Checking the Air Seal Line to Ensure Air Tightness

Checking the Air Seal Line to Ensure Air Tightness

Many companies don’t fully understand the importance of the air seal line in regards to air tightness. The air seal line is usually the building envelope but this is not always the case. In many instances buildings may have plant rooms where are heavily vented to outside atmosphere, in these instances the air leakage line will be the internal wall that encapsulates the plant room.

Also, the incorrect sequencing of construction work may weaken the air seal line prior to the air tightness test, such as the late addition of mechanical and electrical pipework & cables just prior to the air test, obviously the M&E should have been installed earlier in the project; however, due to insufficient information i.e. missing details on drawings, the M&E is often added at a later stage, thus requiring additional penetrations through the newly completed building fabric, thus compromising the potential air tightness of the building envelope.. Unfortunately once newly formed penetrations are in the envelope, nobody wants to take ownership for the new penetrations and the resealing of the areas, so the air leakage paths are left to the end of the project, often resulting in air tightness test failures.

Air_Leakage_Paths_Through_House

In many instances – due to programme constraints) operatives are rushed to install new installations, resulting in much larger access holes than is strictly necessary for the service pipework/cables, this often happens in kitchens, utility rooms, bathrooms, toilets and service cupboards. In these rooms service penetrations are often hid behind Kitchen cupboards, behind toilets, sinks, bath panels and under shower. Other areas are around services in airing and boiler cupboards. Once cupboards and boilers etc. are installed, it makes it almost impossible to seal the air leakage paths – especially if it’s close to the air seal line.

Room_integrity_test_With_blower_fan

In many cases a lack of understanding by building contractors can lead to multiple air test failures.  One common problem is the client putting cosmetic appearance above general airtightness; however, with careful air sealing both can be achieved.  Unfortunately, with the airtightness target being halved from the old standard of 10m3/hr/m2 to 5m3/hr/m2 or even as low as 1m3/hr/m2, it is absolutely essential that the all air leakage paths are sealed as soon as the M&E is installed.

In our experience another reasons for air tightness testing failures is down to a general lack of understanding as to where the air seal line within the building.  Some of the issues that may need to be addressed to overcome this would include adequate training, quality control and building design.

If you employ APT from the start of the project, we can send out our air tightness checklist to help you prepare for the air testing. If each item is actioned in-line with the checklist then our clients usually pass first time. We also offer a site visit service to make sure that the building is being adequately sealed as works progress, so the air leakage paths can be sealed prior to the air tightness test.

If you would like more information in regards to preparing for you air tightness test in London, please contact us at: info@airpressuretesting.net or phone us on 07775623464.

The Importance of Airtightness Testing

The Importance of Airtightness Testing

The importance of air tightness testing is often overlooked within the build process. Approved document L1 & L2 suggests that air permeability is the physical property used to measure the airtightness of the building fabric.  The test measurement is defined as air leakage rate of m3/hr/m2. The old building regulations stipulated an air leakage rate of 10m3/hr/m2; however, this has now been lowered to an average of 5m3/hr/m2 which is far more difficult to achieve

Wherever air infiltration occurs, there is a corresponding exfiltration somewhere else in the building. During the summer, infiltration can bring humid, outdoor air into buildings. In winter, exfiltration can result in moist indoor air moving into cold wall cavities and may result in condensation and ultimately mould and/or rot, which could result in serious lasting damage to the property.
Air_Tightness_Testing

The ATTMA – Air Tightness Testing and Measurement Association governing body for air tightness testing and  the defines ‘air leakage’ as the uncontrolled flow of air through gaps and cracks in the fabric of a building. The general public recognise it as draughts. In most cases the main air leakage paths are:

Services Penetrations

  • Service penetration’s around boilers pipes.
  • Service penetration’s around under floor heating.
  • Service penetrations in the kitchen and utility room.
  • Service penetrations in the toilets, bathroom and en-suite.
  • Pipework penetrations behind the radiators.
  • Service penetrations in the bathrooms and en-suite.
  • Around electrical fuse box.
  • Around extract fans.

General Air Leakage Paths

  • Gaps between skirting board and floor on each floor level.
  • Behind kitchen units.
  • Behind Utility Cupboards
  • Around poorly fitted trickle vents.
  • Around Patio doors.
  • Gaps around the stairs.
  • Around loft hatch.
  • Gaps around the bath panel and the shower tray.

If you employ our services from the start of the project, we will send out our air tightness checklist to help you prepare for the air testing. We also over an air tightness design and site survey service, to ensure the building envelope or the defined air leakage line is being constructed properly, we can then highlight any potential air leakage paths so they can be sealed prior to the air tightness test.

If you would like more information in regards to preparing for you air tightness test in London, please contact us at: info@airpressuretesting.net or phone us on 07775623464.