Link points to Internet Archive / others. Not hosted by InfraLens. Details
IS 12347:1991 is the Indian Standard (BIS) for fire safety of buildings: smoke control systems. This code provides guidelines for the design, installation, and maintenance of smoke control systems in buildings. It covers three primary methods: pressurization of escape routes, smoke venting, and mechanical smoke extraction, aiming to maintain tenable conditions for occupant evacuation and firefighting operations.
Provides guidance on the design, installation, and maintenance of smoke control systems to facilitate evacuation and firefighting.
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! This standard should be read in conjunction with the National Building Code of India (NBC) 2016, Part 4 'Fire and Life Safety', which provides more updated and comprehensive requirements for smoke control.
! The maximum door opening force (110 N) is a critical life safety check; high pressurization levels can make doors difficult to open, trapping occupants.
! Effective smoke control design requires close coordination between architects, MEP engineers, and fire safety consultants, especially for damper locations and fan specifications.
NFPA 92:2021National Fire Protection Association (NFPA), USA
HighCurrent
Standard for Smoke Control Systems
Covers design, installation, testing, and maintenance of all types of smoke control systems, including pressurization.
EN 12101-6:2022European Committee for Standardization (CEN), Europe
HighCurrent
Smoke and heat control systems - Part 6: Specification for pressure differential systems - Kits
Specifically focuses on pressure differential systems, which is the primary method described in IS 12347.
AS 1668.1:2015Standards Australia, Australia
HighCurrent
The use of ventilation and air-conditioning in buildings - Part 1: Fire and smoke control in buildings
Provides comprehensive requirements for various smoke control methods, including stair pressurization.
BS 7346-4:2003British Standards Institution (BSI), UK
MediumWithdrawn
Components for smoke and heat control systems - Part 4: Functional recommendations and calculation methods for smoke and heat exhaust ventilation systems
Though focused on exhaust ventilation, it shares the fundamental goal of smoke management in buildings.
Key Differences
≠IS 12347 is largely prescriptive, providing fixed values. Modern standards like NFPA 92 extensively support performance-based design using engineering tools like CFD (Computational Fluid Dynamics).
≠The Indian standard focuses almost exclusively on pressurization systems. Modern codes like NFPA 92 and AS 1668.1 provide detailed guidance for a wider variety of systems, including smoke extraction/exhaust and zoned smoke control.
≠Modern European standards (EN 12101 series) mandate rigorous third-party testing and certification (CE marking) for all system components (fans, dampers, controls), a level of component-specific regulation not detailed in IS 12347.
≠NFPA 92 includes specific design considerations for the interaction between automatic sprinklers and smoke control systems (e.g., smoke cooling effects), an interaction that is not explicitly detailed in IS 12347.
Key Similarities
≈All standards share the core principle of using mechanical fans to create a positive pressure differential in protected spaces (stairwells, lobbies) to prevent smoke ingress from the fire area.
≈There is a universal focus on protecting critical means of egress, specifically staircases, lift lobbies, and corridors, to ensure a tenable environment for occupants to escape.
≈All standards recognize that excessive pressure can prevent doors from being opened and specify a similar maximum door opening force limit (around 133 N) to ensure escape is not hindered.
≈The requirement for automatic activation of the smoke control system upon detection of smoke by a fire alarm system is a fundamental and common principle.
≈All codes mandate the provision of a secondary (standby) power supply to ensure the system remains operational during a mains power failure in a fire scenario.
Parameter Comparison
Parameter
IS Value
International
Source
Minimum Pressure Differential (Stairwell vs. Fire Floor)
50 Pa
50 Pa (for Class A/B/C/D systems, with doors closed)
EN 12101-6
Minimum Air Velocity (Through open doorway)
1.0 m/s
0.75 m/s (for Class B/D occupant escape systems)
EN 12101-6
Maximum Door Opening Force (at handle)
133 N
133 N (30 lbf)
NFPA 92
System Activation
Automatic by smoke detectors.
Automatic activation by a suitable fire detection system (e.g., smoke detectors or waterflow switch).
NFPA 92
Air Supply Point
Supply at multiple levels; recommends at least every third floor for high-rise.
Supply air shall be introduced at a sufficient number of points to ensure the design pressure difference is maintained.
EN 12101-6
Secondary Power Supply Duration
As per National Building Code of India (typically 2 hours).
1.5 times the calculated egress time or 20 minutes, whichever is greater.
NFPA 92
⚠ Verify details from original standards before use
Key Values5
Quick Reference Values
Minimum pressure differential (doors closed)50 Pa
Minimum pressure differential (doors open)15 Pa
Minimum air velocity through open doorway0.75 m/s
Maximum force to open a door110 N
Number of air changes for smoke extraction (basements)12 per hour
Key Formulas
Q = 0.827 × A × (P^(1/n)) — Airflow through leakage paths (where Q=airflow, A=leakage area, P=pressure difference, n=flow exponent)
Q = A × v — Airflow required for velocity control (where Q=airflow, A=doorway area, v=air velocity)
What is the main purpose of a smoke control system?+
To maintain tenable conditions in escape routes (like staircases and lobbies) by preventing smoke ingress, allowing for safe evacuation and firefighting. (Clause 4)
What is the recommended pressure difference for a pressurized staircase?+
50 Pa relative to the adjacent fire floor when all doors are closed. (Table 1)
What minimum air velocity should be maintained through an open door to a pressurized area?+
0.75 m/s to prevent smoke from flowing against the airflow. (Clause 6.4.2)
What are the three main types of smoke control systems specified in this code?+
Pressurization, Smoke Venting (natural), and Smoke Extraction (mechanical). (Clause 5)