Fire, Oxidation & Matter
It is a rapid oxidation of combustible matter, so rapid that the heat of reaction is unable to get dissipated to the surrounding atmosphere at the same rate as is being produced. Heat, light, sound, smoke, CO2, CO etc. are the products of fire.
It is the chemical combination of oxygen with the fuel. It is an exothermic creation. Since the reactions are slow, the amount of heat generated gets dissipated to the surrounding atmosphere simultaneously. Hence, there is no appreciable rise in temperature. Rusting of iron due to its oxidation is an example. Oxidation reactions which proceed at fast rate the heat of endothermic unable to get dissipated to the surrounding atmosphere simultaneously, the term RAPIDOXIDATION is used.
It is the substance which has mass and occupies space. It is found in three physical states. Matter is either combustible or incombustible.
Three states of Combustible Matter:
- All combustible matter is termed as “Fuel” also.
Specific Area: It is the area occupied by the solid fuel in square centimeter per gram.
Density: It is the mass per unit volume of a substance. It’s unit of measurement is gm/cc.
Specific Gravity: It is the ratio between mass of a unit volume of the substance and mass of the same volume at 40C of water at 40C.
Vapour Density: The density of a gas or vapour is often given in-relation to the density of equal volume of Hydrogen under the -same conditions of temperature and pressure. Vapour density of Air as compared to hydrogen is 14. 4. for C02 the corresponding value is 22. Therefore, C02 is approx. 5 times heavier than air.
To calculate vapour density of a substance the following formula may be used:
VD of a Compound= Molecular weight of the compound or matter 29
(Composite molecular weight of Air is 29)
Miscibility with water: It is the ability of the substance to mix with water.
Force: Force is that which changes or tends to change the position of a body from rest to motion or motion is rest.
Pressure: It is the force per unit area. Its units are kg/cm2 or Pounds per square
Centrifugal Force: It is that force which acts upon a body moving in a circular path to force it farther from the axis or center of the circle described by the body.
Centripetal Force: This is force acting on a moving body in the direction of the centre of the circle about which it is moving.
Exothermic Reactions: The chemical reactions which releases heat are known as exothermic are actions.
Endothermic Reactions: The chemical reactions which absorbs heat are called as endothermic reactions.
Definitions of few terms related to Fire:
As pherical mass of flame that sometimes occurs when a large quantity of vaporized flammable liquid suddenly combust.
A canvas paddle used to beat out grass fires.
A birch broom or piece of rubber or wire netting attached to a long handle, used to beat out grass and brush fires. This is a kind of fire bat.
Fire blanket: A non combustible cloth of asbestos or one treated with fire retardant chemicals, used to wrap around clothing fire victims to smother the flames.
Hot, flaming or glowing solids, generally of celluloid material, rose by strong convective currents and carried by high winds in large scale fires. Fire brands are the most common sources of spot fires.
And open space between buildings, stocks of combustible materials, stored goods, and the like, serving to interrupt the spread of fire. A natural barrier to fire spread or cleared and some times ploughed strip of land in a forest serving the same purpose.
Fire check door:
A door assembly conforming to certain structural specifications or one that will meet the stability and integrity requirements of the fire resistance test from a give time period for maintenance of integrity being less than that for stability. Its function is to check the spread of fire in a building.
A specifically treated curtain that is drawn or dropped across the proscenium arch in a theater to form a fire barrier between the stage and auditorium, sometimes it is termed as “satety curtain”.
Anyun-breathable, flammable, or explosive underground gas such as methane can 0e regarded as “fire damp”. Defines as an explosive gas mixture consisting chiefly of methane (ch4) occurring specially in coal mines.
A device that automatically seals off air flow through part of an air handling system in olde to restrict or block the passage of heat and combustion products. The device usually consists of a flap or shutter controlled by a fusible link, though recentiy honey comb partition coated with in tumescent paint has been developed.
A comparatively small, rapidly, whirling vortex of flame seen in a forest or brush fires, but some times in freely burning buildings, resulting from hot gases rising and cool air rushing into the low pressure area.
A fire resistive door, including it’s frame and hardware, which under standard test conditions, meet the fire protective requirements for the location in which it is to be used, usually a self tripping door that doses automatically when a fire is detected or an alarm is actuated.
It is a practice exercise by a fire service’ unit in fire fighting procedures and the use of fire fighting equipments.
Fire endurance- ability to do cope with:
A measure of the elapsed time during which an assembly, material, product, element, structural member, or the like maintains it’s design integrity underspecified conditions of test and performance. The capability of a material, structural member, or assembly to retain its design load bearing capacity or other function and resist failure under given conditions of exposure to fire.
A continuous path of travel to the ground, or other safe area or refuge, for use if fire or other emergency conditions make normal exits unusable. A separate means for leaving a building in case of a fire, such as chute, emergency fire exit etc. Fire flow: The flow rate of water in the mains of a given are quire for fire protection in addition to the normal water consumption for that area.
The procedure of assessing grades of fire resistance to various structural elements e building as defined in specifications appropriate to the fire hazard arising from the occupancy an according to the height, floor area or cubic capacity of the building. The investigation and assignment of suitable fire precautions of any kind to attain an adequate standard of safety according to the fire hazard of the building under consideration.
The property of a material, such as concentrate of iron, not to burn or decompose when exposed to ordinary fire. To treat a combustible material with a fire retardant to reduce the fire hazard.
- The spread of fire through over a combustible medium.
- This is a phenomenon that depends on the ignite ability, flame spread, and heat release characteristics of the material.
- The penetration and travel of fire through openings and concealed’ spaces.
Possessing or imparting low flammability or flame spread properties.
A substances or treatment that reduces the flammability of a material. Some common fire retardants used for wood, cloth etc. Are ammonium phosphate, mono ammonium sulphate, borax, boric acid, zinc chloride, sodium dichromate etc.
Floor or wall either without openings, or with adequately protected openings that meets specified fire endurance requirements for a barrier against the extension of a fire from one area of a building to another. A space provided between objects. Such as goods in storage buildings, or structures that serves as a fire lane for fire fighting operations.
The potential of afire to damage. A measure of the intensity of afire over time expressed in degree hours. Fire severity is determining by the nature and quantity of the fuel. It’s burning rate, temperature, and other factors. Fire stop: fire resistant material, barrier, or construction installed in concealed spaces or between structural elements of a building to prevent the extension of fire through walls, ceilings: and the like.
A large, rapidly developing fire ignited roughly simultaneously over a large, characteristically accompanied by fire generated winds and turbulent convective currents.
A stream of water delivered from a nozzle and used to control and extinguish a fire. The portion of a water stream from the nozzle tip to the point of impact.
The activity involved in controlling and reducing a fire by constructing fire breaks. Back firing, applying fire retardants etc.; as opposed to direct fir extinguish.
A standard experimental procedure for assessing the reaction of a material. Product or system to a specified fire exposure. the behavior observed bay or may not related to other fire exposure conditions. Such as full scale fires of matter.
- A fire department training tower.
- A structurally in dependent stair way attached to a building and used as a fire escape and as a means of access for fighting fire.
A building or structure lacking adequate exits, or fire protection equipment’s. Or one which because of interior layout presents a major hazard to life in case of fire.
A fire resistant solid wall of masonry or equivalent material provided to ‘delay or restrict the horizontal spread of fire for a specified period of time. Generally, self-supporting assembly designed to maintain its integrity even if the structures on both side collapse.
Movement of air caused by a large fire depleting the oxygen from the atmosphere and thereby creating a partial vacuum.