bc practice notes/maintenance

1 Plumbing work must comply with the Plumbing Regulations 1998. Technical information about these plumbing options can be found on the Plumbing Industry Commission’s website.

Level 27, Casselden Place, 2 Lonsdale Street, Melbourne, Victoria 3000PO Box 536E, Melbourne Victoria, Australia 3001Telephone + 61 3 9285 6400 Facsimile + 61 3 9285 6464DX 210 299 Melbourne, www.buildingcommission.com.au

Practice Notes Issued May 2008

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1. Summary

This Practice Note provides advice about Victoria’s 5Star Standard, together with options for compliance.The 5 Star Standard applies to Class 1 and 2buildings. Class 3 – 9 buildings must comply withthe energy efficiency measures in Section J ofVolume One of the Building Code of Australia (BCA).

2. Building and plumbing controls

2.1 Requirements

For Class 1 buildings, the BCA provides a number ofoptions to demonstrate compliance with thePerformance Requirements. Compliance with theperformance requirement can only be achieved bycomplying with the Deemed to Satisfy (DTS)provisions or by formulating an Alternative Solutionwhich complies with the Performance Requirementsor is shown to be at least equivalent to the DTSprovisions.

2.1.1 New Class 1 Buildings – options forcompliance

(a) DTS provisions

Under the DTS provisions of the BCA, new Class 1buildings are required to comply with the acceptableconstruction practice or manuals in Part 3.12.

(b) Using the Verification Method

When assessing an Alternative Solution using theVerification Methods in the BCA, new Class 1buildings are required to achieve a House EnergyRating (HER) of 5 stars using software compliant withthe Australian Building Codes Board (ABCB)protocol. The application of software is discussedlater in this practice note.

2.2 Rainwater tanks and solar hot water heater systems

Both the DTS and the Verification Method requirethat new Class 1 buildings also require1:(i) A rainwater tank connected to all sanitary

flushing systems; or(ii) A solar water heater system.

In either case, documentation must be provided tothe Relevant Building Surveyor (RBS) to ensurecompliance.

Where a solar water heater system is the chosencompliance option and a reticulated gas supply isavailable for connection to the building, the systemmust be a gas boosted solar water heater.

A list of solar water heater systems which meet therequirements is available on the SustainabilityVictoria website.

A note of caution regarding Heat Pumps:Where a solar water heater system is selected as theoption for compliance with the 5 Star Standard, theplumbing regulations do not allow for the installationof heat pump solar water heater system wherereticulated gas supply is available.

The Plumbing Industry Commission has providedadvice that this restriction is not applicable where theheat pump solar water heater system is not beinginstalled to meet the 5 Star Standard for a newhouse.

2.3 Class 2 and 4 buildings

For Class 2 buildings, an average 5 star rating isrequired for the whole building. Each sole-occupancy unit/dwelling (SOU) is to achieve a ratingof at least 3 stars. There is no requirement to install arainwater tank or solar water heater system in aClass 2 building. The BCA requirements for servicesmust also be complied with.

Residential sustainability measuresThis updates the previous Practice Note 2007-55 issued May 2007.

Part A: General requirements and new dwellings

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Practice Notes

A Class 4 part of a building must achieve an energyrating of not less than 4 stars.

2.4 Detailed plans to be provided by building designers, architects, and draftspersons.

Regulation 302 of the Building Regulations 2006(the Regulations) sets out the minimum informationthat applicants need to provide to the RBS whenapplying for the building permit. It includes anyreports or computations that show compliance withthe Building Act 1993 (the Act) or the Regulationsmust be provided.

Building designers must provide sufficientinformation on plans to enable the RBS todetermine that the application complies with theRegulations.

This requires designers to provide detailed plansand specifications. For example, window scheduleswill require specific details. This will include glasstype, frame type, U-values, SHGC values,orientation sector, and a copy of the glazingcomputations. If used, a copy of glazing calculatorresults must also be included. It is not theresponsibility of the RBS to use the glazingcalculator. This information must be provided by thebuilding designer in the building permit applicationdocumentation.

Building designers should limit the use of generalnotes. A note such as “The builder is to ensurecompliance with BCA Part 3.12” is not appropriate.The design itself must show full compliance.

