Understanding IS 4923: the standard behind hollow steel

IS 4923:2017 is the governing standard for hot-formed welded and seamless structural steel hollow sections used in general construction.

It fixes the dimensional tolerances, mass per meter, and mechanical properties a section must hit — so a 100×100×4mm SHS from any certified mill behaves the same way on your drawings.

Reading the standard once is worth it if you specify steel regularly — it explains exactly what tolerance band you're allowed to hold a fabricator to.

The standard is periodically revised as manufacturing capability improves, so a section produced under an older revision can carry slightly different tolerance limits. Always check the revision year printed on the mill certificate against the year you're designing to.