Explosion Proof Equipment


Thread Starter


I have a problem regarding the area classification according to NFPA standard and selection of instruments & electrical equipment for 2x60 tons/hour Auxiliary indoor Boilers. Please help me.
How about providing a bit more information regarding your problem.

Bill Mostia
William(Bill) L. Mostia, Jr. P.E.
Excellence in Dependable Automation
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Thank you for your attention to my question regarding the area clasification. I want to know which type of instruments & electric equipment shall be selected around the indoor auxiliary boilers.for example the equipment on the fuel line, around the burner area,... shall be explosion proof or not.My problem is detemination the type of equipment around the auxiliary boiler (2x60 tons/hour) according to NFPA standard. my client asks EX type equipment in the all area around the auxiliary boiler, while it isn't economic. please help me.

The answer is simple, but you probably will not be satisfied.

In Europe and USA as well, before designing electrical and Instrumentation detail design, The specialists shall define the zones. Usually it is a work that have to be done by the technologist who knows the process and the electrician. Both have to be accredited engineers.

After that I&C engineer is designing the Instrumentation and control part.

In case the boiler uses gas, the area around the valves etc is zone 1. It is a complete system how to define the zones. In Europe it is a part of EU

Never think how to save money for the client, because later you will be responsible for any damage that happens, even if the instrument you
installed did not cause a problem.

good luck. In case you need the standard which gives some advises for determine the zones, please write.

Thank you very much for your reply. Please determine the relevant standards which specify the clasification of this area exactly and clearly. If it is possible please send me a copy of mentioned standards.
Your kind cooperation is appreciated.
Yours truly
Nader Adibi

I cannot send you a copy of the standards, because it is against the law.

The standard for defining zones is IEC 79-10.
Standard for equipment-general requirements is EN 50014
All type of protection are in other standards (IEC or EN)
Visit the IEC or European organisations on web.


INENCO d.o.o.
Instrumentation engineering & consulting

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