Chapter 9 Book 3 Fire Safety And Site Hazards Flashcards
What is the main code that makes up rule for building fire safety
The national building code which outlines the minimum fire safety regulations building, should comply with to safeguard against loss of life and property from a fire that code covers alarm systems, firefighting, equipment, fire exits, construction of the buildings the materials used in the building and electrical systems
Carbon dioxide fire extinguisher
Reduces the oxygen content of the atmosphere to a point where combustion can no longer be supported. It can also have a cooling effect which is helpful carbon dioxide is non-combustible, provide its own pressure for discharge, does not conduct electricity, leaves no residue upon application these make it good for class A, b, and C fires.
Dry chemical fire extinguisher
Regular dry chemicals are used for a class B fire in class C fires multipurpose, dry chemical’s can be used on class a a as well as class B and C if possible use carbon dioxide fire extinguishers on electrical fires because dry chemical leaves a mess and can cause corrosion, abrasion current leakage and may reduce conductivity. Do not mistake dry chemical for dry powder as dry powder is used to put out class D fire.
Aqueous film forming form, fire extinguisher
Used on class a and B fires when used on liquid flammables it creates a layer to seal the vapors from the hydrocarbons and when used on class a fires, it excludes air and cools
Standpipe
Is a vertical pipe that runs from the lowest floor to the top floor or roof and is supplied by either the city water supply or fire pump. Each floor has valves and outlets for fire hoses to be attached when sprinkler protection  is not provided than a standpipe must be installed. These can be classified as dry or wet systems. The wet system is always under pressure and the pipe is full of water were the dry system. Must have a valve either manually remotely or automatically turned on to fill the system after 12 floors of fire pump is generally needed to give enough pressure to the top floors.
Care of fire hoses
Rubber lined lightweight cotton fire hoses should be tested at least once a year to ensure they hold pressure and do not leak. Unlined linen cannot be tested as any small amount of moisture will cause them to rot. Both types should be unfolded and re-folded 3 to 4 times a year in the folds should be made in a different spot each time to avoid cracking
Type of fire sprinkler system suppression system
What pipe systems, dry pipe, system, combined, wet, and dry pipe system, reaction system, deluge system
Wet versus dry pipe systems
Wet pipe is constantly under pressure and use in areas maintained above 4°C. Once a fire produces enough heat to activate one or more sprinkler the water will discharge immediately from any open sprinkler. The dry pipe system uses a dry pipe valve that is held in place by the pipe in system being pressured with air. Once the fire gives off enough heat to activate a sprinkler head. The air pressure will drop in the water pressure will open the dry pipe valve. The system is much more complex and requires a reliable air supply.
PReaction system
The water is held back by a pre-action valve that is tied to a supplemental detection system. Once the detection system operates it allows the pre-action valve to automatically open and admit water into the pipe not work water will not discharge from the system until the fire has generated enough heat to operate, one or more of the sprinklers, the pipe is charged with a small amount of air to indicate integrity of the pipe. If the pressure drops an alarm will sound, indicating low air conditions within the pipe and a possible leak.
Two types of sprinkler heads
The quartz bold type, which has a transparent bulb containing a color liquid which expands and burst at a predetermined temperature, can be used vertically or projected down. The second type is the soldered link type a valve disk is held on its seat by two lovers, which are held in position by a soldered link, that will melt at a low melting point.
Fire detectors
Basically, a heat sensing device usually mounted against ceiling. It responds when the temperature in the area it is supervising reaches a predetermined level, or if the temperature in the area rises at an unusually fast rate.
Smoke detectors
Often used in preference to fire detectors as a fire may produce a lot of smoke before heat. Smoke detectors can be either photo electric smoke detector for ionization smoke detectors.
Photo electric smoke detector
Consist of a light source which sense out a beam of light in the receiving unit containing a photo electric guy as long as the photo electric eye receives a strong beam of light. The switch remains open when smoke starts of scaring the light beam and reaches a critical value the receiving unit trips the alarm system.
Ionization smoke detector
Electronically response to the presence of combustion particles in the air when the amount of particles reaches a predetermined level, the detector triggers the alarm
Care of portable fire extinguishers
Portable fire extinguisher should be checked every three months to give assurance that they have not been activated. The hose and horn are free of obstruction. There is no obvious physical damage or deterioration after inspection record the date on the attached tag and initial it at six month intervals, the holes should be examined for deterioration and the cartridge should be weighed if the weight is 10% below the stamped weight on the head it must be replaced.
