Domain 4: Fire Prevention and Protection
Deflagration
A very rapid oxidation reaction accompanied by the generation of a low-intensity pressure wave that can disrupt the surroundings
Smoke
A visible suspension of carbon or other particles in air, typically emitted from a burning substance.
Auto Ignition Temperature
AKA the kindling point, is the lowest temperature at which a substance will ignite in a normal atmosphere without an external source of ignition from a spark or flame. The temperature at which a chemical will ignite decreases as the pressure increases or oxygen concentration increases.
Immovable hot work (Welding)
According to 1910.252, if an object to be welded or cut cannot be readily moved, all movable fire hazards in the vicinity shall be taken to a safe place.
Type of forklift authorized for use around / in flammable atmospheres?
According to 29 CFR 1910.178, the electric forklift is the only forklift truck authorized in certain flammable atmospheres.
CBRNE (Weapons of Mass Destruction WMD)
According to the Department of Defense CBRNE is defined as: Chemical, biological, radiological, nuclear, and (high-yield) explosive. High-yield explosives. Materials that rapidly release large amounts. of energy and produce a pressure shock. wave during detonation.
Static electricity
Best Described as a condition of high voltage and low current. A statc electrical charge may be either positive (+) or negative (-) and is manifested when some force has separated the positive electrons from the negative protons of an atom. Typical forces include flowing, mixing, pouring, pumpingm filtering, or agitating materials where there is forceful separation of two like or unlike materials. Examples of static generation are common with operations involving the movement of liquid hydrocarbons, gases contaminated with particles (e.g., metal scale and rust), liquid particles (e.g., paint spray, stream), and dust fibers (e.g., drive belts, conveyors). The static electric charging rate is increased greatly by increasing the speed of separation (e.g. flow rate and turbulence). Low-conductivity materials (e.g., hydrocarbon liquids), and surface area of the interface (e.g., pipe or hose length, and micropore filters). Protection from the effects of static electricity include identification of potential static buildup areas measures to reduce the rate of static electricity generation and provisions to dissipate accumulated static electricity charges. Control measures include bonding and grounding, inserting, and humidity control. The lower the humidity, the higher the potential for static electricity buildup.
BLEVE
Boiling Liquid Expanding Vapor Explosion, which is a major container rupture due to a form of pressure release explosion. This can be caused from external heating such as an adjacent container fire. For this reason, the fire attack scenario of a tank fire would include hose streams directed on adjacent containers, as well as on the burning tank.
Exit doors
-Must swing in the direction of travel if the room holds more than 50 people or is used in high hazard areas. -Exit doors must be self-closing and remain closed or automatically close in an emergency upon the sounding of a fire alarm or employee alarm system. -Exit doors must be unlocked, allowing employees to open an exit door from the inside at all times without keys, tools, or special knowledge. -Exit doors are permitted to use panic bars that lock only from the outside. - Exits must be easily identified through the use of emergency lighting and clearly identifiable exit signage.
Dry Pipe Sprinkler Systems
Dry pipe systems are normally installed in areas where there is a potential for freezing, which would render the system basically inoperable when needed. For example, dry pipe sprinkler systems are normally installed in areas where there is a potential for freezing, which would render the system basically inoperable when needed. For example, dry pipe systems are normally installed in parking garages, unheated buildings, or outside canopies that may be attached to buildings. According to NFPA, dry pipe systems cannot be installed unless the range of ambient temperatures reaches below 40 F. In this type if system, water is not present in the pipe until the system is triggered and the water is released into the distribution system.
Hydrostatic Testing Portable Fire Extinguishers
Evaluates the integrity of the shell and protect against unexpected in-service failure. Shell failure can be caused by internal corrosion, external corrosion, and/or damage to the shell itself.
