In dealing with a stairway to the roof, Section 1003.3..3.12.1 of IBC states '...In buildings without an occupied roof from the top story shall be permitted to be by an alternating tread device'. But nowhere in the IBC is a occupied roof defined.
Furthermore to complicate things 1003.3.3.10 Alternating treade devices states 'a.t.d. are limited to an element of a means of egress in buildings of Groups F,H,and S from a mezzanine not more than 250 s.f. in area which serves not more than 5 people..."
Question being can I use a a.t.d. with shaft and hatch in a 16 unit, 7 story, r-3 to access the roof? To make it more interesting I need to go up 2 floors with the shaft due to a top penthouse level (which have their own access to the roof (decks) in private stairways).
I don't have IBC 2000 in front of me but I have 2003. I'm studying for ICC code certification and a similar question came up in my study guide.
An unoccupied roof is just that - a space that is not meant to be occupied. Access is allowed for maintenance of rtu's etc. An alternating tread device is not to be used for sun decks or any other space meant to be occupied by anyone other than a person with a specific reason to be in that space. The definition (They made it section 1009.10 in 2003) leaves a lot to interpretation but that is the interpretation.
You can use the alternating tread to access the roof for maintenance purposes only. Are you trying to get on top of the penthouse or on top of the roof level that is the same as the penthouse floor? It sounds like you are definitely accessing an unoccupied roof, which is OK, but if you're trying to access the penthouse that's not OK. Section 1009.6 (or it's 2000 counterpart - there is no change in the code between 2000 and 2003) states that a flight of stairs must not have a rise greater than 12' between floor levels or landings. This would apply to alternating tread devices also. Can you explain the relationship of the penthouse to the stair more?
This hatch (if possible) would not be accessing the penthouse level. It would be from the common hall to the roof. The penthouse occupies the 6th and 7th floor and have their own interior stairs for roof/floor change access). I forgot to clarify that the penthouses are duplex's with deeded roof decks.
There is no living space on the roof only mechanicals and bulkheads. So the a.t.d. needs to go up aprox. 20'. I understand that a landing is needed but again I found nothing on a a.t.d. landing. If following the rules for a stair landing it would have to be at least the width of the a.t.d. The a.t.d. can have a minium tread width of 7" on each side. So this allows for a landing of around 16"x32" (need to snake to another a.t.d. to reach 20' height).
it is sounding like this is a bit different question than the IBC deals with directly and could be an OSHA issue. Mum nailed it on the occupied roof though.. depending on your local code official they might even require a lock on the hatch to ensure that it could not be accessed other than to maintain the rtu's
good luck
I just found something else. 1009.12 (not sure what it is in 2000) states that buildings 4 or more stories must have one stairway to the roof. It may be ATD. If a stairway is provided, it must be provided with a penthouse that complies with section 1509 - rooftop structures. It sounds like your "penthouses" are only 6th and 7th floor apartments, and not penthouses in the true sense of section 1509. The exemption to the penthouse requirement is if the roof is unoccupied, which yours is, and requires a 16 sf opening w/ a min. dimension of 2'. You might want to take a look at this section and your penthouse apartments and see if they might be construed as penthouses to be used for stairway access to the roof.
El jeffe may be right about the landing exemption, but I can't find it in the code. It's logical that there might be an exemption but OSHA may require landings. 20' is a long fall.
You might try contacting a mfr of alternating tread stairs and ask them about the height. They usually know these things. Otherwise, go ahead and submit the project with the 20' ATD to the roof and see if it gets kicked back as a comment.
Personally, I favor ladders over alternating tread devices. I think they're a little harder to navigate. I've heard from contractors that they hate them.
FYI, I just spoke with a rep. from Lapeyre Stair, Inc. and she said they do sell a good amount of a.t.d. at 20' for above it travel distance. She also hinted that it is up to interperation of the person reviewing the plans at the building department.
I guess I'll roll with it. Thanks for all the replies.
occupied or unoccupied roof? roof access question
In dealing with a stairway to the roof, Section 1003.3..3.12.1 of IBC states '...In buildings without an occupied roof from the top story shall be permitted to be by an alternating tread device'. But nowhere in the IBC is a occupied roof defined.
