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PVC Schedule 80 pipe

Entry in Drain pipe and retired pipe · Updated · Written by the Know Your Pipes editors from the sources listed under References

PVC Schedule 80 is thick-wall polyvinyl chloride pressure pipe made to ASTM D1785; comparing PVC Schedule 40 vs 80, both share an outside diameter at each size, but Schedule 80 has the heavier wall.[1][3] One maker describes its Schedule 80 as dark gray and its Schedule 40 as white.[2]

Because the extra wall is added on the inside, Schedule 80 has a smaller bore and a higher pressure rating than PVC Schedule 40 pipe of the same nominal size.[1][2]

1 Schedule 40 vs 80 by size

The table pairs one maker's published wall thickness and 73°F water rating for each schedule.[1][2] The bore figures are the outside diameter minus two walls.

PVC Schedule 40 vs Schedule 80, one maker's data (water at 73°F)
Nominal sizeOutside diameterSch 40 wall / boreSch 40 ratingSch 80 wall / boreSch 80 rating
1/2 in0.840 in0.109 / 0.622 in600 psi0.147 / 0.546 in850 psi
3/4 in1.050 in0.113 / 0.824 in480 psi0.154 / 0.742 in690 psi
1 in1.315 in0.133 / 1.049 in450 psi0.179 / 0.957 in630 psi
2 in2.375 in0.154 / 2.067 in280 psi0.218 / 1.939 in400 psi
4 in4.500 in0.237 / 4.026 in220 psi0.337 / 3.826 in320 psi

Both schedules lose rating as temperature rises; at 140°F, the top of the range, the 73°F figure is multiplied by 0.22.[2] The maker's own example is 6 in Schedule 80 rated 280 psi, which drops to 62 psi at 140°F.[2] Neither schedule is a hot-water pipe; hot-and-cold lines in a house use materials such as CPVC pipe.[2]

2 Threading

The thicker wall is what allows threads to be cut. Charlotte Pipe does not recommend threading any thermoplastic pipe except CPVC and PVC Schedule 80.[2] Cut threads remove wall, so threaded joints are rated at 50% of solvent-cemented ones, and plastic threaded fittings take a further 50% derating.[2] How tapered threads seal is covered under threaded pipe joints.

Plain-end Schedule 80 is otherwise joined like Schedule 40, by solvent-weld joints, using Schedule 80 socket fittings made to ASTM D2467.[3]

3 Where Schedule 80 is used

The maker lists Schedule 80 for pressure applications up to 140°F.[3] Its wall is the reason it is picked where a threaded PVC connection is wanted, since the maker does not recommend threading Schedule 40.[2] Exposed pipe still needs sunlight protection, such as latex paint, as described under sunlight and UV limits.[2]

Safety

Never test or use PVC pipe of any schedule with compressed air or gas; the maker warns that a rupture under air pressure may be explosive, with a risk of serious or fatal injury.[1]

See also

  • PVC Schedule 40 pipeWhite rigid PVC pipe made to ASTM D1785; used for cold-water pressure lines outside the house and, when dual-marked, for drains.
  • Nominal pipe size, CTS and IPSWhy pipe sizes are names rather than measurements, and how the CTS and IPS outside-diameter systems differ for the same nominal size.
  • PVC DWV and foam-core pipeWhite PVC drain, waste and vent pipe, made solid-wall (ASTM D2665) or with a lighter cellular foam core (ASTM F891); drainage only.
  • ABS pipeBlack acrylonitrile butadiene styrene drain, waste and vent pipe; solvent-cemented with ABS cement and used much like white PVC DWV.
  • Polybutylene pipeGray, flexible plastic water supply pipe used in US homes from the late 1970s; leaks and class actions ended its use.
  • Kitec pipeMultilayer plastic-aluminum water pipe with brass fittings made by IPEX; its fittings were prone to dezincification and leaks.

References

  1. Charlotte Pipe and Foundry Co., "Product Data Sheet PVC-80-PIPE-225" (2025) — charlottepipe.com
  2. Charlotte Pipe and Foundry Co., "Plastics Technical and Installation Manual" — charlottepipe.com
  3. Charlotte Pipe and Foundry Co., "PVC Schedule 80 Pipe & Fittings" — charlottepipe.com