Guide to Fire Safety and Temperature Concepts
Fire safety and temperature management are essential components of various industries, from construction to chemical processing. This article delves into critical definitions, including Absolute Temperature, a universal temperature scale vital in scientific measurements, and Autoignition Temperature, which highlights the minimum temperature for a material to ignite without external flames.
It also explains fire safety essentials such as Compartmentation, Fire Retardants, and Fire Resistance, which are designed to contain and prevent fire spread. By understanding terms like Combustion, Flammability, and Spontaneous Heating, professionals can enhance safety protocols and develop innovative solutions for fire prevention and management.
Absolute Temperature:
Temperature scale. Absolute zero (-273.15C). The temperature at which particles would lose all their kinetic energy.
Adsorption:
The retention of solid or liquid particles at the surface of another solid or liquid.
Alarm:
A signal or message from a person or device indicating the existence of a fire, medical emergency, or other situation that requires fire department action.
Alternative escape route:
A path, sufficiently separated by either direction and space, or by fire resisting construction, to ensure that one is still available should the other be affected by fire.
Ambient temperature:
The temperature of the surroundings.
Arson:
Fire originated by malicious intent.
Assembly occupancy:
An Occupancy: (1) used for a gathering of 50 or more persons for deliberation, worship, entertainment, eating, drinking, amusement, awaiting transportation, or similar uses; or (2) used as special amusement building, regardless of occupant load.
Atmospheric pressure:
The weight of one sq cm column of the earth’s atmosphere. At sea level, this pressure is 1 kg per sq cm (76 cm of mercury column).
Autoignition Temperature:
Minimum temperature at which a material will ignite by itself in air and sustain combustion without initiation by an external spark or flame under specified test condition.
Automatic Fire Detecting and Alarm System:
An arrangement of automatic fire detectors, such as fuse working at a given temperature, a thermostat or a fluid filled tube or an electronic device, for detecting an outbreak of fire, and sounders and other equipment for automatic transmission and indication of alarm signals without manual intervention. The system also has provision for testing of circuits and, where required for the operation of auxiliary services.
Automatic fire extinguishing system:
Any system designed and installed to detect a fire and subsequently discharge and extinguishing agent without the necessity of human intervention.
Automatic Sprinkler System:
An arrangement of piping, sprinklers and connected equipment designed to operate automatically by the heat of fire and to discharge water upon that fire which may also simultaneously give automatic audible alarm.
Back Draft:
An explosion, of greater or lesser degree, caused by the inrush of fresh air from any source or cause, into a burning building, where combustion has been taking place in a shortage of air.
Basement:
Any storey that has more than 50% of the total area of the building’s perimeter below grade.
Beam, Fire-resisting:
A structural member with or without any additional protection, capable of satisfying one of the criteria of fire resistance namely, resistance to collapse.
Blast Effect:
Damage caused by shock waves from an explosion.
BLEVE (Boiling Liquid Expanding Vapour Explosion):
An explosion caused by rapid expansion of flammable gas stored in a container resulting in sudden release of huge quantities of atomized burning liquid which appear as a fire ball and radiating intense heat all around.
Burning Rate:
The rate at which combustion proceeds across a fuel. A specialized use of this term describes the rate at which the surface of the pool or burning liquid recedes. For gasoline, this rate is reported to be approximately 6 mm per minute.
Cavity Wall:
Built in two thicknesses, separated by an air space, the two thicknesses being connected by occasional ties of metal or brick. Known as hollow wall.
Ceiling (suspended, fire-resisting):
A ceiling assembly capable of contributing, wholly or in part, to the overall fire resistance of the floor above and/or its supporting members.
CFC:
A Chlorofluorocarbon molecule consisting of chlorine, fluorine, and carbon atoms.
Chain reaction:
A self-propagating chemical reaction in which activation of one molecule leads successfully to activation of many others. Most, perhaps all, combustion reactions are of this kind.