Ensuring the appropriate details are provided on theplans enables the RBS to ensure compliance isachieved in order to issue the building permit. Thisalso ensures that the builder can construct thebuilding in accordance with the approved buildingpermit documentation.

2.5 Relevant Building Surveyor role inassessing plans

The RBS has a responsibly to ensure that thebuilding permit application contains sufficientinformation to determine compliance with the Actand the Regulations. Where the RBS is not satisfiedthat the appropriate information has been providedthey must not issue the building permit and shouldrequest further information to be provided. It is notappropriate that the RBS “mark-up” plans or acceptnotes on plans that are too general. The RBS shouldalso limit the use of conditions on the buildingpermit. Reliance on general conditions such as theexample previously provided is a failure of the RBSto ensure that compliance with the Act and theRegulations has been achieved prior to issuing thebuilding permit.

3. Applying the energy standards

3.1 Building permit

As noted earlier, it is the applicant’s responsibility toprovide the RBS with evidence that the proposedbuilding design will meet the DTS requirements ofPart 3.12 or show compliance with the relevantPerformance Requirements.

If a HER is provided as a Varification Method thenan accredited residential thermal performanceassessors2 must stamp the plans, recording theenergy rating and their accreditation number, whichare to be submitted with the application for abuilding permit.

For new Class 1 buildings, the applicant mustseparately provide details of any rainwater tank orsolar water heater system, including size andlocation of rainwater tank and the type and size ofsolar water heater system to be installed. This willassist the RBS in checking compliance andensuring that any possible effects on the structurehave been considered.

3.2 Averaging ratings for Class 2 buildings

The average 5 star rating for a Class 2 building isdetermined by finding the average energy load in

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2 The term “residential thermal performance assessor” is acceptednationally and used by the ABCB meaning a person assessing thethermal performance of a building. Sustainability Victoria isproposing to align with this terminology and cease using the term“energy rater”.

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Practice Notes

MJ/m2 of each SOU, or in the case of FirstRate, theaverage point score (not the average star rating).This average rating for the whole of a Class 2building must achieve the 5 star rating level set out inTable A in the Appendix. The rating for any SOU in aClass 2 building must achieve the 3 star rating levelset out in Table A.

3.3 Ratings of dwellings adjacent to vacantallotments

HERs must include details of existing adjacentbuildings and structures on neighbouring allotments,which overshadow windows of the building beingrated. However, trees, shrubs and other landscapingare not required to be considered. Note that futureconstruction to the north may have an impact on theHER.

3.4 Occupancy permit

During the building process, the RBS may choose tocarry out additional inspections to ensure that thedwelling is constructed in accordance with therequirements of the approved HER report or BCAPart 3.12 where used.

The RBS may, if necessary, request that the builderprovide a statement of compliance regardingsustainability matters. While there is no prescribedformat, FirstRate will automatically produce astatement that lists all the energy features and hassections for the builder to detail any changes tothese features. Users of NatHERS may produce asuitable report, using that software’s Building Datareport. A pro forma report is available on theSustainability Victoria website.

Where an application for an occupancy permit hasbeen submitted to the RBS and the only matters notcomplying relate to energy efficiency, then the RBShas two options:

• Refuse to issue an occupancy permit;• Issue an occupancy with conditions; or• Issue an occupancy permit concurrently

with a building notice or order.

Where a rainwater tank or a solar water heatersystem is installed, the RBS must see a copy of theplumber’s compliance certificate issued under

section 221ZH of the Act before an occupancypermit can be issued.

4. Compliance Options

4.1 Performance-based BCA

The 5 Star Standard is implemented through theBCA. The BCA is a performance based buildingcode. Compliance with the BCA can be achieved bycomplying with the prescriptive requirements or bydeveloping an Alternative Solution, whichdemonstrates that the proposal meets the relevantPerformance Requirement/s. Building practitionerschoosing to develop an Alternative Solution, shouldensure an appropriate Assessment Method is used.Further information on using the performance-basedBCA is contained in Practice Note 2006-29.

4.2 Building Appeals Board

The Building Appeals Board (BAB) is an independentstatutory body established under the Act. The BABhears appeals and disputes in relation to buildingcontrol matters and can waive, modify or vary theprovisions of the Regulations and the BCA basedupon the particular case. The BAB can considerprovisions relating to the residential sustainabilitymeasures in the BCA. Further information on theBAB is contained in Practice Note 2006-39.

