MS Pipe Weight Chart — IS 1239 & ASME Schedules

MS Pipe Weight Chart — Complete Reference

This chart covers the two systems used in India: IS 1239 (Part 1) Light, Medium and Heavy class pipes from ½ inch to 6 inch — the standard for "MS pipe" and "GI pipe" in the Indian market — and ASME B36.10 schedules (SCH 10, 40, 80, 160) from ½ inch to 12 inch, used on export, oil & gas and process-plant drawings. For schedules, the weight is calculated using the standard pipe formula: Weight/m = π/4 × (OD² − ID²) × Density, where ID = OD − 2 × Wall Thickness.

For local purchase, Medium (B) class is the most commonly stocked MS/GI pipe; Heavy (C) class is commonly specified for fire-fighting lines. IS 1239 classes are not the same as ASME schedules — for most sizes Medium is thinner than SCH 40 and Heavy is thinner than SCH 80. Pipes above 150 NB are generally supplied to IS 3589. SCH 80 and SCH 160 are used for higher-pressure industrial and process piping.

Understanding NB, OD, and Pipe Schedule

NB (Nominal Bore) is a standard pipe size designation — it is not the actual measured dimension. A "2-inch pipe" does not have a 2-inch outer diameter or a 2-inch inner diameter. It is simply a label that corresponds to a standardized OD. The NB system originated in the early days of pipe manufacturing and has been retained for convenience, even though it does not match any physical measurement.

OD (Outer Diameter) is the actual physical outer measurement of the pipe. For a given NB size, the OD remains constant regardless of the schedule. A 2-inch pipe always has an OD of 60.3mm — whether it is SCH 10 or SCH 160. What changes is the wall thickness and therefore the inner bore.

Schedule determines the wall thickness for a given OD. Higher schedule = thicker wall = heavier pipe = higher pressure rating. The schedule number is derived from the formula: Schedule ≈ 1000 × (Internal Pressure / Allowable Stress). In practice, you select the schedule based on the working pressure and temperature of your application.

ERW Pipe vs Seamless Pipe — Weight Difference

ERW (Electric Resistance Welded) pipes are made by rolling a flat steel strip into a tube and welding the seam using electric current. Seamless pipes are manufactured by piercing a solid steel billet — they have no weld seam. Both types follow the same OD and wall thickness standards, so the theoretical weight per metre is identical for the same size and schedule.

In practice, seamless pipes show more piece-to-piece variation because the seamless process has a wider wall-thickness tolerance (ASTM A106 allows the wall to be up to 12.5% under nominal). IS 1239 ERW pipes carry a weight tolerance of −8% (Light) and −10% (Medium/Heavy).

For weight calculation and estimation purposes, this chart applies equally to ERW and seamless MS pipes. The weight values are based on nominal dimensions — actual weight at the weighbridge may vary within the tolerance range specified by the relevant standard (IS 1239 / IS 3589 in India, ASTM A53 / A106 for ASME-sized pipe).

Most Used Pipe Sizes in India

Typical guidance only — the project specification decides. Standard supply length for IS 1239 pipes is 6 metres; seamless pipes are often supplied in random lengths, and 12-metre lengths are available on order.