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Unless an industrial electrician has experience in the oil and gas sector, underground coal mines, food processing, or petrochemical industry, they do not understand how to make off an Ex-d Barrier Gland correctly properly.
As a result, significant electrical installation non-compliances were noted in significant oil and gas projects, such as Chevron’s Wheatstone and Gorgon in WA, as well as GLNG and APLNG in Gladstone. A significant amount of time, effort, and resources have been spent on clean-up work, exceeding project budgets and generating delays and frustration.
A barrier gland can be utilised to stop the migration of these flammables when Ex rated enclosures are exposed to significant fluctuations in ambient and/or service temperature conditions. It can lead to a pumping action and transfer the gases or fluids from a hazardous region to a non-hazardous area. However, their most frequent application is in flameproof installations, where they are utilised to stop the flame from an equipment-related explosion from travelling down a wire. To stop the flame from spreading, we frequently employ an Ex-d Barrier Gland to block the cable entry in an Ex-d enclosure.
Sealing of Cables
A barrier gland must be used to seal cables on an Ex-d enclosure in the following situations:
- the attached cable is not round or solidly extruded.
- The linked cable is solidly extruded, round, and shorter than 3 metres.
Other Ex-rated equipment, such as instrumentation that only has a single process seal and comes into touch with a fluid or gas under pressure, is also required to seal cables.
In this situation, a second seal in the wiring can be created using the barrier gland to stop flammables from moving to the non-hazardous section.
Sealing Device
An Ex-d enclosure and another enclosure are usually sealed with a conduit seal or Y-seal to protect against migration and flame propagation.
The Ex-d Barrier or Compound Glands usually consists of a metal tube that fits inside the entry element. In order to prevent flame propagation through the cable’s interstices, this is filled with the solidified compound.
Though the goal is to ensure that flameproof integrity and safety of Ex-d equipment are maintained by providing a seal around cable cores, barrier glands may not completely prevent gas migration. It may be necessary to apply additional attenuation measures in addition to a barrier gland to reduce the vapour transmission rate.
