Protection methods for non-electrical equipment in explosive atmospheres.

Non-electrical equipment intended for use in potentially explosive atmospheres must also be designed according to specific protection methods in order to prevent any ignition sources from causing fires or explosions. The main approaches recognised by international technical standards are as follows:

Construction safety (Ex h): involves design measures aimed at preventing the formation and propagation of ignition sources. This includes, for example, limiting hot surfaces, using appropriate materials and designing to prevent sparks; typical for valves, pumps, gearboxes and the like.

Ignition source control (Ex h): acts directly on potential ignition sources, using control or elimination systems, often through risk analysis or continuous monitoring devices.

Immersion in liquid (Ex h): components at risk are immersed in a protective fluid (oils or other suitable liquids), preventing the formation of an explosive atmosphere in contact with hot spots.

Explosion-proof enclosure (Ex d): parts susceptible to generating sparks are enclosed in a robust casing capable of containing any internal explosion without allowing it to spread to the outside.

Dust-tight (Ex t): prevents combustible dust from entering critical parts of the equipment, reducing the risk of ignition thanks to proper sealing of surfaces.

Pressurisation (Ex p): the equipment is maintained at an internal pressure higher than that of the surrounding environment, preventing dangerous gases or dust from coming into contact with hot or sparking points.