What type of piping should not be used for fill risers?

The type of piping that should not be used for fill risers is nonmetallic piping. Fill risers are critical components in the infrastructure of underground storage tank (UST) systems, designed to transfer fuel from the surface into the tank securely and efficiently.

Nonmetallic piping can be vulnerable to certain environmental conditions and chemical interactions that can compromise its integrity over time. For instance, it may not withstand the same levels of pressure or exposure to fuel as metallic options, or it might degrade faster if exposed to certain materials or conditions found in petroleum products. This makes nonmetallic piping less reliable for the specific demands placed on fill risers, where durability and resistance to chemical exposure are essential.

The other types of piping, whether plastic, steel, or flexible, have properties that are generally deemed acceptable or beneficial for use in fill applications, depending on the specifics of the installation environment and regulatory compliance.