Issue Date: November 22, 1995
Revision Date: April 14, 2015

AMETEK Automation & Process Technologies

(originally listed as MagneTek, then Patriot Sensors and Controls Corp.)

7021 Digital Tank Gauge
(7030 Series Magnetostrictive Probe)

Automatic Tank Gauging Method

As of 2005, the 7021 product line became obsolete.

Certification Leak rate of 0.2 gph with PD = 99.96% and PFA = 0.044%.
Leak rate of 0.1 gph with PD = 95.34% and PFA = 4.66%.
Leak Threshold 0.1 gph for leak rate of 0.2 gph.
0.05 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, fuel oil #4.
Other liquids with known coefficients of expansion and density and where specific gravity is > 0.6 and viscosity is < 1500 cp may be tested after consultation with manufacturer.
Tank Capacity Maximum of 15,000 gallons.
Tank must be between 50 and 95% full for leak rate of 0.2 gph.
Tank must have minimum product height of 18 inches, or be 14% full, whichever is higher, for leak rate of 0.1 gph.
Waiting Time Minimum of 2 hours between delivery and testing for leak rate of 0.2 gph.
Minimum of 8 hours between delivery and testing for leak rate of 0.1 gph.
There must be no dispensing or delivery during waiting time.
Test Period Minimum of 4 hours.
Test data are acquired and recorded by a 7021 controller (computer).
Leak rate is calculated from data determined to be statistically valid.
There must be no dispensing or delivery during test.
Temperature Average for product is determined by a minimum of 1 resistance temperature detector (RTD).
Water Sensor Must be used to detect water ingress.
Minimum detectable water level in the tank is 0.947 inch.
Minimum detectable water level change is 0.0254 inch.
Calibration RTD 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).
  • AMETEK Automation & Process Technologies
    1080 N. Crooks Rd.
    Clawson, MI 48017-1097
    Tel: (800) 635-0289
    URL: www.ametekapt.com
  • Evaluator: Ken Wilcox Associates
    Tel: (816) 443-2494
    Date of Evaluation: 02/07/91, 4/25/1995

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