Fixed area fire

Electricity, Valves, Heaters Fixed Protection Fire Areas, Water Demands,... 

Monitors are fixed water hydrants with an attached discharge gun. They are also installed in process areas and storage tank areas. Fire hydrants and monitors are spaced 150 -250 ft apart around process units, located so that all areas of the plant can be covered by 2 streams. The monitor is usually located 50 ft from the equipment being protected.14 Fire monitors discharge water at a rate of 500-2000 gpm. 

The active methods of fire extinguishing use the forced delivery of extinguishing media and materials to the area of fire origin. In some cases, for the small cells nitrogen delivery is envisaged. In the cells with non-radioactive sodium transportable fire-extinguishers are used. Also, fixed powder fire extinguishing systems are provided. 

Radiation Protection (fixed area monitors) Fire Detection Water Purification. In operation In operation In operation... 

Provide adequate fixed fire protection for tanks and vessels containing flammable, unstable or reactive materials. This can include fire loops with hydrants and monitors in the storage area, foam systems for individual tanks, and deluge spray systems to keep the exposed surfaces of tanks cool in case of fire in an adjacent tank. 

Leakage from Use adequate shaft sealing (mechanical or multimill ignited by pie gas purged lip or chevron seals). Harden spark or hot shafts in seal area surface., pressure tight flexible connections and clamps on mill inlets and outlets Provide adequate fixed fire protection where appropriate CCPS G-23 CCPS G-29 NFPA 13 NFPA 15 NFPA 16... 

The area should be at the separation distance from the property boundary, any building or fixed source of ignition quoted in Table 9.1 7. This may only be reduced if suitable fire-resisting separation is provided. 

Some new features of furnaces available today include variable speed blowers, which deliver warm air more slowly and more quietly when less heat is needed, and variable heat output from the burner, which when combined with the variable speed blower allows for more continuous heating than the typical fixed firing rate. Distribution system features can be sophisticated with zoned heating which employs a number of thermostats, a sophisticated central controller, and a series of valves or dampers that direct airflow or water to different parts of the home only when needed in those areas. 

Fixed fire area, representative of a fully involved fuel package, e.g. chair, crib, pool... 

Water is the most useful and vital fire suppression medium, whether used for fixed systems or manual fire fighting efforts for petroleum facilities. It is relatively inexpensive and normally plentiful. It has enormous heat absorption properties. Approximately 3.8 liters (1.0 gal.) of water absorbs about 1,512 k cal (6,000 Btu), when vaporized to steam. Steam created by water evaporation expands to about 17,000 times its volume in open atmospheres, thereby limiting combustion processes by displacing oxygen in the area. 

All fixed fire suppression system control valves should be located out of the fire hazard area but still within reach of manual activation. For high hazard areas (such as offshore facilities), dual feeds to fire suppression systems should be considered from opposite areas. For onshore facilities, firewater isolation valve handles should not be contained within a valve pit or a below grade enclosure within the vicinity of hydrocarbon process facilities, since heavy process vapors travel from the process and may settle inside. 

Hydrants should be considered as a backup water supply source to monitors and fixed fire suppression systems. Hydrants should be located on the ring main at intervals to suitably direct water on the fire hazard with a fire hose. Hydrants monitors and hose reels should be placed a minimum of 15 meters (50 ft.) from the hazard they protect for onshore facilities. Hydrants in process areas should be located so that any portion of a process unit can be reached from at least two opposite directions with the use of 76 meters (250 ft), hose lines if the approach is made from the upwind side of the fire. Offshore hydrants are located at the main accessways at the edge of the platform for each module. Normal access into a location should not be impeded by the placement of monitors or hydrants. This is especially important for heavy crane access during maintenance and turnaround activities. 

Wet or dry chemical fixed suppression systems are typically provided over the kitchen cooking appliances and in exhaust plenums and ducts. Activation means is afforded by fusible links located in the exhaust ducts/plenums usually rated at 232°C (450°F). Manual activation means should not be provided near the cooking area, but in the exit routes from the facility. The facility fire alarm should sound upon activation of the fixed suppression system and power or gas to the cooking appliances should be automatically shut off. The ventilation system should also be shut down by the activation of the fire alarm system. Protective caps should be provided on the suppression nozzles to prevent plugging from grease or cooking particulates. 

For example, if LPG vessels are considered to be within a fire-scenario envelope, they require fireproofing unless protected by a fixed water spray system. API Standard 2510, Design and Construction of Liquefied Petroleum Gas Installations (API, 2001) recommends fireproofing pipe supports within 50 ft (15 m) of the LPG vessel, or within the spill containment area. 

