Classifcation Help!

[jeremyyo]

I work for a pharmaceutical manufacturer and we are looking at making a product with a high amount of isopropyl alcohol (IPA). The basic layout is two rooms, one room for compounding the material and an adjacent room for filling the material, with a transfer pipe between.

In the compounding room there would be approximately 60 gallons of IPA. Given the low flash point (53 F) and the 60 gallons, I would classify it as a Class I, Division II location as most of the product will be in a covered tank and distributed through connected pipes. I am being asked what is the maximum amount of IPA we could have in that room without requiring explosion proof equipment? Does anyone know, is there an established threshold or volume for IPA to declassify it as a hazardous location? Or is there a calculation that can be done based on room size/air changes, etc? I looked on OSHA website for interpretations but couldn?t find anything.

The finished product would have 80% IPA. It would be transferred to the filling room via a teflon hose. In normal operations, the product would be enclosed in the filling room except at the filling area until the container is capped, about 30 seconds later. If this is the case, do you think the filling room would also need to have explosion proof equipment? or how would it be classified?

 

[rbalex]

Re: Classifcation Help!

How is the IPA introduced to the "covered tank?"

This is probably the single most important thing to ask. In fact, from your description, the filling room with its open system would appear to have a Division 1 location near the dispensing point.

NFPA 497 is the "basic" document for determining electrical area classifications and its worth the time to review it as it may apply to your installation.

Technically there is no "minimum" amount to consider but for practical purposes there is. NFPA 497 considers 5000 gal and below "small." Being nearly two orders of magnitude lower, I would almost consider it negligible - almost. Depending on ventilation factors, housekeeping, level of operator training, etc., I would still most likely consider a small area around the dispenser Division 1 and a slightly larger one Division 2. I'd have to be very familiar with process to be sure.

With regard to calculating the need, NFPA is basically silent; however, API RP500 does give the basis for determining electrical area classification by the "Fugitive Emissions" technique. It's a rather involved series of observations and calculations but it may be reasonably applied.

[ July 20, 2005, 04:09 PM: Message edited by: rbalex ]