Emergency Action Plan (EAP) should be reviewed and updated
Every 5 years
Hydrostatic Testing Intervals
Every 5 years: Soda acid (stainless steel shell) Foam (stainless steel shell) Cartridge operated water and/or antifreeze Stored pressure water and/or antifreeze Wetting agent Aqueous Film Forming Foam (AFFF) Loaded stream Dry chemical with stainless steel Carbon Dioxide Every 12 years: Dry chemical Dry powder Halon Or when: -When there have been repairs made by soldering, welding, brazing, or with patching compounds. -When the cylinder or shell threads are damaged. -When there are signs of corrosion that has caused pitting, including corrosion under removable nameplate band assemblies. -When the extinguisher has been burned in a fire
A combustible gas meter reads 25%, what does this indicate?
Concentration is 25 % of the lower flammable limit LFL.
Heat Transfer by convection
Convection can be defined as the process whereby thermal energy is transferred by movement of a heated fluid such as liquid or air. There can be natural convection and forced convection.
Subsonic Explosion
Deflagration is a term describing subsonic combustion propagating through heat transfer, hot burning material heats the next layer of cold material and ignites it. Most "fire" found in daily life, from flames and explosions, is deflagration. Deflagration is a rapid, high-energy release combustion event that propagates through gas or an explosive material at subsonic speeds, driven by the transfer of heat. Deflagration is different from detonation, which is supersonic and propagates through shock. Deflagration to detonation transition refers to a phenomenon in ignitable mixtures of a flammable gas and air (or oxygen) when a sudden transition takes place from a deflagration type of combustion to a detonation type of combustion. I its most benign form, a deflagaration may simply be a flash fire. In contrast, detonation is characterized by supersonic flame propagation velocities, perhaps up to 2000 M/s, and substantial over pressures, up to 20 bars. Under certain conditions, mainly in terms of geometrical conditions such as partial confinement and many obstacles in the flame path that cause turbulent flame eddy currents, a subsonic flame may accelerate to supersonic speed, transitioning from deflagration to detonation.
Inside storage rooms for flammable or combustible liquids
Design requirements: Gravity or exhaust ventilation system that provides complete change of air within the room at least 6 times per hour. Maintained one clear aisle at least 3 ft. wide. Containers over 30 gal capacity will not be stacked one upon the other.
Ground Fault Circuit Interrupter (GFCI)
Designed to interrupt the circuit when leakage current (amps) occurs between a conductor and the shield. The NEC definition of GFCI is "A device intended for the protection of personnel that functions to de-energize a circuit or portion thereof within an estalished period of time when a current to ground exceeds the values established for a class A Device. OSHA definition of GFCI "a device whose function is to interrupt the electric circuit to load when a fault current to ground exceeds some predetermined value, that is less than that required to operate the over-current protective device of the supply circuit. A voltmeter is a tool used to detect current leakage.
Automatic Sprinkler Systems
There are several categories of sprinkler systems that may include dry pipe, wet pipe, wet pipe, deluge, combined dry pipe and preaction, and sprinklers that are designed for limited water supply systems. A fire sprinkler system consists of a water supply that provides adequate pressure and flow rate to a water distribution piping system, which has sprinkler heads attached. The sprinkler heads are heads are held closed by either a heat-sensitive glass bulb or a two-part metal link held together with fusible alloy. The sprinkler heads have varying degrees of temperature sensitivities and are color coded.
Fire Detection
There are wide varieties of fire detectors on the market, including heat detectors, rate-compensation detectors, rate-of-rise detectors, pneumatic detectors, smoke detectors, and flame detectors.
Grounding
occurs when conductive equipment is connected to an earthing electrode to help eliminate the buildup of static electricity by allowing it to safely dissipate into the ground.
Fire extinguisher travel distances.
-Class A fire extinguishers - travel distance for employees to any extinguisher is 75 feet. -Class B fire extinguisher - travel distance from the Class B hazard area to any extinguisher is 50 feet or less. -Class C fire extinguisher - on the basis of the appropriate pattern for the existing Class A or Class B hazards. -Class D - travel distance from the combustible metal working area to any extinguishing agent is 75 feet (22.9 m) or less
Gas
A substance that is in the gaseous state at room temperature and pressure.
