Building Regulationsfor the Conservationof Fuel and Power

BUILDINGS OTHERTHAN DWELLINGS

The latest amendments to Approved Documents Lfor the conservation of fuel and power (England)came into effect on 6 April 2014, and represent thenext in a series of stages leading to the ultimatetarget of net zero carbon for all new buildings by 2019.

The journey began in 2002 with the introductionof more stringent requirements for the thermalperformance of the individual elements of a build-ing, i.e. roof, walls and floor, together with a newmethod for calculating compliance.

Subsequent changes in 2006 and 2010 steadilyimproved standards further, and changed thewhole approach to constructing energy efficientbuildings by looking at the carbon emissions of thebuilding as a whole, rather than simply settingstandards for the thermal elements. This broughtin factors such as lighting systems, air tightness,thermal bridging, occupancy and use, and solar gain.It also recognised the complexities of the differenttypes of non-domestic buildings and started to differentiate between the capacity of each type tomake energy savings.

Interestingly, the latest changes still allow complianceto be achieved through a fabric first approach,without the need to rely on renewable technologies

in most instances. Although the gap between thecurrent standards and the 2019 net zero carbontargets is still significant, having a fresh focus onthe building envelope will provide a solid platformfrom which to work towards this final goal.

This E-brochure takes a look at the requirementsof Approved Documents L2A and L2B 2013 forbuildings other than dwellings.

Introduction

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2006

2010

2014

2016

2002

• Simple but prescriptive methods of compliance using either elemental or target thermal performance values(U-values) or carbon index.

• New Combined Method of calculating compliance using SBEM (Simplified Building Energy Model).

• Introduction of a whole building carbon emissions approach, with minimum Target CO2 Emissions Rate (TER) showingan improvement of between 23-28% in energy performance against a 2002 notional building of the same type. • All buildings must be designed and built such that their Building CO2 Emissions Rate (BER) is no worse than the TER. Compliance claculated using updated SBEM or equivalent.

• Approved Documents split into new build (ADL2A) and refurbishment (ADL2B)

• Average 25% carbon reduction from 2006 standards for new build.• New Notional Building targets set for a variety of non-domestic building types.

• SBEM updated; new focus on heating, lighting, air leakage and solar gain.

• The emission rate calculation has to be completed at design stage and submitted to Building Control with theplanning application.

• New rules for shell and fit out buildings.

• 9% aggregate improvement over 2010 standards• New Notional Building Specification can be used as a route to compliance.

• Design stage submissions are needed 1 day before work starts and evidence of as built compliance is neededwithin 5 days of the work ending.

• Further changes due.

2019

• All new buildings to achieve net zero carbon emission target.

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The 2013 edition of ADL2A came into effect on 6thApril 2014, and is applicable to all new buildingsother than dwellings, including those that exclu-sively contain rooms for residential purposes suchas nursing homes and student accommodation.The regulations cover:

• The construction of new buildings.

• Fit–out works, if included as part of the construc-tion of new buildings.

• Extensions to existing buildings with a total usefulfloor area greater than 100 m2 and greater than25% of the total useful floor area.

There are five criteria given in ADL2A to demon-strate compliance; three of these relate directly tothe fabric of the building. This piece focuses onthose that are related to insulation and the ther-mal performance of the building envelope.

Demonstrating Compliance

First and foremost, there is a need to show thatthe designed building carbon dioxide (CO2) emissionrate (BER) does not exceed the target CO2 emissionrate (TER). TER and BER calculations should becarried out in accordance with the National Calcu-lation Methodology (NCM) e.g. using the SimplifiedBuilding Energy Model (SBEM).

The individual fabric elements and the fixed buildingservices must achieve reasonable overall standards

of energy efficiency. Minimum backstop standardsapply, which limit design flexibility.

It is a requirement to provide evidence that theenergy performance of the building ‘as built’ matchesor exceeds the designed performance.

