NPS 3 1/2 Double Extra Strong (XXS) Pipe
4.000 in (101.6 mm) outside diameter on a 0.636 in (16.2 mm) wall, giving a 2.728 in (69.3 mm) bore and 22.85 lb/ft (34.00 kg/m) empty. ASME B36.10M.
- Nominal size
- NPS 3 1/2 (DN 90)
- Schedule
- Double Extra Strong (XXS)
- Outside diameter
- 4.000 in (101.6 mm)
- Wall thickness
- 0.636 in (16.2 mm)
- Inside diameter
- 2.728 in (69.3 mm)
- Weight, empty
- 22.85 lb/ft (34.00 kg/m)
- Weight, water filled
- 25.38 lb/ft (37.78 kg/m)
- Flow area
- 5.845 in² (3771 mm²)
No other designation in NPS 3 1/2 shares this wall thickness, so Double Extra Strong (XXS) is unambiguous in this size.
Every schedule in NPS 3 1/2
Dimensions are given in inches, with the millimetre equivalent beneath in grey.
| Schedule | Wall thickness | Inside diameter | Weight, empty | Water (US gal/ft) |
|---|---|---|---|---|
| Sch 5 | 0.0832.11 mm | 3.83497.38 mm | 3.475.17 kg/m | 0.600 |
| Sch 10 | 0.1203.05 mm | 3.76095.50 mm | 4.977.40 kg/m | 0.577 |
| Sch 40 | 0.2265.74 mm | 3.54890.12 mm | 9.1113.56 kg/m | 0.514 |
| STD | 0.2265.74 mm | 3.54890.12 mm | 9.1113.56 kg/m | 0.514 |
| Sch 80 | 0.3188.08 mm | 3.36485.45 mm | 12.5118.61 kg/m | 0.462 |
| XS | 0.3188.08 mm | 3.36485.45 mm | 12.5118.61 kg/m | 0.462 |
| XXS this page | 0.63616.15 mm | 2.72869.29 mm | 22.8534.00 kg/m | 0.304 |
Weight is plain-end carbon steel, w = 10.6802 × t × (OD − t) lb/ft.
Flanges for NPS 3 1/2 pipe
Flange dimensions are set by NPS and pressure class, not by schedule, so every flange below fits this pipe. The exception is the weld neck: its bore is machined to the pipe it is welded to, which for Double Extra Strong (XXS) means 2.728 in (69.3 mm). Order the flange to the schedule or the bores will not line up at the weld.
| Class | Flange OD | Thickness | Bolt circle | Bolting |
|---|---|---|---|---|
| Class 150 | 8.50215.90 mm | 0.9423.88 mm | 7.00177.80 mm | 8 × 5/8 in |
| Class 300 | 9.00228.60 mm | 1.1930.23 mm | 7.25184.15 mm | 8 × 3/4 in |
| Class 400 | 9.00228.60 mm | 1.3835.05 mm | 7.25184.15 mm | 8 × 7/8 in |
| Class 600 | 9.00228.60 mm | 1.3835.05 mm | 7.25184.15 mm | 8 × 7/8 in |
Fittings for NPS 3 1/2 pipe
ASME B16.9 dimensions come from NPS alone, so these figures hold for Double Extra Strong (XXS) exactly as they do for every other schedule in the size. Only the wall thickness has to be ordered to match.
| Fitting | Dimension | NPS 3 1/2 |
|---|---|---|
| 90° Long Radius Elbow | Centre-to-end A | 5.25133.35 mm |
| 90° Short Radius Elbow | Centre-to-end A | 3.5088.90 mm |
| 45° Long Radius Elbow | Centre-to-end B | 2.2557.15 mm |
| Straight Tee | Centre-to-end C and M | 3.7595.25 mm |
| Reducing Tee | Run centre-to-end C | 3.7595.25 mm |
| Concentric Reducer | End-to-end H | 4.00101.60 mm |
| Eccentric Reducer | End-to-end H | 4.00101.60 mm |
| Cap | Length E | 2.5063.50 mm |
Common questions
What is the inside diameter of NPS 3 1/2 double extra strong (xxs) pipe?
2.728 in (69.3 mm). The outside diameter is fixed at 4.000 in (101.6 mm) by ASME B36.10M, and the 0.636 in (16.2 mm) wall takes 1.272 in off it — 0.636 in from each side — leaving that bore.
How much does NPS 3 1/2 double extra strong (xxs) pipe weigh?
22.85 lb/ft (34.00 kg/m) empty, as plain-end carbon steel. Full of water it comes to 25.38 lb/ft (37.78 kg/m), because the bore holds 0.304 US gallons per foot. One short ton of this pipe is about 88 ft.
Does NPS 3 1/2 double extra strong (xxs) pipe use special flanges or fittings?
No. Flanges and buttweld fittings are dimensioned from NPS, so NPS 3 1/2 hardware fits this pipe in any schedule. The one thing that does follow the schedule is the bore of a weld neck flange or a fitting end prep, which has to be 2.728 in (69.3 mm) to match.