A paint spray booth operation, according to OSHA, should provide enough dilution air to reduce the vapor of flammable materials to _______% of the lower explosive limit?
25% OSHA 1910.94 (c)(6)(ii) states "The total air volume exhausted through a spray booth shall be such as to dilute solvent vapor to at least 25% of the lower explosive limit if the solvent being sprayed." The standard gives an example of calculation for a typical solvent,
Transfer of heat
3 modes of heat transfer 1. Radiation 2. Convection 3. Conduction It is important to understand the process of heat transfer. Heat always moves from a warmer place to a cooler place. Hot objects in cooler room will eventually cool to room temperature. Cold objects in a warmer room will heat up to room temperature.
Exit access length
75 ft. for un sprinklered high hazard occupancy. 400 ft. for sprinklered ordinary hazard storage occupancy.
Fire extinguisher mounting height
>40 lbs. 3.5 Feet or less. <40 lbs. 5 feet or less.
Tool used for flow testing of fire hydrants
A Pitot tube equipped with a gauge could be used for flow testing water from fire hydrants.
Fire Hydrants
A fire hydrant is an active fire protection measure that provides a source of water from the municipal water system or other source. Buildings located near fire hydrants may qualify for special insurance rate reductions on the basis of the proximity to the hydrant. Fire hydrants are color coded to indicate their specific water flow rate. Red = 500 GPM Orange= 500 - 1000 GPM Green= 1000-1500 Blue= >1500 GPM
Means of egress
A means of egress is an unobstructed, continuous path from any point in a building to a safe location outside. The means of egress consists of three parts. 1. Exit access 2. The exit 3. Exit discharge to a public way.
Exit access criteria
Adequate width to accommodate the maximum number of people in a given area, maintained clean and unobstructed, and meet the maximum travel distances established by codes.
Mist
An aerosol consisting of liquid particles generated by condensation of a substance from the gaseous to the liquid state.
Fire extinguisher inspections and service requirements
An employer is responsible for ensuring that the inspection, maintenance, and testing of all portable fire extinguishers are conducted. Portable fire extinguishers shall be visually inspected monthly. Furthermore, the employer shall ensure that each portable fire extinguisher is services annually and tested in accordance with OSHA 1910.157 (f)(3) Table L-1.
Combustible Liquids
Any liquid having a flash point at or above 140 F and below 200 F
Flammable Liquids
Any liquid having a flash point at or above 140 F and having a vapor pressure not exceeding 40 psia at 100 F
Combustible liquid:
Any liquid having a flash point below 140F and having a vapor pressure not exceeding 40 psia at 100F.
Smoke Detectors
Are classified according to their operating principles, which include ionization- and photoelectric-type detectors. Ionization detectors operate by using a small amount of radioactive material to ionize the air within a sensing chamber inside the detector. The ionization of the air permits the air to conduct electricity between two electrodes within this chamber, As smoke enters the chamber, the smoke particles become ionized and reduce the conductivity of the air between the electrodes. This reduction in conductivity between electrodes is sensed and will cause the detector to respond. Photoelectric detectors: operate on one of three different principles: light obscuration principle, light scattering principle, or cloud chamber principle. Light obscuration Light scattering
Hot Work Permit
Authorizes the performance of work potentially posing a fire hazard. Before a hot work permit (work involving fire, sparks and high temperatures, such as welding) is issued, it may be necessary to use a combustible gas detectors to determine whether a fire hazard (flammable gas/vapor) is present. Hot work permits often require fuels to be removed a minimum of 35 feet (10.7 meters) from the heat source. Combustible gas instruments work on the principle of catalytic combustion.
