Fire and gas detection

Activation of the blowdown, however, will not depressurize a system fully for a considerable length of time. One of the reasons for considering retaining the possibility of human intervention was that the automated blowdown system was not considered completely reliable at the time because of the limitations of the fire and gas detection hardware. This would have the effect of resulting in increasing the likelihood of spurious blowdown production losses. 

Various simple and sophisticated fire and gas detection systems are available to provide early detection and warnings of a hydrocarbon release which supplement process instrumentation and alarms. The overall objective of fire and gas detection systems are to warn of possible impending events that may be threatening to life, property of continued business operations, that are external to the process operation. 

Process controls and instrumentation only provide feedback for conditions within the process system. They do not report or control conditions outside the assumed process integrity limits. Fire and gas detection systems supplement process information systems with instrumentation that is located external to the process to warn of conditions that could be considered harmful if found outside the normal process environment. Fire and gas detection systems may be used to confirm the readings of major process releases or to report conditions that process instrumentation may not adequately report or be unable to report (i.e., minor process releases). 

Alarms should be displayed on a conventional dedicated window annuciator panel or if control room based on a dedicated CRT display for fire and gas detection systems. Each detector location should be highlighted with indications for trouble, alarm low, and alarm high. Where annuciator panel window alarms the alarm indication lights should be provided with specific labels indicating the exact alarm locations. 

The detection and alarm circuits of fire and gas detection systems should be continuously supervised to determine if the system is operable. Normal mechanisms provide for a limited current flow through the circuits for normal operation. During alarm conditions current flow is increased while during failure modes the current level is nonexistence. By measuring levels at a control point the health of the circuit or monitoring devices can be continuously determined. End-of-line-resistors (EOLR) are commonly provided in each circuit to provide supervisory signal levels to the control location. 

BHR Group Ltd., Fire Safety Engineering. "Modem Methods of Designing Fire and Gas Detection Systems", BHRA, Cranfield, U.K., 1989. 

Alarms should be initialed by the local or main control facility for the location. Manual activation means should be provided for all emergency, fire, and toxic vapor alarm signals. Activation of fire suppression systems by automatic means should also indicate a facility alarm. Most fire and gas detection systems are also set to automatically activate alarms after confirmation and set points have been reached. Manual activation of field or plant alarm stations should activate the process or facility alarms. 

Detection and Control The limitation of the severity of incidents by early detection of the incident and the operation of safety systems, including fire protection systems through fire and gas detection and process isolation. 

Bonn, J.C. 1991. Goal-Setting Design for Fire and Gas Detection Systems. SPE 23305. First International Conference on Health, Safety and the Environment. Society of Petroleum Engineers, Inc. 

Cables that must function as long as possible in safety control systems e.g., fire and gas detection systems, ventilation damper control and power systems, UPS, public address and communication systems, intrinsically safe systems. 

Pnblic address system Plant alarm systems System shntdown system Telemetry systems Emergency radio supplies Fire and gas detection system Navigation aids... 

The best response to an emergency is to know about it as soon as possible, which means that instruments for detecting fire and/or gas releases should be provided in all sections of the facility. The signals will go to a central fire and gas detection system, which will call for the appropriate response to the alarm (either from the operators or the automatic instramentation). Responses can include ... 

The present paper considers the safety of different systems or components. A safety instrumented system (SIS) is a system which consists of sensors, logic solvers and actuating items. The sensors may for instance be gas detectors, the logic solver could be a computer and the actuating items may be shut down valves. A fire and gas detection system with an alarm or a sprinkler system is an example of a SIS. A SIS is constructed to take the process into a safe state if a dangerous event occurs. 

Some functions on process plants are invoked after-the-event , i.e. after a loss of containment, even after a fire has started or an explosion has occurred. Fire and gas detection and emergency shutdown are the principal examples of such functions. Assessment of the required SELs of such functions presents specific problems ... 

The TR should provide protection for at least 1 hour against fires, explosions, and smoke ingress. Therefore, it must be provided with an air supply, fire and gas detection devices, and smoke dampers. The TR should be located as far away as possible from likely fires and explosions. It may be possible to place the accommodation module on mounts that will help ensure the structure s integrity if hit by a blast wave. 

Fire and Gas Detection and Mitigation Systems L. Beckman TUV FSExp SafePlex Systems Inc. 

L. Beckman, Fire and gas detection and mitigation systems, TUV FSExp SafePlex Systems, Inc., in Presented at 54th International Instrumentation Symposium, ISA, 2008. 

Fire and explosion protection systems drawings and arrangements (fire and gas detection/alarm, protection—passive/aggressive, etc.)... 

Shutdown systems for processes Interlocks for dangerous machinery Fire and gas detection Instrumentation Programmable controllers Railway signaling Boiler and burner controls Industrial machinery Avionic systems... 

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