…Intrinsically Safe, certified to Zone 0, suitable for hazardous areas. There are a number of impressive statements we have used to introduce our Cygnus 1 Ex Ultrasonic Thickness Gauge, but what do they all really mean? In this campaign we aim to demystify these statements and explain the rules and regulations surrounding the use of equipment in hazardous areas.
Cygnus 1 Ex is Intrinsically Safe
This means the gauge uses intrinsic safety technology to limit the energy present in its system. It becomes 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 Zones 0, 1 or 2.
‘Intrinsically Safe’ is one of the protection concepts used to define Ex equipment designed for safe operation in hazardous locations. Another concept often used is ‘Explosion-proof’ (or ‘flame-proof’). This 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 Zones 1 or 2.
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 protect concepts, only two of which are suitable for Zone 0.
Cygnus 1 Ex does not require a Hot Work Permit
This means it can be used in any environment at any time. Hot Work Permits are used to mitigate the risks of hot work tools or processes capable of creating a spark or generating enough heat to ignite a gas. Cygnus 1 Ex’s intrinsic safety design means this is not possible, and therefore a Hot Work Permit is not needed.
This saves a lot of hassle as obtaining a Hot Work Permit is normally costly and time-consuming. A formal application with a risk assessment is required, along with methods to remove or reduce the risks.
Typically for a permit in a hazardous area:
- The permit must be authorised by a senior person
- A competent person is required to check gas levels
- Oxygen levels and flammable substances must be frequently monitored
- Persons should be competent in emergency response and first aid
- Specialist rescue equipment on standby is required
- Pipes and tanks may need to be purged with nitrogen
- Plant operations should be shutdown.
