Interstitial Sensor for Steel Tanks

The Interstitial Sensor for steel tanks is non-discriminating and detects the presence of liquid between the double walls of the tank.

Detect dangerous leaks in double-walled steel tanks. The presence of liquid in the interstitial space of double-walled tanks triggers an alarm in your automatic tank gauge console. The visual and audible alarm notifies you immediately of the problem, so you take quick and efficient action to help prevent safety and environmental issues. The console can also trigger an on-site alarm for even greater warning capability.

Key Features

  • Logs each incident in the Alarm History Report and logs status changes via the Sensor Status report 

  • Can be used in the annulus of steel tanks with a sensor riser pipe 1.5" I.D. or greater 

  • Only two wires are required to connect the sensor to a TLS or ILS system

Product Form

Part Number



Interstitial Sensor for Steel Tanks with 16’ Cable


Interstitial Sensor for Steel Tanks with 30’ Cable


2” (50mm) Interstitial sensor riser cap kit (sold separately)



Fuel Compatibility

Gas, Diesel, Kerosene, Jet Fuel, Aviation Gas, E15, Bio-Diesel 20, Green Diesel, Waste Oil, Motor Oil

Alarm Notification

Normal: Sensor in Normal State – No liquid detected

Liquid Alarm: Liquid detected

Sensor Out: Sensor not communicating to ATG Console

Operating Principle

Reed switch / float

Product Activation Height

Fuel or Water – 1.4” (3.56cm)

Operating Temp

-4 to +140°F (-20 to +60°C)


2.5” (6.4cm) high, 1.5” (3.8cm) diameter

Standard Cable

16ft (4.9m)