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Building Regulations and Compliance: Control of Energy Use in Buildings

This article explores the history and evolution of Building Regulations in the UK, with a focus on energy conservation and carbon emissions. It discusses the different methods of compliance, including elemental methods and SAP rating. The critique of the Standard Assessment Procedure is also presented.

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Building Regulations and Compliance: Control of Energy Use in Buildings

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  1. N.K. Tovey (杜伟贤) M.A, PhD, CEng, MICE, CEnv Н.К.Тови М.А., д-р технических наук NBS-M017/NBSLM04D 2013 CLIMATE CHANGE GOVERNANCE AND COMPLIANCE Control of Energy use in Buildings Building Regulations Recipient of James Watt Gold Medal 1 1 1 Session3 Session2

  2. Building Regulations • Review of Building Regulations in UK • Factors affecting energy consumption and carbon emissions • Standard Assessment Procedure • Code for Sustainable Homes • Energy Performance Certificates • Introduction in Indian Building Regulations • Introduction to Chinese Building Regulations

  3. Introduction of Building Regulations • Until 1965 there were no national Building Codes. • Previously Local Bye Laws prevailed and modes of construction varied from one part of UK to another. • First Building Regulations did not include requirements for Energy Conservation – these came in 1976 • Building Regulations are divided into sections and associated Approved Documents (ADs) • Part A: Structural Maters • Part B: Fire • Part F: Ventilation • Part H: Heat producing appliances • Part L: Energy Conservation and more recently carbon emissions • Each Part has associated Ads e.g. for Part L the Approved Documents were originally ADL. • Subsequently (from 2002) divided into ADL1 and ADL2 covering dwellings and non-dwelling separately • Then after 2005 subdivided further into ADL1a and ADL1b covering new and existing buildings.

  4. First introduced as Part L in 1976 Basic Statement – largely following what was then common practice e.g. cavity walls brick cavity block with no insulation: - no insulation in floor, minimal insulation in loft. 1994: First attempt to address overall annual energy consumption, although elemental method of compliance was still permitted 2002: Carbon Index introduced – but was flawed 2006: Target Emission Rate and Dwelling Emission Rate introduced. 2010: Came into force Oct 1st 2010 – relatively minor updates on 2006 Regulations but noticeable reductions in allowable emissions. Changes in the Heating Standards of Houses 4

  5. U-Value Specification with different Regulations

  6. Comparison of energy consumption for a standard detached house at various ages and improvements (Heat losses in W0C-1) DG – double glazing CAV – cavity wall insulation Numerical value indicates thickness of loft insulation

  7. Effects of built form on energy consumption (Heat loss WoC-1) Flats Bungalows Houses

  8. Compliance to Building Regulations • Compliance to Building Regulations may be achieved by one of several alternative methods. • Elemental Method • Specifies maximum U-value and perhaps maximum glazed area – valid until 2002 Regs - still used in several other countries • Target U-value – weighted average U-value allowed some flexibility in design • SAP Rating (1994 Regs) – economic assessment • Carbon Index (2002 Regs) • Target Emission Rate (Current Regs)

  9. Building Regulation: Compliance Summary Up to and including 2000 Regulations • Elemental Method – specifying U-values of all fabric elements – e.g. Windows, floors, walls, roofs • Target U-Value – allowed some flexibility of design. • SAP Rating – an economic measure – only permitted for compliance in 1994 Regs. 2000/2002 Regulations • Carbon Index Method- a distorted Carbon Measure 2005/6 Regulations • Dwelling Emission Rating must be better than Target Emission Rating. Latter is a derivative of the Target U-Value Method. 2009/10 Regulations • Retains DER and TER but expects a 25% improvement on performance over 2005/6 standards

  10. Building Regulation: Compliance Target U – Value Method • Calculate Target U-Value • a function of areas of floor, roof, walls, windows etc • i.e. Weighted average U-Value over all fabric components • Modify target • gas & oil boilers: actual SEDBUK efficiency standard SEDBUK efficiency • electric & coal heating: divide by 1.15 • No modification for heat pumps, biomass, biogas, CHP • Purpose of modifications is to give more freedom for designs using efficient oil or gas boilers • Modify target if area south facing windows > area north facing windows • Calculate ACTUAL weighted average U-value of all external surfaces • Weighted average U-value must be <= Target value SEDBUK Database

