Given a 5 story residential building, single-loaded, with the corridors open to the street along one side: I am being told that for the apartments to be allowed to have typical windows ('unprotected openings') to the corridor, then the stairs at each end of the corridors cannot be enclosed stairways --they need to be open stairways, with at least two adjacent sides open to the street or courtyard etc.
The rationale would be somehow linked to the fact that if any point between the two exits for a floor is enclosed, then the whole corridor must be considered enclosed and cannot have windows on it, and that the exit path should take you 'out' once you are 'in' at some point. I should not even try to repeat the explanation because I have been having a hard time making sense of it and would probably be explaining it wrong. I am going into the code and trying to figure it out myself, but if anybody reads the first paragraph and is pretty sure that it does not make sense at all (or, alternatively, is pretty sure he knows why it makes sense), I will be very grateful for any explanation or orientation or reference.
spaceman
Aug 4, 04 1:56 am
Windows in corridor walls must be protected by fixed glazing with at least a 3/4 hr. fire rating. How can it be a corridor with unprotected windows?
IgnacioAzpiazu
Aug 4, 04 3:31 am
Thank you very much for your reply spaceman. You are right, I have finished reading and re-reading Section 10 and the correct term would be 'exterior balcony'.
So the question, correctly put, would be: I am told the flats cannot have unprotected windows looking into the exterior balconies unless both stairs at the ends are 'exterior exit stairways'. I am now thinking that the recommendation may come from mis-reading 1006.3.3.3, Exception 2, 'openings may be unprotected where two separated exterior stairways are served by a common exterior exit balcony', which I would understand/hope refers only to the *openings within 10 ft of the exterior stairway* which would otherwise need to be protected (all other openings 10 ft from the stair, that is).
But after reading and re-reading I am understanding that a 5-story building can have the flats exiting to an exterior balcony at each floor, and that the exterior balcony have either enclosed or unenclosed stairs at its ends. If the stair is 'exterior' and at some point on the way down it becomes 'enclosed', then the exit path needs to be enclosed all the way down to the public way or approved 'safe dispersal area'. Does this interpretation make sense to you?
Again, thank you very very much. This is my first encounter with the CBC and I guess I may be ignoring lots of issues and misunderstanding more than a few terms and concepts.
ArchAngel
Aug 4, 04 12:06 pm
Is your interpretation to suit your needs regarding the windows or stair enclosure? Single Loaded Units are tricky because there is typically one smokeproof/fire rated means of egress needed. Dont miss a step in your code analysis - the exterior balcony allowance may be provided there is a second exit from the unit. You most likely need natural ventilation through that wall right? Exlplain your design implication and maybe the interpretation will change, or become apparent.
Your building sounds like 50's apartment building so far.
IgnacioAzpiazu
Aug 4, 04 1:06 pm
Err, yes, I guess that a 50's apartment building would give you the right picture in terms of access etc. The units are 800 to 1200 sq ft flats. Hallway and kitchen windows on the gallery side (main rooms are on the other side) would be good for giving the flats a less flat-like more house-like interior atmosphere, to allow control (views) of the circulation spaces from the inside, and also to catch/frame some very interesting views out.
The scheme can only accomodate 'exterior stairways' (two adjacent sides fully open) at a huge cost in terms of layout. So the supposed requirement to have exterior stairways if you access them through an exterior balcony/gallery with unprotected windows looking onto it (as opposed to allowing exterior balconies leading to enclosed stairways, which is what would work best for the layout) would really mess up the whole scheme to the point that it would probably make sense to forget about the windows to the balcony if that is what needs to be done to keep the enclosed stairs --which is what a consultant (not a building official) tells me that needs to be done, and I have a hard time making sense of, and I am now thinking/hoping that results from misinterpreting the code.
ArchAngel
Aug 4, 04 3:54 pm
So why is it harder to layout an exterior stair than the same stair in a smoke/fire-proof tower? I would assume an enclosed stair is more difficult due to door swings, areas of rescue, etc.
Design a u-shaped returning to each floor/balcony/gallery....Bookends.
It's better to build to suit the code than it is to interpret the code to suit your design.
Is this what the Street elevation (diagram) would be with u-shaped stairs at each end of the Balcony/Corridor/Gallery?
