Control emergency shutoff

Multiple Operators Ifthere is more than one operator for a machine, each should have a separate set of controls. Each set of controls must link to all other sets. All operators must have their hands free of the point-of-operation before the machine can start its motion. In addition, when there are multiple operators, each should have an emergency shutoff within reach from their work position. 

As a starting point, a plot plan of the site should be prepared showing the locations of existing structures, property lines, entrances, exits, fire hydrants, sprinkler systems, emergency equipment, plant controls and shutoffs, and areas where specific hazardous materials are handled or stored. 

All emergency shutoff control stations should be mounted in some type of break-glass enclosure with the locations coordinated with the local fire chief They could be located at the emergency control station, if approved by the "authority having jurisdiction."... 

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. 

Common controls. All workers handling or using cylinders must have basic training in the use of gas cylinders, emergency shutoffs, proper equipment design, leak-testing procedures, and the use of appropriate respiratory protection in the event of a release of a compressed gas. Other controls include the following ... 

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. 

Special tools, materials, or chemicals Additional hazards not present during normal operations Location and use of emergency equipment Location of alternate control stations or panels Location of manual stops and shutoffs for systems normally under automatic control... 

Quick Reference Cards—Quick reference cards may include wallet or pocket size cards that include information such as alarms, phone numbers, assembly points, main shutoffs, or emergency actions. These cards should be easy to read and should address specific conditions and actions. As with any procedure, the cards must be controlled to ensure that the information is accurate and up to date. 

Condition—less than obvious location of the emergency power shutoff control. Recommendation— relocate and isolate the control to center of panel. 

Utilities locations should avoid creating hazards. For example, gas lines should not be near rail lines or public or employee areas. Shutoff locations should avoid locations where the utilities might create hazards. Shutoff controls should be accessible to emergency crews even during incidents. Power and other utility lines should have protection from vehicle damage. Utilities, such as water, should be sufficient for emergency needs. Supply mains must effectively service use points in the facdity. 

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. 

Ventilation systems must comply with the Mechanical Code except that the automatic shutoffs need not be installed on air-moving equipment. However, smoke detectors shall be installed in the circulating airstream of the cleanroom and shall initiate a signal at the emergency control station. (UBC 307.11.2.4). 

The action functional component represent all the possible predetermined response actions which should occur upon reaching apredetermined alarm/action setpoint. Response actions could include activation of audible and/or visual alarms, annunciation of specific alarm conditions and locations, hardcopy of past and present gas concentrations or environmental conditions, notification of local and remote emergency response personnel, activation of emergency safety control systemsl l through relays such as gas supply source and equipment shutoffs, HVAC system shutdown with 100% exhaust, or one-pass cleanroom air flow operations. The predetermined response actions should follow established emergency response procedures and policies of your organization and all applicable environmental, health, and safety regulations to protect both personnel and the environment and minimize the extent and effect of any hazardous situations. 

Standalone fire or gas detection and alarm panels may be provided in the main control facility for the installation. Recent trends may incorporate the transmittal of fire and gas alarms through the facility process control system (i.e., DCS). When alarm panels are located within a protected building, they should be located for easy access for emergency response personnel and proximity to manual electrical power shutoff facilities. 

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