Schedule 40 Pipe (SCH 40)
The general-purpose standard-wall pipe — from ⅛″ to 12″ NB, to ASTM A53, A106 and API 5L. ERW & seamless, black & galvanized, manufactured in Dammam with full dimensions and weights below.
½″
OD 21.3 · t 2.77
1.27 kg/m
1″
OD 33.4 · t 3.38
2.50 kg/m
2″
OD 60.3 · t 3.91
5.44 kg/m
4″
OD 114.3 · t 6.02
16.08 kg/m
6″
OD 168.3 · t 7.11
28.26 kg/m
What is Schedule 40 pipe?
"Schedule" is the way a steel pipe's wall thickness is classified. For any given pipe size the outside diameter (OD) is fixed, so the schedule simply tells you how thick the wall is — and how much bore is left inside. Schedule 40 (SCH 40) is the standard, general-purpose wall used across the great majority of pipework.
Up to 10″ NB, Schedule 40 is identical to standard weight (STD) — the two terms are used interchangeably. It offers a balanced wall that handles water, gas, low-to-medium pressure lines, fire-fighting and most structural and general-fabrication duties at the lowest weight and cost.
Rouad Steel supplies SCH 40 pipe as ERW and seamless, in black, primed and hot-dip galvanized finish, to ASTM A53, A106 and API 5L — all to ASME B36.10 dimensions, with mill test certificates on every batch.
Good to know: the OD never changes with schedule — only the wall grows inward. So a SCH 40 and a SCH 80 pipe of the same size slip into the same fittings.
Schedule 40 vs Schedule 80 — same OD, different wall
The outside diameter is identical; Schedule 80 just adds wall thickness inward — more pressure, more weight, less bore.
| Feature | Schedule 40 | Schedule 80 |
|---|---|---|
| Outside diameter | Same as SCH 80 | Same as SCH 40 |
| Wall thickness | Thinner (standard) | Thicker (extra-strong) |
| Internal bore | Larger — more flow | Smaller |
| Weight per metre | Lighter | Heavier |
| Pressure rating | Standard / medium | Higher |
| Relative cost | Lower | Higher |
| Typical use | Water, gas, structural, general | High-pressure, steam, critical |
Pick SCH 40 for the majority of water, gas, structural and general-service lines; step up to SCH 80 only where pressure, temperature or a corrosion allowance demands a thicker wall.
Schedule 40 pipe dimensions & weight chart
Outside diameter, wall thickness, internal bore and nominal mass per metre for carbon-steel SCH 40 pipe to ASME B36.10.
→ scroll table| Nominal bore | OD (mm) | Wall t (mm) | Bore ID (mm) | Mass (kg/m) |
|---|---|---|---|---|
| ⅛″ (6 NB) | 10.3 | 1.73 | 6.84 | 0.37 |
| ¼″ (8 NB) | 13.7 | 2.24 | 9.22 | 0.63 |
| ⅜″ (10 NB) | 17.1 | 2.31 | 12.48 | 0.84 |
| ½″ (15 NB) | 21.3 | 2.77 | 15.76 | 1.27 |
| ¾″ (20 NB) | 26.7 | 2.87 | 20.96 | 1.69 |
| 1″ (25 NB) | 33.4 | 3.38 | 26.64 | 2.50 |
| 1¼″ (32 NB) | 42.2 | 3.56 | 35.08 | 3.39 |
| 1½″ (40 NB) | 48.3 | 3.68 | 40.94 | 4.05 |
| 2″ (50 NB) | 60.3 | 3.91 | 52.48 | 5.44 |
| 2½″ (65 NB) | 73.0 | 5.16 | 62.68 | 8.63 |
| 3″ (80 NB) | 88.9 | 5.49 | 77.92 | 11.29 |
| 3½″ (90 NB) | 101.6 | 5.74 | 90.12 | 13.57 |
| 4″ (100 NB) | 114.3 | 6.02 | 102.26 | 16.08 |
| 5″ (125 NB) | 141.3 | 6.55 | 128.20 | 21.77 |
| 6″ (150 NB) | 168.3 | 7.11 | 154.08 | 28.26 |
| 8″ (200 NB) | 219.1 | 8.18 | 202.74 | 42.55 |
| 10″ (250 NB) | 273.1 | 9.27 | 254.56 | 60.31 |
| 12″ (300 NB) | 323.9 | 10.31 | 303.28 | 79.73 |
Weights are indicative and rounded; ID = OD − 2 × wall. SCH 40 = STD up to 10″; from 12″ they differ (STD wall = 9.53 mm). Need a stock list, SCH 80/160 or a size not shown? Contact our sales desk.
Is Schedule 40 the right wall for the job?
SCH 40 is the default for most everyday pipework — here is where it fits, and where to step up.
Choose SCH 40 when…
- Water, gas, drainage & general fluid lines
- Low-to-medium working pressure
- Structural, railing & general fabrication
- Fire-fighting & sprinkler mains
- Best weight & cost for the duty
Step up to SCH 80 / 160 when…
- High pressure or steam / thermal cycling
- A corrosion / erosion wall allowance is needed
- Threaded joints in heavy service
- Critical or code-specified high-integrity lines
- Mechanical impact or burial risk
Schedule 40 in ERW & seamless
ASTM A53 Gr B
The everyday SCH 40 pipe — ERW or seamless — for water, gas, air, structural and general line service. The most widely specified carbon-steel pipe.
- ERW & seamless, black or galvanized
- Plain, beveled or threaded ends
- Hydrostatically tested
ASTM A106 Gr B
Seamless SCH 40 for high-temperature and pressure service — refineries, boilers, steam and power. No weld seam for demanding duty.
- Seamless, high-temp rated
- Refinery, boiler & steam lines
- NACE / sour service on request
API 5L Gr B
SCH 40 line pipe for oil, gas and water transmission and distribution, to API 5L PSL1 / PSL2 — welded or seamless.
- PSL1 / PSL2, ERW or seamless
- 3LPE / 3LPP coating available
- Beveled ends for site welding
Where Schedule 40 pipe is used
As the standard wall, SCH 40 is the workhorse pipe across building services, infrastructure and industry.
- Water supply & distribution
- Gas & compressed-air lines
- Fire-fighting & sprinkler systems
- HVAC & chilled-water piping
- Drainage, vents & conduit
- Structural columns & handrails
- Process & utility lines
- Irrigation & agricultural mains
- Scaffold, fence & gate frames
- Oil, gas & water transmission (API 5L)
Need Schedule 40 pipe for a project?
Send us your size list or BOQ — we reply with pricing, weights and mill test certificates within 24 hours.
Specifications we manufacture to
| Standard | Scope | Common grades | Notes |
|---|---|---|---|
| ASME B36.10 | Dimensions | — | Defines SCH 40 / STD wall by size |
| ASTM A53 | ERW / seamless | Gr A, Gr B | Water, gas, structural & general |
| ASTM A106 | Seamless | Gr B, Gr C | High-temperature service |
| API 5L | ERW / seamless | Gr B, X42–X65 | Line pipe · PSL1 / PSL2 |
| EN 10255 | ERW (BS 1387) | — | Water & screwed/socketed · on request |