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What is SMACNA and why is it important for Indian HVAC ductwork?

A: SMACNA (Sheet Metal and Air Conditioning Contractors' National Association) publishes the globally adopted duct construction standards — referenced by NBC 2016 Part 8 and required for IGBC/LEED green building certification in India.

What gauge GI sheet should be used for HVAC ducts in India?

A: Per SMACNA Table 1-1: ducts up to 750mm wide use 24G minimum (Class A); 750–1,500mm use 22G; above 1,500mm use 20G for Class A systems — heavier gauge required for Class B and C systems.

What is a pre-insulated duct and when should I use it?

A: Pre-insulated duct panels have an integral PIR or PUF foam core with aluminium foil facing — they eliminate external insulation, install 30–50% faster and eliminate condensation risk; ideal where construction timeline is critical.

What is the maximum length of flexible duct allowed in HVAC systems?

A: SMACNA and ASHRAE limit flexible duct connections to 1.8 metres (6 feet); in practice, keep below 1 metre — longer flexible runs add significant resistance and reduce airflow to the served diffuser.

How do I know if my ductwork is leaking and how much does it matter?

A: Leaking ductwork wastes 20–30% of air conditioning energy — equivalent to running the HVAC 3–4 hours more per day; symptoms include hot/cold spots, high energy bills and rooms not reaching set temperature.