Grounding and Bonding
Bonding: Is the process of connecting two or more conductive objects together by means of a conductor to minimize the potential electrical difference between them. Grounding: is the process of connecting the conductive object to the ground, and is a specific type of bonding. A conductive object may also be grounded by bonding it to another conductive object that is already connected to the ground. Bonding minimizes potential differences between conductive objects. Grounding minimizes potential differences between conductive objects and the ground. Transferring flammable liquid to another container: The purpose of grounding or bonding in this question is to ensure that there are no potential differences between the containers and earth ground therefore, all objects must be connected to the same grounding point and bonded together. Alternatively, the same objective could be accomplished by insulating the drum and can from earth ground and then bonding the drum to the can.
High Rise Building
Building where the floor of an occupied story is greater than 75ft (23m) above the lowest level of a fire department vehicle access.
Article 500 of the NEC® (NFPA 70) Class and Division requirements for electrical equipment used in locations where fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids, combustible dust, or ignitable fibers or flyings.
CLASS I, DIVISION 1 - ignitable concentrations of flammable gases or vapors can exist under normal operating conditions, or exist frequently due to repair or leakage, or where breakdown or repair might release ignitable concentrations and might also cause simultaneous failure of electric equipment CLASS I, DIVISION 2 - volatile flammable liquids or gases are handled, processed or used, but are normally confined within closed containers or closed systems. CLASS II, DIVISION 1 - combustible dust in the air under normal operating conditions (grain elevator) sufficient to produce explosive or ignitable mixtures, CLASS II, DIVISION 2 - sufficient quantities of dust not normally present. CLASS III, DIVISION 1 - location in which easily ignitable fibers are handled, manufactured, or used CLASS III, DIVISION 2 - easily ignitable fibers are stored or handled
Mining (longwall faces) Dust Controls
Face Ventilation: As with all mining methods, ventilation is the primary means to dilute liberated methane to safe levels. It is also the principal method of controlling respirable dust on the longwall face. Providing adequate amounts of air to dilute and carry airborne dust down the face and prevent it from migrating into the walkway has been and continues to be a goal for longwall operators. Drum mounted water sprays: Apply water for dust suppression directly at the point of coal fracture and add moisture to the product to minimize dust liberation during coal transport, Although very effective at minimizing dust generation at the point of coal fracture, sheaer drum water sprays can actually increase airborne respirable dust levels if operated at water pressures that are to high. Cutting drum bit maintenance: Previous research has shown that bits with large carbide inserts and a smooth transition between the steel shank and the carbide reduce dust levels. Prompt replacement of damaged, worn, or missing bits is crucial. A dull bit rubs against the coal, which results in an ineffective use of available cutting force and the inability to penetrate the coal at designated rates. This results in shallow cutting, which greatly increases dust generation. Directional water spray systems: water sprays can be very efficient air movers and, if applied properly, can be used to augment the primary airflow and reduce the amount of shearer-generate dust that migrates into the walkway near the shearer. Water sprays mounted on the shearer body act very much like small fans moving air and entraining dust in the direction of their orientation. Poorly designed shear-mounted spray systems with nozzles directed upwind at the cutting drums actually force dust away from the face, where it mixes with clean intake air and is carried out into the walkway over shearer operators.
Heat detector that experiences thermal lag
Fixed temperature detector because they sometimes activate at room temperatures above their preset temperature.
Flammable and Explosive Limit Ranges
Flammability limits, or explosive limits, give the proportion of combustible gases in a mixture. Concentrations between the lower and upper limits of the mixture are flammab,e or explosive. The lower flammable limit (LFL) or lower explosive limit (LEL) is the leanest mixture that is still flammable or explosive. Conversely, the upper flammable limit (UFL) or upper explosive limit (UEL) is the richest mixture that is still flammable or combustible. The concentrations are given in percentage of air.
Flash Point
Flash point of a liquid corresponds roughly to the lowest temperature at which the vapor pressure of the liquid is just sufficient to produce a flammable mixture at the lower limit of flammability. The minimum temperature at which a liquid gives off vapor within a test vessel in sufficient concentration to form an ignitable mixture with air near the surface of the liquid. Flash point is normally an indication of susceptibility to ignition.
