Respiratory protection in potentially explosive atmospheres


Following several accidents at the workplace due to explosions in apparently risk-free atmospheres, current legislation lays down specific obligations for employers to protect the safety and health of workers potentially at risk from explosive atmospheres not only in cases where explosives are handled, but in all cases where potentially explosive dusts, mists and vapors might develop.

Flammable or potentially explosive atmospheres: what are the risks

The aforementioned legislation specifies that employers are to perform in-company risk assessments in order to prevent explosions and the formation of dusts, fumes and mists hazardous to the health of workers both in the event of explosions and for the respiratory system. In both cases workers in contaminated areas are to be provided with respiratory protective devices which will ensure that they will breathe clean air only. Risk assessments are to be carried out, not only in the immediate area at risk of explosion but are to be extended to adjoining areas as well as leakage from the contaminated area could spread throughout the workplace.

In order to reduce occupational risks in explosive atmospheres employers must provide those working in places where explosive atmospheres may occur with sufficient and appropriate training with regard to explosion protection, i.e.  suitable protective clothing not containing synthetic fibers as these attract static electricity and then discharge it into the surrounding environment. Moreover, among the measures to be adopted are optical/acoustic warning signals and evacuation devices which go off before explosion conditions are reached, and the use of particular types of explosives which reduce the effect caused by exploding gases. Lastly, appropriate personal protective equipment for explosive atmospheres is also to be provided.

RPD for potentially explosive atmospheres: which ones to choose

The employer has to provide workers with personal protective equipment and has to ensure that it is in perfect working order. Among the PPE to be used in explosive atmospheres, the respirator is particularly important. Respiratory protective devices (RPD) such as masks or half-masks are highly suitable in explosive environments because, notwithstanding their lightweight, they will protect the wearer against inhaling dust and gas.

Some respirator models provide clean air on demand simply by pressing a button. The best solution is when filtered air is supplied at a controlled pressure and at an average airflow. Respiratory protective devices equipped with filters, however, must not be used in atmospheres where the oxygen percentage in the air is low (i.e. under 17%). It is therefore necessary to choose devices that, in addition to being lightweight, are able to run for the whole work shift without the need of heavy batteries for powering or special maintenance programs and which are easy to clean so that they can be easily managed by the user. Furthermore, respiratory protective devices for use in explosive atmospheres must be equipped with warning devices which indicate when filters are clogged, the battery is running low or when there are problems due to altitude. Respiratory protective devices for use in explosive atmospheres can also be used in mines and in environments where there is risk of methane leakage.

KASCO sr. supplies  an intrinsically safe, ultra-light, compact respirator  suitable for use in flammable or potentially explosive atmospheres and for protection against dusts and gases. It may be equipped with either a half mask or a full face mask.