Issue Date: January 31, 2019


 

AC’CENT Environmental

Dri-Sump Containment Tightness Test Method

SECONDARY AND SPILL CONTAINMENT TEST METHOD

Certification

Leak rate of 0.1 gph with PD = 100%, and PFA = 0%

Please be aware that the authority having jurisdiction in your particular state, territory, tribe or municipality may have set a minimum detectable leak rate for secondary and spill containment testing.
 

Applicability For testing spill and sump containments that are free of debris or measurable liquid, located in non-saturated backfill consisting of sand, pea gravel, or clay/silt.
 
Specification

Containment must be free of debris and measurable liquid.
Containment backfill can be moist but not saturated with measurable liquid as verified by visual observation of liquid level in Vapor Stimulator Tubes (VST) or if the sump bottoms are deeper than the VST through observation wells located in the containment backfill.
VSTs shall be installed per manufacturer’s installation training and certification procedures and instructions which include the minimum number of VSTs, placement and depth for each type of containment.

Vapor Stimulator Tubes (VST) Placement Chart

Containment Sump Type

Minimum Number of VSTs per Containment Sump

Maximum Horizontal Distance from Sump Wall

Minimum Length of VST

Backfill Soil Type Acceptance

Minimum Test Time for pass or fail results

Spill Bucket

1

8 inches
(±1”)

18 inches

All

1 minute

Under Dispenser Containment Sump (UDC)

1

8 inches
(±1”)

18 inches

All

1 minute

Transition Sump (UDC depth)

1

8 inches
(±1”)

18 inches

All

1 minute

Transition Sump (STP depth)

2

8 inches
(±1”)

36 inches

All

1 minute

Submersible Turbine Sump (STP)

2

8 inches
(±1”)

36 inches

All

1 minute


 

Pre-test Verification A manometer is used to indicate adequate air flow and communication between VSTs in a 5-10 second pre-test procedure. Communication will be verified between two VSTs within the tank, piping, and dispenser in the same type backfill.
Waiting Time No waiting time before test begins.
Test Period Minimum of one minute once the test begins.
System Features A leak is determined by observation of a change in the specialized laser light beam from a dot to a line which is indicative of the presence of the proprietary heavy vapor.
Comments

Dri-sump Containment Tightness Test method uses the proprietary heavy vapor aerosol instead of water to completely fill the sump, interstice or vessel.
AC’CENT states this proprietary vapor aerosol is made from a formula of chemicals which are all food grade, pH neutral, non-petroleum based, non-toxic, non-flammable, and pose no environmental impact. The dissipation of the aerosol reverts back to normal organic elements in ambient air.
When installed per the manufacturer’s placement requirements this method allows for detecting heavy vapor egress from the containment at any point. The method automatically tests for adequate flow of air and vapor through the backfill each time the system is activated. Any stoppage of flow through the VST or backfill will cause increased vacuum on the View Chamber that is quickly identified by a significant collapse of the View Chamber side walls.
Temperature is not a factor.
The evaluation testing was conducted with three different non-metallic commercially manufactured deep containment sumps, 300 gallon capacity, 47 inches diameter and 60 inches long. These were installed as would typically be found at a fuel service station. They were tested in different backfill types, including: sand; pea gravel, and clay/silt mix. The presence of water above the bottom of the sumps was not evaluated.

 

Danny Brevard, PG

Evaluator:  Ken Wilcox Associates

AC'CENT Corporate Offices

1125 Valley Ridge Dr

P. O. Box 3289

Grain Valley, MO 64029

Lufkin, TX 75903-3289

Tel: (816) 443-2494

E-mail:  info@info@accent-us.com Dates of Evaluations: 10/04/18
URL:  www.accent-us.com  
 

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