the water efficiency calculator (guernsey) for new dwellings

The Building (Guernsey) Regulations, 2012

The Development and Planning Authority’s calculation methodology for assessing water efficiency in newdwellings in support of Regulation 23

The Water Efficiency Calculator (Guernsey) for new dwellings

Development &Planning Authority

2012

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tion

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May

201

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endm

ents

MAIN CHANGES MADE BY THE MAY 2016 AMENDMENTS

1. Text changes made to reflect the new structure of government post May 1st 2016. All references to Departments have been removed.

How this Water Efficiency Calculator (Guernsey) differs from the UK version1. Ingeneraltherearedifferentlegislative

referencesreflectingGuernseylegislation.

3. The UK Building (Approved Inspectors, etc.) Regulations2010arenotinforceinGuernsey.Thereforeapprovedinspectorsare not recognised on the Island and all references have been removed.

3. There are no references to the UK’s Code for Sustainable Homes requirements.

4. This document assumes that the Water EfficiencyCalculatorsoftwarewillbeusedfor the assessment process.

WaterEfficiencyCalculator(Guernsey) Regulation23

3

PAGE

Introduction 4

The Requirement 4

Section 1 - General Guidance 5 Rainwater harvesting and greywater re-use 7 Swimming pools and Jacuzzis 7

Section 2 - Using the calculator software 8

Table 1 9

Alternative approach 9

Example printout for submission 10

Contents

WaterEfficiencyCalculator(Guernsey)Regulation23

4

Regulation 23

The Requirement

Extract from the Building (Guernsey) Regulations 2012

WATER EFFICIENCY

Waterefficiencyofnewdwellings. 23. (1) Thepotentialconsumptionofwholesomewaterbypersonsoccupyingadwelling,to

whichthisregulationapplies,mustnotexceed125litresperpersonperdaycalculatedinaccordancewiththemethodologysetoutintheWaterEfficiencyCalculatorforNewDwellings,asrevisedfromtimetotime,publishedbytheDepartment.

(2) Thisregulationappliestoadwellingwhichis–

(a) erected, or

(b) formed by a material change of use of a building within the meaning of regulation7(a)or(b).

Introduction

Thefollowingdocumentsetsoutthewatercalculationmethodologyforassessingthewholehousepotablewaterconsumptioninnewdwellings.ThecalculationmethodistobeusedtoassesscomplianceagainstthewaterperformancetargetsinBuilding(Guernsey)Regulations2012,regulation23 as set out below. It is not a design tool for water supply and drainage systems. It is also not capable of calculatingtheactualpotablewaterconsumptionofanewdwelling.Behaviourandchangingbehaviourcanalsohaveaneffectontheamountofpotablewaterusedthroughoutahome.


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Regulation 23

1.1Thisdocumentmustbeusedinconjunctionwiththe‘Excel’spreadsheet‘WaterUseCalculator’available to download from www.gov.gg/planning.AllconsumptionfiguresbelowmustbeinputtedintothiscalculatorandthesummarysheetprintedtobesubmittedaspartofthefullplanssubmissiontoBuildingControlforconsiderationundertheBuildingRegulations

1.2Thecalculationmethodrequirestheuseofwaterconsumptionfiguresprovidedfrommanufacturersproductdetails.Beforetheassessmentcanbecarriedout,figureswillneedtobecollectedfrommanufacturersproductinformationtodeterminetheconsumptionofeachterminalfitting,including:

a. WCsi.FlushingcapacityfortheWCsuiteincludingconsumptionatfullandpartflushfordualflushWCs.

ii.WheremultipleWCsarespecifiedwithvariousflushingcapacities,eachflushingvolumemustbeincluded separately.

b. Bidetsi.BidetsareexcludedfromtheWaterEfficiencyCalculatorfornewdwellingsduetotheirminimal

waterconsumption,andalthoughthereisinsufficientresearchtoquantifythisconsumption,anecdotalevidenceshowsthatthereisevidencethatbidetsoftendisplaceotherwaterconsumptionratherthanincreaseconsumption.

c. Tapsi.Flowrateofeachtap,atfullflowrateinlitresperminutemeasuredatadynamicpressureof

3±0.2 bar (0.3±0.02 MPa) for high pressure (Type 1) taps, or at a dynamic pressure of 0.1±0.02 bar(0.01±0.002MPa)forlowpressure(Type2)taps(BSEN200:2008,sanitarytapware,singletapsandcombinationtapsforsupplysystemsoftype1and2.Generaltechnicalspecifications)includinganyreductionsachievedwithflowrestrictions.

ii.Wheremultipletapsaretobeprovided(e.g.separatehotandcoldtaps)theflowrateofeachtapwillbeneededinordertocalculateanaverageflowrate.

iii.For‘clicktaps’andothertapswitha‘waterbreak’,themanufacturer’sstatedfullflowrateshouldbeusedtoperformcalculations(measuredasdescribedabove).Donotusetheflowrateatthebreakpoint.Afactorforpercentageofflowrateisalreadyassumedwithintheusefactorfortaps.Thereiscurrentlynoresearchtoprovideaseparateusefactorfor‘clicktaps’soastandardusefactor is applied.

