Emergency safety system

However, critical emergency safety systems may also... 

For systems with pipelines filled of sodium, which are in standby mode and are emergency safety systems or part of these systems, very important, that direct method for control availability of these systems is existed. This demand is connected with enough higher temperature of sodium melting. 

In order to prevent these conditions from occurring, redundant alarm and emergency systems are installed. If the temperature falls below 65°C or rises above certain safety limits, or in the case of a lack of air for instruments, the emergency safety system will cut off the reactant feed to the reactor, thus removing the cause of the... 

J. A. Wilkinson and B. W. Balls, "Microprocessor-Based Safety Systems Designed for Fine and Gas and Emergency Shutdown AppHcations,"... 

CCPS G-11. 1998. Guidelines for Pressure Relief and Emergency Handling Systems. American Institute of Chemical Engineers, Center for Chemical Process Safety, New York. 

Emergency Shutdown System The safety control system that overrides the action of the basic control system and shuts down the process when predetermined conditions are violated. 

Safety systems are typically divided into emergency trip/shutdown functions, controlled (slow) shutdown, alarm activation, or startup annunciation of auxiliary equipment such as oil pumps. 

Figure 4-34. Function diagram of the safety systems for emergency and slow shutdowns, and of the speed regulating devices.

Active—Using controls, safety interlocks, and emergency shutdown systems to detect and correct process deviations e.g., a pump that is shut off by a high level switch in the downstream tank when the tank is 90% full. These systems are commonly referred to as engineering controls. 

A pressure sensor giving a continuous indication which is displayed on the control panel and can be observed by the operator. The sensor has a high pressure safety interlock set at a predetermined pressure that activates an emergency shutdown system. 

Accident defenses may be regarded as a series of barriers (engineered safety systems, safety procedures, emergency training, etc.). As barriers fail, incipient failures become real. Inappropriate management policies create inadequate PIFs, which give rise to opportunities foi ermr when initiated by local triggers or unusual conditions. 

The AP600 passive safety system includes subsystems for safety injection, residual heat removal, containment cooling, and control room habitability under emergency conditions. Several of these aspects are in existing nuclear plants such as accumulators, isolation condensers as natural-circulation closed loop heat removal systems (in early BWRs), automatic depressurization systems (ADS - in BWRs) and spargers (in BWRs). 

The safety improvements use redundancy and diversity to prevent and mitigate lents. The safety injection system (SIS) and emergency feedwater system (EFWS) are dedicated four train systems. Containment spray and safety injection pumps take water from the in-containment water storage tank (IRWST), thus, eliminating the need to switch from an external source and provide a. semi-closed system with continuous recirculation. Emergency core coolant flows direc nto the... 

Generally, electrical control systems are designed Fail-Safe. If power is temporarily lost, unnecessary shutdown of the process may occur. Thus, most safety systems such as fire and gas detectors, Nav-Aids, communications, and emergency lighting require standby D.C. power. 

Accordingly, to emphasize the safety problems affecting all industrial process plants and laboratories, the American Institute of Chemical Engineers established the industry-supported Desigm Institute for Emergency Relief Systems. The purposes of the Institute are [51] ... 

Safety Systems. A safety system is provided with built in safety shutdowns and emergency stop buttons. Crash buttons are located in the laser room, the laser table enclosure and the dome. The laser system is tied into the Observatory emergency stop system. Included both in the laser room and on the laser table are surveillance cameras, heat exchangers, alcohol sensors and fire detectors. In addition to personnel safety features, extensive interlocks have been installed in the laser to prevent the operator from inadvertently damaging it. 

G. W. Boicourt, Emergency Relief System (ERS) Design An Integrated Approach Using DIERS Methodology, Process Safety Progress (April 1995), pp. 93-106. 

The concept of PFD is also used when designing emergency shutdown systems called safety instrumented functions (SIFs). A SIF achieves low PFD figures by... 

There are three safety integrity levels (SILs) that are generally accepted in the chemical process industry for emergency shutdown systems ... 

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