IgnacioAzpiazu
Aug 4, 04 5:53 pm
Yes, that's a correct diagramatic elevation, only the stairs would be not on the exterior. The plan would be more like:
I____________
IUOOOOOOOU
I
U = scissor stair, enclosed
O = residential unit
___ = access/exit balcony, open on the side
I = some other building wall
The building layout is very shallow, because of required courtyard distances and site constraints etc. In this project it is harder to lay out exterior stairs because we would have to push them out from where they are now into one of the long sides, inside the building envelope (can't jut out, because of distances etc.), and leave two sides open, which would make a mess of just about everything. The enclosed stairs could fit within the depth of the residential unit bays.
The thing will need to suit the code one way or the other. But it seems to me the code would allow what we need to do for layout reasons (and told we are not allowed to do). If we can go from access balcony into enclosed stairways, we are OK. If we can't, major impact on the whole layout.
Thank you very much again for your insight.
ArchAngel
Aug 4, 04 6:37 pm
Cool,
I was imagining simpy pushing the stairs out to flush with the street elevation and rotating 90 deg. to fit in the depth of the terrace with the street side, and obviously interior sides open (exterior stair scheme) Like:
IU_______U
IOOOOOOO
I
(Except the U's would open towards the interior - don't have a sideways "U" key :)
The stairs would occlude a portion of each end unit's street wall.......
Good Luck
IgnacioAzpiazu
Aug 4, 04 6:52 pm
OK, then: if anybody knows if a 5-story residential in California can have kitchen windows looking onto access balconies, and those balconies exiting to enclosed stairways, please do let me know. Again, thanks in advance for any help.
igloominaire
Aug 5, 04 2:38 am
My understanding of the code's intent with regard to egress system components, post-1999, is that the progression of the escapee is required to be from the most protected egress system component (ie, a rated corridor) to lesser and lesser rated or protective components - in other words, you are deemed to be moving ever further away from the enclosed space (and hence, danger) of the building as you exit, and to re-enter it would be equivalent to going the wrong direction through the egress sytem. (The order of the descriptions in the CBC of the various egress system components (exit access, exit discharge, etc) is actually set up in the order you would need to progress as you escape.)
Therefore, once you have exited the flat, or any corridor leading from the flat, to an exterior exit balcony, you cannot "re-enter the building" as you progress towards safety - and "re-entering the building" from the exterior exit balcony would include entering a corridor, or an enclosed stair, en route to safety. Therefore, I believe your stairs have to be open, exterior stairs, which are considered to be the same or lesser rated/protective status than the exterior exit balcony. It's late, and I think I might have mangled this - but this is more or less my understanding through dealing with similar conditions on a 3-story commercial building recently. Of course, R occupancies might have additional special conditions that I'm ignoring too. Get a more lucid, complete opinion from a code consultant (or another building official) if you can.
As for non-rated kitchen windows facing the exterior exit balcony, I believe you can do this, as long as you have an exit stair (open, of course) at two ends of the balcony. Not sure if the width of the exit balcony might impact this too. Anyone?
David Zeibin
Aug 5, 04 3:18 am
I never thought I'd see ASCII architecture...
IgnacioAzpiazu
Aug 5, 04 8:45 pm
I am now told that the reason why you cannot have exterior balconies leading to enclosed stairs is that exterior balconies and stairways are 'exit discharge elements', while the 'exit enclosure' enclosing the stairway is an 'exit' element which can be before the balcony in the exit path but not after (and you'd be 'going in' when getting into the enclosed stairway).
The fact that the enclosed stairway is a separate 'fire area' (you are not going into the same 'building' you exited) doesn't count, under this approach, and the idea would be that you just cannot exit from an exterior balcony or stair into an enclosed area.
Is that the way things are? No way you can go into an exit enclosure to exit an exterior balcony (or for that matter, an exterior stair), even if it is a different building?
Thanks again for any idea.