Evidence of Compliance

The calculations carried out using compliancesoftware such as iSBEM or other approved soft-ware can be used to supply much of the evidencethat demonstrates compliance.

ADL2A recommends that two versions of the evi-dence are presented to Building Control; the firstshould be submitted at the design stage, not lessthan one day before building work starts, and thesecond ‘as built’, not more than five days afterwork has completed.

Both the ‘designed’ and ‘as built’ submissionsshould include the TER/BER calculation as well asa list of specifications, and evidence of how thesehave been met. The ‘as built’ submission must alsoinclude the assessed air-permeability of the buildingand any changes to the designed specifications. Aclear connection should be made between the datainput into the compliance software and the productspecifications, for example the type of wall con-struction that delivers the claimed U-value.

The calculations for the ‘as built’ submission mayalso be used to provide information for the Energy

Approved Document L2A (ADL2A):Buildings other than Dwellings

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necessarily be replaced upon failure, affecting theoverall performance of the building in the long term.

A limiting value of 10m3/hr/m2 at 50 Pa is set forair permeability. In addition, limits are also set for theenergy performance of the fixed building servicesinstalled in the building.

Linear Thermal Bridging

The building fabric should be constructed so thatthere are no reasonably avoidable thermal bridgesin the insulation layers caused by gaps within thevarious elements, at the joints between elements,and at the edges of elements such as those aroundwindow and door openings.

There is currently no book of accredited details forthe 2013 standards, so either each joint detail willneed to be calculated separately, or the genericlinear thermal bridge values given in BRE IP 1/06(Assessing the effects of thermal bridging at junctionsand around openings), increased by the greater ofeither 0.04W/m·K or 50%, will need to be used.

Achieving Acceptable Air-Permeability

The achieved air-permeability, measured by pres-sure testing at construction stage, is used in thepost-construction BER calculation. If the limitingvalue of 10m3/hr/m2 at 50 Pa is not achieved thenremedial measures will need to be carried out untilthat requirement is met. If the measured air permeability is less than the limiting value of10m3/hr/m2 at 50 Pa, but greater than the designair-permeability, other improvements may still berequired to achieve the TER.

There are a number of exemptions from pressuretesting, including buildings with a total useful floorarea less than 500m2, large extensions covered byADL2A where sealing off the extension from theexisting building is impractical, compartmentalisedbuildings, and buildings that are too large or com-plex to test effectively.

Performance Certificate (EPC) for the completedbuilding.

Determining the TER

A notional building of the same size and shape as theactual building is used to determine the TER. Thenew ADL2A 2013 notional building is categorisedinto three building types.

• Side lit or unlit, HVAC services heating only

• Side lit or unlit, HVAC services heating and cooling

• Top lit.

Although some elements vary across these threecategories, such as the levels of air permeability, thenotional U-values remain consistent at 0.18W/m2.Kfor the roof, 0.26W/m2.K for the walls and 0.22W/m2.K for the floor. Buildings constructed entirelyto the 2013 notional building specification may bedeemed to comply. However, it should be notedthat in some cases achieving the notional levels ofair permeability may be an issue, in which case amore robust and reliable route to making sure thatthe BER meets or exceeds the TER would be tobuild to the backstop air permeability rate and toenhance the U-values.

The ADL2A 2013 notional building specification foreach building type is summarised in Section 5 ofADL2A and detailed in the 2013 edition of the NCMModelling Guide (NCM Modelling Guide 2013).

