5703.6.9.1 Fiberglass-Reinforced Plastic Piping
Fiberglass-reinforced plastic (FRP) piping is not required to be provided with flexible joints in locations where both of the following conditions are present:
- Piping does not exceed 4 inches (102 mm) in diameter.
- Piping has a straight run of not less than 4 feet (1219 mm) on one side of the connection where such connections result in a change of direction.
In lieu of the minimum 4-foot (1219 mm) straight run length, approved and listed flexible joints are allowed to be used under dispensers and suction pumps, at submerged pumps and tanks, and where vents extend above ground.