MS and GI pipes

Steel pipes carry water, gas and air, and hollow sections form frames, sheds and furniture. Black (MS) and galvanised (GI) ERW pipes are sold by size, class and weight - and the class decides the wall thickness, so it must be in every quote.

Standards and classes

Standard	What it covers
IS 1239 (Part 1)	Steel tubes for water, gas, air and steam, up to 150 mm nominal bore, in light, medium and heavy classes - black or galvanised
IS 3589	Larger welded steel pipes for water and sewage
IS 4923	Hollow steel sections (SHS square, RHS rectangular) for structural use
IS 1161	Steel tubes for structural purposes

Pipes are named by nominal bore (NB) - 15, 20, 25, 32, 40, 50, 65, 80, 100, 125, 150 mm - which is not the same as the outside diameter. Always state class or wall thickness.

Weight of a pipe

Weight in kg per metre = (outside diameter - wall thickness) x wall thickness x 0.02466, with sizes in mm. Example: 60.3 mm OD x 3.6 mm wall = (60.3 - 3.6) x 3.6 x 0.02466 = about 5.03 kg/m. For a square hollow section, use (4 x side - 4 x thickness) x thickness x 0.00785 as an approximation.

What to put in a pipe inquiry

Type: MS black, GI, or hollow section (SHS/RHS).
Size (NB or OD) and class (light / medium / heavy) or wall thickness.
Standard: IS 1239, IS 3589, IS 4923 ...; plain end, screwed and socketed, or bevelled.
Length (usually 6 m) and quantity in tonnes or metres.
Make preference, test certificate, delivery site and payment terms.

How buying works on the portal

On Indian Steel Portal you float one inquiry for MS or GI pipes - grade, sizes, quantity, preferred makes, delivery city and payment terms. KYC-verified mills, stockists and traders quote against it in a live reverse auction with a minimum decrement and a soft-close, ranked L1 to L4 on landed cost. You award L1 or any ranked bidder, and the deal note - with GST, MTC and weighment terms - is generated for both sides.

Float a pipe inquiry - free Steel weight calculator

Frequently asked questions

What is the difference between light, medium and heavy pipes?

They are wall-thickness classes in IS 1239. For the same nominal bore the outside diameter is the same, but heavy class has the thickest wall, weighs most and costs most per metre.

What is the HSN code for ERW pipes?

Welded steel tubes and pipes generally fall under HSN 7306, at 18% GST. Seamless pipes fall under 7304.

How do I calculate pipe weight?

(OD - thickness) x thickness x 0.02466 gives kg per metre, with sizes in mm.

What is the standard length of a steel pipe?

ERW pipes are commonly supplied in 6 m random or fixed lengths; other lengths can be agreed.

Are GI pipes priced per tonne or per metre?

Mills and large stockists quote per tonne; retailers often per length. Convert to the same basis before comparing.

Last updated 8 October 2026.