UST Programs - LG 113 - Veeder-Root

Secondary Containment Leak Detection (SCLD)
TLS-450Plus and TLS-350/ProMax/EMC Console with Vacuum Sensors 857280-100, 200, 30x,
330020-4xx*, or Assembly 332175-001


Issue Date: September 1, 2004

Revision Date: March 17, 2016


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, double-walled piping, and double-walled containment sumps.
System is designed to detect a loss of product from primary containment or loss of vacuum from secondary containment by activating a visual and acoustic alarm, and, if programmed, turbine pump shutdown.
System is capable of detecting breaches in both the inner and outer walls of double-walled tanks, double-walled piping, and double walled containment sumps.

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 tanks, connected double-walled piping, double-walled containment sumps, and other interstitial spaces of primary containment areas 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 evaluated but would be expected to be very similar to the system's response when storing diesel.
Evaluations determined that the Vacuum Sensors 857280-100, 200, 30x, responds to 100% Lubrizol Ultrazol 9888, 100% Afton OTR 8332G, and 100% Afton OTR 8843G. Alarm and response can be expected to be very similar to the response values listed above.

Manufacturer’s Specifications:

Alarm will activate when interstitial vacuum decreases to 1.7 psi (3.5” Hg) vacuum for TLS-350; 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 a lower level of vacuum to be maintained (e.g. double walled fiberglass tank with dry interstice).
The interstitial space shall be rated for the operating vacuum of the system, 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.
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, piping and/or containment sumps. Always consult with the manufacturer and the manufacturer’s applicable recommended installation practices before installing this system, or damage may be caused to the tank, piping, or containment sump by its use. 
*Vacuum Sensor 330020-4xx was added at the request of Veeder-Root and uses Assembly 332175-001.

125 Powder Forest Dr.
Simsbury, CT 06070-2003
Tel: (860) 651-2700
Evaluator: Ken Wilcox Associates
Tel: (816) 443-2494
Dates of Evaluation: 06/09/2004, 05/10/2019