Polyvinylchloride (PVC) pipe that is to be used under pressure or as drain, waste or vent (DWV) pipe must be manufactured to specifications set by the American Society for the Testing of Materials (ASTM) and the National Sanitation Foundation (NSF). PVC pipe is separated into schedules by size, and each schedule has different specifications.
Schedule 40 PVC pipe must be made domestically and be Type I Grade I PVC, as required by the ASTM. Its colour must be white or grey, and its trade name is H707 PVC.
PVC markings must include the name of the manufacturer or its trademark, the nominal pipe size, pipe schedule and pressure rating, the date and time of manufacture, and the material designation code. It must also bear the ASTM designation for PVC pipe, D1785, and the ASTM marking for DWV pipes, D2665. The pipe must also have a marking that indicates that it has been tested by an independent testing laboratory and be determined safe for potable water.
Schedule 40 PVC pipe is available in sizes from 1/8 of an inch to 24 inches in diameter. The minimum wall thickness increases as the pipe diameter gets larger. Pipes with a 1/8-inch diameter must have a minimum wall thickness of .068 inches; 24-inch diameter pipe must have a wall thickness of .687 inches. The average interior diameter is roughly the same as the nominal size of the pipe, while the outside diameter is generally larger.
Each size of Schedule 40 PVC pipe is pressure tested to determine the maximum working pressure. This test is executed under 73-degree Fahrenheit water with no shock. The pressure ranges range from 810 psi for 1/8-inch pipe to 120 psi for 20- and 24-inch pipe. If the pipe is to be used at elevated temperatures, the pressure rating must be adjusted using a derating factor. Temperatures at or below 22.8 degrees Celsius may be used at their tested working pressure ratings. A PVC pipe used at 60 degrees Celsius, the maximum temperature Schedule 40 PVC pipe can be used at, must multiply the working pressure by the derating of .22.