PVC Schedule 40 pipe pressure capacity falls as operating temperature rises. Charlotte Pipe publishes maximum working pressure by nominal size for its ASTM D1785 Schedule 40 PVC pipe at both 73°F and 140°F. The table below is pipe-only and uses those two manufacturer-listed temperatures; it is not a generic rating for every PVC brand, fitting or system.

PVC Schedule 40 pipe pressure rating by size and temperature

How to use the ratings

Match the nominal pipe size and select the column for the operating temperature. At 73°F, Charlotte Pipe lists 600 psi for 1/2-inch Schedule 40 pipe and 280 psi for 2-inch pipe. At 140°F, those pipe ratings are 132 psi and 62 psi, respectively. The table is specific to the manufacturer’s pipe product and its stated material and dimensional standard; it does not certify an assembled piping system.

The manual identifies the pressure pipe as PVC 1120 and references ASTM D1785. It lists a maximum working temperature of 140°F. Do not extrapolate above that temperature. Between 73°F and 140°F, use the manufacturer’s exact temperature-derating method for the actual design temperature. The two displayed endpoints are not permission to linearly interpolate unless the manufacturer or applicable code says that method is acceptable.

Worked example

Suppose a water line uses Charlotte Pipe 1-inch Schedule 40 PVC and will operate at 140°F. The table’s pipe-only pressure rating at 140°F is 99 psi. If the operating pressure is higher, the pipe is outside this listed limit. If the system is at an intermediate temperature, obtain the manufacturer’s applicable derating factor before deciding. Then check every other component because fittings and joints may have lower ratings than the pipe.

For example, Charlotte’s manual states that Schedule 40 pressure fittings should be used with this pipe and that the fitting’s working pressure should be reduced above 73°F. Its pressure table gives separate pipe, socket-fitting, threaded-fitting and union columns; the dataset here intentionally shows only the pipe column. A design cannot be approved from the pipe rating if a lower-rated union, threaded adapter, valve, pump or instrument is installed.

Common mistakes

First, do not use a 73°F rating at elevated temperature. Second, do not confuse a Schedule 40 pressure system with DWV pipe, CPVC, SDR pipe or another PVC formulation. Third, do not use the pipe pressure rating for compressed air or gases: Charlotte Pipe explicitly excludes those applications for this Schedule 40 system. Fourth, do not overlook static head, surge, water hammer, support spacing, chemical compatibility, joining procedure, code requirements or the weakest component.

Use the pipe label and current manufacturer manual to verify the exact product. The manufacturer cautions that exceeding maximum working temperature or pressure can cause system failure and property damage. Source: Charlotte Pipe Plastics Technical Manual.

Nominal pipe size is not the measured outside diameter. Charlotte Pipe’s manual separately lists outside diameter, wall thickness and nominal size; use the exact dimensions from the product table when designing supports, adapters or flow calculations. Pressure capacity also depends on the pipe material classification, schedule, joining method and service conditions. The same nominal size in Schedule 80 or an SDR product has a different wall and pressure rating, so do not transfer these values between series.

The 140°F column is a manufacturer-published endpoint, not a general derating formula. If the system operates at 90°F, 110°F or another temperature, find the applicable Charlotte Pipe derating factor and apply it to every pressure-rated component as directed. Also review code limits, chemical compatibility, cyclic loading, pressure surges, installation, solvent-cement cure and inspection requirements for the intended service. The table is not a design pressure allowance for an unverified product or joint.