IS 1649:1962 is the Indian Standard (BIS) for design and construction of flues and chimneys for domestic heating appliances. This code covers the design, construction, and fire safety clearances for flues and chimneys used with domestic heating appliances to ensure efficient smoke draft and structural safety.
Code of practice for design and construction of flues and chimneys for domestic heating appliances
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Minimum Chimney Height Above Pitched Roof Ridge | At least 60 cm above the ridge. | At least 2 ft (~60 cm) higher than any part of the building within a 10 ft (~3m) horizontal distance (The '2-10' part of the '3-2-10 rule'). | NFPA 211 |
| Minimum Masonry Chimney Wall Thickness | Not less than 20 cm. | 4 in. (~10 cm) nominal solid masonry for residential applications (assumes a separate flue liner is used). | NFPA 211 |
| Minimum Clearance to Combustible Materials (Wood) | 20 cm from any timber. | 2 in. (~5 cm) for an interior masonry chimney. | NFPA 211 |
| Flue Liner Requirement | Recommended, not mandatory for all cases. Can be parging render, clay pipes, etc. | Mandatory. A listed/certified liner system appropriate for the appliance and fuel type is required. | BS EN 15287-1 / NFPA 211 |
| Maximum Flue Offset from Vertical | Should not exceed 45 degrees. | Shall not exceed 30 degrees. Systems with greater offsets require engineering. | NFPA 211 |
| Mortar for Flue Gas Contact Areas | Cement mortar (1:3 or 1:4) or lime-surkhi mortar. | Medium-duty refractory mortar conforming to ASTM C199. | NFPA 211 |