When it comes to determining if a duct leak test is necessary, the answer is clear: it is only required when parts of the HVAC system are located outside the conditioned enclosure. The new codes are beginning to mandate leak testing in ducts, but only for 25% of high and medium pressure ducts. A survey conducted by the Building Commissioning Association (BCA) revealed that most respondents believed that leaks in ducts were more common in existing buildings. This is likely due to the fact that sealing materials may be nearing the end of their useful life or have begun to deteriorate, leading to an increase in duct leaks.
The best way to reduce or stop duct leaks is to require testing and verification of the installation of air distribution and exhaust systems and of the HVAC control function through the design and start-up process. Seventy-five percent of survey respondents agreed that leaks in ducts contribute substantially to energy loss in commercial buildings. Therefore, it is essential that engineers mandate pipeline leak tests and that service providers ensure that pipeline leaks are minimized. Although the project designer can specify the level of sealing required for each type of duct, the only way to verify the effectiveness of duct sealing is by testing for leaks.
The main factors that cause problems with leaks in ducts are inadequate sealing of joints and access doors or panels, which is related to the quality of workmanship involved in installation, and overpressurization of the air distribution system, which causes separation of joints. In order to ensure that a building's HVAC system is functioning properly, it is important to conduct a thorough duct leakage test. This will help identify any potential issues with air leakage and allow for corrective action to be taken before any major problems arise. By conducting a duct leakage test, engineers can ensure that their building's HVAC system is running efficiently and effectively.