Piping comes in many materials, sizes, and types.   The more common materials of construction include steel, fiberglass-reinforced plastic, flexible and semi-rigid plastic.  


Piping diameters can vary from less than one inch to several feet.   However, the most common diameters for applications discussed in this course are 2”, 3” and 4”.  


Piping also comes in different configurations including single- and double- wall construction.


Double-wall piping is typically constructed as a primary pipe within a secondary pipe.   There is an interstitial space between the primary and secondary pipe for the purpose of allowing any fluid that escapes the primary pipe to travel to a secondary containment sump or other detection point.  


Double-wall piping can either be constructed as two discrete pipes or as one pipe having two walls that are physically attached to each other in a manner that also provides an interstitial space.


Steel piping must have a means of protection from corrosion.  


Piping used for hazardous substances, used / waste oil, and petroleum products must be compatible with those substances, UL rated®, and have a COMM 10 Material Approval for use with USTs installed in the State of Wisconsin.  


Consult with the UST system owner to determine the type of piping installed at the facility or facilities for which you are responsible.