Explosion proof means that it can contain any spark or flame within a unit or housing that may ignite the flammable gas, vapors, dust or fluids that may lead to an explosion. It cannot prevent the explosion; it can just prevent it from escaping in the external environment. They come under NFPA that defines it and sets standards for it.
Several protection techniques are used to design products that provide protection against hazardous locations. These locations include explosion proof, dust tight, dust ignition proof, intrinsically safe, hermetically sealed, etc. These set the criteria for the components and equipment installed in hazardous locations.
There are several types of explosion proof equipment that are installed in hazardous areas and units to prevent an explosion from spreading outside. They are designed according to the standards layout by NFPA. These equipment include an explosion-proof enclosure, ex socket, ex-proof switches, ex-proof junction box, explosion proof control station, and many more. These equipment are designed to withstand harsh and erratic conditions.
There are different kinds of explosion proof environment such as oil immersed or flameproof enclosure. To ensure that the right component and equipment are used, different protection levels are formed. These include:
Zone 0: This is an area where a mixture of gases is constantly present.
Zone 1: This area may have a mixture of harmful gases during the normal operation of plants.
Zone 2: This area doesn’t usually contain harmful gases but they may be present for a brief period of time.
According to the above protection level, different appliances are built that protect protection according to them.
Ex d protection level: These are designed to prevent the explosion from escaping and cool down the spark or flame within the unit.
Ex e protection level: These are designed to prevent the protection of flames and sparks. These are built according to the ‘increased protection standard’.
This equipment is built to resist high temperature and is made of hard and strong material that provides durability and increases the lifespan. It is necessary that the components build have a higher range of temperature than the ignition temperature of the gases, vapors, and fluids found in the confined area. This is necessary to meet the requirements of the specific area where it will be installed.
The products built have to go through a series of tests and procedures to pass the standards set by NFPA. Only then it will be certified and approve by the organization and allow the manufactures to start designing the product. This is necessary for the safety of workers and the unit from any dangerous accidents.