Limiting Fabric Standards

ADL2A sets out area weighted limiting U–valuestandards for the different fabric elements of thebuilding to ensure a minimum building envelopeperformance. These do not provide a compliantspecification and are simply provided to ensurethat the building envelope design is relativelyrobust, and that performance does not rely onmore short lived elements. For instance, the instal-lation of a renewable energy system, which may not

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Table 1

Design Static Pressure

Duct PressureClass

Maximum Positive (Pa)

Maximum Negative (Pa)

Maximum AirVelocity (m/s)

Air-leakageLimit (l/s/m2)

Low – Class A 500 500 10 0.027 x p0.065

Medium – Class B 1000 750 20 0.009 x p0.065

High – Class C 2000 750 40 0.003 x p0.065

High – Class D 2000 750 40 0.001 x p0.065

Where p is the differential pressure in Pascals (Pa)

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System Efficiencies

Each fixed building service in a building, includingair-conditioning and mechanical ventilation systems,should be at least as efficient as the minimumacceptable values set out in the 2013 edition of the‘Non-domestic Building Services Compliance Guide’(NDBSCG), published by DCLG.

Ductwork Air-leakage

The NDBSCG states that in order to limit air-leak-age, ventilation ductwork should be made andassembled so as to be reasonably airtight. Ductworkis classified according to its pressure classification:A, B, C or D. Air-leakage limits are defined for eachpressure class, Class D being the most stringent.The lower the air-leakage limit, the greater thecontribution towards reducing the overall CO2

emissions per square metre of useable floor areaof the building when setting the TER.

The maximum allowable air-leakage rates, expressedas litres of air per second per surface area of duct(l/s/m2), for each pressure class over a range ofdesign pressures are shown in Table 1.

ADL2A requires ductwork to be tested for air-leak-age where required, and states that if a systemfails to meet the standard, remedial work shouldbe carried out as necessary to achieve satisfactoryperformance in accordance with B&ES DW/143.

Fixed Building Services

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Table 2: Best starting point U-values

Achieving Compliance

The 9% aggregate CO2 savings across the newnon-domestic building mix relative to ADL2A 2010is expected to be achieved primarily throughincreased air-tightness and improved system effi-ciencies. However, the overall focus is still firmlyon ensuring that the building fabric is intrinsicallythermally efficient before other energy reduction/generation measures are considered.

The practicalities of delivering air-permeabilityrates of 7m3/hr/m2 at 50 Pa using traditional build-ing technologies can be challenging, let alonerates of 5 or 3m3/hr/m2 at 50 Pa. Reliance uponlow air-permeability to meet the energy efficiencyrequirements could give rise to potentially heftyremedial costs upon failure to pass pressure tests.A far more prudent approach could be to adoptthe minimum required value of 10m3/hr/m2 at 50Pa, together with improved U-values.

Analysis is showing that, for buildings that are notheavily air–conditioned, the U–values in Table 2 areat or around the best starting point for specifiersto work from to succeed in getting the design tocomply with ADL2A.

Any gap between the performance these U–valuesprovide and the TER can be made up relativelyeasily by any of the other variables in iSBEM orother approved software.

Element U–value (W/m2·K)

All Roofs 0.14

Walls 0.22

Floors 0.18

The University of Exeter’s Environment and Sus-tainability Institute (ESI) at the Penryn Campus inCornwall is a new multi-million pound developmentto lead cutting edge research into environmentalchange, therefore minimising the building’s CO2

emissions and environmental impact were keydesign considerations.

To minimise heatloss from the building’s groundfloor, two 150mm layers of Kingspan’s premiumperformance Kooltherm K3 Floorboard wereinstalled, delivering an outstanding floor U-valueof just 0.05W/m2.K. Kingspan Kooltherm K15 Rain-screen Board was also installed behind therainscreen elements of the building façade, helpingto achieve an external wall U-value of 0.13W/m2.K.Both products have been assigned a highest pos-sible Green Guide Summary Rating of A+.

A layout was produced for the roof insulation toensure optimum use, while adhering to the thermal and structural requirements. The ESI roofwas covered in Kingspan Thermataper TT47LPC/FM, with the exception of the stair tower, lightwell roof and pitched section, where KingspanThermaroof TR27 LPC/FM was installed; and theplant room where Kingspan Thermaroof TR26LPC/FM was fitted. The final roof U-value achievedwas 0.09W/m2.k.