Change of State:
Condition in which a substance changes from a solid to a liquid or from a liquid to a gas caused by addition of heat or the reverse by removal of heat.
Charring:
The formation of a light, friable, mainly carbonaceous constituent residual on wood or other organic matter resulting from incomplete combustion and/or devolatilization following exposure to heat.
Chemical Flash Fire:
The ignition of a flammable and ignitable vapour or gas that produces and outward expanding flame front as those vapours or gases burn. This burning and expanding flame front, a fireball, will release both thermal and kinetic energy to the environment.
Classification of Hazards for Portable Fire Extinguishers: light (low) hazard:
Light hazard occupancies are locations where the total amount of class A combustible materials, including furnishings, decorations, and contents, is of minor quantity. This can include some buildings or rooms occupied as offices, classrooms, churches, assembly halls, guest room areas of hotels/motels, and so forth. This classification anticipates that the majority of content items are either non-combustible or so arranged that a fire is not likely. Flammables used for duplication machines, art departments, and so forth, are included, provided that they are kept in closed containers and safely stored.
Chimney Effect (flue effect):
The upward thrust of convection currents of hot gases through vertical openings. The tendency of air or gas to rise in a duct or other vertical passage when heated.
Clean Agent:
Electrically non-conducting, volatile, or gaseous fire extinguisher that does not leave a residue upon evaporation.
Closed-circuit Self-contained Breathing Apparatus (SCBA):
A recirculation-type SCBA in which the exhaled gas is re-breathed by the wearer after the carbon dioxide has been removed from the exhalation gas and the oxygen content within the system has been restored from sources such as compressed breathing air, chemical oxygen.
Closed Container:
A container, so sealed by means of a lid or other device that neither liquid nor vapour will escape from it at ordinary temperatures.
Code:
A standard that is an extensive compilation of provisions covering broad subject matter or that is suitable for adoption into law independently of other codes and standards.
Combustion:
Exothermic reaction of a combustible substance with an oxidizer, usually accompanied by flames, and/or glowing and/or emission of smoke.
Combustible:
Capable of burning. A material that, in the form in which it is used and under the conditions anticipated, will ignite and burn; a material that does not meet the definition of non-combustible or limited-combustible.
Combustible aluminum dust:
Any finely divided aluminum material 420 microns or smaller in diameter that presents a fire or explosion hazard when dispersed and ignited in air.
Combustible gas detectors:
A device used to detect the presence of flammable vapours and gases and to warn when concentration in air approaches the explosive range.
Combustible Liquid:
A liquid which is capable of forming a flammable vapour / air mixture. All flammable liquids are combustible. Whether a liquid is flammable or combustible depends on its flash point. A liquid that has a closed-cup flash point at or above 37.8°C.
Combustible Dust:
Any finely divided solid material 420 microns or smaller in diameter (material passing a U.S. no. 40 standard sieve) that presents a fire hazard or a deflagration hazard when dispersed and ignited in air.
Compartmentation:
The divisions of a building into fire tight compartments by fire-resisting elements of building construction in order to contain a fire within the compartment of origin for a specific period of time.
Compound:
Material formed when elements combine with one another to form a new substance with homogeneous properties.
Compression:
The reduction of the volume of a gas or vapour by mechanical means.
Compressed Gas Cylinder:
Any portable pressure vessel of 45.4 kg water capacity or less designed to contain a gas or liquid that is authorized for use at gauge pressures over 276 kPa at 54.4°C.
Confined space:
An area large enough and so configured that a member can bodily enter and perform assigned work. An area with limited or restricted means for entry and exit. An area that is not designed for continuous human occupancy.
Containment:
Restriction the spread of fire to surrounding structures or areas.
Corrosive:
As identified by OSHA, a corrosive material is a chemical that causes visible destruction or irreversible alterations in human skin tissue at the site of contact or in the case of leakage will materially damage or even destroy other material.
Cryogenic gases:
Substances in a gaseous state which cannot be liquefied by pressure alone and are therefore cooled to a low temperature for storage and temperature in the liquid state.