5. Software

5.1 Approved software

Under the BCA Volume Two, a HER must bedetermined using a thermal calculation method thatcomplies with the ABCB Protocol for House EnergyRating Software. A thermal calculation method isdefined as a calculation method that identifies-(i) a heating load; or(ii) a cooling load; or(iii) a heating and cooling load (annual energy load),

based on the sum of hourly loads or an equivalentapproach.

The BCA 2008 references two protocol versions.Version 2005.1 sets out the requirements for firstgeneration HER software and Version 2006.1

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sets out the requirements for second generationsoftware. HER software which complies with eitherprotocol is acceptable until such time that ProtocolVersion 2005.1 is removed from the BCA.

The Australian Building Codes Board haveproposed from BCA 2009, Protocol Version 2005.1for first generation HER software will be removed.This means that from BCA 2009 only secondgeneration software can be used.

Software that currently meets Version 2005.1Protocol includes, FirstRate (Version 4.05 or later), NatHERS (version 2.32A or later) and BERS (Version3.2 or later). The use of other software may beaccepted by the RBS as meeting the relevantPerformance Requirement. The protocols requirethat a training program must be available for users.The training program must be for the use of thecurrent version and any new version of the softwareas well as an understanding of the basic principalsof residential building thermal performance.Evidence of training must state the software nameand version.

Users of first generation NatHERS should be awarethat the star rating levels are incorrect for Victorianclimates, and do not take into account areaadjustment. This has been rectified in AccuRate,which is the replacement for NatHERS. The correctstar rating must be determined manually from thepredicted energy load when using NatHERS. Referto Table A in the Appendix for the maximum annualenergy loads for a 3, 4 and 5 star rating whenNatHERS is used in Victoria. As a result NatHERSratings must be accompanied by an additionalstatement from the energy rater showing the areaadjustment allowance3 and fall within the correctstar rating levels

Where FirstRate software is used, a suitable reportis generated automatically.

In Victoria, second generation energy rating toolswill include:

• the AccuRate software (the NatHERSreplacement)

• FirstRate5 (operating with the AccuRate calculation engine)

• BERS second generation

Information about the house energy rating softwarecan be obtained from Sustainability Victoria(www.sustainability.vic.gov.au).The first generation HER tools can continue to beused for regulatory purposes while they meet theminimum protocol requirements as required by theBCA.

5.2 Using rating tools

The standard input assumptions made when ratingthe energy performance of a house are:

• That all windows have an internalcovereing installed which providesequivalent performance to a Holland(roller) blind.

• Where software requires the input of thesize of gaps around window and doorframes, these are assumed to be ‘small’.

• That all floors are carpeted, except wherealternative floor coverings are specified.

For users of FirstRate, ratings in ‘Regulation Mode’will automatically input the first two assumptions.However, areas of carpet and hard floor surfacemust be entered manually.

5.3 Limitations of energy rating software

It is not possible to take into account every featureof dwelling design with the currently approvedsoftware, although over 99 per cent of all dwellingscurrently constructed can be rated in this way.Design features such as:

• earth bermed walls• trombe walls (utilising masonry or water

tanks for storing radiant heat gains)• solar heated rock storage• insulating shutters on windows

cannot be rated with the currently approvedsoftware.

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3 Area adjustment allowance details are available on theSustainability Victoria website.


Practice Notes

In addition, where the following window area limits areexceeded, FirstRate version 4 ratings may not bewithin normal accuracy:

• Dwellings with a total window area inexcess of 60 per cent of the NetConditioned Floor Area (NCFA) of thehouse; and

• Dwellings with a window area in oneorientation of greater than 35 per cent ofNCFA.

These glazing limitations do not apply to the secondgeneration FirstRate5.

In cases where dwellings contain such features orhave window areas greater than the limits statedabove, NatHERS may be used or an AlternativeSolution will need to be provided.

5.3.1 Conservatories and other large glazed rooms

Where it is proposed to construct a building withglazing in excess of the limits stated in clause 6.3, theRBS may accept the design if the house energy raterhas excluded the room from the rating calculation andif the room:

• Does not exceed 20 per cent of the total floorarea of the remainder of the building.

