Fire Prevention and Protection

FIRE PREVENTION & PROTECTION

TYPES OF FIRE

Classes of fire: To make it easier to select the appropriate extinguishing media according to the nature of the material undergoing combustion, fires are arranged in 'Classes'.

Fuel Source	Class of Fire	Type of Extinguisher (Extinguishing Agent)
Ordinary combustibles (e.g. trash, wood, paper, cloth)	A	Water; chemical foam; dry chemical
Flammable liquids (e.g. oils, grease, tar, gasoline, paints, thinners)	B	Carbon dioxide (CO2); halon (Gas), dry chemical and foam
Flammable gases	C	Dry chemicals powder
Combustible metals (e.g. magnesium, titanium)	D	Dry powder (suitable for the specific combustible metal involved)
Electricity (e.g. live electrical equipment)	E	CO2; halon; dry chemical
Combustible Cooking (e.g. cooking oils; animal fats, vegetable fats)	F	Wet chemical (Potassium acetate based)

FIRE EXTINGUISHERS

Types of extinguishers:

Multi-Purpose Dry Chemical (A, B, C)

A dry chemical agent called mono ammonium phosphate. The chemical is non-conductive and can be mildly corrosive if moisture is present. In order to avoid corrosion, it is necessary to scrub and thoroughly cleanup the contacted area once the fire is out. A dry chemical fire extinguisher is usually used in schools, general offices, hospitals, homes.

Regular Dry Chemical (B, C)

 A dry chemical agent called sodium bicarbonate. It is non-toxic, non-conductive and non-corrosive. It is easy to cleanup, requiring only vacuuming, sweeping or flushing with water. Extinguishers with sodium bicarbonate are usually used in residential kitchens, laboratories, garages.

Carbon Dioxide (B, C)

 Carbon dioxide removes oxygen to stop a fire but has limited range. It is environmentally friendly and leaves no residue, so cleanup is unnecessary. Extinguishers with carbon dioxide are usually used in contamination-sensitive places such as computer rooms, labs, food storage areas, processing plants, etc.

Halotron (A, B, C)

 A vaporizing liquid that is ozone friendly and leaves no residue. Because it requires no cleanup, fire extinguishers with halotron are ideal for computer rooms, telecommunication areas, theaters, etc.

Foam (A, B)

 Foam floats on flammable liquids to tame the fire and helps prevent re flashes. To cleanup the affected area, it must be washed away and left to evaporate. Fire extinguishers with foam are usually used in garages, homes, vehicles, workshops.

Purple K Dry Chemical (B, C)

 A dry chemical called potassium bicarbonate. It is non-conductive and non-corrosive. Clean up requires vacuuming, sweeping or flushing with water. Extinguishers with potassium bicarbonate are usually used in military facilities, oil companies, vehicles, etc.

Automatic Sprinklers

They are generally mounted below ceiling height with a temp detector used with each  sprinkler. The temp rise in the environment results in activation of a link on the detector which opens a water valve The water is then sprayed on the ceiling & falls to the floor extinguishing the fire If the volume of fire increases, more sprinklers get opened up The fire detectors are available with a varying temp range to suit specific requirements.

Water (A)

The most common agent is water; however, it cannot be used for class B or C fires because it is conductive. Water-based fire extinguishers are usually used in stockrooms, schools, offices, etc.

Wet Chemical fire extinguishers (F)

The potassium acetate based agent discharges as a fine mist which forms a soapy foam that suppresses any vapors and steam or the risk of fire re flash as it extinguishes the fire. Class K fire extinguishers can usually be found in commercial cooking areas such as restaurants and cafeterias.

Operation & Function

Fire sprinkler control valve assembly

Each sprinkler head is held closed independently by heat-sensitive seals. These seals prevent water flow until a design temperature is exceeded at the individual sprinkler heads. Each sprinkler activates independently when the predetermined heat level is reached. The design intention is to limit the total number of sprinklers that operate, thereby providing the maximum water supply available from the water source to the point of fire origin.

A sprinkler activation will do less damage than a fire department hose, as the fire department's hose streams provide around 250 US gallons per minute (15 L/s) whereas an activated sprinkler head generally discharges around 23 US gallons per minute (1.5 L/s). In addition, the sprinkler will activate immediately; whereas a fire appliance takes an average of eight minutes to reach an incident. This delay can result in substantial damage from the fire before the appliance arrives and will the fire will be much larger; requiring much more water to extinguish.

Hose Reels

It is a semi portable system in which the fire hose box is permanently located but the flexible hose can be moved throughout the building. The hose to fight the fire should be linen type. The linen hoses allow some water to seepage, which prevents their burning. The nozzles are connected to large tanks, which contain extinguishing agent. The tanks are placed outside the room for protection as well as for recharging during the fire fighting operations.

FIRE DETECTORS AND ALARMS

Fire Detection Systems:

Detection systems are based on smoke, heat, flame, gas leakage, combustion, water flow.

Conduction/Convection Heat detection: Housing of detector has a fusible element that melts at a specified temperature causing electrical contact to activate a fire alarm.

Smoke detector: These are used to detect fires in the incipient stages.

Heat detectors: They respond to high temperatures caused by fire.

Flame detector: Detects light from flames where rapid development of flame occurs.

Electromagnetic detectors: They employ photocells sensitive to infrared and ultraviolet light emitted by the fire.

Water flow detector: It indicates because the other detector types (smoke, flame or heat) is activated and starts the water sprinkler system.