Damper, fire-resisting:
A movable closure within a duct, which on operation is intended to prevent the passage of fire or smoke or gases and which together with its frame, will be capable of satisfying the criteria of fire resistance with respect to collapse and flame penetration.
Damper, Smoke:
Movable device for smoke control, open or closed in its normal position, which is automatically or manually actuated.
Danger, Imminent:
Any conditions or practices in any occupancy or structure that pose a danger that could reasonably be expected to cause death, serious physical harm, or serious property loss.
Decomposition:
A chemical reaction in which a compound is split into compounds or elements with simpler molecules. Breakdown of a material or substance (by heat, chemical reaction, electrolysis, decay or other processes) into parts, elements or simpler compounds.
Deluge Valve:
A type of system actuation valve that is opened by the operation of a detection system installed in the same areas as the spray nozzles or by remote manual operation supplying water to all spray nozzles.
Density:
The amount of mass in unit volume of a substance, expressed i gram per cc or kg/cu cm.
Door, fire –check/ fire door:
Door to prevent or restrict the spread of hot gases and smoke. It must hold-back fire for 20 minutes (integrity) and must not collapse within 30 minutes (stability). Used on entrance door to flats and apartments sharing a common access zone area, doors between small garages and houses, doors to habitable rooms and kitchens in buildings of three storey’s or more.
Door, fire-resisting:
A door which, together but also along with its frame, is capable of satisfying the criteria of with respect to collapse, flame penetration and excessive temperature rise. Such a door may be automatic or self-closing.
Drenchers:
A device to give protection to the roofs, windows and door openings of a building by interposing a curtain of water between the protected building and a fire.
Dry chemical:
A mixture of finely divided solid particles, usually sodium bicarbonate, potassium bicarbonate, or ammonium phosphate-based with added particular additives. The mixture receives special treatment to provide resistance to packing, and moisture absorption (caking), and to promote proper flow characteristics.
Duct, fire-resisting:
A duct which conveys liquid, gas or services through building and which is capable of satisfying the criteria of fire resistance with respect to collapse, flame penetration and rise of temperature beyond any prescribed value.
Dust explosion:
Rapid oxidation type of explosion in a suspension of combustible dust air.
Dwelling unit:
A single unit, providing complete, independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating and cooking.
Egress:
A route of travel from any point inside a building to a point outside the building.
Emergency:
A fire, explosion, or hazardous condition that poses an immediate threat to the safety of life or damage to property.
Emergency lighting:
A provision of lighting in designated parts of premises, for use when normal light fails.
Emergency response operations:
Activities related to emergency incidents, including response to the scene of the incident and specific response duties performed at the scene.
Escape Chute:
Open slide-like escape used for emergency evacuation.
Escape Hatch:
A route forming part of the means of escape from any point in a building to a final exit.
Escape route, External:
An escape route external to a building, having an adequate degree of fire protection by way of a roof, staircase, balcony, walkway or external court, and terminating at a final exit.
Escape route, protected:
An escape route having an adequate degree of fire protection.
Evacuation Drill:
Rehearsal of the evacuation procedure involving participation of the occupants of the premises.
Exit:
That portion of a means of egress that is separated from all other spaces of a building or structure by construction or equipment as required to provide a protected way of travel to the exit discharge.
Fire extinguisher (Portable):
A portable device, carried on or wheels and operated by hand, containing an extinguishing agent that can be expelled under pressure for the purpose of suppressing or extinguishing fire.
Fire Hazard:
Characteristics of materials, building construction and occupancy which affect the initiation, development and spread of fire. Any situation, process, material, or condition that, on the basis of applicable data, can cause a fire or explosion or provide a ready fuel supply to augment the spread or intensity of the fire or explosion and that poses a threat to life or property.
Fire Hydrant:
A connection to a water main for the purpose of supplying water to fire hose or other fire protection apparatus.
Fire Lane:
The road or other means developed to allow access and operation setup for fire fighting and rescue apparatus.
