheric vent

PIDB Pipe interrupter with atmospheric vent and moving element

Abbreviations and Symbols