Fire monitor elevated

The last two applications, while convenient and initially appealing, require more maintenance and inspection than a simple, ground level monitor. Significant reactive forces can be generated and, therefore, the support structures must be properly engineered. Elevated monitors also require support and hydraulics to be protected by a water spray system if exposed to fires. An elevated monitor is shown in Eigure 7-12. 

Fire monitors should be provided and positioned so that at least two monitor streams can reach each process area, preferably from opposite sides. Often, fire monitors are mounted directly on hydrants. Care should be taken to select and position fire monitors to ensure that their streams can reach elevated equipment. The local fire main s residual pressure under flowing conditions should be determined to ensure it is adequate to deliver effective water streams capable of reaching all elevated equipment. While monitors need to be close enough such that their stream reaches elevated equipment, if they are too close it may not be possible to physically access the monitor to direct its stream due to radiant heat. In these cases, some form of personnel shielding or remote operation is required. 

Fire monitors and turret nozzles (grade and elevated)... 

Fire monitors are used to direa streams of water to burning pieces of equipment in a plant. Before monitors are selected and located, several faaors must be considered. Fire monitors are lever operated, have a full 360° range, and may be locked in any desired position. They may be located at grade, approximately 4 ft (1,200 mm) above the ground, elevated to heights of 100 ft (30 m) or more, or mounted on a hydrant. The spray pattern of fire monitors depends on water pressure and flow rate. If vendor data is not available when preliminary fire water layouts are made, the chart in Exhibit 13-30 can be used to determine the effective fire water monitor range. This chart is based on a water pressure of 150 psi and a flow rate at the nozzle of 500 gpm. 

Monitor nozzles should be located so that water streams can be manually applied to any outdoor fired heater from at least two different directions. A flow of at least 500 gpm (1,893 Ipm) per monitor nozzle should be provided. In some cases, elevated monitors may be required. 

A fire water main should be provided to the shore terminus area of the wharf. Hydrants and monitor nozzles should be located so that effective fire water streams can be remotely applied to any berth or loading/unloading manifold from two directions. Where the wharf is of such length that onshore monitors cannot adequately cover the berths, the fire water main should be run onto the wharf to permit the required monitor and fire hose coverage. Monitors located on marine wharves may be remotely operated from onshore and use of elevated monitors is common. The offshore segment of the main can be a dry system. In all cases, isolation valves and fire department connections should be provided at the wharf-to-shore connection (ISGOTT, 1996). 

Thomerson and Billings [87] describe field tests in which chlorine was released at up to 70kg min from three 1-ton containers. Typical wind velocities were about 9 m s . Relative humidity was very low, the test site being located in the Nevada desert. It is noteworthy that the temperature of the spilled liquid stabilized at about -50 C, well below the boiling point of —34°C. The wind subcooled the liquid, which was collected in a well-insulated pan, and approximately 50% of the chlorine vaporized during a test. The use of downwind water sprays in these tests reduced the concentration of chlorine in the air by an average of 31%. This was attributed to the induction of dilution air by transfer of momentum from the spray. As noted above, the spray also forced the vapor cloud lower, so that the concentration of chlorine at 1.5 m elevation was actually higher for a distance of 230 m fi om the point of release. In these tests, portable fire water monitors performed relatively poorly. 

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. 

Two teams used a firing range with regularly scheduled cleaning procedures and had a written protocol for maintenance and lead concentration monitoring. Blood lead levels for those two teams were not elevated 1.3 pg/dl and 3-9 pg/dl. 

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