Fire lift:
A lift designated to have additional protection that enables it to be used under the direct control of the fire brigade in fighting a fire.
Fire Load:
Calorific energy, of the whole contents contained in a space, including the facings of the walls, partitions, floors and ceilings.
Fire Point:
The lowest temperature at which a liquid gives off sufficient flammable vapour in air to produce sustained combustion after the removal of the ignition source.
Fire Prevention:
The concept of elimination of all probable causes of a fire outbreak.
Fire Propagation Index:
A comparative measure of the contribution to the growth of fire of a combustible.
Fire Protection:
Design features, systems, equipment, buildings or other structures to reduce danger to persons and property by detecting, extinguishing or containing fires.
Fire Protection System:
Any fire alarm device or system or fire extinguishing device or system, or their combination, that is designed and installed for detecting, controlling, or extinguishing a fire or otherwise alerting occupants, or the fire department, or both, that a fire has occurred.
Fire Retardants:
Liquids, solids, or gases that tend to inhibit combustion when applied on, mixed in, or combined with combustible materials.
Fire Resistance:
Ability or an element of building construction, component for structure to fulfill, for a stated period of time, the required stability, fire integrity and/or thermal insulation and/or other expected duty in a standard fire resistance test.
Fire resistant construction:
The type of construction in which the structural members including wall, partition, columns, floors and roofs are designed to withstand resistance to fire for a specified period.
Fire separation:
The distance in metres measure from any other building on the site, or form other site, or from the opposite side of street or other public space to the building for the purpose of preventing the spread of fire.
Fire Triangle:
Fuel, Heat and Oxygen.
Fire Vent:
An opening in the enclosing walls or roof of a building, intended for releasing heat and smoke in the event of fire and automatically or manually opened or both.
Flame:
A zone of oxidation of gas usually characterized by the liberation of heat and the emission of light.
Flame Arrestors:
A device fitted to prevent the passage of flames.
Flame Ionization Detector (FID):
A nearly universal gas chromatographic detector. It responds to almost all nitrogen hydrogen, helium, oxygen, carbon monoxide or water. This detector ionizes compounds as they reach the end of the chromatographic column by burning them in an air/hydrogen flame. As the compounds pass through the flame, the conductivity of the flame changes, generating a signal. This is the most commonly used detector in non-specific analysis.
Flame-proof Enclosure:
An enclosure for electrical machinery or apparatus that will withstand, when covers or other access doors are properly secured, an internal explosion of the flammable gas or vapor which may enter or which may originate inside the enclosure without suffering damage and without communicating the internal flame (or explosion) to the external flammable gas or vapor.
Flame Spread:
The propagation of flame over a surface.
Flammability:
Degree of ease with which a material catches fire and its intensity.
Flammable Limits:
The minimum and maximum concentration of fuel vapor or gas in a fuel vapor or gas/gaseous oxidant mixture (usually expressed as percent by volume) defining the concentration range (flammable or explosive range) over which propagation of flame will occur on contact with an ignition source.
Flashfire:
A flame or fire of very short duration.
Flashover:
A stage in the development of contained fire at which all the combustibles in the enclosures flash into fire simultaneously.
Floor, fire-resisting:
A floor, with or without a ceiling beneath, which, when exposed to fire conditions from below, is capable of satisfying for a stated period of time the criteria of fire resistance with respect to collapse, flame penetration and excessive temperature rise.
Fuel:
A substance that will produce energy as heat (in useful amounts), it may be gaseous, liquid or solid.
Fuel load:
The total quantity of combustible contents of a building, space, or fire area.
Hazard:
Condition or set of circumstances that presents a specific injury or adverse health potential.
Hazard, High:
High hazard contents shall be classified as those that are likely to burn with extreme rapidity or from which explosions are likely. These are contents that are liable to burn with extreme rapidity or from which poisonous fumes or explosions are to be feared in event of a fire.
Hazard, low:
Hazard contents shall be classified as those of such low combustibility that no self-propagating fire therein can occur.
