FIRE SAFETY. Mr. S. T. Ho Health, Safety and Environment Office

Transcription

1 FIRE SAFETY Mr. S. T. Ho Health, Safety and Environment Office

2 This subject is designed to provide basic concepts and knowledge of Fire Safety to course participants. At the end of the course, course participants should be able to identify and take appropriate actions to reduce or eliminate fire hazards. FIRE SAFETY

3 FIRE SAFETY Contents: Threats from Fire Triangle of Combustible Classification of Fire Methods of Extinguishing a Fire Types of Fire Services Installations and Equipment Portable Fire Extinguishers General Fire Emergency Procedures

4 Threats from Fire Danger to Property: Direct loss - physical loss or damage to property due to heat, smoke and water Consequential loss - business interruption, loss of goodwill, loss of employees Life Threatening: High Temperature - direct burns Reduced Oxygen Concentration - lead through various stages of impairment or suffocation Smoke, Irritant Gases, Toxic Gases - panic due to inhalation - panic due to physical and psychological impairment to escape Explosion

5 Hong Kong Fire Services Review

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7 Hong Kong Fire Services Review hk/eng/review.html

8 Fire Triangle Combustion may be defined as a chemical reaction accompanied by the evolution of light and heat. Three basic requirements are necessary before combustion can occur, involving a combustible substance, heat and oxygen. This is known as the triangle of combustible. FIRE

9 Oxygen A supply of about 21% of Oxygen in air is required to support combustion. It is usually drawn from the atmosphere. In some cases the material themselves contain sufficient oxygen to maintain combustion when deprived of atmospheric oxygen.

10 Sources of Ignition (Heat Energy) Combustible materials may be ignited in various ways: 1. Open Flame e.g. Bunsen burners in lab, welding torch, lighting of a match 2. Electrical Sparks or Arc e.g. static electricity, overloading of supply, short circuit, electric arc welding.

11 Sources of Ignition (Heat Energy) 3. Mechanical Sparks caused by friction, e.g. cutting, grinding 4. Spontaneous Ignition certain chemical reactions generate sufficient heat to cause fire, e.g. yellow phosphorus oxidizes very rapidly and ignites on contact with air 5. Hot Surface e.g. heater

12 Ignition Temperature The temperatures at which combustion can take place fall into three categories: 1. Flash Point: The lowest temperature at which a substance gives off sufficient inflammable vapor to produce a momentary flash on the application of a small flame. 2. Fire Point: The lowest temperature at which the heat from the combustion of a burning vapor is capable of producing sufficient vapor to sustain combustion. It will be seen that the difference between flash point and fire point is that the flash point temperature is only required to produce vapor to enable a momentary flash to take place whereas the fire point temperature has to be high enough to produce sufficient vapor to enable combustion to be maintained.

13 Ignition Temperature 3. Spontaneous Ignition: The lowest temperature at which the spontaneous ignition of a substance can take place. When the cooling becomes inadequate to dissipate the heat developed, the material will begin to self-heat and will eventually burst into flame. It is a type of combustion which occurs without an external ignition source.

14 Fuels 1. Combustible materials exist as solids, liquids and gases. The burning of any substance is usually accompanied by a flame; and as a flame is produced as the result of the burning of a gas or vapor, it can be seen that liquids, and solids with minor exceptions, must emit inflammable vapors before combustion can take place. 2. Most solids and liquids need to be heated above their normal temperatures before they can emit inflammable vapors. Some liquids (e.g. petrol) emit inflammable vapors at normal temperatures.

15 Classification of Fire A. Fires involving solid materials, e.g. wood, paper, textiles, etc. B. Fires involving liquids or liquefiable solids, e.g. petroleum, oil, fat, paint & etc C. Fires involving gases, e.g. LPG, Town Gas D. Fires involving metals, e.g. Magnesium, Sodium & etc. E. Fires involving electrical hazards

16 Dangerous Goods Hong Kong Law - Chapter 295 Dangerous Goods Ordinance SECTION 3 of the Dangerous Goods Ordinance declares the following to be DANGEROUS GOODS: All explosives, compressed gases, petroleum and other substances giving off inflammable vapours, substances giving off poisonous gas or vapour, corrosive substances, substances which become dangerous by interaction with water or air, substances liable to spontaneous combustion or of a readily combustible nature.

17 Dangerous Goods SECTION 6 of the Ordinance states: Except under and in accordance with a licence granted under this Ordinance no person shall manufacture, store, convey or use any dangerous goods. Which means that with the exception of Explosives (Category 1 Dangerous Goods) which can only be manufactured or stored as required by the Commissioner of Mines, these goods can only be used and/or stored in excess of the exempt quantity in accommodation approved and licensed by the Director of Fire Services.

18 Dangerous Goods In the Dangerous Goods (Classification) Regulations, dangerous goods are listed into 10 categories. For example; Category 2 Compressed Gases, Category 5 Substances giving off inflammable vapours.

19 Dangerous Goods

20 Dangerous Goods

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22 Safety Can & Cabinet

23 Three Ways of Extinguishing a Fire 1. Starving (a) By removing combustible material from the neighborhood of the fire. (b) By subdividing the burning material into smaller fires which may be left to burn out or to be extinguished.