Case StudyESI Building, University of Exeter

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Case StudyNorwich Academy

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The Kingspan KoolDuct System is installed in asingle fix and is also the only premium performancepre–insulated ductwork to be UL Listed as a Class1 Air Duct, to Standard for Safety UL 181 (Under-writers Laboratories: Factory Made Air Ducts & AirConnectors), when fabricated to a specificationclearly defined by UL.

The multi-million pound City Academy Norwichreplaced the outdated Earlham High School witha purpose built facility, incorporating a districtheating system linked to the nearby University ofEast Anglia campus. The academy accommodates1,100 pupils from ages 11-19 and on completion wasassessed as BREEAM ‘Excellent’ by WSP Group.

To help attain this high level of energy efficiency,2574 m2 of The Kingspan KoolDuct System wasinstalled to and from air handling units throughoutthe academy. The System comprises premium per-formance Kingspan KoolDuct panels which are themost thermally efficient insulation product commonlyused for pre–insulated HVAC ductwork. With a ther-mal conductivity as low as 0.022W/m.K, KingspanKoolDuct panels can also achieve air leakage ratesfar lower than traditional sheet metal ductwork.

The requirements for refurbishment under ADL2Bremain largely unchanged, apart from someimprovements to the requirements for buildingservices, yet even as they stand they representboth an opportunity and a challenge, as largenumbers of existing dwellings that will be with usfor decades to come currently have little or noinsulation.

New & Replacement ThermalElements

Any new or replacement roofs, walls and floorsshould have U–values no worse than the following:

Pitched roof (insulation at ceiling level) – 0.16 W/m2.K

Pitched roof(insulation at rafter level) – 0.18 W/m2.K

Flat roof or roof with integral insulation – 0.18 W/m2.K

Wall – 0.28 W/m2.K

Floor – 0.22 W/m2.K

However, lesser provisions are allowed wheremeeting these standards would result in a signifi-cant impact on the existing structure e.g. areduction of more than 5% in the internal floorarea of the room bounded by the wall, or problemsin relation to adjoining floor levels.

The new or replacement building fabric should beconstructed so that there are no reasonably avoid-able thermal bridges in the insulation layerscaused by gaps within the various elements, at thejoints between elements e.g. wall and floor junc-tions, and at the edges of elements such as thosearound window and door openings. Reasonable

provision should also be made to reduce unwantedair leakage through the newly constructed thermalelements.

Renovation of Thermal Elements

Renovation of a thermal element i.e. floor, wall or roof,could include the provision of a new layer, such ascladding or rendering an external wall surface ordry–lining the internal surface. It could also involvethe replacement of an existing layer, such asreplacing the water proof membrane on a flat roof.

Where 50% or more of the surface of a thermalelement, or 25% of the total building envelope isrenovated, the performance of the whole elementshould be improved to achieve or better the rec-ommended target U–values (see Table 3)

If achievement of the target U–value is not techni-cally or functionally feasible or would not achievea simple payback of 15 years or less, the elementshould be upgraded to the best standard that fallswithin those criteria.

Retained Thermal Elements

Where an existing thermal element is part of abuilding subject to a material change of use, orwhere an existing element is to become part of thethermal envelope where previously it was not, e.g.as part of a loft or garage conversion where thespace is now to be heated, those thermal elementsshould be upgraded to achieve the target U–valuesin Table 2, provided this is technically, functionallyand economically feasible. A reasonable test ofeconomic feasibility is to achieve a simple paybackof 15 years or less.

Where the target U–value in Table 2 is not techni-cally, functionally or economically feasible, thenthe thermal element should be upgraded to the

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Approved Document L2B (ADL2B):Existing buildings other than Dwellings

best standard that is possible with a simple pay-back period of 15 years or less. Examples of wherelesser provision than the target U–value mightapply are where the thickness of the additionalinsulation might reduce usable floor area of anyroom by more than 5%, or where the weight of theadditional insulation might not be supported bythe existing structural frame.

