Issue Date: October 4, 2007

CGRS, Inc.

iota® VaporTite - V005

Non-Volumetric Tank Tightness Test Method (Tracer)

Certification Leak rate of 0.005 gph as vapor with PD = 100% and PFA = 0%.
Leak Threshold A tank system should not be declared tight when the change in helium concentration in the interstitial space over time exceeds the method's preset threshold.
Applicability Method tests under pressure the primary containment of secondarily contained tanks, piping and other components. The primary and secondary components of the system under test must be dry, containing no liquid.
Tank Capacity Not limited by capacity.
Test Period Minimum 10 minutes for piping and 20 minutes for tanks. Test period varies in accordance with iota® software and test procedures, and is a function of several factors, including interstitial volume, flow rate, diffusion rate, and the concentration of helium in the component being tested.
Waiting Time No waiting period is required between adding helium to the primary containment and starting the test.
Dosage Helium dosage varies depending on the component being tested. In all cases, 100% industrial helium is used as prescribed in the manufacturer's test procedures.
Sampling Points Sampling is performed by circulating air through the interstitial space between the primary and secondary walls of the component(s) being tested and measuring the He levels in the circulated air.
Groundwater Groundwater level is not determined and does not impact the test. Flow meter is used to verify that the interstitial space is dry and has sufficient air movement.
Detector Helium is measured by the helium detector, which supplies data to the iota® system for analysis and pass/fail determination. Third-party evaluation was conducted using the Varian models PHD-04 and 979 detectors, but evaluator indicates that any helium detector meeting at least the following performance standards can be used:
  • Minimum Detectable Concentration: 2 ppm
  • Smallest Detectable Leak: 5 x 10-6 atm-cc/sec
  • Response Time: < 2 seconds
  • Background Suppression: Automatic
Calibration Helium detector performs an auto calibration on start up and must be checked monthly and, if necessary, calibrated in accordance with manufacturer's instructions.
Comments This method is intended primarily for use on new installations before product has been added to the system.
The interstitial volume of the components being tested must be entered manually, or the iota® software can calculate volume based on piping type/length or sump dimensions entered by the tester.
Third-party evaluation included tests to show that the method can find leaks on a variety of UST system components, including double-wall piping, double-wall USTs, and primary components contained within tanktop/under dispenser sumps.
This method is only able to test double-walled tanks that have 2 interstitial access ports on opposite ends of the tank and have a dry primary and interstitial space.
The method was evaluated on a 32 foot long tank with access ports spaced 28 feet apart.
The method cannot be used to satisfy the requirement for ELD testing of existing UST systems that are located within 1000 feet of a drinking water well.
  • CGRS, Inc.
    1301 Academy Court
    Fort Collins, CO 80524
    Tel: (800) 288-2657
  • Evaluator: Ken Wilcox Associates
    Tel: (816) 443-2494
    Date of Evaluation: 07/25/07

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