AWWA C950

Covers — fabrication and testing of fiberglass (GRP) pressure pipe and joining systems, roughly 1 in. (25 mm) through 156 in. (4,000 mm), for aboveground and belowground potable/raw water and wastewater systems.

Does NOT cover (exclusions) — the following are governed elsewhere:

• Oil-and-gas GRP piping → ISO 14692.
• General filament-wound RTR/FRP pressure pipe → ASTM D2996.
• PE/PVC water pipe → AWWA C906 / C900; ductile iron → AWWA C151.

C950 is the waterworks GRP pressure-pipe standard; ISO 14692 governs oil-and-gas GRP.

C950 sets minimum requirements for fiberglass water pipe:

• Materials & Fabrication — resin/glass construction and manufacturing method (filament-wound/centrifugally cast).
• Pressure Class & Stiffness — internal pressure class and pipe stiffness for buried deflection control.
• Joints — bell-and-spigot/gasketed or bonded joining systems.
• Testing — hydrostatic, stiffness, and long-term (regression) performance tests.

AWWA C950 is the waterworks standard for fiberglass (GRP) pressure pipe, covering fabrication, pressure class, stiffness, joints, and testing for water systems from small to very large diameters. It is the water-industry counterpart to the oil-and-gas ISO 14692.

Fiberglass water pipe excels where corrosion resistance and light weight matter — large-diameter transmission and coastal/corrosive water. Design must address its anisotropic behavior and, for buried lines, long-term pipe stiffness controlling deflection, with bedding and backfill quality as decisive as the pipe itself.

Engineering Note: For buried C950 pipe, the installation (bedding, haunching, backfill) governs long-term deflection as much as the pipe's stiffness class — a well-made pipe in poor soil support can still over-deflect and fail.