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Safety shutdown systems are commonly used in industrial settings to protect equipment, processes, and personnel from potential hazards. These systems are designed to continuously monitor conditions such as lack of differential pressure, flammable or noxious gases, and high temperatures. When any of pre-set hazardous parameters are encountered, such systems will go into alarm mode and shut off certain operations such as hot work, flow of gasses or liquids, and supplied power.

How Safety Shutdown Systems Work

Safety shutdown systems typically include a combination of detectors, sensors, controllers, and actuators that work together to monitor equipment and process conditions and take appropriate action when necessary. For example, if a monitored gas exceeds the preset Lower Explosive Limit (LEL), the system will automatically shut down the equipment or process to prevent such gas from coming into contact with an ignition source to avoid a potentially catastrophic explosion.

Safety shutdown systems are used in a wide range of industries, including oil and gas, chemical, petrochemical, and power generation, as well as in plants that manufacture ignitable products such as fertilizer, ethanol, and paper. These systems play a critical role in ensuring the safety of personnel and equipment, as well as safeguarding against environmental damage and financial losses due to equipment failure or process upsets.

Safe-Stop™ Safety Shutdown System

Petrohab’s Atex and IECEx (IEC60079-13) certified Safe-Stop Safety Shutdown System (SSS) is an automatic shutdown system that is specifically designed to enhance the safety of hot work operations conducted near potentially flammable or hazardous gases. This patented system is the most advanced of its kind and is the only one in the world that is certified to the latest version of the pressurized rooms standard regulated by the International Electrotechnical Commission (IEC).

The Safe-Stop SSS is constantly on alert for flammable and dangerous gasses such as Methane and Hydrogen Sulfide both inside and outside Petrohab’s patented Petro-Habitat™ Hot Work Safety Enclosure (HWSE) often referred to in the Oil & Gas Industry as a “habitat” or “pressurized welding enclosure”. First and foremost, the Safe-Stop SSS continuously monitors the desired overpressure inside the habitat to ensure that the required internal positive pressure is maintained and, in the event such pressure falls under a preset amount, the system will shut down all hot work operations and cut off all power leading into the habitat until the desired pressure is re-achieved via the continuous operation of the intake blower. In the event harmful gasses are detected either inside or outside the habitat, one of two scenarios will play out: (a) if such gasses are detected inside the HWSE, the system will shut down the hot work operations while allowing the intake blower to continue introducing fresh air in order to purge any such gasses; or (b) if such gasses are detected outside the enclosure (either at the air intake or the perimeter of the habitat), the entire system (including the intake blower) will shut down.

The Main Control Unit (MCU) sits outside the habitat and is the “brains” of the system. It includes explosion proof junction boxes, sealed cable glands, an electrical blower, electronic damper that’s placed downstream from the blower, hot work and electrical plugs, audio and visual alarm, and an Emergency Shut Down (ESD) button. The other component of the Safe-Stop SSS is a Habitat Gas Assembly (HGA) that goes inside the habitat and includes a low lying Hydrogen Sulphide detector, an LEL detector that can be raised to a height of up to 3 meters to detect light gas such as methane, an ESD, audio and visual alarm, airlock control system, and optional Oxygen and Carbon Dioxide Detectors.


Automatic shutdown systems, such as Petrohab’s Safe-Stop SSS play a critical role in ensuring that hot work, that is conducted in the vicinity of potentially flammable or hazardous gasses, does not come into contact with any such dangers. It is important to note that safety shutdown systems should be regularly tested and maintained to ensure that they are functioning properly. Regular testing and maintenance is necessary for such systems to operate in their intended manner in order to mitigate the risk of hazards.

Overall, safety shutdown systems are an essential component of many industrial processes, and they play a critical role in ensuring the safety of personnel and equipment, as well as preventing damage to the environment and financial losses due to equipment failure or process upsets.

To know more about PetroHab’s revolutionary safety shutdown system, Safe-Stop™, visit our website.