Mum
Aug 6, 04 9:46 am
I'm glad to see you posted this over at the ICC site. You'll probably get a few reasonable interpretations from people familiar with CBC, but you might try calling your local code official to see what their interpretation is. It would probably save some time and aggravation trying to figure out the code yourself.
amrsaad10
Jun 6, 15 7:25 am
i have a question related to codes & standards , should we add a ducted shaft pressurization system to exit stairs connect more than 4 stories , as this shaft shall affect the architectural design .
kindly be noted that my question is related to the ducted shaft pressurization system not about a pressurization system with only single fan above the stair well.
Given a 5 story residential building, single-loaded, with the corridors open to the street along one side: I am being told that for the apartments to be allowed to have typical windows ('unprotected openings') to the corridor, then the stairs at each end of the corridors cannot be enclosed stairways --they need to be open stairways, with at least two adjacent sides open to the street or courtyard etc.
The rationale would be somehow linked to the fact that if any point between the two exits for a floor is enclosed, then the whole corridor must be considered enclosed and cannot have windows on it, and that the exit path should take you 'out' once you are 'in' at some point. I should not even try to repeat the explanation because I have been having a hard time making sense of it and would probably be explaining it wrong. I am going into the code and trying to figure it out myself, but if anybody reads the first paragraph and is pretty sure that it does not make sense at all (or, alternatively, is pretty sure he knows why it makes sense), I will be very grateful for any explanation or orientation or reference.
Windows in corridor walls must be protected by fixed glazing with at least a 3/4 hr. fire rating. How can it be a corridor with unprotected windows?
Thank you very much for your reply spaceman. You are right, I have finished reading and re-reading Section 10 and the correct term would be 'exterior balcony'.
So the question, correctly put, would be: I am told the flats cannot have unprotected windows looking into the exterior balconies unless both stairs at the ends are 'exterior exit stairways'. I am now thinking that the recommendation may come from mis-reading 1006.3.3.3, Exception 2, 'openings may be unprotected where two separated exterior stairways are served by a common exterior exit balcony', which I would understand/hope refers only to the *openings within 10 ft of the exterior stairway* which would otherwise need to be protected (all other openings 10 ft from the stair, that is).
But after reading and re-reading I am understanding that a 5-story building can have the flats exiting to an exterior balcony at each floor, and that the exterior balcony have either enclosed or unenclosed stairs at its ends. If the stair is 'exterior' and at some point on the way down it becomes 'enclosed', then the exit path needs to be enclosed all the way down to the public way or approved 'safe dispersal area'. Does this interpretation make sense to you?
Again, thank you very very much. This is my first encounter with the CBC and I guess I may be ignoring lots of issues and misunderstanding more than a few terms and concepts.
Is your interpretation to suit your needs regarding the windows or stair enclosure? Single Loaded Units are tricky because there is typically one smokeproof/fire rated means of egress needed. Dont miss a step in your code analysis - the exterior balcony allowance may be provided there is a second exit from the unit. You most likely need natural ventilation through that wall right? Exlplain your design implication and maybe the interpretation will change, or become apparent.
Your building sounds like 50's apartment building so far.
Err, yes, I guess that a 50's apartment building would give you the right picture in terms of access etc. The units are 800 to 1200 sq ft flats. Hallway and kitchen windows on the gallery side (main rooms are on the other side) would be good for giving the flats a less flat-like more house-like interior atmosphere, to allow control (views) of the circulation spaces from the inside, and also to catch/frame some very interesting views out.
The scheme can only accomodate 'exterior stairways' (two adjacent sides fully open) at a huge cost in terms of layout. So the supposed requirement to have exterior stairways if you access them through an exterior balcony/gallery with unprotected windows looking onto it (as opposed to allowing exterior balconies leading to enclosed stairways, which is what would work best for the layout) would really mess up the whole scheme to the point that it would probably make sense to forget about the windows to the balcony if that is what needs to be done to keep the enclosed stairs --which is what a consultant (not a building official) tells me that needs to be done, and I have a hard time making sense of, and I am now thinking/hoping that results from misinterpreting the code.
So why is it harder to layout an exterior stair than the same stair in a smoke/fire-proof tower? I would assume an enclosed stair is more difficult due to door swings, areas of rescue, etc.
Design a u-shaped returning to each floor/balcony/gallery....Bookends.
It's better to build to suit the code than it is to interpret the code to suit your design.