iv.Tapsonbathsshouldnotbeincludedinthecalculationasthewaterconsumptionfrombathtapsistakenaccountofintheusefactorforbaths.

d. Bathsi.Totalcapacityofthebathtooverflow,inlitres(excludingdisplacement,thisisalreadyincludedin

the use factor for baths).

ii.Wheremultiplebathsarespecifiedwithvariouscapacities,eachindividualbathmustinincludedseparately.

iii.Jacuzzisarenotincludedinthewaterefficiencycalculatorastheyaregenerallynotfilledonadailybasisandtheirwaterconsumptionoverayearisminimal.

Section 1 - General Guidance


6

Regulation 23

e. Dishwashersi.LitresperplacesettingderivedfromthefiguresquotedontheEUEnergyLabel.

ii.Wherenodishwasheristobeprovidedandthereforeconsumptionfiguresareunknown,afigureof1.25litresperplacesettingmustbeassumed.

iii.Wheremultipledishwashersarespecifiedwithvariousconsumptions,eachappliancemustbeincluded separately.

f. Washing machinesi.LitresperkilogramofdryloadderivedfromthefigurequotedontheEUEnergyLabel.

ii.Wherenowashingmachineistobeprovidedandthereforeconsumptionfiguresareunknown,afigureof8.17litresperkilogrammustbeassumed.

iii.Wheremultiplewashingmachinesarespecifiedwithvariousconsumptions,eachappliancemustbe included separately.

g. Showersi.Flowrateofeachshowerattheoutletusingcoldwater(T≤30˚C),inlitresperminutemeasured

at a dynamic pressure of 3±0.2 bar (0.3±0.02 MPa) for high pressure (Type 1) supply systems, or at a dynamic pressure of 0.1±0.05 bar (0.01±0.005 MPa) for low pressure (Type 2) supply systems (BSEN1112:2008,Sanitarytapware.Showeroutletsforsanitarytapwareforwatersupplysystemstype1and2.Generaltechnicalspecifications).

ii.Wheremultipleshowersarespecifiedwithvariousflowrates,eachappliancemustbeincludedseparately.

h. Water softeners (where present)i.Percentageoftotalcapacityusedperregenerationcycle.

ii.Waterconsumedperregenerationcycle(litres).

iii.Averagenumberofregenerationcyclesperday.

iv.Numberofoccupants(basedontwooccupantsinthefirstbedroomandoneoccupantperadditionalbedroomassuming2occupantsinstudioflats).

v.Watersoftenersthatdonothaveawaterconsumptionsuchaselectromagnetictypes,arenotincludedinthecalculation.

i. Waste disposal units (where present)i.Wherepresent,astandardconsumptionof3.08litresperpersonperdaymustbeassumed.

j. External taps

i.FlowratesofexternaltapsarenotincludedinthecalculationasafixedallowanceoffivelitresperpersonperdayisassumedforexternalwateruseinRegulation23.

GENERAL GUIDANCE


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Regulation 23GENERAL GUIDANCE

Rainwater harvesting and Greywater re-use1.3Insomecasesrainandgreywaterrecyclingmaybeusedasameansofreducingwaterconsumption

toachievehigherwaterefficiencyperformancelevels.Thismaybeneededwhereoptionsforimprovingtheefficiencyofterminalfittings(taps,WCsetc.)hasbeenmaximisedandfurthersavingsarestillneeded.Rainwaterharvestingmayalsobeusedasameansofreducingsurfacewaterrunoff.Thedetailsrequiredtodeterminethesavingsthatcanbemadeusingthesesystemsareasfollows:

a. Greywateri.Manufacturerorsystemdesignerdetailsonthepercentageofusedwatertoberecycled,taking

into account the storage capacity of the system.

ii. The volume of recycled water collected from waste bath, shower and washhand basin, dishwasher and washing machine usage.

iii.TheconsumptionoffittingswheregreywateristobeusedinaccordancewhichcanincludeWCsand washing machines.

b. Rainwater (in accordance with BS8515)i.Collectionarea

ii.Yieldco-efficientandhydraulicfilterefficiency

iii. Rainfall (average mm/year)

iv. Daily non-potable water demand

Swimming Pools and Jacuzzis

1.4LargewaterconsuminginstallationssuchasswimmingpoolsandjacuzziswherethewaterisreplacedoveragreatertimeintervaldonotneedtobeincludedaspartofthewatercalculationsforRegulation23.