Hazard, Ordinary:
Ordinary hazard contents shall be classified as those that are likely to burn with moderate rapidity or to give off a considerable volume of smoke.
Health hazard:
A chemical for which there is statistically significant evidence based on at least one study conducted in accordance with established scientific principles that acute or chronic health effects may occur in exposed persons.
Heat:
A mode of energy associated with and proportional to molecular motion that may be transferred from one body to another by conduction, convection or radiation.
Heat Release rate (HRR):
The rate at which heat energy is generated by burning.
High-rise Building:
A building in which a ‘stack effect’ is created by a fire and in which fire fighting cannot be carried out from outside with the fire appliances available with the fire services. Generally, all buildings more than 15m in height shall be considered as high-rise buildings.
Hot work:
Work involving flames or temperatures likely to be sufficiently high to cause ignition of flammable material.
Hydrostatic testing:
Pressure testing of the extinguisher to verify its strength against unwanted rupture.
Ignition:
The means by which burning is started.
Ignition temperature:
The lowest temperature of a substance at which sustained combustion can be initiated.
Incendiaries:
Substance or mixtures of substance consisting of a fuel and an oxidizer used to initiate a fire.
Lining Material:
Any used for lining walls, ceiling or floors of building for insulation, decoration or other purposes.
Lower Limit of Flammability:
The lowest percentage concentration by volume of flammable vapour (gas) mixed with air which will burn with a flame.
Maintenance:
Work, including but not limited to, repair, replacement, and service, performed to ensure that equipment operates properly.
Means of Egress:
A continuous and unobstructed way of travel from any point in a building or structure to a public way consisting of three separate and distinct parts: (1) the exit access, (2) the exit, and (3) the exit discharge.
Material Safety Data Sheet (MSDS):
Written or printed material concerning a hazardous material that is prepared in accordance with the provisions of regulations.
National Fire Protection Association (NFPA, USA):
NFPA is an international voluntary membership organization to promote and improve fire protecting and prevention and establish safeguards against the loss of life and property by fire.
Non-combustible Material:
Not capable of undergoing combustion under normal atmospheric pressure and oxygen concentration. A material that, in the form in which it is used and under the conditions anticipated, will not ignite, burn, support combustion, or release flammable vapours when subjected to fire or heat. Materials that are reported as passing ASTM E136, standard test method for behavior of materials in a vertical tube furnace at 750°C, shall be considered noncombustible materials.
Occupancy:
Purpose for which a building, or part of a building is used, or intended to be used.
Occupant Load Factor:
A factor used in calculating the population density when planning means of escape from a building or part of a building.
Organic Peroxide:
Any organic compound having a double oxygen or peroxy (-O-O-) group as its chemical structure.
OSHA:
The Occupational Safety Health Administration of the US Department of Labour.
Oxidation:
Originally, oxidation meant a chemical reaction in which oxygen combines with another substance. The usage of the word has been broadened to include any reaction in which electrons are transferred. The substance which gains electrons is transferred. The substance which gains electrons is the oxidizing agent.
Oxidizer:
A chemical or substance other than a blasting agent or explosive that initiates or promotes combustion in other materials, thereby causing fire of itself or through the release of oxygen or other gases. Any material that readily yields oxygen or other oxidizing gas, or that readily reacts to promote or initiate combustion of combustible materials.
Permissible Exposure Limit (PEL):
An exposure limit established by a regulatory authority. May be a time-weighted average (TWA) limit, STEL or a maximum exposure limit.
Petrochemical:
Flammable chemicals which are derived (in whole or part) from petroleum or natural gas constituents.
Physical Hazard:
A combustible liquid, a compressed gas, explosive, flammable, an organic peroxide, an oxidizer, pyrophoric, unstable (reactive) or water reactive.
PPM:
Parts per million. A measurement or concentration such as 1 microgram per gram.
Pyrolysis:
Irreversible chemical decomposition of a material due to an increase in temperature without oxidation. The transformation of substance into one or more other substances by heat alone without oxidation.
