Need to comply with the new Building regulations on air tightness?
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With more stringent building regulations requiring NSAI Certified Air Tightness Testing on new dwellings, improving air tightness is an increasingly important issue. We undertake air tightness testing (sometimes known as air leakage testing or air pressure testing) to comply with the requirements of the new Building Regulations. Air tightness testers have to be Certified by the NSAI. We use calibrated Retrotec equipment to de-pressurise a building and record air flow measurements. If a poor air tightness is detected, our high resolution thermal imaging equipment can quickly locate the cause of costly air leaks. We are able to offer a competitive quotation for all your Air Permeability testing requirements – from early advisory testing through to final certification. Additionally, as we also operate thermal imaging equipment to help locate faults should they exist.
What is Air Leakage
Air leakage is the uncontrolled flow of air through gaps and cracks in the fabric of dwellings (sometimes referred to as infiltration, exfiltration or draughts). This is not to be confused with ventilation, the controlled flow of air into and out of the dwelling through purpose-built ventilators that is required for the comfort and safety of the occupants. Excess air leakage leads to unnecessary heat loss, discomfort from cold draughts and increased energy costs. With more stringent building regulations requiring mandatory pressure tests on all new build dwellings, reducing air leakage, or improving ‘air tightness’, is an increasingly important issue. The aim should be to ‘build tight – ventilate right’. Buildings should not be too airtight and it is, however, essential to ensure appropriate ventilation. The overall air tightness of the finished dwelling depends heavily on getting the original design and specification right.
Standards for air leakage
Air leakage is quantified as air permeability (q value). This is the rate of leakage expressed in cubic metres per hour per metre of envelope area (m3 /hr / m2) in or out of the dwelling. It is measured at a reference pressure difference of 50 Pascals (Pa) by a fan pressurisation test.
Advantages of airtight dwellings
Compliance-With the new Building regulations CO 2 emissions -An airtight dwelling will ensure lower carbon emissions. Space heating -The reduced heat loss will mean that a potentially smaller sized heating system may be able to meet the demand temperature and therefore decrease occupants’ energy bills. Comfort -Draughts and localised cold spots can cause discomfort. In extreme cases, excessive infiltration may make rooms uncomfortably cold during cooler periods. An airtight dwelling will significantly improve occupants’ comfort. Interstitial Condensation -An airtight dwelling will reduce the likelihood of interstitial condensation and improve building fabric lifespan.
Sound -Joints between elements and unwanted gaps in the building fabric are sealed as a part of the air tightness requirements. This reduces sound transmission, both from outside to inside the dwelling and also across party walls between dwellings.
What is the difference between air permeability and air changes per hour?
There is often confusion on this. Air changes per hour (ACH) is the number of times the complete volume of air in the house is changed. 0.6 ACH is a typical standard for Passive houses. (passivhaus). For example if the internal volume of the house is 500 m3, and 300m3 of air is escaping in an hour then an ACH of 0.6 is achieved. Air Permeability is the amount of air that escapes from a building in an hour, divided by the external envelope in square metres. For example if the area of the floors, walls and ceilings combined is 400 m2, and 4,000 m3 of air is escaping in an hour (as measured by our fan), the Air Permeability is 7 m3/h/ m2. This is the new minimum standard. When an air tightness test is combined with a thermal imaging survey there is no better way to identify areas of air leakage