How to select the right Ex-certified equipment?

When operating in a potentially explosive atmosphere, there are several crucial aspects to look out for. This includes understanding the potential hazards and choosing the correct tools for the identified hazardous area.

The Cygnus 1 Ex Ultrasonic Thickness Gauge is certified intrinsically-safe to Zone 0 – the most hazardous area, negating the need for Hot Work Permits. But what does it really mean? Let’s decipher these statements and explain the rules and regulations surrounding the use of equipment in hazardous areas.

Intrinsically-Safe vs Explosion-Proof

‘Intrinsically Safe’ is one of the protection concepts used to define Ex equipment designed for safe operation in hazardous locations. The Cygnus 1 Ex gauge uses intrinsic safety protection to limit the energy present in its system, meaning it is insufficient to ignite a hazardous atmosphere under any conditions. This includes low power levels and low stored energy. Intrinsically-safe equipment can be Ex-certified to Zone 0, 1 or 2.

Another concept often used is ‘Explosion-proof’ (or ‘flame-proof’). This type of equipment is sealed and rugged, such that it will not ignite a hazardous atmosphere. However, it is possible for a spark or explosion to be generated within the equipment itself. For this reason, ‘Explosion-proof’ equipment can only be Ex certified to Zone 1 or 2.

This means that only Intrinsically-Safe equipment can be used in Zone 0.

What you need to know about Equipment Protection Levels (EPLs)

All certified Ex equipment (portable or fixed) designed for operation in hazardous areas, will have an Ex Certificate of Conformity (C-of-C) which states its Equipment Protection Level (EPL), represented by a ‘G’ code. The table below shows the correlation between Zones, EPLs and different protection concepts. Cygnus uses the Intrinsically Safe protection type for its Ex products.

For more information on How to select the right Ex-certified equipment? talk to Cygnus Instruments Ltd