Minimum CFM is the flow rate that causes a 0.4 in.wg. pressure drop across
the orifice plate. Therefore, Minimum CFM is limited by the orifice plate
used, not the tester. We have limited the smallest pressure drop across
the orifice plate to 0.4 in.wg.
Maximum Test Pressure
is the maximum pressure the tester/plate combination can obtain at the
user entered flow rate (cfm), taking into account the inline losses due
to user-entered straight run of flexible duct and number of 90 degree
For a value in the
column titled "Will this Tester/Plate Work for you?" to display
"YES", the following conditions must exist: (1) the user-entered
maximum allowed leakage must be greater than our recommended minimum cfm,
and (2) the user-entered test pressure must be less than the calculated
maximum test pressure.
We assume no liability
for use of this program. We have made every effort available to make sure
this program calculates correctly. Data used in this program was derived
from laboratory testing using ORIFLOW LLC equipment. Actual results will
vary depending on line voltage, the condition and capacity of your equipment,
and actual inline losses. Calculations for inline losses assume
ORIFLOW flexible duct is used. Using hard pipe without elbows will increase
the capacity of your tester (to see how much, enter 0 for both "length
of flex duct" and "number of bends".