Beware the cheap option

It’s not difficult to see that with both internal andexternal insulation, there are potential space con-straints: floor area reduction for internal and limitscreated by eaves overhangs for external. There isalso an inevitable temptation on cost grounds touse as cheap an insulation material as possible.However, cheap insulation materials also tend tobe at the low end of the performance spectrumand, therefore, the thickness needed to achieve therequired U-value of 0.30W/m2.K is more likely totransgress the 5% floor area reduction limit or to betoo thick to fit under an existing eaves overhang.

The temptation would be to argue to building con-trol that the thickness should be reduced to fit thespace available. However, LABC has produced aguidance document on the renovation of thermalelements, which sets out the circumstances underwhich this might be acceptable. The guidancemakes it absolutely clear that the U-value cannot

be debased, without first considering whether ahigher performing insulation material can deliverthe required U-value within the space constraintsof the building and the 15 year simple paybackperiod.

Specification Matters

Working within the constraints of an existingstructure is bound to have its challenges, but thisguidance from the LABC makes it clear that thetarget U-values set out in ADL2B should not bederogated if it is technically and economically fea-sible to achieve them. Using high and premiumperformance products such as rigid thermosetinsulation make this possible by providing thin,lightweight solutions that offer a payback within15 years.

Material Change of Use andChange of Energy Status

Where a building is subject to a change of use, ora change to its energy status, which results in abuilding becoming subject to the energy efficiencyrequirements of the Building Regulations, wherepreviously it was not, then ADL2B requires thatthe thermal performance of the walls, floors androofs achieve a minimum standard of perform-ance, which varies depending on the nature of theworks taking place.

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ElementThreshold U-value

(W/m2.K)Target U-value (W/m2.K)

Pitched roof – insulation at ceiling level 0.35 0.16

Pitched roof – insulation at rafter level 0.35 0.18

Flat roof or roof with integral insulation 0.35 0.18

Wall – cavity insulation 0.70 0.55

Wall – external or internal insulation 0.70 0.30

Floor 0.70 0.25

Table 3

Case StudyLowery Centre, Waltham Forest College

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Forming part of the second stage in the multi-mil-lion pound ‘Heart of the College’ development, the1960’s Lowery Centre was externally refurbished,using Structural Insulated Panels (SIPs) to re-cladthe existing building.

The original cladding of the centre’s upper threefloors was stripped back to reveal the concretefloor slabs. Screws were drilled through the fourcorners of the Kingspan TEK® Cladding Panelsand fixed into brackets; these were then fixed toseparate slotted brackets which were secured tothe floor slabs. This double bracket arrangementallowed the position of the Kingspan TEK®Cladding Panels to be adjusted in order to ensurea smooth exterior surface. The external walls weredesigned to achieve a U-value of 0.25W/m2.K.

Window openings in the Kingspan TEK® CladdingPanels were designed to be smaller than those inthe original cladding solution, minimising solargains during summer and heatloss in winter. Abreather membrane was stapled to the exteriorface of the Kingspan TEK® Cladding Panels andthe windows were bracketed within the openings.To allow the application of the external render tim-ber battens were screwed in place outside thebreather membrane and particle boards werefixed to these. The grey and white external rendersystem was then applied to the surface of the par-ticle boards.

Thinner insulation frees space With a lambda value as low as 0.019 W/m.K, soon to be 0.018 W/m.K, Kingspan Kooltherm®

can free up more space than other commonly available insulation materials, freeing up your design options.

Visit www.kingspaninsulation.co.uk/free6 or call 01544 388 601 for more details

@KingspanIns_UK

Free Thinking

Over the past 8 months the government has pub-lished revised Building Regulations, new editionsof the Part L Approved Documents for new build-ings (ADL1A and 2A) and the non-domesticand domestic Compliance Guides, together withamendments to the Part L Approved Documentsfor works to existing buildings (ADL1B and 2B). Aswe prepared for when these came into force on6th April, the picture is now pretty much complete.

