Non-Discriminating Interstitial Sensor

The Non-Discriminating Interstitial Sensor for double-wall fiberglass tanks detects the presence of liquid in the interstitial space of the tank.

The Veeder-Root Interstitial Sensor detects the presence of liquid between the double wall of fiberglass tanks. Liquid triggers an alarm signal to your automatic tank gauge. You’ll know immediately where the problem is so you can take action to prevent serious and costly safety and environmental problems.

Key Features

  • Used in the annulus of a fiberglass tank with a riser pipe of 4”

  • Detects leaks in interstitial space of fiberglass tanks

  • Cable length of 25'

  • UL and NWGLDE approval

  • Compatible with gasoline, diesel, kerosene, jet fuel, aviation gas, waste oil, motor oil, gasoline with up to 15% ethanol, diesel with up to 20% biodiesel

Product Number Description


Non-Discriminating Interstitial Sensor for Double-Wall Fiberglass Tanks for up to 12" Diameter Fiberglass Tank


Key Benefits

  • Updated compact design for easier installation and navigation of 90º bends 

  • Easily identifiable "black top" and "white bottom" for sensor orientation during installation

  • Single part number reduces part inventory in-house and on service trucks 

  • Two wire connection


Fuel Compatibility

Gas, Diesel, Kerosene, Jet Fuel, Aviation Gas, E15, Bio-Diesel 20, Green Diesel, DEF, 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

Optical sensor and conductivity

Product Activation Height

Fuel or Water – 0.28” (0.71cm)

Operating Temp

-4 to +140°F (-20 to +60°C)


2.2” (5.6cm) length, 1.3” (3.3cm) width,

0.6” (1.5cm) thick

Standard Cable

25ft (7.6m)

Tank Size

Fits 4 to 10ft (1.2 to 3m) I.D. Fiberglass Tanks