• Is physically separated from the remainder ofthe building, i.e. any openings must have doors or windows.

• Is thermally isolated from the rest of thebuilding. Walls must be insulated as if theywere external. To minimise air leakage fromthe room to the main house, windows installed in the walls between them must achieve an air leakage of no more than 2 L/s/m2 of window area, as tested under AS 2047 at 75 Pa pressure difference.

• Does not contain any heating or coolingdevices.

• Has openable doors and windows in its external walls equivalent to at least 10 per cent of its floor area.

When completing the rating, if the room has a solidroof this must be entered as a fixed eave if it shadeswindows in the walls between the house and the

room. Furthermore, the rater may consider windowsbetween the main house and the room to be double-glazed if the room meets the requirements listedabove and the air leakage of the external windows tothe room achieve an air leakage of no more than 5L/s/m2 of window area, as tested under AS 2047 at75 Pa pressure difference.

5.4 Accreditation of residential thermalperformance assessors

HERs must be prepared by persons accredited inthe use of the rating tool. Residential thermalperformance assessors require separateaccreditation for each rating tool they use – thisincludes the second generation rating tools. Forinstance, to use second generation software,residential thermal performance assessors mustseek accreditation.

Organisations such as Association of BuildingSustainability Assessors and Sustainability Victoriaprovide the accreditation, a list of accreditedassessors and the specific energy rating tools theyare accredited to use is listed on their websites.

The assessor will need provide a certificate andreport and will need to stamp the plans accordingly.In the event that your design does not meet therequired minimum standard, the assessor maysuggest some alternatives to improve theperformance of the design.

5.5 Victorian climate zones

The second generation energy tools include 11climate zones for Victoria, compared to 5 for the firstgeneration rating tools. Melbourne is now dividedinto 3 climate zones, Tullamarine (climate 60),Melbourne RO (climate 21) and Melbourne Airport(climate 62).

To assist builders who construct homes acrossmetropolitan Melbourne, residential thermalperformance assessors and the RBS are advisedthat, when using the second generation energyrating tools, there are two options for the houses tobe constructed in climate zones 62 (MoorabbinAirport) and 21 (Melbourne RO):

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• either choose the correct climate zone forthe postcode in which the dwelling will beconstructed; or

• alternatively the ‘Tullamarine’ climate zone(climate 60) can be chosen as the defaultclimate zone for houses construc

6. Alternatives to rainwater tanks

6.1 Greywater treatment systems

Greywater is the waste water from your washingmachine, laundry tub, shower, hand basin, and bath- excluding the waste water from your kitchen andtoilet.

Using greywaterThere are two main options for greywater re-use –direct diversion to the garden or installing adomestic greywater treatment system.

Domestic greywater treatment systemsA domestic grey water system collects, stores andthen treats grey water. Different systems treat thewater to varying levels of purity. Some treatmentsystems only allow direct water diversion to agarden, while some achieve a water quality whichallows the treated water to be used for toiletflushing and in clothes washing machines. Clause 1.0.5 of the BCA Volume Two states thatcompliance can be achieved by formulating anAlternative Solution that complies with thePerformance Requirement. Treatment systems thatachieve a water quality that can be connected andused for toilet flushing can be considered by theRBS as an Alternative Solution but it must complywith the relevant BCA Performance Requirement(P2.6.1).

Greywater - Direct diversionThis is when grey water is diverted directly to agarden. This is the cheaper option, but it restrictsuse. Diverted grey water cannot be stored andcannot be used as an Alternative Solution. It mustnot be connected to sanitary flushing systems, andcan only be diverted through subsoil drains.

6.2 Dual water reticulation and water recycling systems

Dual water reticulation systems and mains waterrecycling raise the possibility of using a BCAperformance approach to approve a 5 star ratedhouse design that uses a dual water reticulationsystem connected to toilet flushing systems ratherthan a rainwater tank.

Some new housing estates are providing a sourceof recycled water and include a recycled watermain, as well as a drinking water main. This is oftenreferred to as a ‘dual supply’ system or previouslyas a ‘third pipe’ system. Typically, the water willcome from one of Melbourne’s major seweragetreatment plants, but supply is also possible fromsmaller localised treatment plants. The recycledwater must be supplied by the Responsible WaterAuthority and must only be used for approvedpurposes, including toilet flushing and gardenwatering.

