Valves emergency shutoff

Propagation Diminish Emergency material transfer Reduce inventories of flammable materials Equipment spacing and layout Nonflammable construction materials Installation of check and emergency shutoff valves... 

Fire fighting equipment should be mounted at heights that are easily accessible by the average person. This includes portable fire extinguishers, hose connections to fire hydrants, access to emergency shutoff valves, emergency stop/ESD push buttons, etc. 

TANK FILL CAP AND DROP TUBE ADAPTER 0 TANK DROP TUBE 0 SUBMERGED TRANSFER PUMP 0 PIPELINE LEAK DETECTOR 0 EMERGENCY SHUTOFF VALVE 0 SWING JOINT AT A CHANGE OF DIRECTION 0 EXTRACTOR ASSEMBLY [Pg.94]

Safety assurance in the design of the HTTR steam reforming system against fire or explosion of flammable product gas mixtures is the task of the secondary helium piping system which is designed to limit gas ingress by means of a combination of containment vessel isolation valves and emergency shutoff valve in the process gas feed line [33]. 

The different methods of unloading may require different valve types and related equipment. In all cases, the liquid unloading line should be equipped with a pressure gauge and shutoff valve. As mentioned earlier, the unloading lines should be equipped with properly sized excess flow valves or emergency shutoff valves to protect against loss of product in the event of a hose failure. 

Many vendors now sell gas cabinets equipped with self-closing and latching doors and windows, sprinkler heads and various types of purge assemblies (see Fig. 5). Cabinets should be provided with a minimum flow of 100 feet per minute through the louver on the cabinet bottom. When the window is opened, the face velocity through the window should be maintained at 100 fpm. Purge assembhes may contain many different types of safety devices. An emergency shutoff valve should be located as close to the cylinder as is practicable. An air operated remotely activated cylinder valve is more preferable. System shutoff may be by manual activation of a remote switch in the laboratory or fabrication area or caused by other system defaults interlocked to gas flow. System defaults may include ... 

Emergency shutoff valve. This valve is usually automatic and will shut off the cylinder source when tripped. 

There are a number of automatic monitors available that combine a number of the functions mentioned above into a single unit. These are sometimes connected to the panel s emergency shutoff valve or plant alarm systems, and will usually allow the operator to shut off the cabinet/panel by depressing an emergency shutoff button. For more extensive system control, the automatic gas cabinet controller, explained in the next section, should be used. 

The functions of emergency stop of an engine, of access management, or of ESV (emergency shutoff valve) are intended to ensure the safety of the system in the presence of danger and, therefore, are crucial to prevent damage to goods and people. Risk analysis is used to indicate the safety level that can be achieved. 

A credible spill for Probable Maximum Loss Potential. The minimum spill source is the largest process vessel. The maximum spill size is the combined contents of the largest process vessel, or train of process vessels connected together if not readily isolated. Between these extremes, a credible spill may be estimated after taking into account the presence of remotely operated shutoff valves adequate for an emergency, and automatic dump or flare systems. 

Pumps, compressors, turbines, drivers, and auxiliary machinery should be designed to provide reliable, rugged performance. Pump selection and performance depend on the capacity required and tlie nature of Uie fluids involved. Remotely controlled power switches and shutoff valves are necessary to control fluid flow during an emergency. The inlets for air compressors should be strategically located to prevent the intake of hazardous materials. 

It should be possible to easily isolate fluids in equipment and piping when potentially dangerous situations occur. This can be done using emergency block valves (EBVs). An EBV is a manually or remotely actuated protective device that should be used to provide manual or remote shutoff of uncontrolled gas or liquid flow releases. EBVs can be used to isolate a vessel or other equipment, or an entire unit operation. Manual valves are often used on piping at block limits where it is unlikely that there would be a hazard to personnel if an accident occurs. Remotely controlled EBVs are recommended on tanks and on piping in areas where it may be hazardous for personnel in the case of an accident, or where a quick response may be necessary. 

If you think about it, who best knows where the shutoff valves on a unit are, what chemicals are in what lines and vessels, and where the unit s emergency equipment is located than the operators of the affected unit This is why most, if not all, process technicians are designated First Responder, Operations Level. 

A continuous gas detection system must be provided to detect the presence of hazardous (toxic or highly toxic) gases at or below the permissible exposure limit (PEL) orthe ceiling limit (see UFC 8003.3.1.6). The detection system must initiate a local audible and visual alarm as well as transmit a signal to a constantly attended plant Emergency Control Station (ECS). Activation of the alarm/monitoring system must automatically close the shutoff valve on highly toxic or toxic gas supply lines. 

An Isolation Valve (BV200) is required by NFPA 86 (sect. 4-2.4.1.1 and sect. 5-2.2). The purpose of the isolation valve is to provide a manual shutoff for maintenance and emergency conditions. Therefore, the valve must be located in a position where a hazardous condition will not impede access to the valve by plant personnel. A quarter-turn ball or butterfly valve with usual indication of valve position is required by NFPA 86 (sect. 4-2.4.1.2). The valve should include a locking feature so that the supply of fuel gas can be locked-out/tagged-out during maintenance operations. 

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