fire prevention and protection
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.
The Fire Triangle
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 it is extinguished. The three parts are
- Fuel: something to burn.
- Air: oxygen to sustain combustion (to keep the fire going)
- Heat: gas, electricity, etc.
To extinguish a fire the three principal methods are:
- Starving: removing the fuel.
- Smothering: removing the air (oxygen).
- Cooling: removing the heat.
The fuel is that which burns, heat is 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, should 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.
TYPES OF FIRE
Class 'A' FireFires occurring in ordinary dry combustible materials such as wood, textiles, paper, rubbish etc are called class 'A'. In these fires quenching and cooling effect of quantities of water or solutions containing high percentage of water are of first importance. Fire extinguishers used are soda acid, water, water glycol.
Class ‘B' FireFires in highly inflammable liquids such as petrol, diesel, paints are called class 'B'. These can be extinguished by smothering! Blanketing effect (suffocating the fire by cutting off supply). The fire extinguishers used are foam, dry chemical powder or CO2 (fog or foam).
Class 'C' FireFires in inflammable pressure gases like LPG, natural gases, H2 are called class 'C'. Blanketing effect is used to extinguish by dry chemical powder CO2
Class 'D' FireFires involving combustible metals such as aluminium, zinc, sodium, potassium where special media and techniques are used.
Class 'E' FireWhen energized electrical equipment is involved in a fire only dry chemical powder! CO2 (fog) extinguishers should be used. All other extinguishing media are conductive and thus risky to be operator. Once de-energized, all extinguishers can be used. In case of all electrical fires, mostly caused due to overloading. Short circuiting, firstly the power should be cut off and then fire suffocated by cutting off the supply by covering it with a non conductor like CO2/ dry chemical powder
FIRE DETECTORS AND ALARMS
lonization Smoke DetectorThis type of detector generally has chambers. The smoke particles entering the chamber get attached to the ions because of electrostatic attraction slow down their movement. This causes a reduction in current flow. When the current flow falls below the predetermined level, the amplifier senses it and initiates the alarm. This detector refers to invisible part of combustion and is useful in early part of clean burning fire.
Optical Smoke DetectorThis type of detector reacts to the visible product of combustion i. e. the particles of carbon and other chemicals, which give smoke. Two important components are light source and photoelectric cell. In fire like condition, the smoke chamber scatters light on the photoelectric cell. The small electrical charge produced by this is amplified and actuates the detector and the alarm goes on. Optical detector is more useful in situations where the protected risk is likely to rise to dense smoke.
Radiation Detectors(a) Infra red. Main components of this detector are PE cell, lenses and amplifier. Lens and amplifier will allow only infrared radiation to fall on PE cell. On detecting radiation, the cell will feed the timer/integrator thro' filter/ amplifier to activate the alarm. But the pre-requisite is that the detector must see the flame before raising the alarm.
(b) Flame flicker type. This is used for large areas like open storage/aircraft maintenance area. The PE cell is struck by deflected infrared radiation and the amplifier identifies the characteristic flicker. The integrator stops the motor so that the deflector can see the flame and allow radiation to fall on PE cell. If the infrared source is present for more than 12-15 seconds, the alarm goes.
(c) Ultraviolet. This also works on the principle of seeing the flame before activating the alarm. It consists of amplifier, PE cell of gas filled tube sensitive to UV radiation. When UV radiation strikes the gas filled tube, it ionizes the gas and a small current is set up turning the tube into conductor of electricity. When the current flow becomes greater than the preset value the alarm goes.
This type is used to detect fire in its more advanced stage when the temp starts to rise. These work on the principle of:
a) Melting or fusion in metals/plastics.
b) Expansion in solids/liquids/gases.
c) Electrical effect.
Based on the above, there are four types of heat detectors, i.e.
a) Using feasible alloys based on reaching preset temperature value.
b) Using principle of expansion.
c) Linear – used for long areas like cable tunnel.
d) Beam combined heat and smoke.
FIRE ALARMSA fire alarm system is an active fire protection system that controls all the fire alarm components in a building. Fire alarm systems are subject to stringent bounding.
The design of fire alarm systems is required to be performed by competent engineers with experience in fire protection, who are licensed within the geographical area. A fire alarm system should include, but not limited to, alarm initiating devices, alarm notification appliances, control units, fire safety control devices, annunciators, power supplies, and wiring.
A (DACT) digital alarm communicator transmitter should be connected to a pair of dedicated telephone lines to transmit an alarm signal only to a central station that is responsible for dispatching the fire department. The connection to the fire department is usually via a central station monitoring company. If a connection to the fire department is not already present, the facility will need to determine if there are two telephone lines available for this connection.
