UFC 4-390-01
23 July 2003
a)
Leak detecting solution method: For systems tested
with Helium or Hydrogen, mechanical joints (such as union
connections) shall have no detectable leakage. Only leakage
allowed is 0.6 cc/min for each valve system seal. This rate
is identified by the formation of only foam like bubbles, no
large bubbles. Systems pressurized with other media should
exhibit no leakage.
b)
Pressure drop method: Calculate the corrected pressure
as specified below. The pressure drop is considered
acceptable if it is less than 1% of the test pressure (test
pressure divided by 100). If the leakage exceeds 1% the
source must be found, leak repaired and test repeated until
acceptable.
The system corrected pressure (Pc) is found by the following
formula:
Pc = [(Pf+14.7 psig) x [(Ti+460F)/(Tf+460F)]] - 14.7 psig
∆P = Pi-Pc
Where:
Pi = pressure as read at start of
test (psig)
of test(oF)
Ti = temperature as read at start
Tf = temperature taken hourly for
pressure
correction (oF)
Pf = pressure taken hourly, to be
corrected (psig)
Pc = corrected pressure (psig)
∆P = pressure drop (psi)
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