Dual water reticulation systems raise the possibilityof using a BCA performance approach to approve a5 Star rated house design that uses a dual waterreticulation system connected to toilet flushingsystems rather than a rainwater tank.

Analysis by the Victorian Department ofSustainability and Environment confirms that a dualwater reticulation system will provide equivalent orbetter performance than a rainwater tank, in termsof water conservation, when the systems areconnected to domestic sanitary flushing systems.Dual water reticulation systems conserve drinkingwater more effectively than rainwater tanks, as theyare more reliable, regardless of rainfall and are alsoavailable for garden use.

In some housing sub-divisions, it is proposed thatrainwater is collected by each home and pipeddirectly to a treatment plant operated by the waterauthority. The treated rainwater is then piped backthrough the mains drinking water system to eachhome.

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These alternatives must still comply with the relevantBCA Performance Requirement (P2.6.1).

Clause 1.0.5 of the BCA Volume Two states that thiscan be achieved by formulating an Alternative -Solution that complies with the PerformanceRequirement, or is shown to be at least equivalent tothe Deemed-to-Satisfy provisions.Requirement, or is shown to be at least equivalent tothe Deemed-to-Satisfy provisions.

7. General information on insulation

7.1 Reflective foil insulation products

Reflective foil only provides an insulating effectwhen it faces an air space, because it works byreducing radiant heat flow across this air space. Ifreflective foil does not face an air space it does nothave an R value.

Reflective foil must be used in conjunction with anair space and air must not be allowed to leak fromone side of the foil to another. Particular care mustbe taken during construction, to ensure that allpenetrations through the foil and joins are effectivelysealed by taping around the joins and penetrations.

Reflective foil product tests often show the R valueof the whole building element, whereas bulkinsulation tests usually show the R value of theinsulation alone. Whole building element R valuesshould be entered into the ‘Total R value’ field inFirstRate, while insulation product R values shouldbe entered into the ‘Insulation R value’ field.

7.2 Bulk insulation products

Loose fill products will typically settle after a fewyears to provide a lower depth than originallyinstalled.

Batt and blanket products can suffer significantdegradation of their R-value through poorinstallation. To maintain the effectiveness of theinsulation products, it is recommended that buildersensure that:

• Insulation fits snugly against all framingmembers and that where gaps exist, off-cuts of batts are used to fill these gaps;

• Bulk insulation is not compressed; and• Insulation placed near lamps, luminaires

and associated transformers is installed inaccordance with the electrical safety alert,Thermal Insulation in Roof Spaces,published by Energy Safe Victoria.

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8. Specific requirements for alterations todwellings

8.1 Summary

The requirements for alterations to Class 1buildings contained in Vic 1.2.2 of BCA 2007 hasbeen removed from the BCA 2008.

Alterations to Class 1 buildings and Class10abuildings with a conditioned space constructed inaccordance with the Victorian energy efficiencymeasures prior to the 5 Star Standard, i.e. pre 1July 2004, are required to comply with thePerformance Requirements P2.6.1 and P2.6.2 ofthe BCA Volume Two. From 1 May 2008, this caninclude the use of the Deemed to Satisfy (DTS)requirements of Part 3.12, or using an AlternativeSolution. The Verification Methods or otherAssessment Methods may be used to assess theAlternative Solution.

A rainwater tank or solar water heater system isnot required when undertaking an alteration to anexisting dwelling.

Class 1 buildings constructed to the 5 StarStandard i.e. post 1 July 2004

Alterations to a building assessed under the 5 StarStandard must ensure that the existing 4 or 5 starHouse Energy Rating (HER) of the existing buildingis maintained.

It is not appropriate to use a HER to determine therating of the home and then assess an extensionusing the DTS provisions. An alteration or additionmust be assessed using the particular tool (HERsoftware or DTS) for which the building wasassessed prior to when the building was firstconstructed.

Similarly, an alteration to an existing buildingpreviously assessed under the DTS provisions ofPart 3.12 should be assessed by the same method.

