An industrial safety system is a countermeasure crucial in any hazardous

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...

s such as

oil and gas A fossil fuel is a hydrocarbon-containing material formed naturally in the Earth's crust from the remains of dead plants and animals that is extracted and combustion, burned as a fuel. The main fossil fuels are coal, petroleum, oil, and natura ...

plants and

nuclear plant A nuclear power plant (NPP) is a thermal power station in which the heat source is a nuclear reactor. As is typical of thermal power stations, heat is used to generate steam that drives a steam turbine connected to a generator that produces ele ...

s. They are used to protect

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...

industrial plant Physical plant, mechanical plant or industrial plant (and where context is given, often just plant) refers to the necessary infrastructure used in operation and maintenance of a given facility. The operation of these facilities, or the department ...

, and the

environment Environment most often refers to: __NOTOC__ * Natural environment, all living and non-living things occurring naturally * Biophysical environment, the physical and biological factors along with their chemical interactions that affect an organism or ...

in case of the

process A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: Business and management *Business process, activities that produce a specific se ...

going beyond the allowed control margins. As the name suggests, these systems are not intended for controlling the process itself but rather protection. Process control is performed by means of process control systems (PCS) and is

interlock An interlock is a feature that makes the state of two mechanisms or functions mutually dependent. It may be used to prevent undesired states in a finite-state machine, and may consist of any electrical, electronic, or mechanical devices or system ...

ed by the

safety Safety is the state of being "safe", the condition of being protected from harm or other danger. Safety can also refer to the control of recognized hazards in order to achieve an acceptable level of risk. Meanings There are two slightly dif ...

systems so that immediate actions are taken should the process control systems fail. Process control and safety systems are usually merged under one system, called an integrated control and safety system (ICSS). Industrial safety systems typically use dedicated systems that are SIL 2 certified at minimum; whereas control systems can start with SIL 1. SIL applies to both hardware and software requirements such as cards, processors redundancy and voting functions.

Types

There are 2 main types of industrial safety systems in process industry: * Process safety system (PSS) or process shutdown system (PSS). * Safety shutdown system (SSS): This includes emergency shutdown (ESD) and emergency depressurization (EDP) systems. A third system also exists which acts as a barrier and contains the spray out of hot oil & gases from flanges, valves & pipe joints. These systems are popularly known as safety spray shields and flange guards. The use of spray guards is mandated by

OSHA OSHA or Osha may refer to: Work * Occupational Safety and Health Administration, a federal agency of the United States that regulates workplace safety and health * Occupational Safety and Health Act (United States) of 1970, a federal law in the Un ...

Emergency shutdown (ESD)

These systems may also be redefined in terms of ESD/EDP levels as: * ESD level 1: In charge of general plant area shutdown, can activate ESD level 2 if necessary. This level can only be activated from main

control room A control room or operations room is a central space where a large physical facility or physically dispersed service can be monitored and controlled. It is often part of a larger command center. Overview A control room's purpose is produc ...

in the process industrial plants. * ESD level 2: This level shuts down and isolates individual ESD zones and activates if necessary EDP. * ESD level 3: provides "liquid inventory containment".

Safety shutdown system (SSS)

The safety shutdown system (SSS) shall shut down the facilities to a safe state in case of an emergency situation, thus protecting personnel, the environment and the asset. The safety shutdown system shall manage all inputs and outputs relative to emergency shutdown (ESD) functions (environment and personnel protection). This system might also be fed by signals from the main fire and gas system.

Fire and gas system (FGS)

The main objectives of the fire and gas (FGS) system are to protect personnel, environment, and plant (including equipment and structures). The FGS shall achieve these objectives by: * Detecting at an early stage, the presence of flammable gas, * Detecting at an early stage, the liquid spill ( LPG and

LNG Liquefied natural gas (LNG) is natural gas (predominantly methane, CH4, with some mixture of ethane, C2H6) that has been cooled down to liquid form for ease and safety of non-pressurized storage or transport. It takes up about 1/600th the volu ...

), * Detecting incipient fire and the presence of fire, * Providing automatic and/or facilities for manual activation of the

fire protection Fire protection is the study and practice of mitigating the unwanted effects of potentially destructive fires. It involves the study of the behaviour, compartmentalisation, suppression and investigation of fire and its related emergencies, as we ...

system as required, * Initiating environmental changes to keep liquids below their flash point * Initiating signals, both audible and visible as required, to warn of the detected hazards, * Initiating automatic shutdown of equipment and ventilation if 2 out of 2 or 2 out of 3 detectors are triggered, * Initiating the exhausting system.

Emergency depressurization (EDP)

Due to closing emergency shutdown valves in a process, there may be some trapped flammable fluids, and these must be released in order to avoid any undesired consequences (such as

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...

increase in vessels and

piping Within industry, piping is a system of pipes used to convey fluids (liquids and gases) from one location to another. The engineering discipline of piping design studies the efficient transport of fluid. Industrial process piping (and accompa ...

). For this, emergency depressurization (EDP) systems are used in conjunction with the ESD systems to release (to a safe location and in a safe manner) such trapped fluids.

Pressure safety valves

Pressure safety valve A safety valve is a valve that acts as a fail-safe. An example of safety valve is a pressure relief valve (PRV), which automatically releases a substance from a boiler, pressure vessel, or other system, when the pressure or temperature exceed ...

s (PSVs) are usually used as a final safety solution when all previous systems fail to prevent any further pressure accumulation and protect vessels from rupture due to overpressure by their designed action.

Notes

{{DEFAULTSORT:Industrial Safety System Telemetry Industrial automation Secondary sector of the economy Safety