We now know the major changes to the require-ments for 2013. Homes must achieve a 6%improvement in carbon emissions relative to 2010,and a new regulation requires a calculation of thefabric energy efficiency both at the design stageand on completion. This calculation must be sub-mitted to building control at each point. Nondomestic buildings will, on aggregate, need toachieve a 9% improvement, but the exact figuresvary by building type. For offices and hotels theimprovement required is 12 or 13�, whilst for ware-houses it is between 3% and 8% depending on thelayout and size of the warehouse. Table 5 ofApproved Document L2A (1) contains a summaryof the key characteristics of the notional building.

To support these changes in the non-domestic target, there is a wider range of notional non-domestic buildings, including smaller warehouses,top lit and side lit buildings. The Department ofCommunities and Local Government (DCLG) andits advisers consider that these requirements areachievable with good fabric and building services

design, and construction or installation in mostbuilding types. They do not see the installation ofrenewable energy generating equipment as beingnecessary to achieve the new targets in mostcases.

There are also changes to the detailed standardsfor building services, contained within the nondomestic compliance guide, specifically relating tochillers, fan coil units and lighting. The minimumcooling efficiency of chillers is increased from 2.5to 2.7, and the specific fan power of fan coil unitsis reduced from 0.6 to 0.5 W/l/s. It is also worthnoting that in calculating the costs of thesechanges, a service life of 15 years is assumed forthe fan coils and chillers, and 20 years for lighting.Other aspects of the building are assumed to havea service life of 60 years, for the purposes of calculating costs for the impact assessment.

“Homes must achieve a 6%improvement in carbon emissionsrelative to 2010, and a newregulation requires a calculationof the fabric energy efficiencyboth at the design stage and oncompletion.”

The 2013 edition sees the introduction of theLighting Energy Numerical Indicator, or ‘LENI’, asan alternative compliance route for lighting design.Lighting professionals, led by the Society of Lightand Lighting, have been seeking this change for

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Introducing Part L 2013Part L 2013 came into force on 6th April, andHywel Davies, Technical Director of the CharteredInstitution of Building Services considers the2013 changes…

some time, as it helps to align lighting design prac-tice with other aspects of European Standards forlighting. It also gives competent lighting designersadditional flexibility and design freedom. However,for smaller lighting installations, that are ofteninstaller designed or specified, the existing simplerequirements have been strengthened with anincrease in initial luminaire efficacy to 60 lamplumens per circuit watt.

The 2013 edition of the regulations also includesconsolidated requirements introduced in 2012 toimplement some aspects of the Energy Perform-ance of Buildings Directive (EPBD), which requires“the feasibility of high-efficiency alternative sys-tems to be taken into account before construction

commences”. It is not entirely clear what this willmean in practice. Whether it will require a specificreport to be submitted to building control, or justan affirmation that “something has been done”, orindeed whether there will be any meaningfulenforcement at all, remains to be seen.

A further welcome change is to the layout of theApproved Documents, which are now in a singlecolumn format and so far easier to read on screenon a desktop, laptop or even a tablet. And finally,Part L 2013 only applies to England, and not toWales, who are producing their own regulationsand guidance for the first time since Building Reg-ulations were devolved to the Welsh Assembly.