  11. Standard Assessment Procedure • Calculate U-values • Check U-values are achieved • i.e. Check for bridging • Calculate • gross heat requirements (Heat Loss Rate) • hot water requirements • incidental & solar gains • effective gains • effective internal temperature • corrected degree-day parameter • net space heating total energy requirement • Select heating method (pumps, appliance efficiency) • Calculate Total Energy Requirement • Estimate energy costs of total space heating, hot water & pumps • Deflate energy by Energy Cost Factor (ECF)– e.g. 1994:0.96, 2001:1.05 etc • Estimate SAP on scale 0 – 100+ based on ECF It is the Economic Aspects which cause problems with SAP Rating

  12. Critique of the Standard Assessment Procedure (SAP) • Energy efficiency index – but gives a rating that is monetary based not energy based • Assumes a general heating level in house – two zones (one living area one other). Does not allow for actual temperature settings. • Hot water requirements based on floor area formula not occupancy • Incidental gains based on floor area not occupancy • Problem: Is this a sensible approach? • If occupancy changes then Rating would change, but it is difficult to compare actual readings with predicted. • Alcantar (2008) found problems with methodology for incidental gains etc • 2010 Regulations partly address issue with regard to occupancy – e.g. • if TFA > 13.9: N = 1 + 1.76 × [1-exp (-0.000349 × (TFA-13.9)² )] + 0.0013 × (TFA-13.9) if TFA ≤ 13.9: N = 1 • N is the assumed number of occupants, TFA is the total floor area of dwelling.

  13. 2006 Regulations Dwelling Emission Rate is method of compliance- essentially the 2010 Regs are similar with only minor variations in detail • Criterion 1 • A Dwelling Emission Rating (DER) must be calculated taking due account of the U-values, the size, the types of heating etc using the Standard Assessment Procedure (SAP) • The DER must be shown to be less than the Target Emission Rating (TER) which is computed with the same size of building and U-values meeting those as specified in the Regulations. Essentially this is a derivative of the target U – value method • Details are shown in Section 2.1.11 of handout

  14. 2006 Regulations Dwelling Emission Rate is method of compliance- essentially the 2010 Regs are similar with only minor variations in detail Criterion 2 – limits on design flexibility • Performance of the building must not be worse than a given standard. • gives considerable latitude in design – the old trade-off problem. • However criterion attempts to limit this type of trade-off – see pages 5 and 6 of the Approved Document Criterion 3 – Limiting effects of solar overheating • Requires that the effects of overheating in summer must be addressed

  15. 2006 Regulations Dwelling Emission Rate is method of compliance- essentially the 2010 Regs are similar with only minor variations in detail Criterion 4 Quality of Construction • Criterion requires evidence of actual performance – e.g. changes arising from design modifications, quality of workmanship. Some of the requirements involve pressure testing the building to ensure they have achieved those used in the design specification. Criterion 5. Providing Information • Requires information on the maintenance and operation of the building to be made available.

  16. Simplified Description of Standard Assessment Procedure (SAP) Stage 1 Assess overall heating requirements for building (E) Annual Energy Requirement E = H * DegreeDays *86400 Stage 2 Assess hot water/lighting requirements and incidental gains, efficiency of heating appliance and solar energy etc. Correct annual consumption to allow for these facts. Analysis of Stage 1 and 2 generally sound – gives estimates to around 10-15% Stage 3. Determine the Energy Costs to determine the SAP Rating– - Serious issues arise with stage

  17. CALCULATION of SAP RATING • While the Standard Assessment Procedure makes sense the final Rating known as the SAP Rating creates problems • The SAP rating is related to the total energy cost by the equations: • Energy Cost Factor (ECF) = deflator × total energy cost / (TFA + 45) (10) • The total energy running cost includes not only heating but also requirements for hot water, lighting etc as well as pumps/fans associated with heating. These are proscribed costs according to a table which are not actual costs. • The deflator is a factor which varies according to energy costs and is intended to keep SAP Ratings constant with time irrespective of changes in fuel prices - this has not been the case in the past. But this still causes problems with relative changes between different fuels