Fire tetrahedron
For combustion to occur four components are necessary: Oxygen (oxidizing agent), fuel (substrate), heat (ignition), and a self sustained chemical reaction (also referred to as the chain reaction). These components can be graphically described as the fire tetrahedron. Each component of the tetrahedron must be in place for combustion to occur. Remove any one of the four components and combustion will not occur. If ignition has already occurred, the fire is extinguished when one of the components is removed from the reaction.
Foam water sprinkler system
For special applications, the foam water sprinkler may be used. Foam water sprinkler systems discharge a mixture of water and low expansion foam concentrate which results in a foam spray from the sprinkler head. These systems are usually used in areas that have high challenge fires, such as flammable liquids and airport hangars.
Fuel and oxidizers storage
Fuel and oxidizers shall be segregated by 20 feet as per OSHA and NFPA. In cases in which this is not possible, they must be separated by a firewall that has at least a 30 minute fire rating and be at least 5 feet high.
Circuit over current device
Fuse and circuit breaker. They should be installed in every circuit to interrupt the current flow when it exceeds the safe capacity of the conductors. Expulsion fuses are intended for use in central distribution stations, in generation plants, or in overhead lines, and are designed such that when they blow, the gases generated aid in quenching the arc.
Oxidizing agents
Generally are recognized by their structure or names. They tend to have a high oxygen ration in their structures and sometimes release oxygen as a result of thermal decomposition. Oxidizing agents often have per prefixes (perchlorate, peroxides, and permanganate) and end in -ate (chromate, nitrate, chlorate). Strong oxidizers have more potential incompatibilities than perhaps any other chemical group (with possible exception of water-reactive substances). Oxidizers should not be stored or mixed with any material except under carefully controlled conditions. Storing oxidizing and reducing agents where they could mix could be a recipe for disaster. Common oxidizing agents listed in decreasing order of oxidizing strength include: -Flourine - Chlorine -Ozone -Sulfuric Acid -Hydrogen peroxide -Oxygen -Perchloric acid (concentrated) - Hypochlorous acid -Metallic iodates -metal chlorates -bromine -lead dioxide -metallic permanganates -iodine -metallic dichromates -sulfur -nitric acid -stannic (tin +4) salts
Heat detectors
Heat detectors are devices that are installed in fixed locations. These devices respond to changes in the ambient temperature above a predetermined temperature. Once the ambient temperature rises above the predetermined level, the alarm is triggered, indicating a potential fire. When selecting a heat detector it is important to know the maximum normal temperature. For example, installing a 135F heat detector near a beam of a metal building in hot climates may falsely trigger the alarm.
Hydrocarbons (Flammability)
Hydrocarbons are compounds that contain atoms of carbon and hydrogen only. They are broadly classified into two types: aliphatic and aromatic. Aliphatic hydrocarbons are subdivided into saturated and unsaturated compounds and include the alkanes: methane, ethane, propane, and butane. Aromatic Hydrocarbons: are derivative of the parent compound benzene. Thers are members of a class of organic compounds in which an oxygen atom has bridged between two hydrocarbon groups. Aliphatic ethers are highly volatile and extremely flammable. Hydrocarbons that have been partially halogenated burn, but generally with much less ease than their nonhalogenated analogs. The fully halogenated derivatives such as carbon tetra-chloride are noncombustible.
Classes of flammable liquids
IA - Flash point below 73F; boiling point below 100f IB - Flash point below 73F; boiling point at or above 100F. IC - Flash point at or above 73F but below 100F II - liquids having flash points at or above 100F and below 140F. IIIA - Liquids having flash points at or above 140F and below 200F IIIB - Liquids having flash points at or above 200F.
Hypergolic
Igniting spontaneously on mixing with another substance. Fuel that will ignite with an oxidizer but does not require outside ignition source.
Exit Access Width Requirements
International building code and NFPA 101 both require a minimum of 36 inches for corridors serving 50 people or less and a minimum of 44 inches for more than 50 people. This is a minimum width and can increase depending on the type of occupancy.
