Underground Tank Repair/Retrofit with Fill Indicator
 
By President Mark Davis
January 3, 2014
 

One of the issues with the use of underground storage tanks for fire protection water is the maintenance of water levels. When used in a fixed-fire protection system at installations like chemical plants and factories, fire water storage tanks normally have some type of electronic monitoring system installed.

In the rural environment, the use of underground tanks for fire protection water generally does not incorporate any type of electronic monitoring system. In most cases, in order to inspect the levels of these tanks, one must dip the tank or connect a pumper to it and "top it off."

ETT,LLC (Alabama) makes a cistern vent that has a built-in sight glass that shows the leve of water in the tank. The device uses a simple float attached to a colored cylinder that is displayed in a window on the vent assembly. The device is meant to show if the tank is full (a green display). If "red" is seen, then the tank is not full.

These cistern vents with sight assembly are used in a number of jurisdictions as part of the "spec" for 30,000-gallon (ISO) underground tanks.
 
Three of the four pipes on this tank were broken by a snow plow [lack of protective bollards]; however, you would never know this by just looking at the pipes from a distance. The other item that you don't know is whether the tank is full or not.
Three of the four pipes on this tank were broken by a snow plow [lack of protective bollards]; however, you would never know this by just looking at the pipes from a distance. The other item that you don't know is whether the tank is full or not.
This 30,000-gallon underground tank in Lineboro, Maryland was retrofitted with a cistern vent assembly equipped with a tank level indicator.
This 30,000-gallon underground tank in Lineboro, Maryland was retrofitted with a cistern vent assembly equipped with a tank level indicator.
 
The ETT,LLC cistern vent assembly is a simple device that not only provides adequate tank venting but also provides a tank level indicator.
The ETT,LLC cistern vent assembly is a simple device that not only provides adequate tank venting but also provides a tank level indicator.
The tank level indicator works on a simple "float" concept.
The tank level indicator works on a simple "float" concept.