Importance of Air Pressure Testing in UK Construction Industry

1. LEVEL 4 Air Pressure Testing 11.0 - Air Pressure Testing: ADL2A & ATTMA TS1

2. LEVEL 4 Air Pressure Testing We are going to look at: • What it’s about • Why it matters • The Regulations • Where it can go wrong • The consequences of failure • Recommended approaches

3. LEVEL 4 Air Pressure Testing What is it about? • Part L2A relates to ‘Work in New Buildings, other than Dwellings’ • Substantial reductions on CO2 emissions must be achieved (and proven), compared to an identical ‘Notional Building’ that would have just complied with the 2002 version of Part L. • SBEM can be used a concept design stage to calculate the relative CO2 savings achieved by measures such as: • Improving U-values (e.g. through more insulation) • Improving HVAC & lighting efficiency • Reducing cold bridging and/or solar gain • Using ‘renewable’, and ….. • Reducing air-leakage • Whether or not improved air-tightness is used as a ‘compliance tactic’ it must not exceed 10m3 of air leakage, per m2 of envelope, per hour at 50 Pascal's differential pressure. TheKey Requirement is to prove a reduction of CO2 emissions….

4. LEVEL 4 Air Pressure Testing Why it matters ? • It contributes to UK’s CO2 Reduction Target (Kyoto), by causing buildings to be more energy efficient. • Enables right-sizing of HVAC Plant, and… • Reduced Energy Costs (for Heating & Cooling) • Protection of Building ‘Fabric’ by reducing Interstitial Condensation • More Comfort for Occupants (Improved Productivity)

5. LEVEL 4 Air Pressure Testing The consequence of failure? • Air leakage accounts for a significant proportion of the overall energy losses in UK buildings. • In leaky buildings it can occur constantly, driven by wind, internal/external pressure differences and the ‘stack effect’. • Buildings don’t need to breathe, only people do! Therefore…. “Build Tight – Ventilate Right!”

6. LEVEL 4 Air Pressure Testing Where it can go wrong? • Eaves details • Voids/cavities left open to interior • Voids above solid ceilings • Gaps between steel frame and inner-leaf masonry • Service penetrations • Unsealed dry-lining • Windows, doors, weather seals • Unsealed layers in built-up roof systems • Risers & plant rooms • Hollow floor planks • Leaky HVAC systems • Permeable materials

7. LEVEL 4 Air Pressure Testing Where improved Air-tightness is not being used as a compliance tactic, the building must still be proven to meet the following minimum standard.… The rate of air leakage through the building envelope must not exceed 10m3 of air, per square-meter of Envelope, per hour at 50 Pascal's differential pressure (between inside & outside the building).

8. LEVEL 4 Air Pressure Testing The ‘Envelope’ is the “shell” of the building that contains the “conditioned air”. In most cases this would comprise the ground floor slab, the perimeter walls and the underside of the roof. If the roof-void is naturally ventilated then the top floor ceiling becomes the top part of the envelope

9. LEVEL 4 Air Pressure Testing The regulation in ADL2A and ADL2B: • All buildings, with over 500m2 gross floor area, must be air-tightness tested to prove they do not leak air at a rate more than the target air-permeability rate required by the design (which must be no more than 10 m3/(m2.hr) @50Pa.) • Buildings with a gross floor area below 500m2 don’t necessarily have to be tested, but if they aren’t, an penalising ‘result’ of ’15’ has to be used for the SBEM calculations! • Extensions to existing buildings, have to be tested if they are over 100m2 and more than 25% of the existing total floor area.

10. LEVEL 4 Air Pressure Testing Recommendation approach? • Reduced Air-Leakage can help with overall compliance • A lower ‘air-permeability’ figure (than the maximum of ‘10’) will count further towards the overall CO2 emissions savings required, as calculated by SBEM. • It can offset the cost of other carbon-reducing measures, such as using ‘renewable’ or more efficient services. • However, if a lower air-leakage rate is specified, it has to be ‘designed and built-in’, then proven by testing. Currently, roughly half of the larger, more complex buildings tested fail to achieve the minimum Part L standard of ’10’ at the 1st attempt, despite it having been a requirement for the last 4 years!

11. LEVEL 4 Air Pressure Testing

12. LEVEL 4 Air Pressure Testing

13. LEVEL 4 Air Pressure Testing • Reasonable Pressure test Target Setting. • If When conducting the SBEM calculation on new builds, if the pressure test result is set too low and becomes unachievable. • Your final result will fail your EPC

14. LEVEL 4 Air Pressure Testing ANY QUESTIONS OR FEEDBACK