Fire Hazards

FIRE HAZARDS

Fire hazards include all types of live flames, causes of sparks, hot objects and chemicals that are potential for ignition, or aggravate a fire to become large and uncontrolled.

Fire hazards also include all types of potential threats to fire prevention practices.

Types of fire hazards

The fire hazards are of the following three types.

1. Exposure hazard

2. Internal hazard

3. Personal hazard

1. Exposure hazard

Sometimes a fire spreads into a building through the open air from adjacent buildings or same building. The risk involved in such fire spreading is known as the exposure hazard.

2. Internal hazard

This type of hazard causes damage or destruction of the building itself. It is directly related to the fire-load which, in turn, enables the building to be graded when considered along with the duration of fire.

3. Personal hazard

The possibility of loss or damage caused to the life is referred to as personal hazard.

The fire safety provisions should be liberally provided for this type of hazard. The safe fire-proof exits should be suitably accomodated in the design of buildings.

Causes and Effects of Fire

The causes of fire are as follows:

• Improper storage of inflammable materials in and around the premises.

• Heating sources are often causes of fire space heaters, electric heaters and fireplaces should be used with caution.

• Cooking accidents.

• Smoking.

• Electrical wiring.

• Rubbish and waste materials.

• Combustible materials such as glues, solvents, packing materials, flammable liquids or gases stored near or around the factory premises can be major causes of a gridis fire.

• Oil leakage.

• Non-removal of dry grass and vegetation.

Effects of Fire

The different materials produce different gases when ignited by fire. The effects of these gases are as follows:

1. Carbon monoxide

This gas hampers oxygen from reaching the brain. It is the most abundant of fire gases. It is invisible and odourless. 

2. Carbon dioxide

This gas overstimulates the rate of breathing and it is thus responsible for increasing the intake of other toxic gases. 

3. Hydrogen sulphide

This gas affects the nervous system and it causes dizziness and pain in the respiratory system. 

4. Nitrogen dioxide

This gas is extremely toxic and it numbs or deadens the throat. 

The human body can withstand temperatures between 65°C and 120°C. The smoke hampers vision and gases impair rational thought.

In many cases, a fire victim loses consciousness before he has a chance to plan out an effective route to safety. Thus, many people have been killed by lack of clear thought rather than flames.

The content of oxygen is normally 21 percent in air. If it falls below 17 percent during a fire, rational thought and muscle control become extremely difficult.

When the oxygen level falls below 6 percent, the breathing stops and after about 4 minutes to 6 minutes without oxygen, the brain death occurs.