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SAP, Building Regulations and the Code Prof. David Strong, Chief Executive, Inbuilt Ltd. Good Homes Alliance Christmas Event, The Princes Foundation 9th December 2009 Regulatory and other key drivers in the UK Policy framework • Climate Change Act: legal obligation on Government • CLG consultation on Zero Carbon Definition • Minimum energy efficiency standard • Heat &Energy Saving Strategy • EC initiatives: Energy Using Products Directive, EPBD Mk2 • to name a few ........ Policy framework Timetable for new homes: • 25% improvement in 2010 CSH energy level 3 • 44% improvement in 2013 CSH energy level 4 • Zero carbon from 2016 CSH energy level 6 Key changes to SAP • Fully monthly calculation • Updated weather file • Revised emissions factors SAP 2005 SAP 2009 Gas Biomass Heating House Electricity LPG (pellets) (kg/kWh) Oil Coal (kg/kWh) 1.00 2.18 0.13 1.21 1.37 1.50 (0.194) (0.422/0.568) 1.00 2.87 0.18 1.22 1.38 1.85 (0.206) (0.591) • CO2 equivalent • Upstream emissions • Liquid biofuels included Key changes to SAP • Boiler systems – modification to SEDBUK – Different summer and winter efficiencies • Thermal mass and cooling (regionality) Key changes to SAP • Hot water use – same volume but cooler • Auxiliary energy use – energy use – energy gains • Occupancy – more crowded than we thought! Key changes to L1A Same general 5 step approach – familiar and welcome • DER ≤ TER • Limits on design flexibility • Limiting the effects of solar gains in summer • Quality of construction & commissioning • Providing information / O&M instructions 1. DER ≤ TER Target 2006 Adjusted for - X 0.75 = Target 2010 New CO2 factors Party wall bypass 2.Limits on design flexibility • Largely unchanged • Updated building series compliance guide • Methods to stop easy compliance with renewables 3. Limiting impact of solar gain in summer • • • • SAP - 3 separate months assessed Cooling demand calculated regionally Test applied even if cooling installed Policing – need much greater attention 3. Limiting impact of solar gain in summer Education for designers (and planners?) • Shading • Reduce internal gains • Add mass where possible • Night ventilation 4. Construction & commissioning Airtightness • Doubled sampling rate • Changes to testing regime Thermal bridging • ACD scheme in the making? Commissioning plan required Improving compliance and confidence • Energy Assessor checks • BCB provided with a specification – not just a sheet of U-values • Margin added to non-pressure tested units • Margin added to ‘non-accredited’ details Part F ADF 2006 only designed for 3 m3/h/m2 @50Pa However AECOM study showed: • 52% of door undercuts less than 10mm • 72% of trickle vents areas less than ADF • 89% of kitchen extracts less than ADF and 79% of batroom extracts less than ADF • Overall 55% of dwellings have ventilation rates less than ADF. • Can local extract be trusted? Part F • In eight out of nine dwellings, the MEV systems failed to achieve their design flow rates, in some cases by as much as 63% • Can mechanical ventilation be trusted? How airtight are our homes? Part L study • ~30% of new dwellings tested < 5 m3/h/m2 @50 Pa • ~3-5% of new dwellings tested < 3 m3/h/m2 @50 Pa NHBC data • ~70% < 7 m3/h/m2 @50 Pa • ~40% < 5 m3/h/m2 @50 Pa • Need robust approach to ventilating new homes ADF new requirements For dwellings designed to an air permeability of 5 m3/h/m2 @ 50 Pa or tighter: • Extract vent (local, PSV and MEV) - bigger trickle vents • PSV – bigger duct sizes • MVHR – Increased air flow rate requirements ADF new requirements For new dwellings only, new requirements for: • Air flow rates of mechanical systems (including intermittent extract fans) should be measured on-site. • Owner to be given information to operate and maintain natural and mechanical systems properly • Check list to be given to building control body as evidence that all the above have been done Code for Sustainable Homes • • • • • Faster delivery of certification Bringing forward some of the evidence Greater stability – too many versions Lifetime homes Conflicts with Passivhaus and innovative housing – interpretation of requirements varies Summary • Beware! - The Law of Diminishing Returns - The Law of Unintended Consequences - Murphy’s Law Prof. David Strong, Chief Executive, Inbuilt Ltd E-mail: [email protected] Tel: 01923 277061 www.inbuilt.co.uk