Checked the Canadian electric code book.
There is mention of Intrinsic safety requirement for Class I, Div. 1.
But there is not mention about it, on Class I, Div 2.

Does that mean that Class I, Div. 2 transmitters in field do not require barriers.

The company specs. gives higher priority to Intrinsically safe, as compared to the explosion proof.
Presently, all Hazardous area instruments (4-20mA) have been designed to be through barrier.

 

> Checked the Canadian electric code book. There is mention of Intrinsic safety
> requirement for Class I, Div. 1. But there is not mention about it, on
> Class I, Div 2.

Dear Mr. Bhashkar Mittal,

You’re right. I looked at my present 2009 Canadian Electric Code book and there is no reference to Class I, Div. 2 let alone anything about barriers. I’m not sure why this is but I’m looking into it. However, IS barriers are not necessarily required for Division 2 installations. On the other hand, the use of IS barriers provides many advantages including a higher level of plant/worker safety, standardization, improved performance with hot work and other activities and improved ROI.

Benefits of using intrinsic safety Barriers in a Class I Div. 2 area
* If intrinsic safety wiring practices are used in part of the plant by having intrinsic safety barriers reduces errors in the event personnel have to work in both areas.

* The user does not need to mix and match hardware.

* Only one method of wiring techniques.

* No confusion about what precautions to take.

* Reduction of maintenance costs due to standardization.

* Cost of ownership is very low: The explosion proof method requires large heavy enclosures; with interface wiring sealed in heavy conduit and armored cables. Not only are these enclosures expensive but also there are other issues that drive up the costs of this method of protection. There are rigid procedures the (NEC in the USA) CEC in Canada requires to be adhered to when conducting modifications and maintenance on the enclosed equipment. Worst of all equipment must be locked out and shut down. Economics are driving plants to stay operational 24-7. Just calculating the cost of stopping production 14 days out of a year can be daunting.

* If a part of the plant may revise their production in the future there may be an advantage of flexibility to change the processes. If they increase the pressure or temperature of a process that might warrant the changeover to Division 1 in the future.
If you would like to discuss this further please call me at (330) 486-0113 or e-mail me at [email protected]-fuchs.com