The main fire alarm control unit should automatically transmit alarm signals to a listed central station using a digital alarm communicator transmitter.
FIRE EXTINGUISHERSWater Type Fire Extinguishers
Water Soda AcidThis type of fire extinguisher is used for class 'A' fires. It consists of an iron cylinder that is painted red from outside and contains sodium bicarbonate solution. On top of it a small bottle of acid, usually sulphuric acid is fixed. Whenever the cylinder is required to be used, it is inverted and the knob strikes the ground, the acid bottle breaks on impact and CO2 is produced which comes out with great force and stops the contact of O2, with the fire and fire is extinguished. This is now mostly out of use as the chemical ejected can cause damage to the surrounding.
Water (Gas Cartridge)The water content of this steel cylinder is 9/6 liter and the expelled gas, generally CO2 is contained in a cartridge fitted inside the body of the FE. The expelled water is pure water. Removal of a safety pin/plug and pressure on the operating lever sets the process in motion. With exertion of pressure of gas on the surface of water/ it is forced out of the nozzle .The discharge can be controlled by the lever.
Water (Stored Pressure)
The function is practically same except that whole container is pressurized or N2 is pumped in until the pressure reaches specified limit.
Foam Fire Extinguishers
Chemical FoamThis is also used for class 'A' fires. These have now been replaced by more modem FEs. The chemical reaction in the FE produces foam containing CO2 bubbles and the gas pressure itself causes the discharge.
Self Aspiring Foam.Here a foam solution (foam concentrate in water) is stored in a container, usually 6/9 Itrs capacity and either discharged by a gas cartridge of CO2 fitted in the body of FE or by compressed air or Nv2 which has been pumped in. Both can be used with some low freeze depressant.
CO2 Fire ExtinguisherPortable Fire Extinguishers are often installed in kitchens in hotel and large restaurants and in fish frying establishments since C02 does not contaminate the oil when discharged onto it. The discharge horn should be directed at the heart of the fire, starting at the edge and sweeping across the surface of the burning material. The discharge range of the C02 FE is fairly limited. After using it indoors, the room should be ventilated. When using it in open air, the operator should stand upwind and apply the gas in downwind direction.
Dry Chemical Powder Fire ExtinguisherThis can be used for class 'A', 'B', and 'C’ fires. The most common extinguishing agents are sodium bicarbonate or baking soda. The extinguisher is charged with dry chemical and a small tank of C02. The C02 gas exerts pressure on the dry chemical and forces it out of the nozzle directly to the fire. The powder strikes the fire and the heat from the fire breaks down the chemical that releases C02 gas cooling and smothering the fire.
Halon Fire ExtinguisherPortable Halon fire extinguishers are generally available in the range of 0.7 - 7 kg and are invariably of stored pressure type. Most Halon fire extinguishers have their discharge controlled by a lever but a few have a striker, which may fire a controllable discharge. Once used, these have to be recharged by manufacturers.
|types of fire|
Stationary EquipmentIt includes Automatic sprinklers, fire hose system and permanently connected foam, C02 dry chemical powder.
Automatic SprinklersThey 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 and falls to the floor extinguishing the fire. If the volume of fire increases, more sprinklers get opened up.
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.
Wet SystemsTypical "wet" systems are simple and passive. They have water already pressurized in the pipes held back by the sprinkler head. These systems require manual controls to activate, so long as adequate water supplies are provided.
Dry SystemsSpecialty systems called "dry" systems, designed for unheated spaces, have a low "maintenance" air pressure in the pipes. Water is fed into the system when the sprinkler "fuses" allowing the maintenance air pressure to reach the minimum pressure point. "Pre-action" systems are highly specialized for locations where accidental activation is unacceptable such as museums with rare art works, manuscripts or books. Pre-action valves are connected to fire alarm initiating devices such as smoke detectors or heat detectors and virtually eliminate the possibility of accidental water flow.
Deluge Systems"Deluge" systems are systems that have open sprinklers, i.e. the fusible link is removed, so that every sprinkler served by the system will discharge water. This ensures a large and simultaneous application of water over the entire hazard. These systems are used for special hazards where rapid fire spread is a concern.
Pre-action Systems"Pre-action" systems are similar to "deluge" except the sprinklers are closed and the system is filled with compressed air known as "maintenance air". These systems are desirable where water discharge through accidental damage to the system piping and/or sprinklers presents an unacceptable loss risk to valuable electronic components or other water reactive materials and/or equipment. As the name implies, these systems require that a "preceding" and supervised event (typically the activation of a heat or smoke detector) take place prior to the "action" of water introduction into the system's piping. There are basically three (3) types of pre-action systems including interlock, non-interlock and double-interlock, all which offer differing levels of accidental water discharge protection.