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Regulation 23

Section 2 - Using the calculator software

2.1 ThefollowinguserguidanceistoaidwiththeuseoftheWaterUseCalculatorsoftwareavailabletodownload from www.gov.gg/planning

2.2 Flow rate from taps (excluding bath and bidet taps) at a standard three bar dynamic pressure (0.3MPa) ( l/min)

2.3 Flow rates from showers at a standard three bar dynamic pressure (0.3MPa) at temperature of 37 C (l/min)

2.4CapacityofBaths(litres)(Note-asthecalculationworksonbathcapacity,thereisnoneedtoincludebathtapsinthe“Taps-excludingkitchentaps”sectionofthecalculator)

2.5 Flushing Volumes for Dual and Single Flush WCs (litres)

2.6WateruseperplacesettingforDishwashers(litres)

2.7WateruseperkgofdryloadforWashingMachines(litres)

2.8WhetheraWasteDisposalunitisattachedtothesink(litres)

2.9Theamountofwateroverthestandard4%allowanceusedperregenerationcycleifinstalled(litres)

2.10Thecapacityofanygreyorrainwaterharvestingsysteminstalled(litres)

2.11 Thisinformationshouldbeavailablefromthesuppliersoftheseproductsandatableisprovidedbelowwhichprovidesguidanceoftheaverageflowratesandcapacities

2.12Thecalculationallowstheuseofgreyorrainwatertoreducemainswaterdemand

2.13FurtherinformationisavailableinGuernseyTechnicalStandardGoftheBuildingRegulations.

Oncompletionofthespreadsheetsoftware,thatindicatesapositiveassessmentresult,thecalculationsheetmust be printed and included as part of the full plans submission to Building Control when applying for a building licenseundertheBuildingRegulations.


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Regulation 23USING THE CALCULATION SOFTWARE

Table 1 showssomesamplevaluesbasedoninformationfromwww.waterwise.org .uk actual values must be obtainedfromtheindividualappliancestobeusedforthefitoutstageoftheconstruction.

Component Typical Range of Consumption Consumption Taps Basin 6 l/min 2 - 20 l/min Kitchen 9 l/min 6 - 25 l/min

Baths Undersized 165 l Corner 140 l Shower 250 l Standard 225 l Roll Top 205 l

Whirlpool Spa 225 l

Washing Machines 8l/kg6-12l/kg Dishwashers 0.9 l/place 0.8 - 1.6 l/place Toilets Single Flush 6 l Dual Flush 6 l / 3 l

Alternative approach2.14Asanalternativetousingthecalculationsoftware,thesameresultcanbeobtainedfollowingthe

calculationmethodassetoutintheUK’sWater Efficiency Calculator for new Dwellings available to down load from www.Planningportal.gov.uk,copiesofthisarealsoavailablefromthereceptioninSirCharlesFrossard House.

Table 1 Sample Values


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Regulation 23


11

GUERNSEY TECHNICAL STANDARDSThe following documents have been approved andissuedforthepurposeofprovidingpracticalguidance with respect to the requirements of the BuildingRegulations

Guernsey Technical Standard A:Structure,2012editionwithMay2016amendments.

Guernsey Technical Standard B: Fire Safety - Volume1-Dwellinghouses,2012editionwithMay2016 amendments.

Guernsey Technical Standard B: Fire Safety - Volume 2 - Buildings other than dwellinghouses, 2012editionwithMay2016amendments.

Guernsey Technical Standard C: Sitepreparationand resistance to contaminants and moisture 2012editionwithMay2016amendments.

Guernsey Technical Standard D:Toxicsubstances 2012editionwithMay2016amendments.

Guernsey Technical Standard E:Resistancetothepassageofsound,2012editionwithMay2016amendments.

Guernsey Technical Standard F:Ventilation,2012editionwithMay2016amendments.

Guernsey Technical Standard G:Health,hygieneandwaterefficiency,2012editionwithMay2016amendments.

Guernsey Technical Standard H:Drainageandwastedisposal,2012editionwithMay2016amendments.

Guernsey Technical Standard J:Heatproducingappliancesandfuelstoragesystems,2012editionwith May 2016 amendments.

Guernsey Technical Standard K:Safemeansofaccessandegress,2012editionwithMay2016amendments.

Guernsey Technical Standard L1:Conservationof fuelandpower–Dwellings,2012editionwithMay2016 amendments.

Guernsey Technical Standard L2:Conservationof fuelandpower–Buildingsotherthandwellings,2012editionwithMay2016amendments.

Guernsey Technical Standard M:Accesstoanduseofbuildings,2012editionwithMay2016amendments.

Guernsey Technical Standard N:Glazing-Materialsandprotection,2012editionwithMay2016 amendments.

Guernsey Technical Standard P:Roads-Layoutdesignandconstruction,2012editionwithMay2016 amendments.

Guernsey Technical Standard Regulation 11:MaterialsandWorkmanship,2012editionwithMay 2016 amendments.

Crown copyright material is reproduced with the permission of the Controller of HMSO and the Queen’s Printer for Scotland

This Document is available in PDF format for downloading ontheStatesofGuernseywebsitewww.gov.gg

States of Guernsey - Building ControlLa CharroterieSt Peter PortGuernseyGY11FHTelephone +44 (0) 1481 717200Facsimile +44 (0) 1481 717099Email [email protected]

States of GuernseyBuilding Control

the water efficiency calculator (guernsey) for new dwellings

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