24 Three Ways of Extinguishing a Fire 2. Smothering By reducing the oxygen which support the combustion; e.g. 1. use of covers or blankets 2. use of foam on oil 3. use of finely divided particles of dry powder (e.g. sodium bicarbonate) Add an inert gas to the burning mixture.

25 Three Ways of Extinguishing a Fire 3. Cooling Cool the heat source. If the rate at which heat is generated by combustion is less than the rate at which it is dissipated, the combustion cannot persist. In applying this principle to fire extinction, the first step is to accelerate the speed with which heat is removed from the fire, thus reducing the temperature of the burning mass and as a consequence the rate at which heat in lost from the fire exceeds the rate of heat production and the fire dies away.

26 Types of Fire Services Installations and Equipment Fire hydrant / hose reel installation Dry riser Sprinkler Automatic fire detection system (heat / smoke) Drencher Manual fire alarm Fixed inert gas systems (CO 2, BTM) PA system Portable fire extinguishers Sliding doors, drop shutters, smoke stop doors Fireman s lifts Exit signs

27 Fire Service Installations and Equipment Audio/Visual Advisory Systems: Exit signs, fire alarm warning devices to provide indication of safe direction of egress from the area. Automatic Actuating Devices: Shutters, doors automatically controlling their movement in the event of fire.

28 Fire Hydrant (street)

29 Fire Hose Reel Systems A jet of water can be delivered to any part of the building Fire Alarm Systems: Break glass / fire alarm - manually operated system designed to give warning of fire.

30 Dry Riser & Water Inlet

31 Automatic Fixed Installations Water sprinkler systems; Fixed inert gas systems (CO 2, BTM); Foam; Powder - designed to automatically detect and instantaneously attack a fire and sound an alarm. - must have a vertical clearance of at least 600 mm for normal operation

32 Automatic Fixed Installations Fire Sprinklers

33 Auto inert gas systems & others Fixed inert gas systems Foam/Powder

34 Automatic Fixed Installations Drencher

35 Automatic Fire Detection System Smoke detector, heat detector (fixed temp.) system designed to detect automatically the presence of smoke, heat. A heat detector is a device that responds to changes in ambient temperature. Typically, if the ambient temperature rises above a predetermined threshold an alarm signal is triggered. The most common fixed temperature point is F (58 C). A smoke detector is a device that detects smoke. Commercial, industrial, and mass residential devices issue a signal to a fire alarm system.

36 Automatic Warning System Audio & Visual Warming

37 Automatic System Fire Shutter

38 Fire Service Installations and Equipment Emergency Lighting: designed to provide adequate illumination and indication of exit routes within a building under emergency conditions. Fire blankets

39 Portable fire fighting equipment Fire beater Sand bucket Water can

40 Portable Fire Extinguishers 1. Water Type Extinguisher Use on fires involving wood, textiles and paper. Never use water to extinguish an electrical fire. Water is a good conductor, and there is some concern for electrocution if you use water to extinguish an electrical fire. Never use water to extinguish flammable liquid fires. Using water will spread the fire.

41 Portable Fire Extinguishers 2. Foam Type Extinguisher use on fires involving flammable liquids, such as gasoline, oil, and solvents.

42 Portable Fire Extinguishers 3. Carbon Dioxide ( CO 2 ) Gas Extinguisher CO 2 gas extinguishers are designed for flammable liquid and electrical fires only. 4. Dry Powder Extinguisher use on most solid, flammable liquid, metal or electrical fires. 5. B.C.F. Extinguisher (BROMOCHLORODIFLUOROMETHANE) use on electrical fires, flammable liquids, delicate equipment and important documents.

43 Fire Doors

44 Smoke Lobby

45 Fireman s Lift A designated lift(s) designed to allow Fire Services personnel safe access to alternate floors of a building

46 Exit Signs

47 PA System

48 Training is important to ensure the safe use of fire Extinguishers d= &sec_id=4104&subsec_id=11866&art_id=

49 General Fire Emergency Procedures If you discover a fire: Remain calm and do not panic. Activate the fire alarm by pressing the nearest breakglass point. Report the fire to the Security Control Center of your company or dial 999 for emergency. Giving the exact location and nature of the fire. Alert other people by shouting FIRE. If safe to do so, attempt to put out the fire by using the nearby fire fighting equipment. Do not use water or foam for putting out electrical fire. Do not take any personal risk. If the fire gets beyond your control, evacuate immediately.

50 General Fire Emergency Procedures If you hear the fire alarm and are informed of a fire: - Remain calm and do not panic. - Leave the area and proceed to the designated assembly point immediately via the nearest exit. Walk, don t run. - Be considerate, try to help those who have difficulty leaving the building such as disabled and pregnant persons.

51 General Fire Emergency Procedures You should be familiar with: - The escape routes in your work area. - The locations of the breakglass points, fire extinguishers, and hose reels. - The designated assembly points. - Do not use the lifts. - Report to your Fire & Safety Officer at the assembly point as far as practicable. - Do not return to the building until permission is given by the Officer In- Charge of the Fire Services Department.

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53 Fire Safety - Practical Training Recommend - Practical Training Practical Uses of Fire Extinguishers, Fire Blankets and & Fire Hose Reels

54 Questions?