Interstitial Tightness Test Method

Certification Leak rate of 0.1 GPH with PD = 99.99% and PFA = 3.3%
Leak rate of 0.005 gph with PD = 99.97% and PFA = 3.3%
Leak Threshold 0.0017 gph
Applicability Liquid filled interstices. Approved liquids: Water and Brine.
Interstitial Capacity Maximum of 1,500 gallons.
Waiting Time Tanks in service must be placed out of service for 72 hours before testing on the interstice can begin.
If the tank is a new installation, the tank must be installed for a minimum of 72 hours for the test on the interstice to be valid due to potential thermal changes after installation.
No wait time for UDCs, Sumps or Spill Buckets.
Test Duration The test duration varies based on the surface area of the top of the interstitial liquid where the leak detection method�s measurements are being taken.
Temperature Measurement not required by this method.
Ground Water Ground water level must be determined.
When one or both sides of the interstice is under liquid, the test duration is determined by calculating the flow rate produced by the pressure differential and extending the test duration period to achieve the test sensitivity. See Comments below for additional information.
Calibration Not required with this test method.
Comments The MC Leak Enhanced Leak Detection Method has a test duration calculator that automatically calculates the test duration when a tank, UDC, Sump or Spill bucket interstice has liquid on either the exterior or interior walls. Extend the interstitial fluid above the operating fluid level to overcome the head pressure of the liquid inside the primary tank or outside the secondary interstice wall. At no time can the interstice pressure exceed manufacturer specifications.
The interstice to be filled to100% capacity.
The minimum waiting period between topping off the fluid level in the interstitial reservoir to fine tune the desired level for testing is 1 hour. If a 4 inch riser is used to create the fluid reservoir in tank related components not affected by groundwater the test time after stabilization is 1 hour.
The minimum measured liquid level change that exceeds the leak threshold of 0.0017gph that indicates a leak is variable due to the difference in the cross sectional surface area of the fluid reservoir.

Leak Detection Technologies, Inc.
2765 East Wieding Road
Tucson, AZ 85706
Tel: (855) 255-5325

Evaluator: Ken Wilcox Associates
Tel: (816) 443-2494
Date of Evaluation: 04/18/19