The effect of a fire

The design of the stmcture (and its operation) will greatly influence the effects of a fire. For instance ... 

All telephone points can be considered a method of notification. Telephones can be easily placed in a facility but may be susceptible to ambient noise impacts and the effects of a fire or explosion. Additionally information from verbal sources can be easily misunderstood of spoken during an emergency. Simultaneous use of the phone system during emergency situations may also cause it to be overloaded and connections difficult to achieve. 

Fire barriers should be considered when the spacing recommended can not be met and hazards are not easily mitigated with active fire protection systems. Barriers, such as walls, partitions, and floors, provide physical separation of spaces and materials. The effectiveness of a fire barrier is dependant on its fire resistance, materials of construction, and the number of penetrations. Inattention to the integrity of penetrations is one of the primary reasons fire barriers fail to provide proper protection. Factors to consider in the design and placement of fire barriers include ... 

In the aftermath of the Bhopal disaster, OSHA s Process Safety Management (PSM) has come into play and dictates the procedures to minimize the possibility of fire, explosion, or chemical release. If a project contains a regulated hazardous chemical, a process hazards analysis must be conducted to ensure that the likelihood of a fire, explosion, or release of hazardous chemicals is minimized and that equipment and facilities are included to minimize the effects of a fire, explosion, or release, if one does occur. 

In any given fire retardant one or more above methods may be used. The effect of a fire-retardant strongly depends on the basic chemical structure of the polymeric material. Owing to complexity of the processes and the experimental limitations, it is difficult to predict which mechanism is most important or operative for any system. A list of commercially available fire-retardants is given in Appendix-1. These materials are classified as organic, inorganic and reactive types. A fact to be kept in mind is that for blends or alloys, the fire retardancy behavior is usually between those of the base resins for example, consider Arylon and Kydene (acrylic/PVC) [Landrock, 1983]. 

We have examined a number of materials in terms of toxic gas evolution during pyrolysis or combustion. For example, the products from fibreglass insulations included isocyanic acid and hydrogen cyanide, while the support backing and adhesive of a made-up panel produced acetic acid, acetaldehyde and vinyl chloride as well. The effect of a fire in a confined space such as a surface ship or submarine can be imagined. The products come from thermal decomposition of polymer coatings etc, and while the experimental conditions may not duplicate those of a fire, the information is very useful. 

Material incapable of burning. The X rmfire proof is considered false. No material is immune to the effects of a fire possessing sufficient intensity and duration. It is com-... 

Control the risk at source > Mitigate the effects of a fire > Ensure the safe handling, storage, transportation of dangerous substances > Maintain the necessary measures. 

A wide variety of off-the-shelf products are available to deal with spillages or to contain spills in emergency containment areas. Any materials or equipment used must be located at accessible positions which are clearly marked with durable notices explaining their use. In addition, any equipment must be fit for the purpose and effectively well maintained ready for use. The pollution incident response plan will identify the pollution prevention equipment and materials and their location. The type of materials and equipment that may be provided to mitigate the effects of a fire on the environment include ... 

In the steady state, p = pa and Wd = Sudden opening of a steam valve will raise W but drop p. Until the effect of a firing rate change is felt, pressure ill fall to a lower level and steam flow will return to its previous value. But the existence of a pressure error directly proportional to the desired increment in steam flow will maintain the higher level of firing. The pressure is only restored when steam flow is raised to its demanded value. Figure 9.9 outlines the system together with the feedback loop. 

HRR is a very important variable and represents how fast a fire can reach an uncontrollable stage. This single parameter provides information regarding the size of the fire and how fast it grows. The effectiveness of a fire retardant additive in a polymer can also be assessed with respect to this parameter. Figure 25 shows that increasing the concentration of LDH in... 

A boding liquid-expanding vapor explosion occurs when a pressure vessel containing a liquid is heated to a temperature liigh enough to cause tlie metal to lose strength and rupture. The source of tlie heat is nonnally another fire near tlie vessel. The effects of a BLEVE depend on whether tlie liquid in tlie vessel is flammable. If the liquid is flammable, it may eitlier cause a fire, which radiates heat, or fonii a vapor cloud, which could result in a second explosion. 

Effect models describe the impact of the physical effects of a fire, e.xplosion, or toxic gas release on exposed people, the environment or property, based on the results of tlie source, dispersion, and fire and explosion models. 

In the glass-bottle industry the bottles can be cooled in a dilute SOj/SO, atmosphere to increase chemical resistance. A similar effect has been noted with vitreous enamel. It has been postulated that a thin layer of —OH groups or — OH—HjO (hydronium) ions is adsorbed on the surface of a fired enamel. These ions are transformed into — OSO, or —OSO3 in the presence of oxides of sulphur which are more resistant to further acid attack. It is known that the acid resistance of a recently fired enamel improves on ageing, probably due to the enamel reaction with SOj/SO, in the atmosphere and it is quite common for the grading to improve from Class A to Class AA (BS 1344). 

These coatings bubble and foam to form a thermal insulation when subjected to a fire. They have been used for many decades. Such coatings cannot be differentiated from conventional coatings prior to the occurrence of a fire situation. Thereupon, however, they decompose to form a thick, nonflammable, multicellular, insulative barrier over the surface on which they are applied. This insulative foam is a very effective insulation that maintains the temperature of a flammable or heat distortable substrate below its ignition or distortion point. It also restricts the flow of air (oxygen) to fuel the substrate. 

Atmospheric releases of flammable gases such as hydrogen may lead to major fires with extensive effects on the surroundings. In activities where hazards are associated with cloud fires, there is the need of societal risk assessment that involves the estimation of hazardous zones due to the resulting thermal radiation. However, till now only limited work has been done on modeling the effects of flash fires, in a way that available techniques may be judged insufficient [47],... 

