-by Santosh S. Warick (CFO & FA,MIDC, Director, MFS, MAITRI)

Fire Compartmentation as per Clause 4.5 of Part 4 of NBC 2016

The Fire Prevention & Protection Focus is Shifting from Active to Passive Fire Protection. Compartmentation Crucially Important aspect of any effective fire safety strategy. Infect, These Benefits have today become necessities in building. It involves the division of a larger space into smaller spaces. In the event of a fire, the spread of fire and smoke can be restricted and even controlled by subdividing areas up into fire compartments.

Chapter -2 Terminology

• • 2.21 Fire Compartment: A space within a building that is enclosed by fire barrier or fire resistant walls on all sides, including the top and bottom.
• • 2.20 Fire Barrier (or Fire Resisting Barrier): A fire barrier is a vertically or horizontally aligned member such as a wall or a fire curtain, or a floor. These may be with discontinuities created by openings with a specified fire resistance rating, where such member saredesigned and constructed with a specified fire resistance rating to limit the spread of fire that also restricts the movement of smoke.
• • 2.30 Fire Resistant Wall: Fire resistance rated wall, having opening(s) with specified fire resistant rating, which restricts the spread of fire from one part of a building to another part of the same building.
• • 2.57 Smoke Compartment: A space within a building enclosed by smoke barriers on all sides.
• • To Note: Compartment only speaks about fire barrier and fire resistant wall and not about smoke barrier.

Example for Smoke Compartment / Barrier

• 3.4.5.2 For escalator openings, the smoke spill shall be avoided by provision of smoke barrier (of 450-600 mm) thereby creating smoke compartment. Further, the protection shall be ensured through installation of sprinklers on all sides of the cut out opening on each floor.  

The Concept of Fire Compartmentation  

What is the purpose of Fire Compartmentation?

• • Fire compartmentation is an important element of ‘passive fire protection’ and is achieved by dividing the premises into ‘fire compartments through the use of fire doors, floors, ceiling and side walls of fire-resisting construction, and fire stopping to services that penetrate through these dividing elements.
• • A compartmentation is a defined space, the area of which varies with type of the building and its construction and which is a protected area against the spread of fire and smoke and hot gases.
• • The defined area is treated as a fire zone which is protected from fire and smoke spread using compartmentation, such as the construction of fire resistant walls, ceilings and floors, together with relevant penetration seals.

Fire Compartmentation will be dependent on:

• • The use or occupancy of the building.
• • The fire load in the building.
• • The height of the building.
• • The availability of a sprinkler system. 

4.5 Compartmentation

4.5.1 General

a) It is important to limit the spread of a fire in any building. The usual method is to use fire barriers. In some instances, these barriers need to be penetrated for ductwork, plumbing and electrical systems, and in such cases, use of passive fire protection measures shall be done so that the integrity of these barriers is not compromised.

b) Floor(s) shall be compartmented with area as given below.

4.5.2 All floors shall be compartmented/zoned with area 2 of each compartment being not more than 750 m. The maximum size of the compartment shall be as follows, in case of sprinkle red basement/building: 

Note: - Compartmentation for low hazard and moderate hazard industrial buildings and storage buildings shall be done in consultation with local fire department.

As per IS 3594: 1991 Code of Practice for Safety of industrial buildings: General storage and warehousing including cold storage-the compartment size is recommended as 2250 Sq. Mtrs. With sprinklers In addition, there shall be requirement of a minimum of two compartments if the floor plate size is equal or less than the areas mentioned above. However, such requirement of minimum two compartments shall not be required, if the floor plate is less 2 than 750 m.

Compartmentation shall be achieved by means of fire barrier having fire resistance rating of 120 min.

Another clause of Part 4 emphasizing on re compartmentation

4.4.2.5 Smoke control of exits

a) In building design, compartmentation plays a vital part in limiting the spread of fire and smoke. The design should ensure avoidance of spread of smoke to adjacent spaces through the various leakage openings in the compartment enclosure, such as cracks, openings around pipes ducts, airflow grills and doors. In the absence of proper sealing of all these openings, smoke and toxic gases will obstruct the free movement of occupants of the building through the exits. Pressurization of staircases is of great importance for the building design.