Foam and Gas SystemsOther specialty systems may have foam instead of water suppression agents for fire protection in occupancies with flammable liquids, such as airport hangars. "Clean agent" gaseous systems, such as Argon/C02/Nitrogen mixtures can be used in very small spaces where water cannot be used for suppression.
Hose ReelsIt 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.
In the hospitality industry, fire prevention should be the responsibility of every employee. The first step in fire management is to provide the means to reduce fire damage through alarms and suppression. The second critical step is employee training. The causes of most fires in the service industry are
1. Incendiary / Suspicious
2. Electrical distribution
3. Cooking equipment
5. Appliance, tools, or air conditioning
6. Heating equipment
These fire problem areas should be brought to the attention of all employees, particularly those who are responsible for the operation and servicing of various building equipment.
Fire training includes fire prevention, operation of fire suppression equipment, and alarm response. Each of these topics must be discussed with every employee. Additionally, there is currently considerable interest in the hospitality industry in the concept of an in-house fire response team. Generally, the fire response team includes at least two employees from every shift, with the duties of the fire response team chief being handled by the chief engineer and/or the director of security.
It is essential that members of the fire response team have hands-on familiarity with fire-fighting equipment, know all the exit locations in the building, and understand current evacuation procedures, as well as the operation of the building's evacuation alarm system. However, it should also be noted that the actions of the fire response team during an emergency are essentially limited to the time between the fire alert and the arrival of the local fire department.
Guest SafetyIn addition to the fire training and/or education provided employees, the manager must never overlook the guests, customers, patients, members, and other building occupants. Fire codes will usually require the posting of exit and evacuation diagrams and instructions in guest rooms and in public areas of the building.
This information might be supplemented with information about the meaning of various alarm signals (alert versus evacuation), how guests will instructions in a fire emergency (by telephone or over a speaker in the guest room), and what to do if a guest is handicapped and needs special assistance (provide a special telephone number).
Fire HazardsA 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 (as a blocked cooling vent, overload electrical system), ways fires can spread rapidly (such as insufficiently protected fuel store or areas with high oxygen concentrations) or things which in fire pose a hazard to people (such as materials that produce toxic fumes when heated or blocked fire exits).
Fire safety is a component of building safety. It concerns safety measures to prevent the effects of fires and is the result of proper use of fire protection measures.
Some elements include:
• Having built a facility in accordance with the version of the local building code that was in effect at the time a building permit was applied for.
• Maintaining a facility and conducting oneself in accordance with the provisions of the fire code, from the moment that the building was occupied.
Examples of such lawful conduct include, but are not limited to, the following:
• Not exceeding the maximum occupancy listing for any part of the building (making sure that an area isn't so full of people that they can't all get out quickly in an emergency).
• Maintaining proper fire exits and proper signage of them (e.g., exit signs pointing to them that can function in a power failure).
• Placing and maintaining fire extinguishers and fire alarms in easily accessible places.
• Properly storing/using, and/or banning of flammable materials that maybe needed inside the building for storage or operational requirements (such as solvents in spray booths).
• Routinely inspecting public buildings for violations, issuing orders to comply and potentially prosecuting or closing buildings that are not in compliance, until the violations are corrected or condemning it in extreme cases.
• Installing and maintaining fire alarm control panels for quick detection and warning of fire.
• Obtaining and maintaining a complete inventory of firestops.
• Insuring that all spray fireproofing remains undamaged.
• Maintaining a high level of training and awareness of occupants and users of the building to avoid obvious mistakes, such as the propping open of fire doors.
• Conduct fire drills at regular intervals throughout the year.
A fire code (also called fire prevention code or fire safety code) is a model code adopted on a regional basis and enforced by fire prevention officers within municipal fire departments. It is a lawful set of rules prescribing minimum requirements to prevent fire and explosion hazards arising from storage, handling or use of dangerous materials or from other specific hazardous conditions. The fire code complements the building code. The building code includes construction requirements to minimise fire spread, enable suppression and detection and to provide for safe and rapid evacuation in the event of a fire. Although both codes address similar issues, the fire code is aimed primarily at preventing fires in the first place, including outside of buildings, and that necessary training and equipment will be on hand and the design basis of the building, which includes a basic plan set out by the architect, is not compromised. The fire code also addresses inspection and maintenance requirements of various fire protection equipment in order to maintain optimal active fire protection and passive fire protection measures, with the aim of preserving stringent bounding.