8.2 Regulation 608 and partial compliance

Regulation 608 of the Building Regulations 2006(the Regulations) applies to alterations to anexisting building and requires that building work toalter an existing building must comply with theRegulations. Regulation 608 also requires an entirebuilding to comply with the Regulations where thevolume of the proposed alterations, together withany other alterations completed or permitted withinthe previous 3 years represents more then 50 percent of the original volume of the building.Regulation 608 also provides that the RBS hasdiscretionary power to consent to partialcompliance with the Regulations in certaincircumstances. This does not mean that the RBScan allow non compliance. When consideringpartial compliance the RBS must take the followinginto account:(a) the structural adequacy of the building;

and(b) the requirements necessary to make

reasonable provision for-(i) the amenity of the building and the safety

and health of people using the building; and

(ii) avoiding the spread of fire to or from any adjoining building.

The circumstances where the relevant buildingsurveyor (RBS) can accept partial compliance are—

• Any building work to alter an existingbuilding including an extension that is notgreater than the lesser of: (a) 25% of the floor area of the existing building; or(b) 1000m2.

• Any alteration that represents more then50% of the original volume of thebuilding, including any alterations carriedout in the previous 3 years. The discretionto allow partial compliance applies toboth the building work associated withthe alteration and the requirement to bringthe remainder of the building into fullcompliance.

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Part B: Applying residential sustainability measures toalterations and relocation of dwellings

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There is no discretion to allow partial compliancewhere the alteration is an extension to an existingbuilding and the floor area of the extension isgreater than 25% of the floor area of the existingbuilding or 1,000 square metres (whichever is thelesser). The requirement for full compliance onlyapplies to the extension and has no impact on theexisting building (unless the volume is greater than50%).

A summary of the requirements of Regulation 608and where the RBS has discretion to allow partialcompliance is included in Table B of the Appendix tothis Practice Note.

Section 28 of the Act and regulations 502, 503, 609and 1011 provide the RBS with other discretionarypowers related to partial compliance.

Where alterations constructed using concretepanels, cavity brick, earthwall construction, andashlar stone or other masonry walls including anycavity, the RBS will need to be provided withsufficient information to determine the R-value of thewall system.

Calculation of Volume and Floor AreaWhen calculating volume for the purposes ofRegulation 608, the volume of the building includesthe space above the sub-floor defined by:

• External walls;• Roof space and roof structure;• Verandas and other roofed structures

Sub-floor below floor framing areas are not includedexcept for rooms, garages etc that are enclosed bywalls, floor and roof/ceiling.

The BCA volume 2 includes a definition of floor area.Part 1.1 defines floor area as the area measuredwithin the finished surfaces of the walls and includesthe area occupied by any cupboard or other built-infurniture, fixture or fitting.

Satellite Habitable BuildingsBuildings such as a sleepout or bungalow are to beassessed as an alteration to the existing dwelling.

There is currently no requirement to install solarwater heater systems or rainwater tanks to thesestructures.

8.3 Regulation 608 – What is reasonable?

When deciding whether to permit partial complianceunder regulation 608, the RBS should consider howreasonable full compliance would be in a particularinstance, along with the likely cost and benefit.

The Macquarie Dictionary defines “reasonable” as“agreeable to reason or sound judgment”. The RBSshould apply their own judgement (using theirqualifications and experience) to the specific mattersbeing assessed. In some instances the RBS willneed to seek the advice of other suitably qualifiedpractitioners or industry experts in determining theacceptability or otherwise of a specific building,element of construction or use.4

The energy efficiency provisions have beendeveloped on a basis of saving energy and long-term cost effectiveness for the building owner. Onthe same basis, when determining whether adispensation from the energy efficiency provisionsshould be granted, it may be reasonable to ask "Is itcost effective?"

8.3.1 Principals in applying Part 3.12 Deemed to Satisfy provisions

Building fabricWhere a building is being extended, the fabric of theextension should fully comply with the BCA fabricprovisions. Partial compliance may be consideredwhere the extension is relatively small (i.e. less and25% or 1000m2 whichever is the lesser). Where thenew work includes replacement of existingelements, such as roof cladding, wall cladding orwall lining, compliance with the BCA fabricprovisions should be achieved. However, if the roofcladding, wall cladding or wall lining is only beingrepaired, then it may be unreasonable to require thisto be removed, solely to install new insulation. Fullycompliant ceiling insulation should be installedwherever there is access to the roof space.

