3-1/2 inch pipe dimensions: OD and wall thickness by schedule
Deskely Completions team Singapore
A 3-1/2 inch pipe, NPS 3-1/2 or DN 90, has an outside diameter of 101.6 mm (4.000 inches) in every schedule. The nominal size is a name, not a measurement: the outside diameter is larger than 3-1/2 inch. The schedule sets the wall thickness, and with it the inside diameter and the weight.
The table gives every schedule listed for NPS 3-1/2 in ASME B36.10M and B36.19M, in mm and inches.
- Outside diameter: 101.6 mm (4.000 in), the same for every schedule.
- Schedule 40: 5.74 mm wall, 90.1 mm inside diameter.
- Schedule 80: 8.08 mm wall, 85.4 mm inside diameter.
- Metric equivalent: DN 90.
3-1/2 inch pipe dimensions by schedule
| Schedule | Wall mm (in) | ID mm (in) | kg/m (lb/ft) |
|---|---|---|---|
| Schedule 5S | 2.11 (0.083) | 97.38 (3.834) | 5.18 (3.48) |
| Schedule 10S | 3.05 (0.120) | 95.50 (3.760) | 7.41 (4.98) |
| STD (standard) | 5.74 (0.226) | 90.12 (3.548) | 13.57 (9.12) |
| Schedule 40 | 5.74 (0.226) | 90.12 (3.548) | 13.57 (9.12) |
| XS (extra strong) | 8.08 (0.318) | 85.44 (3.364) | 18.64 (12.52) |
| Schedule 80 | 8.08 (0.318) | 85.44 (3.364) | 18.64 (12.52) |
Nominal dimensions. Weights are for plain-end carbon steel; stainless steel is about 2 percent heavier. Mill tolerances apply, and your project pipe specification takes precedence.
3-1/2 inch pipe outside diameter
The outside diameter of NPS 3-1/2 pipe is 101.6 mm, or 4.000 inches, whatever the schedule, so 3-1/2 inch fittings and flanges fit every wall thickness. In metric drawings and specifications the same size is called DN 90.
It is larger than 3-1/2 inch because, below NPS 14, the nominal size is a traditional name that once roughly matched the bore, not the outside.
Nearby sizes
- 3 inch pipe dimensions: OD 88.9 mm
- 4 inch pipe dimensions: OD 114.3 mm
Every size and schedule in one table: the pipe schedule chart.
The Deskely products for this
Frequently asked questions
What is the OD of 3-1/2 inch pipe?
101.6 mm (4.000 inches), the same for every schedule.
What is the wall thickness of 3-1/2 inch schedule 40 pipe?
5.74 mm (0.226 in), giving an inside diameter of 90.1 mm (3.548 in).
What is the wall thickness of 3-1/2 inch schedule 80 pipe?
8.08 mm (0.318 in), giving an inside diameter of 85.4 mm (3.364 in).
What is 3-1/2 inch pipe in DN?
DN 90.
How much does 3-1/2 inch schedule 40 pipe weigh?
13.57 kg/m (9.12 lb/ft) for plain-end carbon steel.
- In production since 2014
- Thousands of daily users
- On MODEC FPSO projects since 2016