The necessity to make waterproof sanitary water ducts or central heating tubing and to make airtight natural gas distribution tubing is of primary importance to both construction professionals and the public. However, the airtightness of ventilation ducts and heating or cooling ducts is subject to less attention.
An assessment campaign, aimed to measure the latter, was conducted within the framework of a European project , and demonstrated that the leakage in air ducts in France and Belgium reached figures up to 20% of the average nominal flow rate.
What importance can that have, how does one measure leakages, what airtightness criteria can one adopt and finally, what are the possibilities of improvement. All these are questions to which this document aims to bring an answer or solution.