The direct benefit from this simulation study was in using some
of the “n” exponent and C values that were derived in Table 1 which
were used in some of the generated artificial leakage holes in the
test facility mentioned above (ADLL) for calibration purposes of
simulated pressure drop vs. leakage flow in the system according
to the existence of these simulated hole shapes where the leakage
rates varied from about 1% to 25% of the supply fan flow. Then
according to the number of leakage holes chosen for a particular test
one can predict how much flow can be expected to flow out of these
holes for the measured pressure drop measured between inside of
the duct around that area and the ambient conditions. Although this
paper is not aimed at describing the current method of air leakage
determination, it can be briefly said that the state of the art method
of determining air leakages works on the basis of determining these
leaks (in a global sense i.e. over the whole duct system) where the
calculation method assumes an average duct pressure for the system
for which the leakage of the supply and return duct system are
calculated (Delta-Q method). This assumed average duct system
pressure may not coincide with the actual pressure of the system
at hand at each local leak. Of course if anything, the pressure is
expected to vary from a high (near the supply fan) to a relatively
low pressure at the end of the duct system. The method of determining
air leaks as part of the current larger study mentioned above
is aimed at determining local leakage of sections of ducts as well
as the global leakage rate. By doing this, one can hopefully isolate
those critical duct sections and try to fix (seal) those duct sections
as opposed to more expensive duct leak mitigation which can easily
cost for a typical home around $2000.