Structures with equipment on two or more levels, not protected by water spray or deluge systems, should be counted as double the grade area beneath the multilevel structure plus the areas as noted above. Where fixed water spray systems are provided, their water requirements should be added to the fire water demand. Water demands for other areas within a plant may include ... 

Fixed temperature detectors are preferred because they require less calibration and maintenance. Heat detectors are normally more reliable than other types of detectors because of the simple nature of their operation and ease of maintenance. These factors tend to lead to fewer false alarms. The main disadvantage of heat detectors is that they are unlikely to detect fires in the incipient stage, where little heat is generated, but much smoke is likely.. Since heat detectors are inherently slower in operation than other types of detectors, they should be considered for installation in areas where high speed detection is not required. 

One effect that a flaming fire has on the surrounding area is to rapidly increase air temperature in the space above the fire. Fixed temperature heat detectors will not initiate an alarm until the air temperature near the device exceeds the design operating point. The rate-of-rise detector, however, will function when the rate of temperature increase exceeds a predetermined value, typically around 12 to 15°F (7 to 8°C) per minute. Rate-of-rise detectors are designed to compensate for the normal changes in ambient temperature [less than 12°F (6.7°C) per minute] which are expected under nonfire conditions. 

Deluge protection can be applied over the entire hazard area with open sprinkler heads located at various floor levels or fixed water spray systems can be applied specifically on the equipment to be protected. Specific water spray application is preferred because it provides better equipment cooling and reduces the water wasted due to wind and fire draft. 

Portable equipment comes in a variety of sizes, shapes, and usage. Selection of portable equipment should be based on an assessment of the site s fixed fire suppression equipment, availability of personnel, and access to mutual aid. Portable equipment assists in being able reach the problem area with fire suppression equipment in a timely and efficient manner. 

Where the need for fire detection is identified, the required performance of the fire detection system is already specified as part of the grading process. Fixed fire detection is typically installed to protect equipment that is high value, long lead time, or likely to be significant fire escalation hazards. The performance specification defines fire size and response time thresholds for alarm and action(s). Fire hazards are defined by radiant heat output (RHO). RHO gives a reasonable indication of the potential damage and the probability that the fire will escalate or cause loss. The RHO should not be used to determine fire thermal loading onto equipment and structures. Table 8-3 compares RHO and flame area for some typical hydrocarbon fires. 

The decision to provide or not to provide fixed fire protection systems within process structures, areas, or on specific vessels or equipment is usually based on a qualitative assessment of the following factors such as ... 

In general, fixed water spray fire protection has the two-fold purpose of cooling the affected equipment and flushing any burning liquids from the immediate fire area. This can reduce local damage, limit fire spread, and allow time for other response actions. It should not be expected that these systems will extinguish a fire without the use of other fire protection systems, such as foam, dry chemical, or manual firefighting. 

Fixed fire protection systems for process structures and areas can be activated automatically or manually. Automatic activation provides quicker and more reliable response than is typically possible with manual activation. Vari-... 

The required protection may be obtained by active, passive, or a combination of both protection systems. For example, steel support located in a fire exposed area within process unit battery limits may be protected by either a fixed water spray system or the application of fire resistant insulating material to the steelwork or possibly both. Note Passive protection is generally the preferable method for protecting structural steel. 

Manual firefighting capability is a general requirement for each process structure or area, regardless of any fixed fire protection that may be provided. See Chapter 7, Section 7.4.16. 

Fire protection can be provided to process vessels with either manual firefighting or fixed water spray systems. Manual firefighting with monitors and hoses can be used to protect process vessels against exposure to fire. See Chapter 7, Section 7.4.3. If water spray is used, it should be applied to all outer surfaces at a rate of 0.25 gpm/ft (10 Ipm/m ) of projected (surface) area. See Chapter 7, Section 7.4.8. Multiple nozzles are typically required. Where water spray from upper nozzles can flow down the sides of the vessel, the nozzles or... 

The design of fixed water spray fire protection over pumps should provide one or more spray nozzles positioned so that all parts of all objects within the protection pattern are thoroughly wetted and enveloped by the spray. The recommended water spray densities based on the horizontal coverage area is a minimum of 0.5 gpm/ft (20 Ipm/m ) (API 2030). 

Fixed (cone) roof tanks Vent fire Overfill ground fire Unobstructed full liquid surface area Obstructed full liquid surface fire if frangible roof remains partially in tank For volatile liquids, the rich vapor space typically prevents ignition within the tank. Environmental regulations typically prevent storage of Class 1 flammable liquids in larger fixed roof tanks. 

A fixed roof tank with an internal floating roof should have fixed fire protection only for the floating roof seal area when the tank design satisfies the following criteria ... 

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