Furthermore to complicate things 1003.3.3.10 Alternating treade devices states 'a.t.d. are limited to an element of a means of egress in buildings of Groups F,H,and S from a mezzanine not more than 250 s.f. in area which serves not more than 5 people..."
Question being can I use a a.t.d. with shaft and hatch in a 16 unit, 7 story, r-3 to access the roof? To make it more interesting I need to go up 2 floors with the shaft due to a top penthouse level (which have their own access to the roof (decks) in private stairways).
Anbody who reads this and replys is cool.
I don't have IBC 2000 in front of me but I have 2003. I'm studying for ICC code certification and a similar question came up in my study guide.
An unoccupied roof is just that - a space that is not meant to be occupied. Access is allowed for maintenance of rtu's etc. An alternating tread device is not to be used for sun decks or any other space meant to be occupied by anyone other than a person with a specific reason to be in that space. The definition (They made it section 1009.10 in 2003) leaves a lot to interpretation but that is the interpretation.
You can use the alternating tread to access the roof for maintenance purposes only. Are you trying to get on top of the penthouse or on top of the roof level that is the same as the penthouse floor? It sounds like you are definitely accessing an unoccupied roof, which is OK, but if you're trying to access the penthouse that's not OK. Section 1009.6 (or it's 2000 counterpart - there is no change in the code between 2000 and 2003) states that a flight of stairs must not have a rise greater than 12' between floor levels or landings. This would apply to alternating tread devices also. Can you explain the relationship of the penthouse to the stair more?
Thanks for the response Mum-
This hatch (if possible) would not be accessing the penthouse level. It would be from the common hall to the roof. The penthouse occupies the 6th and 7th floor and have their own interior stairs for roof/floor change access). I forgot to clarify that the penthouses are duplex's with deeded roof decks.
There is no living space on the roof only mechanicals and bulkheads. So the a.t.d. needs to go up aprox. 20'. I understand that a landing is needed but again I found nothing on a a.t.d. landing. If following the rules for a stair landing it would have to be at least the width of the a.t.d. The a.t.d. can have a minium tread width of 7" on each side. So this allows for a landing of around 16"x32" (need to snake to another a.t.d. to reach 20' height).
stairs or ladders are exempt from the landing requirement if they're used only for equipment access.
it is sounding like this is a bit different question than the IBC deals with directly and could be an OSHA issue. Mum nailed it on the occupied roof though.. depending on your local code official they might even require a lock on the hatch to ensure that it could not be accessed other than to maintain the rtu's
good luck
I just found something else. 1009.12 (not sure what it is in 2000) states that buildings 4 or more stories must have one stairway to the roof. It may be ATD. If a stairway is provided, it must be provided with a penthouse that complies with section 1509 - rooftop structures. It sounds like your "penthouses" are only 6th and 7th floor apartments, and not penthouses in the true sense of section 1509. The exemption to the penthouse requirement is if the roof is unoccupied, which yours is, and requires a 16 sf opening w/ a min. dimension of 2'. You might want to take a look at this section and your penthouse apartments and see if they might be construed as penthouses to be used for stairway access to the roof.
El jeffe may be right about the landing exemption, but I can't find it in the code. It's logical that there might be an exemption but OSHA may require landings. 20' is a long fall.
You might try contacting a mfr of alternating tread stairs and ask them about the height. They usually know these things. Otherwise, go ahead and submit the project with the 20' ATD to the roof and see if it gets kicked back as a comment.
Personally, I favor ladders over alternating tread devices. I think they're a little harder to navigate. I've heard from contractors that they hate them.
they say!
FYI, I just spoke with a rep. from Lapeyre Stair, Inc. and she said they do sell a good amount of a.t.d. at 20' for above it travel distance. She also hinted that it is up to interperation of the person reviewing the plans at the building department.
I guess I'll roll with it. Thanks for all the replies.
a friend of mine once punched in the distance form the eartth to the moon into the Lapeyre calculator and it spit out the shop drawings...no landing.
I love Lapeyre!
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