Issue Date: June 1, 2001
Revision Date: October 18, 2002

OPW Fuel Management Systems

(originally listed as Petro Vend, Inc.)

Site Sentinel Models 1, II and III, (Model 924, 4 inch dia Floats, Magnetostrictive Probe)

Automatic Tank Gauging Method

Certification Leak rate of 0.2 gph with PD = 97.8% and PFA = 2.2% for 30 minute test.
Leak rate of 0.2 gph with PD = 98.7% and PFA = 1.3% for 1 hour test.
Leak rate of 0.2 gph with PD = 99.2% and PFA = 0.8% for 2 hour test.
Leak rate of 0.2 gph with PD = 99.5% and PFA = 0.5% for 3 hour test.
Leak rate of 0.1 gph with PD = 96.9% and PFA = 1.9% for 2 hour test.
Leak rate of 0.1 gph with PD = 98.2% and PFA = 1.0% for 3 hour test.
Leak Threshold 0.1 gph for leak rate of 0.2 gph.
0.053 gph for leak rate of 0.1 gph.
A tank system should not be declared tight if the test result indicates a loss or gain that equals or exceeds this threshold.
Applicability Gasoline, diesel, aviation fuel. Other liquids with known coefficients of expansion and density may be tested after consultation with the manufacturer.
Tank Capacity Maximum of 20,000 gallons.
Tank must be minimum 14% full for leak rate of 0.2 gph.
Minimum product level required based on 14% full tank and tank diameter is as follows:
48" dia/min 9.5";
120" dia/min 24.7".
For other tank diameters, consult manufacturer.
Tank must be minimum 90% full for leak rate of 0.1 gph.
Waiting Time Minimum of 8 hours between delivery and testing for leak rate of 0.2 gph.
Minimum of 12 hours between delivery and testing for leak rate of 0.1 gph.
There must be no delivery during waiting time.
Minimum of 30 minutes between dispensing and testing.
Test Period Variable:
Minimum of 30 minutes, 1, 2 or 3 hours for leak rate of 0.2 gph and minimum of 2 or 3 hours for leak rate of 0.1 gph.
Test data are acquired and recorded by system's computer.
Leak rate is calculated as the difference between the first and last data collected.
There must be no dispensing or delivery during test.
Temperature Average for product is determined by a probe containing 5 thermistors with the lowest thermistor located at the 10% tank volume level above the bottom of the tank.
Water Sensor Must be used to detect water ingress.
Minimum detectable water level in the tank is 0.848 inch.
Minimum detectable change in water level is 0.043 inch.
Calibration Thermistors and probe must be checked and, if necessary, calibrated in accordance with manufacturer's instructions.
Comments

Not evaluated using manifolded tank systems. Therefore, this certification is only applicable when there is a probe used in each tank and the siphon is broken during testing.
Tests only portion of tank containing product.
As product level is lowered, leak rate in a leaking tank decreases (due to lower head pressure).
Consistent testing at low levels could allow a leak to remain undetected.
EPA leak detection regulations require testing of the portion of the tank system which routinely contains product.

California regulations require at least one test per month after routine product delivery or when the tank is filled to within 10% of the highest operating level of previous month. If the 0.1 gph test is used as a tank tightness test there must be no water present in the backfill (groundwater must be below the bottom of the tank), the tank must be equipped with an overfill protection device, and the product level in the tank must be at the overfill protection device set point. Local agency pre-approval is required. To use the 0.1 gph test as a monthly option see title 23 CCR Section 2643 (b)(2).

  • OPW Fuel Management Systems
    6900 Santa Fe Dr.
    Hodgkins, IL 60525
    Tel: (708) 485-4200
    URL: www.opwglobal.com/opw-fms
  • Evaluator: Ken Wilcox Associates
    Tel: (816) 443-2494
    Dates of Evaluation: 11/03/00

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