SpecBase

NPS 32 (DN 800) pipe — dimensions and weight

Outside diameter 812.8 mm (32 in), unchanged by schedule. This page lists all 7 tabulated schedules that fit on that diameter, with wall thickness, bore, mass per metre and internal volume.

Outside diameter
812.8mm
32 in · same in every schedule
Schedules tabulated
7
0.31–0.69 in wall
Sch 40 mass
342.757kg/m
230.322 lb/ft · 17.48 mm wall
Sch 40 bore
777.8mm
475.21 L/m internal volume
Mass range
157.3–342.8 kg/m
thinnest to heaviest tabulated wall
NPS 32 does not measure 32 inches anywhere

Nominal pipe size is a label, not a dimension. The outside diameter of NPS 32 is 32 in (812.8 mm), and the bore depends entirely on the wall you choose — 797.0 mm on the thinnest tabulated wall down to 777.8 mm on the heaviest. The naming convention was fixed decades ago so that a fitting size could serve every wall thickness; it is not a measurement, and treating it as one is how a line gets sized off a table for the wrong pipe.

NPS 32 (DN 800) — every tabulated schedule

NPS 32 (DN 800) — all schedules
Schedule Wall mm Inside dia. mm Metal area mm² Mass / length Water capacity L/m
10 7.92 797.0 20,038.6 157.303 kg/m · 105.703 lb/ft 498.830
20 12.70 787.4 31,922.6 250.592 kg/m · 168.390 lb/ft 486.946
30 15.88 781.0 39,744.9 311.997 kg/m · 209.652 lb/ft 479.124
40S 9.52 793.8 24,036.9 188.690 kg/m · 126.794 lb/ft 494.832
40 17.48 777.8 43,663.3 342.757 kg/m · 230.322 lb/ft 475.205
STD 9.52 793.8 24,036.9 188.690 kg/m · 126.794 lb/ft 494.832
XS 12.70 787.4 31,922.6 250.592 kg/m · 168.390 lb/ft 486.946

Wall thicknesses derived from ASME B36.10M / B36.19M. Outside diameter 812.8 mm. Mass computed for Carbon Steel at 7850 kg/m³.

STD and XS are derived rather than tabulated: STD equals Sch 40 up to NPS 10 and is fixed at 0.375 in above it; XS equals Sch 80 up to NPS 8 and is fixed at 0.500 in above. Both appear here as separate rows because both are orderable designations.

How NPS 32 pipe weight is calculated

Sch 40 at this size, step by step

m = π/4 · (D² − d²) · 10⁻⁶ · ρ

D is outside diameter, d is bore (D − 2t), ρ is density in kg/m³, m is mass in kg per metre.

Worked through with the default dimensions:

D = 812.8 mm (32 in, fixed for every schedule)t = 17.48 mm (Sch 40)d = D − 2t = 812.8 − 34.95 = 777.8 mmA = π/4 × (812.8² − 777.8²) = 43,663.3 mm²m = 43,663.3 × 10⁻⁶ × 7,850 = 342.757 kg/m (230.322 lb/ft)
D
812.8 mm — fixed by the standard for NPS 32
t
17.48 mm for Schedule 40 at this size
d
777.8 mm — the bore, and the dimension that governs flow
ρ
7,850 kg/m³ for carbon steel

Internal volume and surface area

Mass is only one of the quantities that fall out of the same geometry. Two others decide real work on a line, and neither appears on a printed pipe chart:

Per metre of NPS 32 pipe, across the tabulated wall range
Wall vs range Wallmm Boremm Masskg/m
25 % 0.41 812.0 8.13
50 % 0.50 811.8 10.02
100 % 0.69 811.4 13.78
200 % 1.06 810.7 21.30
500 % 2.19 808.4 43.82
1,000 % 4.07 804.7 81.21

Sampled across the lightest to heaviest tabulated wall at this size. Mass rises roughly linearly with wall while the bore falls, which is the trade-off a schedule choice actually represents.

  • Internal volume — 475.205 L/m in Sch 40 ( 125.536 US gal/ft). Multiply by the line length to size a hydrostatic test or a flush.
  • External surface — 2.5535 m² per metre of pipe, which is what a coating or insulation quantity is priced against. It depends only on the outside diameter, so it is identical in every schedule at NPS 32.
  • Water mass — 475.21 kg per metre of water at 1,000 kg/m³. This is the number that decides whether a support is adequate during a test, not in service.

Download this size

NPS 32 pipe — CSV

Exports the schedule table above. The full pipe dataset, every size against every schedule, is on the downloads page.

All pipe data (CSV · 31 sizes)

Frequently asked questions

What is the outside diameter of NPS 32 pipe?

NPS 32 pipe has an outside diameter of 812.8 mm (32 in), and that diameter is fixed for every schedule at this size. Nominal pipe size is a label, not a dimension: NPS 32 does not measure 32 inches anywhere. The naming convention was chosen so that the outside diameter stays constant while the wall varies.

How much does NPS 32 pipe weigh?

In Schedule 40 it weighs 342.757 kg/m (230.322 lb/ft) with a 17.48 mm wall and a 777.8 mm bore. Not every schedule is tabulated for this size.

How many schedules are available for NPS 32?

This page lists 7 tabulated schedules, including the derived STD and XS walls. Note that STD and Sch 40 are the same thickness at the small sizes and different from NPS 12 upward, and XS and Sch 80 are the same up to NPS 8 and different above — the two confusions that most often produce a wrong order.

What is the internal diameter of NPS 32 pipe?

The bore is the outside diameter minus twice the wall thickness. The table above gives it for every tabulated schedule at this size.

Nearby nominal sizes

Adjacent sizes in the NPS series. Outside diameters step non-uniformly — the jump from NPS 14 to NPS 16 is 2 in, the same as from NPS 2 to NPS 4.

Schedules at this size

Each schedule page lists every size that carries that wall.

Pipe reference and tools

Data source and method

Outside diameter for NPS 32 is the standard's governed value of 32 in, converted at exactly 25.4 mm per inch. Wall thicknesses are the tabulated B36.10M / B36.19M values. Mass, bore, internal volume and surface areas are computed on this page.

  • ASME B36.10M — Welded and Seamless Wrought Steel Pipe (dimensional tables).
  • ASME B36.19M — Stainless Steel Pipe (dimensional tables).
  • BIPM / NIST definitional constants: international inch = 25.4 mm, foot = 0.3048 m, pound = 0.45359237 kg.

Dataset version 2026.09.1 · dimensions last verified against source 2026-09-21. Found an error? Report it — corrections are issued with a version bump.