What is the minimum shell thickness for a self-supporting steel chimney?

The minimum thickness for any part of the shell plate is 6 mm (Clause 6.1).

Does this code specify how to calculate wind or seismic loads?

No, this is Part 1 (Mechanical Aspects). Load calculations are covered in Part 2 (Structural Aspects), which references IS 875 (Part 3) for wind and IS 1893 for seismic loads.

What is the specified minimum corrosion allowance?

A minimum of 1.5 mm is specified where effective protective measures are not provided. For severe conditions, a greater allowance is necessary (Clause 5.3.1).

Are clean-out doors covered in this standard?

Yes, Clause 9.3 provides guidelines for the design and stiffening of clean-out doors and their openings in the chimney shell.

IS 6533

: 2000

Code of practice for design and construction of steel chimneys, Part 1: Mechanical aspects

CurrentSpecializedCode of PracticeBIMStructural Engineering · Structural Engineering and Structural Sections

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This Indian Standard (Part 1) provides guidelines for the mechanical aspects of designing and constructing steel chimneys. It covers selection of materials, determination of shell plate thickness, corrosion allowance, design of openings, and requirements for appurtenances like ladders, platforms, and lightning protection.

Code of practice for design and construction of steel chimneys, Part 1: Mechanical aspects

Quick Reference Values

Minimum shell thickness for self-supporting chimney6 mm

Minimum shell thickness for guyed chimney5 mm

Minimum corrosion allowance (unprotected)1.5 mm

Permissible tensile stress for IS 2062 Gr A steel150 MPa

Minimum thickness for base plates20 mm

Minimum diameter of lightning conductor (Copper)20 mm

Minimum diameter of lightning conductor (GI)25 mm

Practical Notes

This standard (Part 1) focuses on mechanical details and must be read in conjunction with IS 6533 (Part 2), which covers the structural design and analysis for loads like wind and earthquake.

Corrosion allowance is a critical parameter not explicitly defined for all cases; it must be determined by the engineer based on flue gas characteristics, operating temperature, and expected service life.

The code specifically excludes the design of refractory linings but requires their weight to be considered in the overall design.