Design practices stem from standard fire test procedures in which the temperature history of the test furnace is regarded as an index of the destructive potential of a fire. Thus, the practice of describing the expected effects and damage mechanism is based on temperature histories. This standard design practice is convenient but lacks accuracy in terms of structural performance. The severity of a fire should address the expected intensity of the heat flux that will impact the structure and the duration of heat penetration. A simple analysis of the expect nature of an unwanted fire can be based on the heats of combustion and pyrolysis of the principal contents in the facility. The heat of combustion will identify the destructive nature of the fire, while the heat of pyrolysis will identify the severity of the fire within the compartment itself and will also identify the destructive potential of the fire in adjacent spaces. 

To overcome the possibility of a vessel rupture from a hydrocarbon fire exposure several methods are available. Depressuring, insulation, water cooling or draining are usually employed in some fashion to prevent of the possibility of a vessel rupture from it s own operating pressures. A generalized method to qualitatively determine the effect of a hydrocarbon fire on the strength of vessels constructed of steel is available. With this method one can estimate the time for a vessel to rupture and therefore the need to provide protective measures. 

There are two common types of heat detectors - fixed temperature and rate of rise. Both rely on the heat of a fire incident to activate a signal device. Fixed temperature detectors signal when the detection element is heated to a predetermined temperature point. Rate of rise detectors signal when the temperature rises at a rate exceeding a pre-determined amount. Rate of rise devices can be set to operate rapidly, are effective across a wide range of ambient temperatures, usually recycle rapidly and can tolerate a slow increase in ambient temperatures without providing an alarm. Combination fixed temperature detectors and rate of rise will respond directly to a rapid rise in ambient temperatures caused by fire, will tolerate a slow increase in ambient temperatures without effecting an alarm, and recycle automatically on a drop in ambient temperature. 

A gas detection system monitors the most likely sources of releases and activates alarms or protective devices to prevent the ignition of a gas release and possibly mitigate the effects of a flash fire or explosion. 

The use of two separate electrical or mechanical zones of detectors, both of which must be actuated before the confirmation of a fire or gas detection. For example, the detectors in one zone could all be placed on the north side of a protected area, and positioned to view the protected area looking south, while the detectors in the second zone would be located on the south side and positioned to view the northern area. Requiring both zones to be actuated reduces the probability of a false alarm activated by a false alarm source such as welding operations, from either the north or the south outside the protected area. However this method is not effective if the zone facing away from the source, sees the radiation. Another method of cross zoning is to have one set of detectors cover the area to be protected and another set located to face away from the protected area to intercept external sources of nuisance UV. If welding or lighting should occur outside the protected area, activation of the alarm for the protected area would be inhibited by second... 

The objectives of fire suppression systems are to provide cooling, control the fire (i.e., prevent it from spreading) and provide extinguishment of the fire incident. A variety of fire suppression methods are available to protect a facility. Both portable and fixed systems can be used. The effectiveness of all fire extinguishing measures can be determined by the rate of flow of the extinguishing agent and the method or arrangements of delivery. 

Fusible Link - A release device activated by the heat effects of a fire. It usually consists of two pieces of metal joined by a low melting point solder. Fusible links are manufactured at various temperature ratings and are subject to varying normal maximum tension. When installed and the fixed temperature is reached, the solder melts and the two metal parts separate, initiating desired actions. 

The scope of this book is to provide a practical knowledge and guidance in the understanding of prevention and mitigation principals and methodologies from the effects of hydrocarbon fires and explosions. The Chemical Process Industry (CPI), presents several different concerns that this book does not intend to address. However the basic protection features of the Hydrocarbon Process Industry (HPI) are also applicable to the chemical process industry and other related process industries. 

Concretes made with Portland cement have a specific weight of 140 to 150 Ib/ft (2,242 to 2,400 kg/m ). Concrete absorbs the heat of a fire when chemically bound water is released from a crystalline structure and is reduced to lime. Dense concretes can be formed in place, or pneumatically sprayed to the required thickness using steel reinforcement. The corrosive effect of chlorides on the steel surface in moist saline environments (coastal or other chloride environments) dictates the use of protective primers and topcoat sealers. Major advantages of dense concrete are ... 

The elimination of a fire hazard may be the ideal solution, but it is often not possible. In general, the optimum level of fire protection is achieved by selecting from the other appropriate prevention and mitigation options. The higher the performance availability (or lower the probability of failure-on-demand) of each selected fire protection feature, the more effective the overall fire protection system. The generally preferred approach to improve effectiveness is to select a combination oipassive and active fire protection features. 

Although field models generate detailed estimates of the effects of compartment fire environments, they are time consuming because of the enormous number of computations that are made. Some effects, such as radiation, can only be treated on a simplified level. In many instances, such a detailed solution is not needed, and simpler approaches are appropriate. Field models are useful to resolve problems that yield excessively conservative results when calculated using other model types. 

Park and Giammona l reported the effects of a 2- to 3-h exposure to CS on a 4-mo-old child. The infant was in a house into which police fired several canisters of CS. No estimate of concentration was available. On admission to the hospital, the child was suffering from severe respiratory distress and first-degree burns on the cheeks. Despite a week of treatment, pneumonia developed. The child was released after 28 d of hospital care. 

These tests are more varied in their nature and complexity than are the input tests. This difference may be attributed to the fact that the output of a firing train component may be req uired to produce a wide variety of effects to detonate a lead or booster by shock to do mechanical work in driving a firing pin to initiate a detonator by shock, flame, or hot particles to ignite a delay by flame hot particles or to lock a train in the armed position by moving detents or expanding confining walls... 

Fire Resistive Material and design of building construction meant to withstand the maximum effect of a fire for a specific period of time. 

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