AC'CENT Environmental A

Issue Date: January 31, 2019
Revision Date: April 13, 2022

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. Dri-sump test equipment and technicians must be current in certifications through ACCENT or its authorized representative.

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. Test data and any associated telemetry are required to be in the current report format (e.g. written, online, cloud-based, etc.) designed by ACCENT or its authorized representative.

System Features

A leak is determined by observation through one of two view ports for a change in the specialized digital laser light beam from a “dot” to a “ line”, which is indicative of the presence of the proprietary heavy vapor. Either view port can be used to see the laser, or a smart phone or other visual aid can be used from outside the view chamber.

Comments

All consumables (e.g., VSTs and Aerosol) are manufactured exclusively by AC’CENT or its authorized representative. 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

Appearance on this list is not to be construed as an endorsement by any regulatory agency nor is it any guarantee of the performance of the method or equipment.
Equipment should be installed and operated in accordance with all applicable laws and regulations. For full details, please refer to our expanded "DISCLAIMER" page.