  18. Critique of the Standard Assessment Procedure (SAP) • Standing charge ignored for electricity, included for gas. Oil doesn’t have a fixed charge • Can lead to some perverse consequences • Lower efficiency oil heating can give a higher SAP rating than more efficient gas • Energy Cost Deflator is needed • Unnecessary complication that allows for inflation • But does not allow for differential prices changes between fuels • SAP 1995 – possible SAP rating of over 110 • SAP of 100 readily achievable • SAP 2001 – widened scale (over 120) for consistency with existing scale • SAP 2005 changed scale to have 100 for zero energy house – means all previous calculation have to be redone. • Now possible to get > 100 if a house is carbon negative – i.e. will be exporting more energy than it consumes.

  19. Impact of Changing Methodology on SAP Rating These changes are relatively small compared with changes in previous methodology changes – i.e. 1995 – 2001 and 2001 – 2006. However these demonstrate the problem of using Economic Cost as a Key Factor in determining the SAP Rating

  20. Climatic Issue with 2010 Calculations Calculations have to take account of Climate Variations of Solar Gain for Assessment of Cooling Requirements But NOT Heating (even though heating requirements will vary by up to +/-25% from one part of country to another Benefit of Solar Panels does not account for geographic variations in solar radiation even though this information is available for cooling calculations.

  21. Improvements for 2010 - Environmental Impact Rating (EI) Calculating the TER • TER2010= (Ch x FF x EFAh + Cl xEFAl) x (1–0.2)* (1 – 0.25) i.e. a 25% improvement on 2005  This is partly to bring things in align with Code for Sustainable Homes * The (1 – 0.2) represents a carry over from TER-2005 which indicated a 20% improvement on 2002 Regulations • Where Ch are the carbon emissions associated with for space heating and hot water including any used in circulating pumps, Clis the equivalent associated with lighting FF is a fuel factor – this is NOT the Emission Factor for the Fuel EFA is the relevant Emission Factor Adjustment and is a ratio of the emission factors used in the 2009 calculations divided by the equivalent ones in the 2005 calculations.

  22. Improvements for 2010 - Environmental Impact Rating (EI) • Carbon Factor (CF) = (CO2 emissions) / (TFA + 45) where TFA is the Total Floor Area • if CF >= 28.3 EI rating = 200 – 95 x log10(CF) • if CF < 28.3 EI rating = 100 – 1.34 x CF where the CO2 emissions are calculated according to the Standard Assessment Procedure • The EI rating is essentially independent of floor area • It will vary slightly depending on actual plan shape • A house with zero emissions will have the EI at 100 • An EI > 100 if a house is a net exporter of energy. • Primary energy requirements are also calculated in a similar way to CO2 emissions.

  23. Improvements for 2010 - Environmental Impact Rating (EI) • Letter Rating bands are assigned as follows It applies to both the SAP rating and the Environmental Impact rating (why the SAP Rating??). Rating Band

  24. How has the performance of a typical house changed over the years? • Original Construction • Brick – brick cavity walls • Metal windows • Solid floor no insulation • No loft insulation Bungalow in South West Norwich built in mid 1950s

  25. Changing Energy Requirements of House First attempt to address overall consumption. SAP introduced. House constructed in mid 1950s Part L first introduced ~>50% reduction In all years dimensions of house remain same – just insulation standards change As houses have long replacement times, legacy of former regulations will affect ability to reduce carbon emissions in future 25

  26. Changing Energy Requirements of House As Existing but with oil boiler House constructed in mid 1950s Existing house – current standard: gas boiler Improvements to existing properties are limited because of in built structural issues – e.g. No floor insulation in example shown. House designed to conform the Target Emission Rate (TER) as specified in Building Regulations 2006 and SAP 2005.

