Ignition sources protection measures

If the answer to one or more of the above questions is no, then in addition to taking all reasonable steps to reduce the possibility of formation/spread of dust clouds and exclude potential ignition sources, other measures, such as exclusion of oxidant or explosion protection, should also be considered. 

Type of ignition source Ignition process Protective measures... 

Ignition Sources Normally it is best practice not to base explosion safety solely on the presumed absence of an ignition source. Explosion control should be based on prevention or protection techniques, or both. Even so, all reasonable measures should be taken to eliminate ignition sources. 

Ignition sources at devices, protective systems, and components must be avoided, depending on zones (Table 23-7) i.e., the zone determines the minimum extent of preventive measures against danger of ignition. 

Easily sensitive (3 mj < MIE < 10 mj) Expert decision or Avoidance of effective ignition sources and additional protective measures. 

Table 4.18 provides an overview of protective measures against ignition sources. 

Electrical equipment With electrical equipment, e.g. PCE equipment or motors, even low voltages may produce electric sparks (e.g. when opening or shutting electrical circuits). Leakage currents and hot surfaces may be sources of ignition, too. Provide for efficient protective measure by following pertinent technical standards... 

The assessment may suggest the conclusion that more than one protective measure must be installed in order to sufficiently reduce the probability of flame propagation. A relevant safety concept may consist, for example, of an inline detonation arrester, which is located as closely as possible to the installation to be protected, and (as an additional measure) an inline deflagration arrester close to the potential source of ignition. 

The number of situations in which ignition can be reliably prevented by the avoidance of ignition sources are limited. Situations where prevention is viable include batch reaction processes and isolated liquid storage. However, it is good practice to ensure that all reasonable measures are implemented to eliminate the development of sources of ignition. This is particularly important when using an explosion protection technique in order to minimise down time and unnecessary refurbishment of the system which can be costly. 

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