5) _________
4) <_________>
3) <_________>
2) <_________>
1) < _______ >
Is this what the Street elevation (diagram) would be with u-shaped stairs at each end of the Balcony/Corridor/Gallery?
Yes, that's a correct diagramatic elevation, only the stairs would be not on the exterior. The plan would be more like:
I____________
IUOOOOOOOU
I
U = scissor stair, enclosed
O = residential unit
___ = access/exit balcony, open on the side
I = some other building wall
The building layout is very shallow, because of required courtyard distances and site constraints etc. In this project it is harder to lay out exterior stairs because we would have to push them out from where they are now into one of the long sides, inside the building envelope (can't jut out, because of distances etc.), and leave two sides open, which would make a mess of just about everything. The enclosed stairs could fit within the depth of the residential unit bays.
The thing will need to suit the code one way or the other. But it seems to me the code would allow what we need to do for layout reasons (and told we are not allowed to do). If we can go from access balcony into enclosed stairways, we are OK. If we can't, major impact on the whole layout.
Thank you very much again for your insight.
Cool,
I was imagining simpy pushing the stairs out to flush with the street elevation and rotating 90 deg. to fit in the depth of the terrace with the street side, and obviously interior sides open (exterior stair scheme) Like:
IU_______U
IOOOOOOO
I
(Except the U's would open towards the interior - don't have a sideways "U" key :)
The stairs would occlude a portion of each end unit's street wall.......
Good Luck
OK, then: if anybody knows if a 5-story residential in California can have kitchen windows looking onto access balconies, and those balconies exiting to enclosed stairways, please do let me know. Again, thanks in advance for any help.
My understanding of the code's intent with regard to egress system components, post-1999, is that the progression of the escapee is required to be from the most protected egress system component (ie, a rated corridor) to lesser and lesser rated or protective components - in other words, you are deemed to be moving ever further away from the enclosed space (and hence, danger) of the building as you exit, and to re-enter it would be equivalent to going the wrong direction through the egress sytem. (The order of the descriptions in the CBC of the various egress system components (exit access, exit discharge, etc) is actually set up in the order you would need to progress as you escape.)
Therefore, once you have exited the flat, or any corridor leading from the flat, to an exterior exit balcony, you cannot "re-enter the building" as you progress towards safety - and "re-entering the building" from the exterior exit balcony would include entering a corridor, or an enclosed stair, en route to safety. Therefore, I believe your stairs have to be open, exterior stairs, which are considered to be the same or lesser rated/protective status than the exterior exit balcony. It's late, and I think I might have mangled this - but this is more or less my understanding through dealing with similar conditions on a 3-story commercial building recently. Of course, R occupancies might have additional special conditions that I'm ignoring too. Get a more lucid, complete opinion from a code consultant (or another building official) if you can.
As for non-rated kitchen windows facing the exterior exit balcony, I believe you can do this, as long as you have an exit stair (open, of course) at two ends of the balcony. Not sure if the width of the exit balcony might impact this too. Anyone?
I never thought I'd see ASCII architecture...
I am now told that the reason why you cannot have exterior balconies leading to enclosed stairs is that exterior balconies and stairways are 'exit discharge elements', while the 'exit enclosure' enclosing the stairway is an 'exit' element which can be before the balcony in the exit path but not after (and you'd be 'going in' when getting into the enclosed stairway).
The fact that the enclosed stairway is a separate 'fire area' (you are not going into the same 'building' you exited) doesn't count, under this approach, and the idea would be that you just cannot exit from an exterior balcony or stair into an enclosed area.
Is that the way things are? No way you can go into an exit enclosure to exit an exterior balcony (or for that matter, an exterior stair), even if it is a different building?
Thanks again for any idea.
I'm glad to see you posted this over at the ICC site. You'll probably get a few reasonable interpretations from people familiar with CBC, but you might try calling your local code official to see what their interpretation is. It would probably save some time and aggravation trying to figure out the code yourself.
i have a question related to codes & standards , should we add a ducted shaft pressurization system to exit stairs connect more than 4 stories , as this shaft shall affect the architectural design .
kindly be noted that my question is related to the ducted shaft pressurization system not about a pressurization system with only single fan above the stair well.
thanks