  27. Changing Carbon Dioxide Emissions As Existing but with oil boiler House constructed in mid 1950s Existing house – current standard: gas boiler Notice significant difference between using gas and oil boiler. House designed to conform the Target Emission Rate (TER) as specified in Building Regulations 2006 and SAP 2005. 27

  28. N.K. Tovey (杜伟贤) M.A, PhD, CEng, MICE, CEnv Н.К.Тови М.А., д-р технических наук Energy Science Director CRedProject HSBC Director of Low Carbon Innovation Code for Sustainable Homes Move towards Zero Carbon Homes But what does Zero Carbon Mean? Recipient of James Watt Gold Medal 28 28

  29. The Future: Code for Sustainable Homes • Introduced over next few years to improve standards to ultimate “zero carbon house” • But objectives of a low carbon future may be jeopardised if attention is not also paid to sustainable transport associated with new dwellings Data for 1 household with 2 cars

  30. The Code For Sustainable Homes • The Code for Sustainable Homes is a set of sustainable design principles covering performance in nine key areas. 9 key areas of performance…. • Energy and CO2 • Water • Materials • Surface water run-off • Waste • Pollution • Heath and well being • Management • Ecology http://www2.env.uea.ac.uk/cred/harrisongroup/Code_for_Sustainable_Homes.htm

  31. Code for Sustainable Homes: Certificates

  32. Credits gained for different improvements Dwelling Emission Rate DER (Maximum 15 credits)

  33. Implications of Code on Carbon Dioxide Emissions House constructed in mid 1950s -10% -25% -44% -18% Code 5: Zero Carbon House for Heating/Hot Water and Lighting Code 6: Zero Carbon House overall but in reality is this achievable?

  34. Responding to the Challenge: Improvements on the SAP 2005 standards as required by the different code levels can be met by: • Improved Fabric performance • Lower U-values • Technical Solutions • Solar Thermal • Solar Photo-voltaic • Heat Pumps • Biomass • Micro- CHP • Low Energy Lighting (SAP 2005 already specifies 30%) • Energy Service Companies may offer a solution for financing • Issues of Carbon Trading

  35. Responding to the Challenge: Technical Solutions What can be achieved through • Improved Fabric / standard appliance Performance • Using SAP 2005 standard reference • Explore different combinations of following improvements.

  36. SEDBUK DataBase (Seasonal Efficiency of Domestic Boilers in UK) WEB PAGE: www.sedbuk.com/index.htm

  37. The Future: Code for Sustainable Homes Improvements in Insulation and boiler performance Code 1 Code 2 Option H nearly makes code 3 SAP 2005 standard Walls: 0.35 Wm-2oC-1 Windows: 2.0 Wm-2oC-1 Boiler η 78%

  38. The Future: Code for Sustainable Buildings • All non-dwellings must display a certificate such as shown • >10000m2 from 6th April 2008 • > 2500m2 from 1st July 2008 • All non-residential buildings > 1000m2 from 1st October 2008. • Separate assessments for air-conditioning plant will be phased in from 1st January 2009 Elizabeth Fry Building: Initially Penalised because it does not have thermostatically controlled radiator values . Does not get credit for triple/ quadruple glazing – analysis system cannot cope!!!!! There are no radiators!!!!!!

  39. Indian Building Code • WEBSITE: http://www.hareda.gov.in/ECBC.pdf • Also available at UEA at • http://www2.env.uea.ac.uk/gmmc/energy/NBS-M14x/Indian_DRAFTECBC27MARCH2006.pdf Code was formulated following Energy Conservation Act of 2001 According to Saurabh Kumar, Secretary of Ministry of Power (18th April 2007), Code was to be trialled in demonstration areas from July 2007 An initial appraisal suggests that code tends to follow the equivalent of an Elemental Approach, but with differences

  40. Indian Building Code Unlike UK, elemental standards vary from region to region according to climate. UK has 18 zones each with different Degree-Days, but elemental standards are same [Technically Scotland could modify standards in Scotland] Two identical houses in UK, one in South West, the other in North East Scotland, the energy consumption for space heating in latter would be 47% higher than former Is it sensible to have different standards in different climate regimes?

  41. Indian Building Code Example of U-values for walls Based on Table 4.3.2 of ECBC 2006. Note: The U-value in the UK is 0.35 W/m2 oC-1

  42. Chinese Building Code China is adopting a similar approach to that suggested for India

  43. Chinese Building Code

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