The new guidance came into effect on 6th April2014, and any work started before then is coveredby the 2010 edition of the guidance. Any workwhich is subject to a building notice, full plansapplication or an initial notice submitted before6th April 2014 will also be covered by the 2010guidance provided it is started before 6th April2015. �

http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_L2A_2013.pdf

Hywel DaviesTechnical DirectorChartered Institution of Building ServicesTel: 020 8675 5211www.cibse.orgwww.twitter.com/CIBSE

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Hywel Davies, Technical DirectorChartered Institution of Building Services

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The Association of Consultant Approved Inspec-tors (ACAI) welcome the recent initiative of theDepartment for Communities and Local Govern-ment (DCLG) who have now developed a morecomprehensive strategy to deliver the zero carbonbuildings of our future. The consultations onchanges to the Regulations, and the introductionof Allowable Solutions has developed a roadmapto meet the deadlines set between 2016 and 2020.This brings a welcome business certainty (if government policy is unchanging) to developersand architects. We can now plan how we push developments to meet these targets knowingwhen, and more importantly, being guided as tohow this is being delivered.

It is clear the DCLG appreciated the impact of therecession and resultant house-building crisis by

setting the 2013 Part L as reasonably achievableimprovements. The uplift from the 2010 standardsare in the order of improvements of 6% on housingand 9% on non-domestic. This is also averagedover different building types (including housing) toappreciate the different energy profiles. Thismeans that there is a sympathetic approach to tar-gets ranging down to 3% in difficult buildings.

Some key points are:

Fabric and services: The 2010 standards of effi-ciency is close to the optimum. The 2013 changesto U-values and efficiency of services in theApproved Documents and notional buildings pushstandards to the best level without, if possible,resorting to renewables. This means that in theory,standards for services and fabric will not change

The next step to zero carbonPaul Wilkins, Chairman of the Association ofConsultant Approved Inspectors outlines how PartL 2013 has provided some business certaintyfor developers and architects…

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radically all the way to 2020 as we are reachinglimits of efficiency with these components.

Generation: Renewables will, however, need to bespecified more often to meet the 2013 standardsdue to difficult sites, options available anddesign/cost choices. Certainly for the next push in2016 to meet higher standards, it will mean thatwe will have to now consider generation as a stan-dard concept in design (not as a bolt on fix for ashortfall). We trust as happened with PV – over thenext few years the market and industry willrespond to demand, and renewables will developby being both more efficient, and cheaper.

“It is clear the DCLG appreciatedthe impact of the recession andresultant house-building crisis bysetting the 2013 Part L as reason-ably achievable improvements.”

Allowable solutions: The appreciation of a route tomeet the toughest zero carbon goal. This “endgame” is a route to meeting the toughest targets– even on difficult sites. This will allow offsiteoptions and financial redress if you cannot make abuilding perform at a figure of zero (BER) on theSAP/SBEM. The option of payment is a careful andbalanced thought provoking process to encourageon site solutions but allow alternatives.

Clearly the changes have developed a 2 sidedapproach to the targets. Firstly (and the title ofPart L) Conservation of fuel and power which hasa value in energy terms. The reduction of carbonemissions is an independent value within the newSAP and SBEM tool. The software packages nowevaluate both these values and report pass/failvalues on energy and carbon efficiencies. This alsoprevents “greenwashing” which was a potential aswe push the limits of our building performance.Loading up a poorly designed and inefficient build-ing with PV is not an option. The strategy is topush the design and specification of services to

the best values – for instance designing out solargains (not simply adding cooling).

One area of specialist advice that will no doubtdevelop further is the interpretation of SBEM andSAP assessments. The complex and hidden dataand information which is driven to a single figureanswer will need to be analysed, and be subject toexpert advice and guidance. Building control staffare trained and used to dealing with hundreds ofthese documents and build up an expertise andanalytical ability to offer proactive guidance. A fewexamples are:

• Increasing a canopy by 600mm to prevent solargain following a SBEM failure due to the coolingload. A simple fix with no maintenance and longterm benefits;

• Advising on over specification of lighting andidentifying that this was an unreasonably highproportion of the building energy profile;

• Choosing which element of energy profile wouldbe most beneficial by considering the supportingdata on annual energy use. �

Paul WilkinsChairmanAssociation of Consultant Approved Inspectors(ACAI)chairman@approvedinspectors.org.ukwww.approvedinspectors.org.uk

www.kingspaninsulation.co.uk