Fire monitor selecting

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 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. 

Let s take the example of benzene, which at 12,000 ppm, is 100% LEL. The National Fire Protection Association (NFPA) states that equipment can operate, without LEL monitors or controls, if the LEL is less than 25% LEL. For benzene then, 25% LEL is equal to 3,000 ppm. This upper boundary becomes a dictating factor in the selection and design of the oxidation equipment. If the concentration is higher than 25% LEL, the NFPA requirements state that an LEL monitor is required. Using an LEL monitor, NFPA guidelines allow operation up to 50% LEL (a 2 1 safety factor). Thus, 100% LEL is explosive if the stream is at 25%, a factor safety of four exists. 

The excellent detection ability for flames makes UV sensing a good method for remote fire alarm-monitoring. UV radiation after the outbreak of a fire reaches a sensor much faster than heat or smoke. Also, the distance between sensor and fire is less critical. Requirements for the sensor are high sensitivity and excellent selectivity. Radiation intensities at the sensor position may be even lower and the ambient light conditions less restricted than for combustion controlling. When used outside, solar-blindness is a must. These stringent requirements make UV fire alarm monitors expensive, and they are used in industrial environments such as production floors or warehouses rather than in private homes. 

Rarified Research operates a ram-fed incinerator for destruction of select wastes at its large, centralized research facility, including liquid flammable solvents in small plastic containers. The incinerator is fired by natural gas and is brick-lined. Temperatures are closely monitored, and stack emissions are routinely sampled. 

Figure 12-1. Schematic diagram to illustrate double resonance techniques, (a) REMPI 2 photon ionization. The REMPI wavelength is scanned, while a specific ion mass is monitored to obtain a mass dependent SI <- SO excitation spectrum, (b) UV-UV double resonance. One UV laser is scanned and serves as a burn laser, while a second REMPI pulse is fired with a delay of about 100 ns and serves as a probe . The probe wavelength is fixed at the resonance of specific isomer. When the burn laser is tuned to a resonance of the same isomer it depletes the ground state which is recorded as a decrease (or ion dip) in the ion signal from the probe laser, (c) IR-UV double resonance spectroscopy, in which the burn laser is an IR laser. The ion-dip spectrum reflects the ground state IR transitions of the specific isomer that is probed by the REMPI laser, (d) Double resonance spectroscopy can also use laser induced fluorescence as the probe, however that arrangement lacks the mass selection afforded by the REMPI probe...

An emergency response team, under the control of the emergency response coordinator, should be assembled with a clearly defined chain of command. The members of this team should be selected and trained for specific mitigative and communication tasks. Specific duties might include spill cleanup, first aid, employee evacuation and headcount, incipient fire response, fire pump/sprinkler control valve/fire door monitoring, firefighting, fire/emergency responder communications, and rescue. 

Direct Potentiometry Detemdnatiou of Hydrogen Chlonde Gas. A system has been described for the continuous monitoring of the HCl levels in gases or aerosols using a chloride-ion-selective electrode [IS]. This arose from a study on the loss of volatile decomposition products from poly(vinyl chloride) (PVQ and other chlorocarbon polymers in simulated fires. The method works well because of the excellent solubility of HQ in water, and the fact that the chloride electrode senses only free Q ion. Thus, other volatile chloride compounds will not be sensed. 

Fire prevention methods are based on proper operation and cleaning of the dryer. An important safety device is an automatic control systan (ACS), as it can maintain the tanpera-ture within 1 C range whereas the manually controlled temperature may vary 10 C. The control system shonld include a detection system of parameter deviation, deposit deteaion, drying gas analysis, and continuous monitoring of the humidity and temperature at selected locations. 

Laser SNMS requires the operation with properly selected duty cycles that control the delay times between the primary ion pulse, a pulsed extraction voltage for separating the secondary ions from post-ionized neutrals, and the firing of the postionizing laser pulse. Such duty cycles have, in addition, to be synchronized with the stepwise motion of the pulsed primary ion beam across the sample surface in the microprobe mode of laser SNMS. The selection of appropriate duration and decay times of the ion and laser pulses, of the laser intensity, and beam shape is important to make the photoion yields independent on the sputtered particle velocities. The detection volume must be matched to the entrance ion optics of the TOP such that it becomes independent of the individual ionization process. Usually, laser intensities in the range from 10 to lO Wcm are applied. While the particle density in the detection volume is monitored at small laser intensities, the particle flux is measured at high photon densities. 

In addition to being a green house gas, CO2 is an important component for metabolism process of plant and many living creatures [34]. Thus, reliable and selective CO2 detectors are needed for a variety of applications including environmental and health monitoring [35, 36], fire detection [37], and controlling of fermentation [38]. There are several types of commercially available CO2 gas sensors and most of them are based on nondispersed infrared (NDIR) and electrochemical methods. 

Material flow risks Many examples of natural disasters such as labour strikes and fires have brought an end to supply of material. In supply chain material flow, demand fluctuations and supply dismptions are two types of primary uncertainties which involve issues as single sourcing risk, sourcing flexibility risk, supplier selection/outsourcing, supply product monitoring/quality and supply capacity. 

SIL Information How Can lEC 61508 Approval Aid Users in the Selection and Application of SIL Suitable Fire and Gas Detectors General Monitors http //www. gmsystemsgroup.com/sil/sil info 105.html. 

Exhibit 13-29 illustrates some additional features that the plant layout designer should consider when selecting and planning the installation of fire hydrants and monitors, including ... 

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