Issue Date:  October 4, 2007
Revision Date:  February 24, 2009

CGRS, Inc.

iota  VaporTite - V005
Enhanced Leak Detection (ELD) Method



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.


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.


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 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.


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:
Smallest Detectable Leak:
Response Time:
Background Suppression:

2 ppm
5 x 10-6 atm-cc/sec
< 2 seconds


Helium detector performs an auto calibration on start up and must be checked monthly and, if necessary, calibrated in accordance with manufacturer’s instructions.


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 tank top/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.


CGRS, Inc. Evaluator:  Ken Wilcox Associates
1301 Academy Court Tel:  (816) 443-2494
Fort Collins, CO 80524 Date of Evaluation:  07/25/07
Tel:  (800) 288-2657  


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