Annex H for Car Parking Facilities

b) For basement car parking, compartmentation can be achieved, with fire barrier or with water curtain nozzle (K-23) or with combination thereof. Automatic deluge system comprising deluge valve, piping, nozzles, etc. shall be used to zone the compartment in case of water curtain system. In case of water curtain, existing water storage shall be supplemented by water demand for water curtain nozzles for 60 min considering the largest compartment's perimeter out of all compartments of car parking in any of the basements.

Annex - J Fire and Life Safety Requirements for Metro Stations

J-6 Fire Separation and Compartmentation

J-6.1 Fire compartments shall be provided in transit stations in accordance with the provisions of this Section. Fire ratings of various occupancies within open stations and enclosed stations shall be as indicated in Table 27.

J-6.2 Further transit station shall be divided into fire compartments by means of compartment walls and compartment floors by a fire separation of at least 120 min between following occupancies:

a) Public areas and non-public areas,

b) Transit and non-transit areas, and

c) Ancillary areas located beneath and within 3 m of the train way in open stations

Horizontal Exit in Hospital Buildings 

Institutional Occupancy 

Components of Means of Egress 

Fire Tower or Firefighting Shaft  

Advantages of Fire Compartmentation

• • To contain the fire in compartment of origin.
• • To limit the potential size of fire & product of combustion.
• • To separate areas of different levels of hazards.
• • To separate areas of safe exit passages, evacuation means and refuge areas.
• • To limit the threat of building collapse due to fire exposure.
• • It improves the Integrity & Stability 

How to achieve fire compartmentation?

• Where an escape route needs to be separated from the rest of the premises by fire-resisting construction e.g. a dead-end corridor or protected stairway the following compartmentation should be ensured:

• Doors (including hatches to cupboards, ducts and vertical shanties linking floors), walls, floors and ceilings protecting escape routes should be capable of resisting the passage of smoke and fire for long enough to enable people to escape the building.

• Where suspended or false ceilings are provided, the fire resistance should extend up to the floor slab level above.

• Cavity barriers, fire stopping and fire dampers in ducts should be appropriately installed.

• Ensure proper Exhaust and Ventilation System, especially in multi-level basement where Exhaust Fans at the respective levels shall be provided with back draft damper connection to the common smoke exhaust shaft ensuring complete isolation and compartmentation of floor isolation to eliminate spread of fire and smoke to the other compartments/floors.

• Sealing of Horizontal and Vertical Openings E.g. Ducts and Shafts.

Fire Stopping

• Openings in walls or floors which are provided for the passage of all building services like cables, electrical wiring and telephone cables etc., shall be protected by enclosures in the form of ducts/shafts with a fire resistance of not less than 2 hours.

• Fire rated barriers/fire stopping systems will provide the required solution. The system installed shall be such that the normal functioning of the services penetrating the compartment shall not be affected.

Fire Compartmentation

The shafts across the floors to carry services through floor levels can result in fire and smoke spread to other floors. The shafts shall be protected at every floor and wall penetration with fire tested fire stopping systems.

Any opening with in the shaft wall or floors through which pass electrical conduits should also be sealed to have a fire resistance of not less than 1 hour.

 

Fire Stopping Service Ducts and Shafts  

Compartmentation to segregate different occupancy e.g. Mall Building

 

Conclusion

• Whatever the building occupancy, fire compart mentation is fundamental to its safety, creating a series of protected fire zones to ensure that the fire is contained in one place.

• Fire is spread through three methods: convection, conduction and radiation, of which convection is the most dangerous. This is when smoke from the fire becomes trapped by the roof, spreading in all directions to form a deepening layer. Smoke, rather than fire, is often the real danger.

• Materials such as metal can absorb heat and transmit it to other rooms by conduction, where it can cause new fires to break out. Radiation transfers heat in the air, until it too sets off secondary fires, spreading the danger away from its original location

• Preventing fire and smoke from spreading quickly in the building. By creating the se fire – resistant compartments.

• Fire compartmentation is also used in order to create a safe, protected means of escape for the building occupants and also for fire fighters to enter affected building for carrying out firefighting & rescue operations.