Chapter 7 Flashcards
(44 cards)
1
Q
Fire is a
A
- chain reaction
- chemical reaction
- Fireor combustionis a chemical reaction between oxygen and a combustible fluid
2
Q
For combustion(burning)to continue, there must be
A
a constant source of:
- fuel,
- oxygen (air), and
- heat
3
Q
Combustion (الإحتراق):
A
The process by which fire converts (changes)fuel and oxygen into energy, usually in the form of heat.
4
Q
•The ignition (اشتعال)point or (combustion point):
A
The temperature at which a given fuel can burst (explode)into flame
5
Q
Carbon
A
- Carbon is found in almost every flammable substance.
- When a substance burns, the carbon is released and then combines with oxygen.
- That produces either carbon dioxideor carbon monoxide.
6
Q
Carbon dioxide (CO2)
A
- is produced when there is more oxygen than the fire needs. It is not toxic, but can be produced in such volumes that it seriously reduces the concentration of oxygen in the air surrounding the fire site…..
- Suffocation.
7
Q
Carbon monoxide (CO)
A
- a colorless, odorless(no smell), fatal(deadly) gas,
- It is the result of incomplete combustion of a fuel.
- It is produced when there is insufficient (little or short) oxygen to burn the fuel completely
8
Q
Combustion of liquids and solids
A
Liquids and solids such as oil and wood do not burn directly but must first be converted into a flammable vapor by heat.
Example: Burning a paper (look to the vapor area just above the surface of the paper).
9
Q
Methods of heat transfer
A
Conduction (توصيل الحرارة)
Convection (move) (إنتقال الحرارة)
Radiation(spread) (الإشعاع)
10
Q
Conduction (توصيل الحرارة)
A
is direct thermal energy transfer (move).Metals are very good conductors of heat. [The opposite are insulators such as Concrete, rubber and glass which are poor conductors].
11
Q
Convection (move) (إنتقال الحرارة)
A
•is heat transfer through the movement of hot gases. Convection determines the general direction of the spread of a fire.
12
Q
Radiation(spread) (الإشعاع)
A
Is electromagnetic wave transfer of heat to a solid. A fire in one oil tank can spread to nearby tanks through radiated heat, raising the temperature and pressure of the other tank contents.
e.g. sun’s radiation of heat.
13
Q
Spontaneous combustion: الاحتراق التلقائي
A
- A classic example of spontaneous combustion is a pile (mass) of oil rags (wet old cloth). The fibers (tissues) of the rags expose a large surface area to oxidation. Theporous (spongy)nature of the rags allow additional oxygen to be absorbed(taken in), replacing the oxygen already consumed (used).
- When the temperature rises enough, the surfaces of the oil on the rags vaporize.
- Spontaneous combustion is rare, but it can happen.
14
Q
Sources of Fire Hazards
A
- Almost everything in industrial environments can burn.
- Metal furniture, machines, plaster, and concrete block walls are usually painted. Most paints and polish will easily catch fire.
- The principal method of fire prevention is passive – the absence of sufficient heat
15
Q
Packing material
A
•All of the packing materials such as cardboard (thick paper), Styrofoam, papers, bubble wrap and shrink wrap easily burn.
16
Q
Classes of fires
A
- Class A fires: Solid materials such as wood, plastics, textiles and their products: paper, housing, clothing.
- Class B fires: Flammable liquids and gases.
- Class C fires: electrical – live electricity situations.
- Class D fires: Combustible, easily oxidized metals such as aluminum, magnesium, titanium and zirconium.
- Special Categories: extremely active oxidizers or mixtures, flammables containing oxygen, nitric acid, hydrogen peroxide, and solid missile(bullet)propellants (gun powder, pushing).
17
Q
Flash point
A
The lowest temperature for a given fuel at which vapors are produced in sufficient concentration to flash (flame)in the presence of a source of ignition.
18
Q
Fire point:
A
The minimum temperature at which the vapors continue to burngiven a source of ignition.
19
Q
Auto-ignition temperature:
A
The lowest point at which the vapors of a liquid or solid self-ignite without a source of ignition.
20
Q
Flammable liquids
A
- have a flash point below 1000F [37.70C]
- are lighter than water
- So water cannot be used to put the fire out
21
Q
Crude oil fires
A
burn even when floating on fresh or sea water.
22
Q
Combustible liquids
A
•have a flash point at or higher than 1000F.
23
Q
National Fire Protection Association (NFPA) hazards identification system
A
- National Fire Protection Association (NFPA) red, blue, yellow and white diamond is used on product labels, shipping cartons and buildings.
- Ratings within each category are 0 to 4,
- where 0 represents no hazard; and 4 the most severe hazard level.
- Colors refer to a specific category of hazard:
- Red = flammability (fire hazard)
- Blue = health (health hazard)
- Yellow = reactivity (chemical hazard)
- White = special information (special hazards presented by the material written in)
24
Q
Leading causes of fire related deaths
A
- National Fire Protection Association statistics (data) show that most people die in fires from suffocating or breathing smoke and toxic fumes.
