Combusting building material

What is combustibility of material?
Combustibility of building material is the time factor required for material to burn until the breakage of its strength.
There is now a fast awareness to design the structure in such a manner that the safety of occupants is assured to maximum possible extent .
Once the fire starts, it tends to ignite all the combustible material in the surrounding areas & in case it is not checked it may spread to other areas in building.
If the fire is not controlled within the reasonable period it may lead to collapse entire structure.
It is not possible to attain absolute safety from fire but by adopting certain measures it is definitely possible to provide reasonable safety from fire.
The byproduct of fire I.E. The smoke & hot toxic gases causes maximum damage to human life.
Smoke reduces the visibility & hot toxic gases produce suffocating effect & the combined effect of both bring mass panic which turns maximum damage to life.
Thus besides making building resistant to fire it is equally important to plan it such a way that risk to panic due to smoke & hot gases is minimized.
The nature of damages or danger caused by fire can be broadly divided in to:-
Danger to life of occupants:
Danger of spread of fire to other areas:
danger of damage to property:

Danger to life of occupants:-
Providing adequate means of escape for the occupants so that they can reach the place of safety in shortest possible time.
Building should be so planned that it has sufficient provision for safe exit from passage, corridors & stairs leading to open space.
Lifts & escalators are not considered as fire exits;this issue needs special attention In case of multistoried building.

Every tall building should have minimum two stair cases.
The travel distance for different types of building should be as under:
Residential, educational & institutional.
Assembly, mercantile,industrial & storage.
Business …45m.
No revolving door should be treated as exit.
A separate fire lift should be provided use for fire brigade in the event of fire.

Danger of spread of fire to other areas:
Building should be so planned that the fire can be contain un limited areas to escape from danger zone.
Building should be so planned in the form of serious of compartments enclose by floor or walls.
All stairwells,service shafts & elevators should be so treated in the form of vertical compartment from top to bottom of building.

Danger of damage to property:
This damage can be minimized by use of fire resisting material, in such a way that at times of fire they should act as structural element till all occupant escape to safe place.
National building code has classified constructional into four classes namely type1,type2,type3,type4 on the basis of fire resistance offered by building component for 4 hours ,3 hours, 2 hours & 1 hours resp.

Conclusion :-
Maximum number of non combustible material should be used.
The load bearing walls or column should be thicker in section so that they may successfully act as a fire barrier .
In case of wooden floor thicker joists spaced at greater distance.
Fire stop should be provided in wooden floor at suitable intervals.
Other floors like concrete, brick are considered to be the most suitable for fire resistance construction .
Incase, cast iron, wrought iron material like rubber, cork have to be used in flooring with insulating material like ceramic tiles, terracotta should be used.
Reinforced steel structure should be preferred to steel structures.

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