Pipe Tolerances Specified by ASME B36.10/36.19
Pipes Diameter Tolerance
| PIPE NPS/ DN/ OD | Allowed Outside Diameter Tolerance | |||
|---|---|---|---|---|
| Over | Under | |||
| inches | mm | inches | mm | |
| NPS 1/8 to 1½ DN 6 to 40 OD 10.3 to 48.3, mm |
1/64 | 0.4 | 1/64 | 0.4 |
| Over 1½ to 4 DN 40 to 100 OD 48.3 to 114.3 mm |
1/32 | 0.8 | 1/32 | 0.8 |
| Over 4 to 8 DN 100 to 200 OD 114.3 to 219.1 mm |
1/16 | 1.6 | 1/32 | 0.8 |
| Over 8 to 18 DN 200 to 450 OD 219.1 to 457 mm |
3/32 | 2.4 | 1/32 | 0.8 |
| Over 18 to 26 DN 450 to 650 OD 457 to 660 mm |
1/8 | 3.2 | 1/32 | 0.8 |
Pipes Thickness Tolerance
| PIPE NPS/ DN/ OD | Tolerance, % from Nominal | |
|---|---|---|
| Over | Under | |
| NPS 1/8 to 2½, all t/D ratios DN 6 to 65 OD 10.3 to 73.0, mm |
20.0 | 12.5 |
| NPS 3 to 18, t/D up to 5% DN 80 to 450 OD 88.9 to 457 mm |
22.5 | 12.5 |
| NPS 3 to 18, t/D ＞ 5% DN 80 to 450 OD 88.9 to 457 mm |
15.0 | 12.5 |
| NPS 20 and larger, welded, all t/D ratios DN 500 OD 508 mm |
17.5 | 12.5 |
| NPS 20 and larger, seamless, t/D up to 5% DN 500 OD 508 mm |
22.5 | 12.5 |
| NPS 20 and larger, seamless, t/D ＞ 5% DN 500 OD 508 mm |
15.0 | 12. |
Pipes Length Tolerance
- Seamless and Welded (no filler metal added): if cut lengths are ordered, no length of pipe shall be under the length specified and not more than 1/4 in. (6.35 mm) over that specified.
- Forged and Bored, Cast, and Cast Cold-Wrought: if definite cut lengths are ordered, no length of pipe shall be under the length specified and not more than 1/8 in. (3.2 mm) over that specified.
- For stainless steel pipe ordered to random lengths, the lengths and variations shall be agreed upon between the manufacturer and the buyer
Pipes Weight Tolerance
The pipes’ weight tolerance depends on the nominal pipe size, as listed below:
- Pipe of NPS 4 (DN100, 114.3mm) and smaller may be weighed in convenient lots; pipe in sizes larger than NPS 4 shall be weighed separately
- Pipes NPS 12 (DN300, 323.8mm) and under, weight tolerance is: -3.5% / +10%
- Pipes over NPS 12 (DN300, 323.8mm),weight tolerance is: -5% / +10%
Pipes Quantity Tolerance
Should be within -10% to +10% tolerance, as a rule of thumb (-3/+3% should be acceptable)