- The number one killer in fires is carbon monoxide (CO), which is produced in virtually all fires involving organic compounds.
- Carbon monoxide is produced in large volumes and can quickly reach lethal (poisonous)dosage concentrations.
- Carbon dioxide can lead to suffocation because it can be produced in large volumes, depleting (emptying) oxygen from the air
25
Carbon dioxide can lead to suffocation because it can be produced in large volumes, depleting (emptying) oxygen from the air
for this reason
Many fire extinguishers use carbon dioxide because of its ability to deprive (يجرد)the fire of oxygenwhile simultaneously cooling the fire.
26
The major chemical products of combustion:
* Ammonia,
* Carbon dioxide,
* Carbon monoxide,
* Hydrogen Chloride,
* Hydrogen Sulfide,
* Nitrogen dioxide, and
* Sulfur dioxide.
Not all of these gases are present at any particular fire site.
Many of these compounds will further react with other substances often present at a fire.
27
•Many of these compounds will further react with other substances often present at a fire.
for example
* sulfur dioxide will combine with water to produce sulfuric acid.
* Oxides of nitrogen may combine with water to produce nitric acid.
* Sulfuric acid and nitric acid can cause serious acid burns.
28
Smoke Detectors Techniques
* Thermal expansion detectors
* Heat sensitive insulation
* Photoelectric fire sensors
* Ionization or radiation sensors
* Ultraviolet or infrared detectors
29
Thermal expansion detectors
•use a heat-sensitive metal link that melts at a predetermined temperature to make contact and ultimately sound an alarm.
30
Heat sensitive insulation
•can be used which melts at a predetermined temperature thereby initiating a short circuit and activating the alarm.
31
Photoelectric fire sensors
detect changes in infrared energy that is radiated by smoke, often by the smoke particles obscuring (interupt) the photoelectric beam.
A relay is open under acceptable conditions, and closed to complete the alarm circuit when smoke interferes.
32
Ionization or radiation sensors
use the tendency of a radioactive substance to ionize when exposed to smoke.
The substance becomes electrically conductive with the smoke exposure and permits the alarm circuit to be completed.
33
Ultraviolet or infrared detectors
•sound an alarm when the radiation from fire flames is detected.When rapid changes in radiation intensity are detected, a fire alarm signal is given.
34
Life saving for a fire disaster
* Fire Hazard prevention and,
* Fire Hazard Control
* Training employees (The most successful life saving preperation)
35
Preventing Office Fires
* Confine or restrictsmoking to designated areas that are equipped with non-tip ashtrays and fire-resistant furnishings.
* Periodically check electrical circuits and connections. Replace frayed (old, worn) cables immediately.
* Make sure there is plenty of air space left around copying machines and other office machines that can overheat.
* Locate(put) heat producing appliances (tools, instrument) away from the wall or anything else that can ignite.
* Frequently inspect personal appliances such as hotplates, coffee pots and cup warmers. Assign responsibility for turning off such appliances every day to a specific person.
* Keep passages, stairwells, and exits clear of paper, boxes and other combustible material.
36
Life safety involves
* protecting the vehicles, vessels and lives of people in buildings and structures from fire.
* The primary reference source for life safety is the Life Safety Code published by the National Fire Protection Association. It addresses(treat, handle) the construction, protection, and building shape necessary to minimize the hazards of fire, smoke, fumes, and panic
37
Life Safety
A major part of the code is devoted to
the minimum requirements for design necessary to ensure that occupants (residents) can quickly evacuate (empty) a building or structure.
38
prohibited Fabrics (forbidden cloth)
Clothing made from the following types of fabrics (cloth material)
(nylon,acetate,polyester, rayon.) either alone or in blends is _prohibited_, unless the employer can show that the fabric has been treated to withstand (resist) the conditions that may be encountered (met) or that the clothing is worn in such a manner as to eliminate (take out) the hazard.
39
OSHA regulations for fire brigades
فرق الاطفاء
* With this option only those employees who are part of an established fire brigade are allowed to fight fires
* Fire brigades (bands, groups) are divided into two types:
* Incipient (primary)and
* Interior structural
* An incipient fire brigadeis used to control only small fires. It requires no special protective clothing or equipment.
* An interior structural fire brigade may fight any type of fire provided it has been issued the appropriate protective clothing and equipment.
40
Fire safety program components
* Assessment of the workplace
* Planning
* Awareness and Prevention
* Response
41
Fire safety program components
Assessment of the workplace
* Fire hazards assessment should be continuous and ongoing.
* Members of the fire safety committee should be trained in the fundamentals of fire hazard assessment by the safety and health professional.
42
Fire safety program components
Planning: Fire safety plan should have:
* emergency escape procedures and routes,
* critical shutdown procedures,
* employee headcount procedures,
* rescue and medical procedures,
* procedures for reporting fires and emergencies, and
* important contact personnel for additional information.
43
Fire safety program components
Awareness and Prevention
All employees should receive awareness training so that they understand the role in carrying out the emergency plan.
44
Fire safety program components
Response
One of the fire safety committee’s most important responsibilities is to arrange periodic drills (training, exercise) so that employees automatically respond properly
