Information for Building Control Officers & Approved Inspectors

Golden Rules to Ensure Part L is met.

Ensure that the air tightness test is carried out by a member of the ATTMA – Air Tightness Testing and Measurement Association. The CLG recognises members as being ‘suitably qualified’ and/or having the ‘recognised qualifications’ to carry out air tests.

FREQUENTLY ASKED QUESTIONS

How can a building fail the air tightness Part L?

A building will fail Part L if the air permeability rate is >10m³/(h.m²). More stringent requirements may be in place, depending on the requirements within the SBEM calculation to satisfy the carbon emissions target.

Buildings could also fail if thermographic inspections of the visible envelope, shows that insulation is not reasonably continuous.

How accurate are the tests?

ATTMA TS1 states that fan flow rates should be measured to ± 7%. The accuracy of the air leakage pressure test itself will be affected by the strength and gustiness of the wind. The wind will impose both positive and negative pressures on the building envelope, which will vary during the test. ATTMA TS1 states that tests should normally only be carried out when static pressures within the building are excessive. Decisions will be made on a job specific basis.

How can fire walls be made airtight?

Use the same principles of design and construction as for other air tightness works but use fire rated materials. Compliance to various sections of Part L1 and L2 can be achieved by a ‘competent person’ reviewing the design and/or site works and deeming them adequate. These sections include air tightness and continuity of insulation for all buildings. HRS can take on this role and issue the necessary declaration to the Building Control Officer.

HRS Services Ltd have air tightness testing equipment suitable for testing buildings with floor areas from 100 to 60,000 square metres. For small buildings, HRS use Blower Door systems, which are small diameter fans which can be built into sets of up to 4 fans. These are electrically powered, quiet, clean and portable. They can easily test whole buildings or if necessary be erected inside buildings to test plenums, service ducts, fire ompartments, upper storeys, extensions, etc.

To test larger buildings HRS have developed the MIDIFAN system which is a 1.25m diameter fan. Self powered, the MIDIFAN has been designed to test the largest buildings in the UK. A major advantage of the unit is that it is self contained with all ancillary equipment including smoke testing equipment. When other air test companies state that they haven’t the equipment to test the building, you know where to come.

 

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Air Sealing - Flagship Projects

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Air Sealing Contracting - 800 retail stores for 4 major retail chains

Since 1995 for 4 major retail companies, whom HRS still work for on a regular basis

250 existing Morrisons Stores fire stopped over a period of 18 months

HRS were directly employed by Wm Morrisons to upgrade fire stopping

New & existing Tesco stores air sealed by HRS Services

For over 10 years, Kiers has appointed HRS to air seal over 50 TESCO stores