Missing Groups / Temperature Code For Hazardous Area Classifications

Status
Not open for further replies.
C

cowski

Member
Location
New York
Occupation
Engineer
I design control panels for an OEM. Often, our customers will specify "Class 1 Division 1" without listing groups. I've never seen them list a temperature code...

Should every hazardous area classification be accompaied by Groups? Likewise, should there always be a temperature code? Or is the temperature code derived from the performance of my equipment? Would I 'calculate' the temperature code based on the worst compoenent in my system and use that on the nameplate?

Is this all described in NFPA 499? I assume I need to get a copy of that...
 
Back when I did the job you are doing (early 80s), we would not accept an order for our equipment unless the customer specified the environment completely.
 
Right, makes sense. Just trying to make sure I understand everything correctly before causing a stir.

Do temperature codes come from the customer as well? The more I read, the more I'm thinking they're derived from the equipment (i.e. if there is a P+F 6000 series purge with code t4 then it's t4 minimum).

The customer must have to check the temperature code though, and make sure it's less than 80% of their auto-iginition temp. Or tell us that up front?
 
cowski said:
Right, makes sense. Just trying to make sure I understand everything correctly before causing a stir.

Do temperature codes come from the customer as well? The more I read, the more I'm thinking they're derived from the equipment (i.e. if there is a P+F 6000 series purge with code t4 then it's t4 minimum).

The customer must have to check the temperature code though, and make sure it's less than 80% of their auto-iginition temp. Or tell us that up front?
Click to expand...

I would say that equipment that is custom designed for a specific application, the maximum allowable temperature should be specified by the customer. The manufacturer then selects components and designs to meet.

For non-custom equipment, the manufacturer states the temperature code of the equipment and the customer must ensure it fits their application.
 
cowski said:
I design control panels for an OEM. Often, our customers will specify "Class 1 Division 1" without listing groups. I've never seen them list a temperature code...

Should every hazardous area classification be accompaied by Groups? Likewise, should there always be a temperature code? Or is the temperature code derived from the performance of my equipment? Would I 'calculate' the temperature code based on the worst compoenent in my system and use that on the nameplate?

Is this all described in NFPA 499? I assume I need to get a copy of that...
Click to expand...
Actually, NFPA 499 is for Class II (Dusts); however, the answer you are asking for is in Sections 500.8, especially Subsections (B), (C), and (D). That is, equipment must be identified for Class, Division, Group, and T-Code. You will need to familiarize yourself with the whole Section since there are a few exceptions and workarounds, but none that would permit simply specifying "Class I, Division 1."

The client should know the "Class and Properties" since they have already complied with Section 500.4, right?
 
Status
Not open for further replies.
Top