Air Pressure Test for Building Energy Rating Assessments
Purpose
The sampling regime required for pressure testing of dwellings for Building Energy Rating (BER) purposes. This sampling regime is based on the existing system for demonstrating compliance with Part L of the Building Regulations in the UK. (Source; UK’s Approved Document L1A, 2006 edition). This initial sampling regime may be revised to reflect future revisions to the Building Regulations Part L or the Technical Guidance Document to Building Regulations Part L in Ireland.
Context
The Dwelling Energy Assessment Procedure (DEAP) is used for the energy rating of dwellings in Ireland. As detailed in Section 2 of the DEAP Manual, the DEAP methodology includes two options for calculating background air leakage into and out of a dwelling:
- A calculated value may be used base on number of storeys, structure type, floor type and draught-stripping of windows in dwelling, or
- Adjusted air leakage pressurisation test data may be used. In this case Section 2.3 of the DEAP Manual states that the air leakage pressurisation test must be performed in accordance with IS EN 13829.
Required Sampling Regime
Where a BER Assessor is rating several dwellings of the same type, and (s)he opts to use adjusted air leakage pressurisation data, air pressurisation tests may be carried out on a sample of the relevant dwellings. The required sampling regime for all types of construction in each development is detailed in Table 1 .
For dwellings to be considered part of the same development, they should be:
· Constructed on the same site (i.e. a single tract of land). This includes neighbouring houses.
· By a single developer (i.e. the same company / builder is responsible of all construction)
· Are contemporary (i.e. all constructed in the same time period).
Each of the following constitutes a change of dwelling type:
· Change in method of construction e.g. timber frame and brick & block
· Ground floor, mid floor & top floor flats
· End of terrace & mid terrace
· Semi-detached & detached
· Changes in building floor area
50% of the required air tightness tests should be carried out during construction of the first 25% of each dwelling type. For best practice, it is recommended to test the first of each dwelling type on each site in order to identify and modify any details that are causing an air tightness problem
Air Pressurisation Test Results in DEAP
Where air pressurisation tests are carried out on a sample of dwellings representing a specific dwelling type, the maximum air pressure test result for that dwelling type, q50, measured in m3 per hour per m2 envelope area, should be divided by 20 to give the “Adjusted result of pressurisation test”. This is the value that should be entered into the DEAP software for all of the untested dwellings of that type.
Where an individual dwelling has actually been tested, the air pressure test result for that dwelling, q50, measured in m3 per hour per m2 envelope area, should be divided by 20 to give the “Adjusted result of pressurisation test”. This is the value that should be entered into the DEAP software for that actual dwelling.
BER Assessor Records
BER Assessors are required to keep appropriate records of the air pressure test results. Evidence and records of air pressure test results will be inspected during routine BER Quality Assurance audits.
In general, for BER assessments, SEAI encourage BER Assessors to use non-default certified test data wherever possible. This non-default data must be properly certified and substantiated. Where actual air permeability test results are identified in a BER assessment audit, SEAI may look for supporting evidence that the permeability test results are available, and that the test was carried out by an individual or organisation competent to do so. Individuals may, for example, demonstrate competence to carry out permeability tests on dwellings by being registered under the NSAI's Air Tightness Testers Scheme
Additionally, individuals and organisations may demonstrate competence by being accredited to carry out tests to I.S.EN 13829:2000 by the Irish National Accreditation Board (INAB) or any other bodies capable of providing accreditation to ISO/IEC 17025: "General Requirements for the Competence of Testing and Calibration Laboratories".
