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Certification
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Leak rate of 0.2 gph for tanks and associated pipelines with PD > 99% and PFA < 1%.
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Leak
Threshold
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0.1 gph for single and manifolded tank systems including associated pipelines.
A tank system should not be declared tight if the test result indicates a loss or gain that equals or exceeds this threshold.
Gains (water ingress) are analyzed and evaluated on an individual basis.
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Applicability
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Gasoline, diesel, aviation fuel, fuel oil #4, solvents, biodiesel blends B6-B20 meeting ASTM D7467, biodiesel B100 meeting ASTM D6751
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Tank
Capacity
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Maximum of 36,096 gallons for single tanks and for up to 3 tanks manifolded together.
The tank must be between 8.9% and 92.5% full.
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Throughput
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Monthly maximum of 289,250 gallons.
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Waiting Time
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None. The algorithm tests the data for stability and discards those before the tank is stable.
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| Test Period |
Data collection time ranges from 2.8 to 11.6 days
Data sampling frequency is multiple times per minute.
System collects data (sales and levels) multiple times per minute without interfering with normal site operation.
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| Temperature |
Average for product is determined by a probe that contains 5 thermistors. |
| Water Sensor |
Must be used to detect water ingress. Automatic tank gauges that pass the US EPA standard are sufficient. |
| Calibration |
Dispenser meter calibrations must be known.
Thermistors and probe must be checked and, if necessary, calibrated in accordance with manufacturer’s instructions. |
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| Comments |
System tests each tank and associated piping for the tank system.
System reports a calculated leak rate and “Pass” or “Fail” for each tank system.
System notifies operator for each tank system that is not “Passing”.
System tested on tank systems that operated 24-hours per day, had stage 2 vapor recovery and blending dispensers.
ATGs used at the sites in the evaluation were from:
Franklin Fueling 550, Colibri, 1001
Veeder-Root TLS-350, TLS 450
OPW fuel Management System EECO 1000, EECO 2000
ATGs all equipped with magnetostrictive probes.
Automatic tank Gauges used with this method must be on the NWGLDE list, employ a magnetostrictive probe, and be certified at a leak rate of 0.1 gph.
The maximum size tank system in the evaluation was 40,373 gallons. |
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