Electrical Mezzanine

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sacast33

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Location
Texas
Occupation
Electrical Designer
Dealing with a project where we have an electrical mezzanine with permanent pull down stairs for access. Its a fairly large space, about 500sqft. The gear we will have here will be almost 900A. My questions is, according to NEC 110, spaces with over 800A that have a personnel door, the door shall open in direction of egress and require panic hardware if within 25'. What if we don't necessarily have a door, but these permanent pull down stairs? Is this considered a "door"? Or will this just not fly at all? Any insight will help, thanks in advance!
 

brantmacga

Señor Member
Location
Georgia
Occupation
Former Child
Questionable design decision. I know this is common for HVAC equipment but I would hate to be servicing equipment in what really could be considered an attic.


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retirede

Senior Member
Location
Illinois
For a question like this, we can go back to the intent of the rule in section 110....the outswinging exit door rule was to be able to exit the room if you are injured.
Permanent stairs yes, pull down no, IMO.

My take also.
Consider what could happen if someone goes up there and someone else on the ground folds up the stairs!
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Dealing with a project where we have an electrical mezzanine with permanent pull down stairs for access. Its a fairly large space, about 500sqft. The gear we will have here will be almost 900A. My questions is, according to NEC 110, spaces with over 800A that have a personnel door, the door shall open in direction of egress and require panic hardware if within 25'. What if we don't necessarily have a door, but these permanent pull down stairs? Is this considered a "door"? Or will this just not fly at all? Any insight will help, thanks in advance!
It's not a door. It's not an unheard of arrangement either. I wouldn't get overly worried about it. It seems to me it violates the spirit of the rule that you can get out of there quick but I don't think it violates any code..
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
For a question like this, we can go back to the intent of the rule in section 110....the outswinging exit door rule was to be able to exit the room if you are injured.
Permanent stairs yes, pull down no, IMO.
We don't know what the intent of the rule is. Rule says nothing about stairs. Maybe it's a bad design choice maybe it's not the best idea but there's no way to claim that this rule prohibits this kind of installation.
 

WA_Sparky

Electrical Engineer
Location
Vancouver, WA, Clark
Occupation
Electrical Engineer
Isnt the rule of the outswinging door intended for crashbar/panic hardware? If an incident were to happen and someone 3rd degree burned their hands, i dont know if they couldnt safely leave the space.
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
Who knows? Intent does not matter much. What it says matters and since there is no door it's a moot point.

I say the stair assembly is also a door since it forms a barrier:

Door - a hinged, sliding, or revolving barrier at the entrance to a building, room, or vehicle, or in the framework of a cupboard.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I say the stair assembly is also a door since it forms a barrier:

Door - a hinged, sliding, or revolving barrier at the entrance to a building, room, or vehicle, or in the framework of a cupboard.
It is only a barrier if someone were to close it up while someone else was upstairs. How is that any different than someone parking a forklift in a hallway outside a door so the door cannot be opened anymore. One could argue a regular stairway is also a door if someone puts a big garbage can in it and blocks it off.
 

tom baker

First Chief Moderator
Staff member
We don't know what the intent of the rule is. Rule says nothing about stairs. Maybe it's a bad design choice maybe it's not the best idea but there's no way to claim that this rule prohibits this kind of installation.
I instructed code update classes for many years and remember when the outswinging door with panic hard ware requirement was added. The commentary on the change was an injured worker would need to be able to exit the room easily (outswinging door) and with out use of hands (panic hardware).
The intent of the code change was for worker safety. While there is no door, the pull down stairs do not allow ready egress.
But the NEC does not address this issue of pull down stairs.
 
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steve66

Senior Member
Location
Illinois
Occupation
Engineer
It is only a barrier if someone were to close it up while someone else was upstairs. How is that any different than someone parking a forklift in a hallway outside a door so the door cannot be opened anymore. One could argue a regular stairway is also a door if someone puts a big garbage can in it and blocks it off.

Its completely different than a forklift or a garbage can. The stair is part of the building construction. The other things are all movable. Do you think the code should say these items shall not block an exit from an electrical room, and then list every single item that could possibly be used to block an exit?

A door only forms a barrier when its closed too. If being able to leave it open had any effect, we wouldn't need any doors with panic hardware or doors that swing outward from electrical rooms. We could just expect everyone to prop the door open before they work on any equipment.

IMO, an inspector would be rightly justified in saying no way.
 

tom baker

First Chief Moderator
Staff member
Except the definition of readily accessible, as required for disconnecting means, states "being able to be reached quickly" or resort to "portable ladders". Having to pull down a ladder does not meet readily accessible
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Except the definition of readily accessible, as required for disconnecting means, states "being able to be reached quickly" or resort to "portable ladders". Having to pull down a ladder does not meet readily accessible
It's not a portable ladder. If readily accessible includes being behind a locked door (and it does), having to pull down a staircase is no less readily accessible.
 

Barbqranch

Senior Member
Location
Arcata, CA
Occupation
Plant maintenance electrician Semi-retired
Perhaps the thought is that it could be closed while someone is working there. If that is the only concern, some sort of locking mechanism could probably be built into to hold it open.
 
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