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4 In addition, Minister’s Guideline 05 states “Municipal buildingsurveyors and private building surveyors must only acceptappointment as relevant building surveyors in the area of theirown competence.”


Practice Notes

External glazingWhere an existing building is being extended, theglazing in the extension should comply with theBCA glazing provisions. However, this iscomplicated by the fact that the glazing provisionsare determined on the basis of the whole storey.This means that the existing glazing also needs tobe considered. In some cases, it may beunreasonable for new glazing in an extension tocompensate for the poor performance of existingglazing. In this instance, it would be reasonable todetermine compliance by applying the performanceof the new glazing uniformly to the whole storey butonly require the complying glazing to be installed inthe extension.

If all the existing glazing in a building is beingreplaced, then the new glazing should comply withthe current BCA glazing provisions.

Shade is integral to glazing performance. However,there may be site constraints or planningrequirements that prevent external shading beingadded to an existing building. In such instances,the required performance level may be achieved byunshaded glazing, but only by using costlymaterials. It would therefore be “reasonable” toallow a reduced level of glazing performance, wheresuch constraints on shading exist.

Building sealingAn extension should be sealed in accordance withthe BCA sealing provisions. If an existing room isbeing extended, the need for sealing may dependupon its condition. Sealing of an existing room isan all-or-nothing matter. If the existing part is notsealed – having large areas of unsealed louvredglazing, for example – then there may be littlebenefit in sealing the new part. In the case of a newextension to an existing unsealed building, apractical approach may be to accommodate thedifferent amounts of sealing in the new and existingparts of the building by installing sealed doorsbetween the two parts. The final decision should bebased on the relative size of the extension and theextent to which the existing part is unsealed.However if sealing is practical and achievable itshould be undertaken.

Air movementThe BCA air movement provisions generally requiretwo openings in a room, or a breeze path throughto another room. In the case of some extensions, itmay not be possible to comply with theserequirements – for example, where there isinsufficient room for the two openings to beinstalled in the external wall and the existingbuilding does not have complying breeze paths.

ServicesNew building work must comply with PerformanceClause P2.6.2. for Services.Although Victoria does not call up Part 3.12.5.0 ofthe BCA. Plumbing work must comply with thePlumbing Regulations 1998. Technical informationabout these provisions can be found on thePlumbing Industry Commission’s website. – seepractitioner’s technical assistance.

Parts 3.12.5.1 to 3.12.5.3 set out the requirementsfor the insulation of services, central heating waterpiping and heating and cooling ductwork. Whetherusing HER software or applying other parts of3.12.5, insulation for service piping and ductworkmust be provided.

It is important the designers provide the RBSsufficient details of piping and ductwork insulationso that the RBS can ensure that PerformanceClause P2.6.2 is complied with.

8.3.2 Principals in using HER software

For existing dwellings that have previously beenassess using HER software, it may be necessary tohave two HER’s submitted. One of the existingbuilding design, and a second of the total buildingdesign incorporating the proposed alteration. Thesecond HER must give a higher star rating than thefirst. If the two ratings were the same, (exceptwhere they both achieve a 5 star HER) then theonly conclusion would be that no level ofcompliance has been achieved. As the RBS canonly approve a design where at least someimproved level of compliance is achieved (partialcompliance), the proposed design could not beapproved.

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9. Alternative Solutions for alterations Installing rainwater tanks or solar hot water systems

The Regulations do not require the installation ofrainwater tank for toilet flushing or a solar hot watersystem in relation to an alteration to an existingbuilding. However, as the relevant PerformanceRequirement P2.6.1. makes provision for efficientenergy and water use, it is possible for the RBS toconsider the installation of these items as anAlternative Solution to achieve compliance if theyare satisfied that the proposal contributes withother measures to satisfying the requirement of thePerformance Clause.

10. Relocated and prefabricated homes

10.1 Relocated homes

The definition of ‘alteration’ in the Regulationsmeans “construction in relation to an existingbuilding” includes building work to an existingbuilding. An existing dwelling moved from oneallotment to another or relocated on the sameallotment is considered an alteration to the dwellingexceeding the 50% volume trigger. This means thatthe RBS has discretion to allow partial complianceunder regulation 608. It is recognised that there aresometimes limited opportunities to improve thethermal performance of an existing building where itis being relocated in its original condition.

