Fire compartmentation means dividing a building into zones with fire-resisting walls, floors and doors, so a fire stays in the zone where it starts for a set time. The National Building Code of India 2016, Part 4, sets when compartments are needed and how large they may be. Every opening through a compartment wall or floor must be sealed to keep the rating.
What is fire compartmentation?
Fire compartmentation is the practice of dividing a building into smaller fire zones. Each zone, or compartment, is bounded by walls, floors and doors that resist fire for a set period, often expressed in minutes such as 60, 90 or 120. If a fire starts inside one compartment, the boundary holds it there for that period.
That time is what everything else depends on. It is the time people have to reach a protected staircase. It is the time firefighters have to arrive and set up. It is the time that keeps a fire on one floor from becoming a fire in the whole building. Sprinklers fight the fire. Compartments buy the time.
In India the main reference is the National Building Code of India 2016, Part 4, Fire and Life Safety. It sets when compartmentation is required, how big compartments can be for different types of building, and what fire resistance their boundaries need. We explain how compartments fit into the wider picture in what is passive fire protection.
How big can a compartment be?
NBC sets maximum compartment sizes that depend on the occupancy, such as offices, hospitals, hotels, shops or factories, on the height of the building, and on whether it has sprinklers. Sprinklered buildings are generally allowed larger compartments, because the sprinklers help keep a fire small.
We do not quote a single figure here on purpose. The right number for your building depends on several factors together, and the fire consultant who prepares your fire safety drawings will confirm it. What matters for owners is this: once those compartments are drawn, every one of their boundaries has to be built and kept to the rated standard.
Walls, floors and doors
Walls. Compartment walls are usually built from blockwork, concrete or rated board systems. The most common fault is a wall that stops at the false ceiling. It looks complete from the room, but above the ceiling tiles there is an open void running across the building. Fire and smoke travel through that void straight past the wall. A compartment wall must run from the floor slab to the underside of the slab above.
Floors. The concrete slab between floors is normally a good fire barrier on its own. The problem is the holes cut through it: shafts for cables and pipes, openings for ducts, and sleeves for plumbing. Each one turns a solid floor into one with a chimney in it.
Doors. A fire door is tested as a complete set: the door leaf, the frame, the glass panel if any, the closer, the hinges, the seals and the gap at the edges. Remove the closer, wedge it open, or fit a different lock, and it is no longer the door that was tested.
For the numbers behind this, see our fire accident statistics for India, compiled from NCRB data.
Openings: where compartments actually fail
Walls and floors are usually built well. Then the services arrive. Electricians, plumbers, air conditioning teams and IT contractors all need to pass through compartment boundaries, and each one cuts a hole. Months or years later, other contractors cut more.
Every one of those holes has to be closed with a product tested for that situation. A cable tray through a wall needs a different seal from a single plastic pipe through a floor. A large shaft needs a different solution from a small conduit. We cover each type in our guide to service penetrations and fire stopping, and the large floor openings in shaft closing.
| Opening | Typical tested solution | Common wrong fix |
|---|---|---|
| Large cable or pipe shaft through a slab | Fire stop mortar over rebar and mesh | Plywood or sheet covered with cement |
| Cable tray through a wall, changed often | Fire safety pillows or rated barrier | Expanding foam |
| Plastic pipe through a wall or floor | Intumescent collar or wrap | Gap filled with ordinary sealant |
| Small metal pipe or conduit | Fire rated sealant to the tested depth | Cement patch with cracks |
| Gap at the top of a wall | Fire rated joint seal that allows movement | Rigid filler that cracks as the slab moves |
Joints and gaps
Buildings move. Slabs deflect under load, and the structure expands and contracts with heat. The joint where a compartment wall meets the slab above, or where it meets a column, has to allow that movement and still stop fire. Rigid materials such as cement mortar crack. A fire rated sealant designed for movement stays sealed. We explain how to choose one in fire rated sealant.
How to check your own building
- Find the fire compartment drawing. If nobody can, that is the first finding.
- Open electrical and plumbing riser doors on several floors and look at the slab around the services.
- Lift ceiling tiles where cable trays or ducts cross walls shown as rated.
- Check that fire doors close and latch by themselves.
- Photograph anything that looks open, with the room or grid reference in the shot.
If that produces a list, a passive fire audit will do the same across the whole building and rank what needs fixing first.
Where we fit, and where we do not
We seal the openings, joints and shafts that keep compartments working, apply intumescent coatings to steel, and audit what is already installed, with photographs of every item. We do not design fire compartmentation. That is the fire consultant's job. We do not build the walls themselves or supply fire doors. If you want to know whether your compartments are still doing their job, talk to our team.
National Building Code of India 2016, Part 4, Fire and Life Safety, published by the Bureau of Indian Standards. Rules and portals change, so always confirm the current requirement for your building. Last reviewed 26 October 2026 by the Simfy Firesys team.
