On this page 10 sections
What is IS 1239 (Part 1) MS Tubes?
Quick answer
- Standard
- IS 1239 (Part 1)
- Product form
- Pipes
- Typical uses
- Water supply and plumbing; Fire-fighting and sprinkler systems
IS 1239 (Part 1) covers mild steel tubes from 6 mm to 150 mm nominal bore in three wall-thickness classes: Light (A-class), Medium (B-class) and Heavy (C-class). Tubes may be screwed and socketed or plain-ended, black or hot-dip galvanised. Part 2 of the standard covers the matching wrought steel fittings.
It's the everyday standard for water supply, plumbing, fire-fighting, compressed air and general engineering piping in India. Medium and Heavy classes are the norm for pressure and underground use. Buyers should state the class, end finish and coating.
Key characteristics
- Light, Medium and Heavy classes
- Black or galvanised
- Screwed and socketed or plain end
- Nominal bore 6–150 mm
What does the IS 1239 specification cover?
What are the mechanical properties of IS 1239?
| Property | Value |
|---|---|
| Tensile strength | 320 MPa min (typical) |
| Elongation | 20% (typical) |
Sizes and weight chart
Outside diameters and walls follow ASME B36.10M for common sizes. Weights are calculated for IS 1239 (Part 1) MS Tubes at 7.85 g/cm³, and actual weights vary within manufacturing tolerances.
| NPS | OD (mm) | Sch 40 | Sch 80 | Sch 160 | XXS |
|---|---|---|---|---|---|
| NPS ½" | 21.34 | 2.77 / 1.27 | 3.73 / 1.62 | 4.78 / 1.95 | 7.47 / 2.56 |
| NPS ¾" | 26.67 | 2.87 / 1.68 | 3.91 / 2.19 | 5.56 / 2.89 | 7.82 / 3.64 |
| NPS 1" | 33.40 | 3.38 / 2.50 | 4.55 / 3.24 | 6.35 / 4.24 | 9.09 / 5.45 |
| NPS 1¼" | 42.16 | 3.56 / 3.39 | 4.85 / 4.46 | 6.35 / 5.61 | 9.70 / 7.76 |
| NPS 1½" | 48.26 | 3.68 / 4.05 | 5.08 / 5.41 | 7.14 / 7.24 | 10.15 / 9.54 |
| NPS 2" | 60.33 | 3.91 / 5.44 | 5.54 / 7.49 | 8.74 / 11.12 | 11.07 / 13.45 |
| NPS 2½" | 73.03 | 5.16 / 8.64 | 7.01 / 11.41 | 9.53 / 14.92 | 14.02 / 20.40 |
| NPS 3" | 88.90 | 5.49 / 11.29 | 7.62 / 15.27 | 11.13 / 21.35 | 15.24 / 27.68 |
| NPS 4" | 114.30 | 6.02 / 16.08 | 8.56 / 22.32 | 13.49 / 33.54 | 17.12 / 41.03 |
| NPS 6" | 168.28 | 7.11 / 28.26 | 10.97 / 42.56 | 18.26 / 67.56 | 21.95 / 79.21 |
| NPS 8" | 219.08 | 8.18 / 42.55 | 12.70 / 64.64 | 23.01 / 111.26 | 22.23 / 107.92 |
| NPS 10" | 273.05 | 9.27 / 60.30 | 15.09 / 96.00 | 28.58 / 172.31 | 25.40 / 155.13 |
| NPS 12" | 323.85 | 10.31 / 79.72 | 17.48 / 132.07 | 33.32 / 238.73 | 25.40 / 186.95 |
Quick weight calculator (density 7.85 g/cm³)
Testing and documentation
- Specification
- IS 1239 (Part 1)
- Size range
- NPS ⅛" to 48" and larger (DN 6 – DN 1200+), schedules 5S to XXS, single random, double random and cut lengths
- Finish
- Annealed & pickled, bright annealed, mill finish, black, varnished, galvanised or 3LPE / FBE coated (by material)
- Ends
- Plain end (PE), bevelled end (BE, ASME B16.25), threaded (NPT / BSP), grooved
Testing & documents
- Chemical and mechanical (tension, flattening, flare/bend) tests
- Hydrostatic test or non-destructive electric test (UT/ET) on each length
- Dimensional and visual inspection
- Intergranular corrosion (stainless), impact (low-temperature), hardness (sour service) when specified
- PMI and third-party inspection on request
- EN 10204 3.1 certificate; 3.2 with third-party inspection
Where is IS 1239 used?
- Water supply and plumbing
- Fire-fighting and sprinkler systems
- Compressed air and gas lines
- Scaffolding and structural uses
- General engineering piping
Industries
What to include in your enquiry
- Specification and grade: IS 1239 (Part 1) MS Tubes
- NPS × schedule (or OD × WT), seamless/welded, length, ends
- Quantity and destination
- Tests and certificates (3.1 / 3.2)
Explore more
Carbon Steel pipes
Guides
Frequently asked questions
What are Light, Medium and Heavy class pipes in IS 1239?
They're wall-thickness classes, often colour-coded as A (Light), B (Medium) and C (Heavy). Heavier classes are used for higher pressure and buried service.
What is IS 1239 (Part 1) MS Tubes used for?
Water supply and plumbing, Fire-fighting and sprinkler systems, Compressed air and gas lines, Scaffolding and structural uses.
How do I calculate the weight of IS 1239 (Part 1) MS Tubes pipe?
kg/m = π × (OD − WT) × WT × 7.85 / 1000 for carbon steel, with dimensions in mm. See the weight chart on this page.
Which documents are supplied with IS 1239 (Part 1) MS Tubes?
EN 10204 3.1 mill test certificate as standard, with 3.2 and third-party inspection on request.