Issue Date: October 28, 2019


Secondary Containment Leak Detection (SCLD)
TLS-450Plus and TLS-350/ProMax/EMC Console with Vacuum Sensors 857280-100, 200,
30x, or Assembly 332175-001


Certified as equivalent to European leak detection standard EN-13160-2, Part 2, as a Class I leak detection system.

Operating Principle:
System uses vacuum generated by the turbine pump to continuously maintain a partial vacuum within the interstitial space of double-walled tanks and double-walled piping.
System is designed to activate a visual and acoustic alarm, and turbine pump shutdown before stored product can escape to the environment.
System is capable of detecting breaches in both the inner and outer walls of double-walled tanks and double-walled piping.

Alarm Condition:
System alarms when a liquid or air leak occurs which causes the interstitial vacuum to decrease (pressure to increase) and the system is unable to maintain minimum vacuum.
System will also alarm if liquid is detected in the interstitial space, or if the vacuum level in the interstitial space decreases at a rate exceeding 85±15 liters/hour.

Underground double-walled tank, connected double-walled piping, and other connected interstitial spaces storing gasoline, gasohol, diesel, heating oil #2, kerosene, aviation fuel, motor oil, water.
Storage of biodiesel blends B6-B20 meeting ASTM D7467 and biodiesel B100 meeting ASTM D6751 would also produce a system alarm if the system threshold is exceeded. Responses to these fuels were not determined but would be expected to be very similar to the system's response when storing diesel.

Manufacturer’s Specifications:
Alarm will activate when interstitial vacuum decreases to 1.7 psi (3.5” Hg) vacuum; 1.8 psi (3.6” Hg) vacuum for TLS-450Plus.
Default maximum vacuum level (pump-off pressure) is 8 psi vacuum (16.3” Hg), but can be set as low as 4 psi (8.2” Hg) if the monitored system requires that a lower level of vacuum be maintained.
The interstitial space shall be rated for the operating vacuum of the leak detector, regardless of temperature and groundwater level fluctuations.
Volume of monitored interstitial space must not exceed 8 m3 (2,114 gal) for tanks and 10 m3 (2,642 gal) for piping.
When monitoring double-walled tanks, a liquid sensor must be located at lowest point of interstitial space.

Functional and operational safety tests should be performed in accordance with manufacturer’s instructions.

Interstitial space is tested continuously.
System is connected to the interstitial space by a single vacuum line.
System was not evaluated with manifolded piping.
Vacuum is generated by the turbine pump and is measured and controlled by a vacuum control valve.
This system may not be compatible with all secondarily contained tanks and/or piping. Always consult with the tank and/or piping manufacturer and the manufacturer’s applicable recommended installation practices before installing this system, or damage may be caused to the tank or piping by its use.


Evaluator: Ken Wilcox Associates

125 Powder Forest Dr.

Tel: (816) 443-2494

Simsbury, CT 06070-2003

Dates of Evaluation: 06/09/2004, 05/10/2019

Tel: (860) 651-2700



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