The code offers detailed instructions for the structural design and erection of steel chimneys, emphasizing stability, load combinations, corrosion protection, and maintenance. It is intended for professionals involved in the engineering, fabrication, and upkeep of steel chimneys to ensure safety under wind, seismic, and thermal influences.
Overview
The code offers detailed instructions for the structural design and erection of steel chimneys, emphasizing stability, load combinations, corrosion protection, and maintenance. It is intended for professionals involved in the engineering, fabrication, and upkeep of steel chimneys to ensure safety under wind, seismic, and thermal influences.
Audience
Contents
Structure
Frequently Asked
Per IS 6533 Part 2, Clause 7.5, the corrosion allowance is the sum of external (Tce) and internal (Tci) allowances listed in Table 1, added to the structurally designed thickness. The allowances vary depending on steel type (copper bearing or not), corrosion environment, and design life (10 or 20 years). Stainless steel shells require no allowance. The minimum shell thickness must be no less than 6 mm or D/500, whichever is greater, ensuring durability against corrosion over the chimney’s lifespan.
According to IS 6533 Part 2, wind and earthquake loads are considered separately rather than combined simultaneously. Design load combinations include dead load with wind, dead load with earthquake, and dead load with lining and imposed loads combined with either wind or earthquake loads. Stability is checked using specified factors, and an increase of up to 33% in allowable stresses is permitted under earthquake loading, provided minimum steel thickness requirements are met.
The code mandates annual inspections of steel chimneys. For unlined and uninsulated chimneys, thickness measurements using ultrasonic or drill testing methods are required alongside external surface condition checks. Internal inspections, especially for larger diameters, should be conducted using devices like painter’s trolleys. Lined chimneys require close internal examination to assess lining integrity. Fabrication and welding should comply with relevant IS standards.
Steel chimney fabrication welding must adhere to IS 816:1969 (metal arc welding for mild steel) and IS 9595:1980 (welding steel structures for power plants). The overall fabrication and erection processes should follow IS 800:1984 to ensure structural quality and safety.
IS 6533 Part 2 accounts for dynamic oscillations caused by resonance and vortex shedding phenomena. Design involves combining static and dynamic wind forces vectorially, considering multiple vibration modes. Resonance effects are addressed by calculating resultant forces and moments using root-sum-square methods. Mitigation measures such as helical strakes or damping are recommended to reduce oscillation amplitudes and ensure structural stability.
Ask AI about any clause, requirement, or provision in IS 6533 PART 2. Get instant, clause-cited responses powered by our indexed library.
Free tier includes 150 queries (50 AI + 100 Reference) · No credit card required