Class I div I or div II, need some help

Being a control panel guy, I suggest that you check out Hoffman's (the enclosure people) website at:

http://www.hoffmanonline.com/Technical_Info/

Especially look under the tab of "Hazardous Locations". You can do a variety of things to meet the safety requirements, but you really need to know exactly what you are facing in the way of the presence of explosive gases. You can't take safety lightly!

Hoffman, for one, has a few "purge" packages they offer. I'm sure other vendors do also. Check out their technical resources so you get the one that's right for your application

DISCLAIMER: I only mention Hoffman because I use them a lot. I don't work for them.

Division 2

This would be classified as a division 2 because the egnitable substance will only be present under abnormal conditions.

As far as the prevention factor go, purging the box only keeps that area in the box safe, what about other connections in the zone area.

Safety barriers are mostly used, they limit the capacitance and inductance in the loop and clamps when it exceeds the barriers allowed values in Div 1 loops and you must make absolutely sure about the classification.

The instruments that you use must be classified to your zone div 2.

Here is a helpfull link

http://www.hubbell-canada.com/whitePapers/wiring/codesSWP.asp

On this site is a table showing you what certification for which zones and divisions.

Hope it helps

Rheinhardt

Stooperbike, the first thing to be done is have them determine the classification of the area. I cannot do it, you cannot do it, RheinhardtP can only guess at it. The customers insurance Co, safety person, the local fire marshall and others will do it.

Get that done and then you can procede. Until they, only guesses will be had. You may be surprized that the area gets no classification, thus no need for any purge & I./S. barriers.

Another link

Here is another helpfull link

http://www.iaei.org/foc/cmp14.htm

theDAve2 is 100% right we can only assume using the code as a guideline and what you tell us, you should get the cetification authority for explosion prevention.

From the link

In Class I, Division 1 locations, it is assumed that ignitible concentrations will exist under normal operating conditions. An acceptable level of safety for the electrical system has been determined to include at least two failures before the system can ignite the atmosphere. In Division 2, there has to be some abnormal condition (failure of containment of the flammable material, failure of ventilation, etc.) before an ignitible atmosphere can exist. Therefore ignition could only occur in Division 2 when the containment of the material and the nonincendive circuit failed simultaneously (two faults).

Click to expand...

Hope this helps with your confusion regarding Div 1 and Div 2.

Regards

Rheinhardt

Yes the definitely helps, I am going to go back to the GC and find out what I am supposed to supply. I am concerned about liability, I do not want to be panel guy that causes a fire or explosion. The customer asked for a purge, in there eyes a needle valve with bulkhead fitting into cabinet was fine, no vent, no regulator, I am planning to supply this with a type Z air purge kit. To add another layer I am a contractor for the GC so my involvement with the customer is limited, my GC called out Class I div II but I am not sure were he got that info from. On top of that we are copying an existing system that has no air purge in the panel, but the panel is in a different room. Maybe I’ll tell them the panel shop is closed and to go away,



Thanks for the feed back, I could not sleep last night thinking about this!!!!

In my humble opinion, based on 20 years of working around hazardous areas, your panel will be in a Class 1, Division II area (not normally hazardous, but can be if something fails or leaks). By all means get a definition of the area if possible. My experiences with this question is that usually you get a long run-around from all parties, no one wanting to make the decision, hoping to pass the buck, or delay making a decision until the need goes away. No company or person wants to put his nead in the noose, in case something goes boom!

An air purge is a good solution. You probably know that your conduits leaving the Division II cabinet and ending in the Division I area, are supposed to be sealed with approved conduit seals poured with sealing compound.

The best way to handle electrical sparking devices in a Class 1 area is to re-locate as many devices as possible into a non-hazardous area.

You will need the exact classification, not just Class I, Div II, but something like Class I, Div II, Groups B & D. I believe Hydrogen is group C.

Any and all devices used must be rated not only for Class I, Div II, but also for group C.


Ken

Stooperbike,
You really need written documentation from the GC AND Architect specifying the EXACT Class, Division, and Group. Don’t build or design anything with out that information delivered to you on a signed letterhead from the specifier. Actually this information should be plasterd all over the job specs, contract and other documentation.

I would agree that you don't want to become the AWJ, or "authority with jurisdiction". That's a big hat to wear. Also, I would consider installing H2 detectors- hydrogen is nasty stuff with a low LEL.

Good luck!

K