Combustion
Is a chemical reaction that occurs between a fuel and an oxidizing agent that produces energy, usually in the form of heat and light. When a fuel is burned, the carbon reacts with the oxygen and can form either carbon monoxide (CO) or carbon dioxide (CO2)
Auxiliary Fire Alarm System
Is a local alarm with the added feature of a circuit to the municipal fire alarm system (usually through a local master alarm box). The remote alarm system sends a signal to a remote location (usually staffed 24 hours per day) that in turn notifies the local fire protection agency.
Panic Bar (A.K.A crash bar, exit device, panic device, or a push bar)
Is a type of door handle that permits opening the door quickly during emergency conditions. The mechanism consists of a spring-loaded metal bar fixed horizontally to the inside of an outward-opening door. When the lever is either pushed or depressed, it activates a mechanism which unlatches the door, allowing occupants to quickly exit the building.
Local Fire Alarm System
Is intended to warn local residents and usually only sounds an evacuation alarm. It does not normally rinf the fire protection service.
Vapor Density
Is the measure of the density of a substance compared to air. Those gases and vapors with densities greater than or equal to 1 are heavier than air and will tend to sink to lower levels. Those gases and vapors with a vapor density less than or equal to 1 are lighter than air and will tend to float upward. Useful in determining location of ventilation system.
Heat Transfer by conduction
Is the transfer of thermal energy between two objects in contact with each other.
Fire extinguishers inspection and testing
Monthly inspection Annual Maintenance Check Hydrostatic Testing Requirements
The three distinct parts of a "means of egress" include:
NFPA 101, Life Safety Code, states, "A means of egress is a continuous and unobstructed way of exit travel from any point in a building or structure to a public way and consists of three separate and distinct parts: (a) Exit access (b) the exit (c) the exit discharge The means of egress comprises the vertical and horizontal travel and shall include intervening room spaces, doorways, hallways, corridors, passageways, balconies, ramps, stairs, enclosures, lobbies, escalators, horizontal exits, courts and yards.
Emergency Lighting
NFPA 101, chapter 31, states that a functional test shall be conducted on every required emergency lighting system at 30-day intervals for a minimum of 30 seconds. An annual test shall be conducted for the 1.5 hour duration. Equipment shall be fully operational for the duration of the test. Written records of visual inspections and tests shall be kept by the owner for inspection by the authority having jurisdiction. Exception: Self testing/ Self-diagnostic, battery-operated emergency lighting equipment that automatically performs a minimum 30-second test and diagnostic routine at least once every 30 days and indicates failure by a status indicator shall be exempt from the 30-day functional test, provided a visual inspection is performed at 30-day intervals.
Dry Pipe Fire Sprinkler System
NFPA 13 establishes the maximum size for dry pipe systems at 500 gallons for gridded systems and 750 gallons for nongridded systems, However, these maximums can be exceeded if delivery of water to inspector's test pipe does not exceed 60 seconds. Many times, to ensure rapid delivery of water, quick opening devices are installed. These devices generally consist of accelerators, which cause the deluge or dry pipe valve to cycle more rapidly, or exhausters, which dump air more rapidly.
Overheated wiring
One of the most common causes of electrically created fires is overheated wiring because of overloading. Many factors contribute to a safe installation. The wire must be sized (correct gauge) properly to handle the current. Overcurrent protection (fuses or circuit breakers) must also be correctly sized and function properly. Additionally, electrical raceways must not be overloaded with electrical wiring. The sizing of wiring and the amount of wiring allowed for a given size of raceway is strictly regulated in the National Electrical Code (NEC). Generally, conduit will not feel hot to the touch, even under severe circuit loading if installed according to code.
Automatic Fire Sprinklers Frangible Bulb Color Classification
Orange - 135 F Red = 135 F Yellow = 175 F Green= 200 F Blue = 286 F Purple = 360 F
Chemical Explosions Require:
Oxidizer, fuel, ignition, chemical reaction and confinement of the oxidizer/ fuel. Without confinement the materials will not explode; they will merely burn with great intensity.