FIRE ALARMS AND FUNCTIONING

The fire alarm system can be set off automatically by smoke detectors, heat detectors or manually. These sensors are set to detect certain levels of heat or smoke that could be an indication of fire. A loud bell or a siren sometimes accompanied by blinking or flashing lights for individuals who have hearing problems, blasts to alert occupants in the building. In a fire alarm system there is always a smoke detector to detect smoke or fire

How does a fire alarm system work by way of smoke sensor?

There are two types of smoke detectors. These are the optical detector and the ionization detector. The optical smoke detector detects smoke by using light sensors (infrared LED). When smoke particles pass thru the chamber of the optical detector, it scatters light that triggers the alarm. In the ionization detector, if the smoke particle enters the chamber of the ionization detector it will reduce air ionization inside the chamber of the ionization detector and triggers the alarm.

FIRE HAZARDS

A fire hazard is any situation in which there is a greater than normal risk of harm to people or property due to fire. Fire hazards can take the form of ways that fires can easily start, such as a blocked cooling vent, overload electrical system, ways fires can  spread rapidly, such as an insufficiently protected fuel store or areas with high oxygen concentrations, or things which, in a fire, pose a hazard to people, such as materials that produce toxic fumes when heated or blocked fire exits. Fire hazards are workplace hazards that involve the presence of flame or the risk of an uncontrolled fire.

Fire hazards include:

• ·         Live flames
• ·         Sparks
• ·         Hot objects
• ·         Flammable chemicals
• ·         Chemicals that can aggravate a fire

Another category of fire hazards are situations and events that impede fire protection and prevention methods. This can include impediments to fire fighting, compromised built-in fire safety systems, and situations that restrict the escape of people from an affected building or area in the event of a fire.

Every workplace that has potential fire hazards must be equipped with a sufficient number of conveniently located and easily accessible fire exits.

The following fire hazards are found in various workplaces:

• Open flames used in various applications (such as welding)
• Electric wires, higher loads, loose connections, and old electrical equipment
• All cooking and heat generating appliances
• Smoking and the use of personal lighters or matches
• Improper or unauthorized stowage of flammable and hazardous materials and chemicals
• Insufficient capacity and numbers of emergency exits and stairs
• Hindrance to sight or reach firefighting equipment, markings, and alarm systems
• Insufficient numbers and types of fire extinguishers
• Absence of fire detection and alarm system
• Violation of building and fire codes

FIRE PREVENTION

To protect the lives of guests, employees and the general public who may visit and use the facilities of a hotel. A basic knowledge regarding fire should assist in preventing fires and extinguishing them quickly if they occur.

Three components are necessary for a fire to start, if one of the three is not present, or is removed, then the fire does not happen or its is extinguished. The three parts are:

Þ    Fuel – something to burn;

Þ    Air – oxygen to sustain combustion (to keep the fire going);

Þ    Heat – gas, electricity, etc.

FUEL                             HEAT OXYGEN

Figure 10.1 The fire triangle

To extinguish a fire the three principal methods are:

Þ    Starving –removing the fuel;

Þ    Smothering – removing the air (oxygen);

Þ    Cooling – removing the heat.

Therefore, one of the sides of the ‘fire triangle’ is removed.

The fuel is that which burns, heat are that which sets the fuel alight and oxygen is needed for fire to burn. Eliminate one of these and the fire goes out. For example, if the clothes of someone working in the kitchen catch alight, then quickly lay them down and wrap a fire blanket round the person and place them on the floor. The oxygen has been taken from the triangle.

FIRE PREVENTION MEASURES

The Regulatory Reform (Fire Safety) Order 2005 requires you to assess fire risks in your hotel. You must implement adequate control measures to prevent fires from starting and enable people to evacuate safely if one does. Fire kills, and it usually takes victims of negligence. But if you apply sufficient fire safety measures in your hotel, you can prevent tragedy.

Hotel Fire Safety Checklist

The Fire Safety Order sets out numerous duties that you must follow to make your hotel safe for guests. Be aware that enforcing authorities have the power to inspect your hotel at any time to check that you comply. If dissatisfied, they may issue a notice that requires you to improve safety measures and, in extreme cases, prohibit access until you make changes.

This guide to Fire Safety in Hotels is separated into the following topics:

• ·         Carry out a fire risk assessment.
• ·         Appoint fire wardens.
• ·         Train staff.
• ·         Install detection and alarm systems.
• ·         Arrange maintenance and repairs.
• ·         Plan fire routes.
• ·         Plan your fire evacuation strategy.
• ·         Provide information to guests.

Carry out a fire risk assessment: To do so, you need to complete five steps:

• ·         Identify the hazards: think about the ways a fire could start (such as faulty plug sockets, damaged kitchen appliances, or obstructed ventilation) and sources of kindling (including furniture, laundry, paper, chemicals, wall hangings, etc.).
• ·         Consider who is at risk: guests are your primary concern. They aren’t familiar with the building and may even be asleep when a fire occurs, which puts them at serious risk. You need to ensure that vulnerable people can escape safely, such as those with mobility or hearing disabilities.
• ·         Determine what measures are needed and apply them: for example, you may need better housekeeping to move sources of kindling away from fire escape routes and may need to arrange regular checks for appliances and plugs. If you don’t have any disability escape routes on floors above ground level, install them.
• ·         Record your findings and changes: enforcing authorities will check your records for evidence that you manage fire safety risks, so keep on top of writing everything down. Records help you track what you’ve done and what you still need to do, and enable you to look back and assess what control measures did or didn’t work.
• ·         Review and update: business premises, particularly hotels, will wear down from use over time, meaning new hazards appear and control measures become less effective. So you need to reassess risks, reapply control measures, and rerecord details.