Pyrophoric Gas:
A gas that will spontaneously ignite in air at or below a temperature of 54.4 C.
Reducing agent:
In a reduction reaction (which always occurs simultaneously with an oxidation reaction), the reducing agent is the substance or chemical which combines with oxygen or loses electrons in the reaction.
Risk management:
The process of planning, organizing, directing, and controlling the resources and activities in order to minimize detrimental effects.
Roof Venting:
A system of vents which will open automatically in the event of a fire and allow the escape of smoke and hot gases.
SCBA:
Acronym for Self-contained Breathing Apparatus.
Self-contained Breathing Apparatus (SCBA):
A respirator worn by the user that supplies a respirable atmosphere that is either carried in or generated by the apparatus and is independent of the ambient environment.
Secondary Fire:
A fire which has started some distance from the seat of the original fire, but is due to the latter.
Self-expelling Fire Extinguisher:
A fire extinguisher in which the agents have sufficient vapour pressure at normal operating temperatures to expel themselves.
Self-heating:
An exothermic reaction occurring without the application of external heat.
Shutter, Fire-resisting:
Shutter which, together with its frame, is capable of satisfying the criteria of fire resistance with respect to collapse and flame penetration.
Smoke Detector:
A device that detects visible or invisible particles of combustion.
Smothering:
Process of fire extinguishment by the limitation or reduction of oxygen.
Smouldering:
Slow combustion of material without visible light and generally evidenced by smoke and an increase in temperature.
Spontaneous Combustion:
A biological or chemical reaction which produces its own heat resulting in combustion.
Spontaneous Heating:
A kind of heating internally developed by a body due to bacteriological and/or chemical reaction without drawing off heat from its surroundings. Also known as spontaneous combustion, initially, a slow, exothermic reaction at ambient temperatures, liberating heat, if undisputed, accumulates at an increasing rate and may lead to spontaneous ignition of any combustible present. Spontaneous ignition occurs sometimes in haystacks, coal piles, warm moist cotton waste, and in stacks of rags coated with drying oils such as cottonseed or linseed oil.
Standard operating Procedure:
A written procedure that establishes a standard course of action.
Standpipe System:
An arrangement of piping, valves, hose connections, and allied equipment installed in a building or structure, with the hose connections located in such a manner that water can be discharged in streams or spray patterns through attached hose and nozzles, for the purpose of extinguishing a fire, thereby protecting a building or structure and its contents in addition to protecting the occupants. This is accomplished by means of connections to water supply systems or by means of pumps, tanks, and other equipment necessary to provide an adequate supply of water to the hose connections.
STP (Standard Temperature and Pressure):
A temperature of 70 °F (21 °C) and pressure of 1 atmosphere (14.7 psi or 760 mm Hg).
Structural Fire Protection:
Features in the layout and/or construction of a building intended to reduce the effects of a fire a building.
Thermal Barrier:
A material that limits the average temperature rise of the unexposed surface to not more than 120 °C for a specified fire exposure complying with the standard time-temperature curve.
Threshold Limit Valve (TLV):
Refers to airborne concentrations of substances and represents conditions under which it is believed that nearly all workers are protected while repeatedly exposed for an 8-hr day, 5 days a week (expressed as per parts per million (ppm) for gases and vapours and as milligrams per cubic meter (mg/ m³) for fumes, mists, and dust).
Vent:
A passageway used to convey flue gases from gas utilization equipment or their vent connector to the outside atmosphere.
Ventilation:
Is either a mechanical system or natural method of exchanging air within a space. Mechanical systems can include fans and blowers. Natural ventilation is caused by wind pressure and infiltration through a structure.
Water-miscible Liquid:
A liquid that mixes in all proportions with water without the use of chemical additives, such as emulsifying agents.
Emma Lee, an expert in fire safety with years of firefighting and Rescuer experience, writes to educate on arescuer.com, sharing life-saving tips and insights.