Pre-action fire sprinkler system
Piping is pressurized. The piping is charged through the activation of supplemental detection systems located in the same area as the sprinklers. Water is then free to flow through he piping to sprinkler heads. If a sprinkler head has fused (through heat from a fire), water will be delivered to the fire. Pre-action systems are used when there is a danger of serious water damaged to the protected area. Calcium hydroxide and liberates acetylene (ethyne). Therefore, it is not recommended to use a water system with calcium carbide.
Exit
Portion of the means of egress that is separated from the building and provides a protected pathway to the exit discharge.
Preaction Fire Sprinkler System
Preaction systems are basically hybrids of wet, dry, and deluge systems. In a preaction system, a water supply valve is added to a dry pipe system. The valve itself is opened by the activation of a fire detection system, such as a fire alarm or smoke detector. Once activated, the water supply valve will send water to the distribution system. This type of system is normally placed in areas where accidental discharge is undesirable. Typical areas include data centers, museums and art centers.
Deluge Fire Sprinkler System
Primarily installed in areas where there are special hazards where the rapid spread of the fire is a major concern, In deluge systems, the heat sensors from the sprinkler heads have been removed by design. There is no water stored in the distribution system. The water is released into the piping distribution system by the activation of the deluge valve, which is activated by a fire alarm system. Deluge systems must be manually reset, by resetting the deluge valve.
Heat Transfer by Radiation
Radiation heat is the amount of thermal radiation between two or more objects (bodies). Radiation travels in wavelengths and does not require that the two objects be in contact, as radiation can travel through a vacuum or space.
Evaporation Rate
Rate at which a liquid is converted to vapor at a given temperature and pressure. Butylacetate, which has an evaporation rate of 1, us the standard by which most substances are compared to. Therefore, if a substance has an evaporation rate of less than 1, it will evaporate more quickly than butylacetate.
Rate Compensation Detectors
Rate-compensated heat or thermal detectors are devices that are designed to activate at a predetermined temperature in a space regardless of the rate at which the temperature in the space increases.
Rate of Rise Heat Detectors
React to sudden change or rise in ambient temperature from a normal baseline condition. The sudden temperature increase that matches the predetermined alarm criteria will cause an alarm.
What should the HSE Professional, consider when evaluating ignition sources such as forklifts, electronics, etc.
Several ignition sources can cause a dust explosion or deflagration. Primary sources of ignition include electrical sparking from tramp metals or broken equipment pieces; heat from bearings, belts and misaligned buckets improperly prepared maintenance and hot work operations forklifts and vehicles; and natural causes, such as lighting. Firest, identify the electrical classification of the area or room volume. NFPA 70, the National Electric Code (NEC), Chapter 5, Special Occupancies, addresses hazardous locations. It defines the classification of several special occupancies, such as flammable liquids, gases and vapors, combustible dusts, and other materials. It is meant to integrate with other NFPA standards that more fully address the particular occupancy. For electrical issues, the NEC defines what electrical devices are permitted in a given area. This section defines terms such as dust ignition-proof, dist tight, purged and pressurized.
Fume
Solid particles generated by condensation from the gaseous state, generally after volatilization from a melted substance (e.g. welding), and often accompanied by a chemical reaction such as oxidation. Gases and vapors are not fumes.
Flammable inside storage locations
Storage within inside storage rooms must comply with NFPA 30, which requires that every inside storage room be equipped with one clear aisle at least three feet wide, The standard also requires a raised 4-inch still to prevent runoff of any spilled material, self closing fire doors, and ventilation system that provides exchange of air 6 times per hour. Containers over 30 gal capacity will not be stacked one upon the other.
Boiling Point
Temp at which the vapor pressure of the liquid is equal to the environmental pressure surrounding the liquid. It is the temperature point at which liquid is converted to vapor.
Heat of combustion
The amount of heat in calories evolved by the combustion of 1g weight of a substance.
