Plastic pipe and fittings are FM Approved for aboveground wet pipe fire protection systems for Light Hazard Occupancy sprinkler systems only. Except where noted otherwise, all pipe and fittings must be completely separated by nonremovable, fire resistant barriers from any area protected by the system. A nonremovable barrier cannot be removed without substantial cosmetic damage. A fire-resistant barrier has a minimum finish fire rating of 15 minutes when tested per ASTM E 119. Except for minimal exposure at a sprinkler connection, the intent is that the sprinkler system will not be exposed to a fire environment. Rated working pressure is 175 psi (1205 kPa) at 120°F (49°C). Manufacturer's installation instructions must be strictly followed to ensure proper performance. The use of these pipes and fittings is prohibited in areas where seismic protection is required. When used in hybrid sprinkler systems composed of steel and plastic piping please refer to steel pipe listings for acceptability.