Part L 2013 Air Tightness Requirements

As experts in air tightness compliance, Stroma Tech is helping clients to understand the impact of the Part L 2013 air tightness parameters, and what this means for their projects.

The Part L 2013 stipulations for air tightness permit a maximum air tightness test result at 10 m3/(m2.hr)@50Pa. However, there are a number of subtler factors to consider – all underpinned by the need for a further reduction in CO2 emissions, and the move towards zero carbon dwellings by 2016 – which will make lower design air permeability inevitable for the majority of projects.

 

Air Tightness Compliance Requirements – Building Regulations

Part L 1A 2013 - New Dwellings
  • Overall a 6% reduction in CO2 emissions is required compared to Part L 2010.
  • “Limiting air permeability” (the worst air tightness test result allowable) is 10 m3/(m2.hr)@50Pa.
  • Design standards are guided by the ‘elemental recipe’ for the notional dwelling (within SAP 2012) – which includes an air permeability rating of 5 m3/(m2.hr)@50Pa.
  • Thermal performance of the fabric – Criterion 1 requires compliance with a new Target Fabric Energy Efficiency (TFEE). The air permeability rating forms part of the TFEE calculation within SAP 2012.
  • Number of tests per dwelling type is 3 or 50% of each dwelling type.
  • It is recommended that 50% of tests for each type are conducted among the first 25% that are built.
  • Separate blocks of flats need to be treated as separate developments.
  • Tests must be conducted by a competent person.
  • If a building “fails” a test, carry out remedial work (and all similar types in the development) then retest it, plus one other.
Part L 2A 2013 – New Build Commercial
  • 9% reduction in CO2 emissions is required compared to Part L 2010 (aggregated – improvement targets differ with building type, from 12.5% for offices down to 3% for small warehouses).
  • “Limiting air permeability” (the worst air tightness test result allowable) is 10 m3/(m2 hr)@50Pa.
  • SBEM or DSM is used to calculate the CO2 emission rates: TER (Target Emission Rate) & BER (Building Emission Rate) (target and actual).

Part L2A Air Testing Regime:

  • All buildings over 500m2 gross internal floor area (GIFA) must be tested.
  • Below 500m2, there is the option to use a default result of 15m3/(m2.hr)@50Pa.
  • Lower levels of Design Air Permeability may be set as a means to make the SBEM calculation work; if so, the test needs to achieve this set result.
  • If a building ‘fails’, it must be retested.

 

Stroma Tech are leading experts in air tightness and wider Part L compliance, and provide a range of consultancy and testing services to assist clients in interpreting and meeting air tightness targets. For further information, please contact us on 0845 621 22 22 or comply@stroma.com, or explore the links below:

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2015-05-11T14:15:09+00:00
Phil Carr