Fire hydrant with monitor

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. 

Every industrial plant is protected by a fire water system that provides water to each piece of equipment through hydrants, monitors, or deluge spray systems. Each process unit has its own underground piping loop system, which is adequately valved to protect the system from a failure in any part of the line or isolation because of maintenance. Although each piece. of equipment must be protected by one hydrant or monitor, client specifications often override this rule and require two sources of fire water for each piece of equipment. Basic fire protection equipment consists of fire hydrants, hydrants with monitors, grade-level and elevated monitors, hose reels, and deluge and spray systems. 

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. 

Provide an adequate number of fire hydrants for fixed monitors for drenching the stacks with water. Stack drums 2 m from any hydrants and leave clear access. 

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. 

Hydrants equipped with monitors should have hose gate valves provided on the hose connections. Hydrants accessible to fire trucks should be equipped with compatible pumper connections as well as same type as public fire department. The pumper connection should face the roadway. 

The local fire department arrivedjust after the explosion at 11 22 A.M. With the limited water supply on two of the fire trucks and the utilization of another fire truck to pump water directly from a nearby cooling water tower basin, the firemen were able to slow the fire spread. By 11 30 A.M., the Maintenance Department was able to transfer the set of batteries from the impaired diesel fire pump to the other diesel fire pump. On completion of this task, this diesel fire pump was started. The automatic deluge sprinkler protection was severely damaged by the fire/explosions and had to be valved into the off position. Three fixed monitors were turned onto lull flow and directed at the fire. Also, the firemen and fire brigade used two hose streams olF nearby fire hydrants for fire fighting purposes. At 11 58 A.M., the fire was under control. Final fire extinguishment was accomplished by 12 10 p.m. 

This system consists of a loop around a process unit or equipment, with branches as required for hydrants or monitors, to protect the unit in case of fire. 

When water is combined with other additives, it can control and extinguish most petroleum fires. A water suppression system consists of a supply source, distribution system, and the end using equipment such as fixed spray systems, monitors, hose reels and hydrants. The objective of water suppression systems is to provide exposure cooling, fire control, suppression of fire incidents and may assist in the dispersion of flammable or toxic vapors. 

Monitors are considered the primary manual water delivery device for hydrocarbon facilities, while hydrants and hose reels are considered secondary. Monitors are an initial manual fire suppression device that can be activated by operators with limited fire fighting training or experience. Use of hydrants and hoses usually require additional manpower and previous training. The use of a fire hose however, provides for more flexibility in the application of water sprays and where it may be needed when it is impractical to install a monitor. Monitors are usually placed at the process areas, while hydrants are placed at the perimeter roads, accessible to mobile apparatus. Most monitor pipe connections may also be fitted with fire hose connections. 

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