Dust Explosion Pentagon
The first three elements are those needed for a fire, i.e., the familiar fire triangle, 1.Combustible dust (fuel) 2. Ignition source (heat) 3. Oxygen in air (oxidizer) 4. Dispersion of dust particles in sufficient quantity and concentration. 5. Confinement of the dust cloud. If one of the five elements is missing, a dust explosion cannot occur.
Lower Flammability Limit
The lower end of the concentration range of a flammable solvent at a given temperature and pressure for which air/vapor mixtures can ignite. The lower flammability limit (LFL) is usually expressed in volume percent.
Upper flammability limit
The maximum concentration of a combustible substance capable of propagating a flame through a homogeneous combustible mixture. The upper flammability limit (UFL) is usually expressed in volume percent.
Exit Access
The route one must take to go from anywhere in the building to reach the exit. Examples: aisle ways, corridors, or rooms.
Exit Discharge
The portion of the egress system between the termination of an exit and a public way.
Grounding and Bonding by definition.
The process of bonding and grounding can be defined as providing an electrically conductive pathway between a dispensing container, a receiving container and an earth ground. This pathway helps eliminate the buildup of static electricity by allowing it to safely dissipate into the ground. Both the National Fire Protection Association (NFPA) and the Occupational Safety and Health Administration (OSHA) have bonding and grounding requirements. NFPA addresses the need for bonding and grounding in NFPA 30, the Flammable and Combustible Code. In the 2015 edition of NFPA 30, Chapter 18 Part 5.2.2 states that a means must be provided to minimize the generation of static electricity when transferring flammable liquids. NFPA 77, Recommended Practice on Static Electricity, covers the fundamental principles of effectively managing static electricity. OSHA's requirements for bonding and grounding in general industry are referenced in the Flammable Liquids Standard, 29 Code of Federal Regulation (CFR) 1910.106(e)(6)(ii). The regulation states, "Category 1 or 2 flammable liquids, or Category 3 flammable liquids with a flashpoint below 100°F (37.8°C), shall not be dispensed into containers unless the nozzle and container are electrically interconnected. Where the metallic floorplate on which the container stands while filling is electrically connected to the stem or where the fill stem is bonded to the container during filling operations by means of a bond wire, the provisions of this section shall be deemed to have been complied with." This means all containers of Category 1, 2 or 3 liquids (liquids with a flashpoint lower than 100°F) need to be bonded and grounded during dispensing. This includes non-metallic containers, even though the construction material may not be recognized as conductive (for example, polyethylene). If the containers are not properly bonded and grounded, the resulting static spark could be capable of raising the vapor temperature above the flashpoint, causing an explosion.
Proprietary Fire Alarm System
The proprietary system is widely used in commercial occupancies. The term "proprietary" indicates that the alarm is received by someone with proprietary interest in the property as well as by the fire department. This system, coupled with central alarm, can allow on-site activation of protections such as closing of doors, adjusting vents for smoke control, control of elevators, start up of ventilators, etc.
Specific Gravity
The specific gravity describes the density of a liquid compared to the density of water. Those liquids with a specific gravity of one or less are lighter than water and those with a specific gravitates of greater than or equal to one are heavier than water. The specific gravity is particularly important when addressing chemical spills.
Common reason why fire sprinkler systems fail inspections
The system has a closed post-indicator valve (PIV) and failed to reopen it.
Water solubility
Water solubility, which is also known as aqueous solubility, is the maximum amount of a substance that can dissolve in water at equilibrium at a given temperature and pressure. Water solubility values are usually expressed as moles of solute per liter. The term water solubility is primarily used in many environmental studies to help determine the fate of chemicals in the environment.
Wet Pipe System
Wet pipe systems are the more frequently installed systems. In this type of system, water is present at all times inside he piping distribution system. Once the sprinkler head is opened, the water in the distribution system will flow out of the distribution system.
The NFPA identifies a combustible liquid as one having a flash point:
at or above 100 F
Bonding
system connects various pieces of conductive equipment together to keep them at the same potential.
