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Duct leakage test in the US. A duct leakage tester is a diagnostic tool designed to measure the airtightness of forced air heating, ventilating and air-conditioning (HVAC) ductwork. A duct leakage tester consists of a calibrated fan for measuring an air flow rate and a pressure sensing device to measure the pressure created by the fan flow.
Duct leakage testing of forced air heating/cooling systems - both supply (vents) ducts and return ducts can be tested to determine if and how much they leak air. A duct test can be combined with a blower door test to measure the total leakage to outside, measuring effective leakage to the outside of the house only.
The relationship between pressure and leakage air flow rate is defined by the power law model between the airflow rate and the pressure difference across the ductwork envelope as follows: q L =C L ∆p n. where: q L is the volumetric leakage airflow rate expressed in L.s −1; C L is the air leakage coefficient expressed in L.s −1.Pa −n
It applies to a fan or other air moving device when air is used as the test gas with the following exceptions: (a) air circulating fans (ceiling fans, desk fans); (b) positive pressure ventilators; (c) compressors with inter-stage cooling; (d) positive displacement machines; (e) test procedures to be used for design, production, or field testing.
In heating, ventilation, and air conditioning (HVAC), testing, adjusting and balancing (TAB) are the three major steps used to achieve proper operation of heating, ventilation, and air conditioning systems. TAB usually refers to commercial building construction and the specialized contractors who employ personnel that perform this service.
The infiltration rate is the volumetric flow rate of outside air into a building, typically in cubic feet per minute (CFM) or liters per second (LPS). The air exchange rate, (I), is the number of interior volume air changes that occur per hour, and has units of 1/h. The air exchange rate is also known as air changes per hour (ACH).
A leak appearing within an analytic region (a rule added to the camera) is immediately analyzed for its attributes, including thermal temperature, size, and behaviour (e.g. spraying, pooling, spilling). When a leak is determined to be valid based on set parameters, an alarm notification with leak video is generated and sent to a monitoring station.
AS/NZS 3760:2010 section 2.3.3.2 requires a leakage test to be carried out if equipment being tested must be energised to close the circuit or operate a switching device. Leakage testing does require the item being tested to be powered up thus meaning the item will switch on and operate.