Total leakage measured with a pressure differential of 0 1 inch w g.
Total leakage duct pressurization test.
Thus it is not worth the cost of testing the low pressure duct for leakage.
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 measurements of flow requirements problem.
A duct leakage tester is a diagnostic tool designed to measure the airtightness of forced air heating ventilating and air conditioning hvac ductwork.
Smacna 2012 hvac leakage test manual shows the recommended leakage class.
In the previous page on the basic duct leakage testing procedure we said that you pressurize the duct system and measure the airflow through the fan.
If the test is at 6 static pressure for leakage class 3 compliance i e 9 6 cfm per 100 s f with 6 orifice differential and 6 duct test pressure the meter could only indicate 24 cfm.
Ducts shall be pressure tested to determine air leakage by either of the following.
To find the total duct leakage that s basically all you do.
Watch this 5 minute video for a quick look at how to use the tec duct blaster to conduct a total leakage duct pressurization test.
For our example with a seal class of c for the low pressure duc t the leakage would be about 2 cfm.
Disregards size of ductwork static pressure i e.
Both the 2009 and 2012 iecc require duct tightness to be verified.
The amount of air flow in cubic feet per minute required to pressurize the ducts to 25 pa of pressure.
The only other thing you need to make sure you do is keep the spaces where the ducts are at the same pressure as the outdoors as much as you can anyway.
25 pa across the system including manufacturer s air handler enclosure all registers taped or otherwise sealed post construction test.
The result of a total duct leakage test is a measurement of cfm25.
1 of flow on 3900 cfm system 39 cfm.
Leaky ducts will require a higher flow rate to achieve this pressure than tight ducts.
However the blower for the test apparatus would have to produce 24 cfm at 10 to 12 static.
The fan speed is increased to attain a pressure of 25 pa in the ducts.
Test pressure higher than duct design.
