Fire-proofing a building reduces damage to life and property by either preventing it or keeping it from spreading. There are two types of fire fighting systems:
- Active fire fighting system: Active fire fighting systems are devices or systems which are activated manually or automatically when a fire breaks out.
- Passive fire fighting system: Passive systems are techniques that are practiced or installed in a building while designing it to prevent fire from breaking out.
This article will focus on passive fire-fighting systems.
- Site setback and open spaces
- Fire escapes and stairs
- Provision of refuge area
- Use of fire-proof materials
- Fire resistant coating
1. Site Setback and Open Spaces:
Setbacks are mandatory and the length depends on the road and building size.
- Sufficient space must be provided around a building (according to standards) to facilitate easy movement of fire service vehicles.
- Setbacks also prevent the spreading of fire from one building to another.
- Minimum two entrances or means of access must be provided for buildings, especially high rise ones.
- These routes must be visible properly, in case of emergency evacuation.
2. Fire escapes and stairs:
Every high rise building should have a minimum of one staircase for fire safety purposes, as defined by the National Building Code (NBC).
- Width of the fire escape stair should be minimum 0.75 meter.
- The routes leading to the stairs and to the outside must be visible properly.
According to NBC, at least one lift should be designed as a fire-lift which carries a minimum of 8 persons or weighing 545 kilograms.
- The landing doors of lifts should open to a well ventilated space.
- The lift should have a fire resistance of one hour.
- Fireman switch should be provided for each lift.
- If more than one lift is installed, the partition wall should have a minimum of two hours of fire resistance.
4. Provision of refuge area:
Refuge areas are spaces designed for the residents in a high rise building to seek shelter in case evacuation is not safe during a fire breakout.
- The first refuge area in a building must be located on the 24 metres mark on a building or the floor near it.
- After that, every seventh floor must have a refuge area.
- Refuge areas must add up to 4% of habitable area.
This method aims to contain the fire and smoke to an area, making sure it doesn't spread. This not only prevents the collapse of the building but also helps prevent casualties.
- These compartments are erected specifically for containing fire and smoke.
- They are made of highly fire-resistant materials
- They include fire barriers, walls and partitions and smoke barriers.
- These barriers also make sure that if collapse occurs on one side, it will not affect the other.
- Sprinkler system is not required if this system is followed.
6. Fire Barriers
Fire barriers are fire-rated walls, floors and ceilings. They are made of concrete, gypsum, brick masonry etc.
7. Use of fire-proof materials:
Use of fireproof materials is the most basic type of passive fire fighting techniques.
Concrete has excellent fire-resisting qualities and it is one of the most commonly used building materials today.
- Concrete is non-combustible and has very low thermal conductivity.
- This means that fire takes a longer time to affect its structural and load-bearing properties.
- Concrete is significantly more fire-resistant than steel, and often used to reinforce and protect steel from fire.
Brick is one of the best fire-resisting materials as they are made in a fire kiln.
- Brick walls can resist fire for one to four hours depending on the type of construction and thickness.
- But it is to be noted that individual blocks of bricks are more fire resistant than brick walls held together with mortar.
Stucco is a mixture of ordinary Portland cement (OPC), sand and lime. It is a type of plaster that has been used for both its functional and aesthetic purposes.
- Stucco is normally used as a covering or coating over brick masonry or timber.
- 1 inch of stucco on a material can resist fire for one hour (one hour fire rating).
Gypsum board or drywall, is a popular choice for interior fire resistance.
- A gypsum board consists of a layer of gypsum sandwiched between two sheets of paper.
- These boards are further treated with additives to improve their fire-resisting qualities further.
- In addition, the gypsum board has a core that has chemically combined water in calcium sulfate.
- When fire reaches this core, the water comes out as steam, slowing down the fire and heat.
- Often, multiple layers of gypsum board are used to increase the fire-resistance rating.
e. Asphalt Shingle
Asphalt shingles is an effective fire resistant roofing material.
- This material can resist fire for upto two hours.
- They are also cheap and affordable.
8. Fire Resistant Coating:
Usually plant based substances have very poor flame resistance. But these materials can be treated with special chemicals to create a barrier which prevents the fire from coming in contact with the material, thereby preventing its spread. Boric acid andBorax are examples.
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