However, wherever possible, compliance with theDTS provisions should be achieved. As a minimum,required levels of insulation should be installed inceilings, walls and floor if there is access to do this.Sealing of windows and doors should beundertaken and if windows are to be replaced, thenthermally efficient windows should be provided.

This does not prevent the owner of the propertyusing best practice principals. Section 8 of thisPractice Note outlines some basic requirementswhen altering a home. These principals should beapplied to a home that is re-erected.

10.2 Prefabricated kit homes

Homes that are prefabricated in a factory, whetherthey are fully assembled or delivered to site as “flatpack” kits are required to comply with theRegulations as they are new dwellings. This meansthat the design will either have been assessedusing HER software and achieve a 5 star rating,meet the DTS provisions, or sufficient evidenceprovided that the design will meet the PerformanceRequirements of the BCA. These homes will alsorequire the installation of either a solar hot watersystem or rainwater tank.

11. Non regulatory matters

Designers, builders and to some extent buildingsurveyors are in a position to encourage greatersustainability measures than those required by theRegulations in their capacity to influenceconsumers. Although the Regulations do notrequire the installation of a rainwater tanks or solarhot water systems, where alterations are proposedto be undertaken, owners should be encouraged toconsider installing these items and potentially takeadvantage of rebate systems that apply.

Where major plumbing work is proposed and whichincludes a new hot water service installation, theowner should also be encouraged to considerinstalling a solar hot water system.

Where new stormwater plumbing work is proposed,such as new spouting and/or downpipes, an ownershould again be encouraged to install a rainwatertank at the same time. The rainwater tank shouldcomply with the minimum plumbing requirementsfor new dwellings and be connected to any newsanitary flushing systems.

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Practice Notes

12. Useful contacts and references

For further information on the 5 Star Standard,plumbing standards, or energy efficient design ingeneral, please contact the following organisations:

Websites

Building Commissionwww.buildingcommission.com.auPlumbing Industry Commissionwww.pic.vic.gov.auSustainability Victoriawww.sustainability.vic.gov.au

The Sustainability Victoria site also has details on:FirstRate training institutionsFirstRate software — cost, suppliers and obtaining ademo version.

Energy Safe Victoriawww.esv.vic.gov.auYour Homewww.greenhouse.gov.au/yourhomewww.makeyourhomegreen.vic.gov.au

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Practice Notes

Climate Zone7

Melbourne andsouthern coastalVictoria

Inland Victoria(e.g. Wangaratta,Wodonga)

Cool Inland (e.g. Ballarat,Bright)

Warm Inland(e.g. Mildura)

Alpine areas

NatHERSmaximum

annual energy load

MJ/m2

239

335

351

262

600

FirstRateminimum

point score

-28

-33

-25

-31

-35

FirstRateminimum

point score

-10

-16

-10

-14

2

NatHERSmaximum

annual energy load

MJ/m2

147

192

221

137

250

FirstRateminimum

point score

7

0

5

3

34

Appendix

Table A – Software rating levels for NatHERS and FirstRate 4

3 Stars 4 Stars 5 Stars

Rating Level

NatHERSmaximum

annual energyload

MJ/m2

191

244

271

189

413

7 Climate selection in energy rating tools is derived from the area postcode.

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Type of work

Building alterationwork includingextensions less than(the lesser of)1000m2 or 25% ofexisting floor area

Building alterationwork that exceedsthe 50% volume rule(including the re-erection of anexisting building)

Building alterationwork that is anextension of floorarea greater than thelesser of 25% offloor area of theexisting building or1,000 m


Practice Notes

Table B – Regulation 608 application to alterations and additions

Y

Y

Y

Compliance required

N*

Y

N*

Entire building tocomply? RBS discretion

Y

Y^(discretion appliesto compliance of

both the alterationwork and the

remainder of thebuilding)

N

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* Subject to the alteration not triggering the 50% rule.

^ If the alteration includes an extension that exceeds the size described in the row below, the discretiononly applies to the requirement to bring the remainder of the building into compliance.

bc practice notes/maintenance

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