Sparks generated mechanically by processes involving friction, impacts, grinding or drilling represent sources of ignition as per EN 1127-1. Whether and to what extent the formation of sparks caused by the use of tools is permissible depends on the corresponding protective zone and the ignitability of the explosive substances. In Zones 0 and 20, no tools that could generate any sparks may be used.
Stainless steel tools such as screwdrivers or wrenches, which typically generate only a single spark when used, but which do not generate any bursts of sparks or hot surfaces, may be used in Zones 1 and 2. However, this does not apply for Zone 1 if there is an explosion hazard in the zone caused by substances in explosion group IIC (acetylene, carbon disulphide and hydrogen) or due to hydrogen sulphide, carbon monoxide or ethylene oxide. In this case, special measures to prevent the generation of ignitable sparks must be taken.
In Zones 21 and 22, the use of stainless steel tools that do not generate any bursts of sparks or hot surfaces is generally permitted. If this cannot be guaranteed, the workplace must be cleared of all dust deposits and shielded to separate it from the surrounding zone area. Additionally, it must be kept humid while the tools are being used, in order to prevent dust from being thrown up and glowing embers from being produced.
Low-sparking tools are therefore not permitted in hazardous areas as a rule. In individual cases, however, they can be practical. However, a risk assessment of the operation is always required.