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A good starting point is the paper "stimulating better envelope and ductwork airtightness with EPBD" by Carrié et al., at the AIVC 2008 conference (www.aivc.org).Another possibility is to check out the presentation “Including leakage in energy calculations” by Dr. J-R Millet, held at the ASIEPI web event on ductwork airtightness (http://www.asiepi.eu/wp-5-airtightness/web-events.html)
Post date: 19 Apr 2010
Type: Ask the Experts

It is not presently mentioned in CEN standards. Other countries might be using the same default level as France in their energy performance calculation standards, but there is no reason to harmonize it. The leakage class 2.5*A is very much leakier than ductwork systems in Scandinavia, for example. By the way, ASHRAE’s classification system for duct airtightness has higher classes near 2.5*A. For more information you can check-out the Information Paper P187 “Duct System Air Leakage — How Scandinavia tackled the problem” by P.G.Schild & J.Railio, on the BUILDUP website
Post date: 19 Apr 2010
Type: Ask the Experts

Sweden does not use its building regulations to impose its strict requirements on ductwork airtightness. Rather it is a voluntary trade standard (the AMA VVS specifications) that has driven the market transformation to more airtight ventilation systems. This trade standard is used in virtually all building projects.
Post date: 19 Apr 2010
Type: Ask the Experts

The reason for this is twofold:(1) When one uses only one test pressure, then the test results can be expressed with just one number, the “flow coefficient”. This is very simple and avoids the need for any calculations. You are suggesting testing with multiple pressures so that the results can be plotted on a log-log scatterplot, and the best-fit line is a power function with two coefficients, the “flow coefficient” and the “flow exponent”. This is unnecessarily complicated.
Post date: 19 Apr 2010
Type: Ask the Experts

The reason for this is twofold:(1) When one uses only one test pressure, then the test results can be expressed with just one number, the “flow coefficient”. This is very simple and avoids the need for any calculations. You are suggesting testing with multiple pressures so that the results can be plotted on a log-log scatterplot, and the best-fit line is a power function with two coefficients, the “flow coefficient” and the “flow exponent”. This is unnecessarily complicated.
Post date: 19 Apr 2010
Type: Ask the Experts

It is important to use the correct type of screw or rivet. Avoid screws with a wide drill tip (which drill a hole in the duct wall) and blind pop rivets (which are not airtight because the inner splint falls out). The best screws are ones with a sharp tip or pressure-tight blind pop rivets (though these are very laborious to fit). For more information see the section on screws and rivets in EN 12237 (“Ventilation for Buildings - Ductwork - Requirements for ductwork components to facilitate maintenance of ductwork systems”)
Post date: 19 Apr 2010
Type: Ask the Experts

In Sweden, according to the trade guidelines VVS AMA, on-site pressure tests need only cover 10% of the duct surface area round ducts, and 20% for rectangular ducts. Denmark has similar rules. In Finland, 20% of the duct surface area is tested in the case of Class C airtightness, and 10% in the case of Class D or better.
Post date: 19 Apr 2010
Type: Ask the Experts

In part. Leakage testing of duct systems, by means of a pressure test, is a very effective way of achieving more airtight duct systems. This type of commissioning is required throughout Scandinavia, to check compliance with minimum airtightness requirements (except for Norway, where the practice has become less common in the last 15 years). However, airtightness testing is no substitute for installing quality duct systems with good airtightness in the first place.
Post date: 19 Apr 2010
Type: Ask the Experts

Post date: 14 Apr 2010
Type: Publication

Information Paper P170 of the ASIEPI European Project. This updated document cancels and replaces a previous version, dated September 2009.
Post date: 12 Apr 2010
Type: Publication