Can Mechanical exhaust duct pass through my Electrical and Data rooms for new build/construction?

JohnnyPElec

Member
Location
Portsmouth, VA
Occupation
EE
Working a new construction commercial office building. A situation has arisen where one set of my electrical and data rooms (You enter electrical room to enter larger, same width, longer data room) now has mechanical exhaust duct running/passing through it.

I know this isn't ideal but there seems to be no way around it. Code-wise, I am keeping in mind the dedicated space required for my electrical equipment - 6' above; As it's exhaust air we aren't currently calling for drip pans. For the data room, I feel like this is more of a concern. If the mech has no other way to route, Code-wise are we ok electrically as long as the exhaust ducts stay above 12' AFF (6' to top of panel, 6' to bottom of duct)? And can the same be said for the data room with the rack?
 
I can't speak to the data room rules. But if the ducts are 6 feet above the top of any electrical panel, you will be code-compliant. However, you still need a drip pan, even though the ducts are for air.
 
Are these ducts directly above the electrical equipment? And what kind of equipment? Not all electrical equipment has the dedicated space requirement.

Not sure about pans being required in data rooms but we typcially see them when the ducts pass directly over the data equipment.
 
Are these ducts directly above the electrical equipment? And what kind of equipment? Not all electrical equipment has the dedicated space requirement.

Not sure about pans being required in data rooms but we typcially see them when the ducts pass directly over the data equipment.
They would pass directly over in some places. Electrical panels, potentially a dry type transformer
 
Are these ducts directly above the electrical equipment? And what kind of equipment? Not all electrical equipment has the dedicated space requirement.

Not sure about pans being required in data rooms but we typcially see them when the ducts pass directly over the data equipment.
I can't speak to the data room rules. But if the ducts are 6 feet above the top of any electrical panel, you will be code-compliant. However, you still need a drip pan, even though the ducts are for air.
Rough layout for clarity
1753289223342.png
 
Sounds like you are considering the dedicated space, so other than that, the Mech guys might need to consider what kind of exhaust it is, to determine if it is safe to run through in case of leakage. For example, for lead acid batteries some mech guys want the exhaust to be direct to the outside to avoid potential leakage in an intermediary space and having hydrogen buildup.
 
FYI, if you are working with a person who cites experience instead of code you could end up with a person falsely telling you you can't run through a data room from their memory. In healthcare, (hospitals, surgery centers, ER's) you can't have ANY foreign systems passing through the data room, including even feeders, branch circuit conduits, water piping or HVAC. That requirement is found in NFPA 99
 
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