IT rooms article 645

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cppoly

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Reading a Mike Holt article, he says regarding the 2011 NEC and article 645... "The change to this Note makes it clear that Art. 645 applies only if the room is constructed per NFPA 75, Standard for the Protection of Information Technology Equipment. So when must you comply with NFPA 75? Only when you want to reap the benefits allowed by Art. 645."

So is the takeaway message that if the room is not built to NFPA 75 standards then it is not considered an IT room according to the NEC? Meaning no requirement that a disconnect be installed at the exit that would power off all IT equipment and HVAC equipment serving the room?
 
cppoly said:
So is the takeaway message that if the room is not built to NFPA 75 standards then it is not considered an IT room according to the NEC? Meaning no requirement that a disconnect be installed at the exit that would power off all IT equipment and HVAC equipment serving the room?
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Yes

I design many data centers and IT spaces with no disconnecting means (EPO) per 645.10 because the "benefits" to be reaped are not worth the prerequisites.
 
Thanks.

I guess the follow up question would be: what exactly is in NFPA 75 standards (without reading the whole thing). And is it possible that a room an "IT room" is built that way regardless and the requirements of article 645 would apply or is this unlikely?
 
cppoly said:
I guess the follow up question would be: what exactly is in NFPA 75 standards (without reading the whole thing). And is it possible that a room an "IT room" is built that way regardless and the requirements of article 645 would apply or is this unlikely?
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NFPA 75 is a standard but not a code in any jurisdiction I've worked in throughout the US.Only invoked by client request.

The little bit of harmful prerequisites found in 645 are part of the even further painful requirements in NFPA 75. I don't know anyone that voluntarily complies with all aspects of NFPA 75. The fire alarm and suppression requirements (above ceilings and below floors) are a pain. Good thing it is not a code.
 
So I'm trying to figure out when you are mandated to follow article 645 from the NEC. If the IT room isn't "completely" built to NFPA 75, then you aren't mandated to follow article 645... Or if you only follow some of the requirements of NFPA 75, then are you still mandated to follow article 645? Seems like a gray area.
 
cppoly said:
So I'm trying to figure out when you are mandated to follow article 645 from the NEC. If the IT room isn't "completely" built to NFPA 75, then you aren't mandated to follow article 645... Or if you only follow some of the requirements of NFPA 75, then are you still mandated to follow article 645? Seems like a gray area.
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645 is an optional Article...it is a design choice as to following it. It does permit you to do some things that the rules in Chapters 1-4 do not permit, so if you want to take advantage of that, you use Article 645. If you are not doing that, you don't need to look at 645.
 
cppoly said:
So I'm trying to figure out when you are mandated to follow article 645 from the NEC. If the IT room isn't "completely" built to NFPA 75, then you aren't mandated to follow article 645... Or if you only follow some of the requirements of NFPA 75, then are you still mandated to follow article 645? Seems like a gray area.
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As mentioned by Don and Bob, you are not mandated to use 645.It is a design choice.

If you want the leniencies provided in 645 (as compared to Chapter 1-4), then you comply with the prerequisites in 645.
 
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