Issue Date: November 22, 1995
Revision Date: April 4, 2007
(previously listed as Sound Products Manufacturing, Inc.)
(Pressure and Vacuum Test)
NON-VOLUMETRIC TANK TIGHTNESS
TEST METHOD (ULLAGE)
||Leak rate of 0.1
gph with PD = 100% and PFA = 0%.
||A tank system
should not be declared tight when there is a substantial increase in the
acoustic noise signal (when the tank is under pressure or vacuum) above
the background signal (prior to pressurization or evacuation) in the
frequency interval of 10 kHz to 20 kHz.
The acoustic signal to noise ratio is preprogrammed into the system's
computer and is not revealed to or adjustable by the operator.
aviation fuel, fuel oil #4, waste oil.
Equipment is not in contact with the product.
volume is 7,550 gallons for pressure test and 5,250 gallons for vacuum
||None if test is
conducted after an underfilled tank tightness test.
||Minimum of 15
minutes (includes collection of background information).
There must be no dispensing or delivery during test.
||Net pressure of
2.0 psi or vacuum of 1.0 psi must be maintained in ullage.
is independent of product temperature.
groundwater in tank excavation backfill must be determined.
If groundwater is above product level, vacuum test must not be used.
Pressure test must be conducted using net pressure exceeding 2.0 psi in
must be checked and, if necessary, calibrated by tester before each test.
using manifolded tank systems.
Evaluated using unleaded gasoline as test product.
Tests only ullage portion of tank.
Product-filled portion of the tank must be tested using an underfill test
Microphone was less than 8 feet, 6 inches from the leak source during
If the background noise is too high, test is inconclusive.
Maximum background noise is preprogrammed into system's computer and not
revealed to or adjustable by the technician.
Vibration due to nearby equipment or dripping condensation may interfere
Vacuum test method may not be effective in some tank excavation backfill
(such as clay) because it may plug holes in tank.
If soil is saturated with product, air or water ingress may not be
declared by vacuum test.
A well point in tank excavation backfill may help identify presence of
Ken Wilcox Associates
102 Abigayle Row
Tel: (816) 443-2494
Scott, LA 70508
of Evaluation: 03/24/92
Tel: (337) 235-1184