Hydrants, Monitors and Hose Reels

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. 

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. 

Before the final placement is made on a monitor location during a design preparation, based solely on the distance a water stream can reach, verification should be made that an obstruction does not exist which can block the water stream. Typical practice is to draw coverage circles from the monitor on a plot plan. Where 

Monitors can be set and locked in place, while the operator evacuates or attends to other duties. A residual pressure of 690 kPa (100 psi) is required for most monitors to effectively provide suppression and cooling water (ref. NFPA 14, Section 5.7) and should be verified when several are flowing simultaneously. 

Oncoming or cross wind effects may reduce the performance of water monitors. When winds of 8 km/hr (5 mph) are present they may reduce the range of water spray by as much as 50%. Consideration should be given to the placement of monitors when the normal wind speed is such to cause performance effects. 

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The surface slope at the placement of all hydrants, monitors and hose reels should be slightly away from the device itself so water will drain away and prevent corrosion effects. Where automobile traffic may be prevalent, protective post or railing should be provided to prevent impacts to the devices. The protective barriers should not affect the hose connection, use of hoses or obscure the spray from monitors. The posts should be provided with highly visible markings or reflective paint. 

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. 

A hydraulically designed system is preferred over standardized approach for optimization of the firewater flows, water storage requirements and piping materials. In any case, the main header should not be less than 203 mm (8 in.) in diameter. Piping routed to hydrants, monitors, hose reels and other protective systems should be at least 152 mm (6 in.) in diameter. 

Fire water lines within process unit areas feeding more than two monitors, hose reels, or hydrants, should be connected to two separate sections of the fire main and separated by a valve in the main. Piping to hose reels and monitors should contain an isolation valve. 

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. 

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