Horizontal exits and standpipes

[Yankee Chronicler]

Things I thought I knew -- but didn't:

Horizontal exits. They've been in the building code since BOCA days. I only recently came across a provision that says horizontal exits must have a standpipe on each side of the opening (doorway). That was news to me, so I did a deep dive into the historical ICC codes to see when that provision first happened. To my surprise, it has been with us since the 2003 IBC (which is the first IBC I worked with - my state didn't adopt the 2000 IBC).

In the 2003 IBC, section 905.4, Item #2, requires a standpipe hose connection on each side of a horizontal exit. No exceptions. This is in chapter 9, and section 905 covers standpipes. There is no reference to this in the section on horizontal exits in Chapter 10.

In the 2006 IBC, there is still no reference to standpipes in the section of Chapter 10 that discusses horizontal exits, but the requirement is again found in Chapter 9, section 905.4, Item #2. But in 2006 they added an exception: If the horizontal exit is within 130 feet (a 100-foot hose plus a 30-foot hose stream) of a hose connection in a stairwell, no standpipe is needed at the horizontal exit.

2009, 2012, and 2015 are the same as 2006.

In 2018 the IBC added section 1026.5, specifying that horizontal exits must have standpipes as required by sections 905.3 and 905.4.

The 2021 IBC is the same as 2018.

Boy, do I feel dumb for not having picked up on this when it first came into the building code.

 

[TheCommish]

Yankee Chronicler, ever day I find something I though I knew has move, changed, or haws left the code. We are not dumb, we carry a whole slew of knowledge that we need to look it up if we do not us a section or provision every day.

 

[princeofpen]

Yes when required by Ch9 ...... One of the reasons I push the designers where I work to limit the use of the term "HE" . Just because you go through a fire wall doesn't mean it's a HE.

 

[Sifu]

Speaking of HE standpipes...

Given a HE in an R2, each side has an exit enclosure and needs the HE to provide the 2nd exit from each side. 905.4 excepts the standpipe if the floor area is reachable by a 100' hose and 30' stream. So from the standpipe in the exit enclosure I pull a hose out the exit door, stretch it down the hall, activate the nozzle and spray 30'. If that 30' reaches the most remote point on that side of the HE then no standpipe required. If the most remote point happens to be around a corner, I don't just to go 130' and call it a day, instead the 100' hose would need to get me to a point where a straight line of the stream would reach the fire. Is that correct? What if that 130' is reachable from one side of the HE and not the other? Does that eliminate the standpipe from only the reachable side? What if one side of the HE is 90' total from the exit enclosure standpipe but the other side is 160'? Is it valid to stretch hose from the 90' side through the HE to reach both sides and eliminate both of them?

 

[Tim Mailloux]

its has been my understanding that standpipes at horizontal exits only come into play when the building is required to have standpipes per 905.3. If the building does not meet the criteria outlined in 905.3 requiring standpipes in general, then they are not required at any horizontal exits in the building.

 

[RBK]

Speaking of HE standpipes...

Given a HE in an R2, each side has an exit enclosure and needs the HE to provide the 2nd exit from each side. 905.4 excepts the standpipe if the floor area is reachable by a 100' hose and 30' stream. So from the standpipe in the exit enclosure I pull a hose out the exit door, stretch it down the hall, activate the nozzle and spray 30'. If that 30' reaches the most remote point on that side of the HE then no standpipe required. If the most remote point happens to be around a corner, I don't just to go 130' and call it a day, instead the 100' hose would need to get me to a point where a straight line of the stream would reach the fire. Is that correct? What if that 130' is reachable from one side of the HE and not the other? Does that eliminate the standpipe from only the reachable side? What if one side of the HE is 90' total from the exit enclosure standpipe but the other side is 160'? Is it valid to stretch hose from the 90' side through the HE to reach both sides and eliminate both of them?

Hopefully the IBC will clarify the language in the next edition to catch up to the intent of NFPA. When all areas on one side of a horizontal exit are within 130' of a hose connection in an exit stair, the intent is to allow the standpipe on the opposite side of the horizontal exit to be omitted. Standpipes at horizontal exits are intended to provide hose connections that are protected from the fire area, similar to the standpipe hose connections within a stair enclosure. If the east side of a horizontal exit is within 130' of a standpipe connection in a stair, there's no need for a standpipe on the west side of the wall. The cutoff at 130' is based on 100' of hose and 30' of spray. For distances beyond that, it requires extending additional hose lengths, and the intent is to do that outside of the fire area whenever possible.

In your scenario where one side is 90' from a stair and the other is 160', a standpipe would be required only on the 90' side. In a fire on the 90' side, you can reach all points easily from the stair using a 100' hose and 30' of spray. On the 160' side, you can't, so you need a standpipe on the 90' side that is protected from the fire so the fire department can stage, make a connection, then go through the door into the fire area to cover that last 30' that is out of reach from the stair on the other side.

 

[Sifu]

its has been my understanding that standpipes at horizontal exits only come into play when the building is required to have standpipes per 905.3. If the building does not meet the criteria outlined in 905.3 requiring standpipes in general, then they are not required at any horizontal exits in the building.

Hmm, a closer reading makes me think you are right. I have commented on this before, but the buildings have always met the criteria. In the one I am working on now it does not. So I can check that off the list.

I admit I didn't read far enough into the code and commentary. The commentary to 1026.5 helps clarify it. The '21 and '24 have the same language as the '18, which is the code I am using for this project.

 

[Sifu]

Hopefully the IBC will clarify the language in the next edition to catch up to the intent of NFPA. When all areas on one side of a horizontal exit are within 130' of a hose connection in an exit stair, the intent is to allow the standpipe on the opposite side of the horizontal exit to be omitted. Standpipes at horizontal exits are intended to provide hose connections that are protected from the fire area, similar to the standpipe hose connections within a stair enclosure. If the east side of a horizontal exit is within 130' of a standpipe connection in a stair, there's no need for a standpipe on the west side of the wall. The cutoff at 130' is based on 100' of hose and 30' of spray. For distances beyond that, it requires extending additional hose lengths, and the intent is to do that outside of the fire area whenever possible.

In your scenario where one side is 90' from a stair and the other is 160', a standpipe would be required only on the 90' side. In a fire on the 90' side, you can reach all points easily from the stair using a 100' hose and 30' of spray. On the 160' side, you can't, so you need a standpipe on the 90' side that is protected from the fire so the fire department can stage, make a connection, then go through the door into the fire area to cover that last 30' that is out of reach from the stair on the other side.

Confusing.

905.5 seems to be the "where required" section, yet 905.1 says to follow the entire section, which is more than just the "where". 905.3 dictates where a class 3 is required. But then 905.4 tells us where a class 1 would be required.

If I follow this, a class 3 would not be required in a 3 story building with < 30' highest floor level. But then 905.4 seems to tell us a class 1 is required for a horizontal exit (that is > 100' + 30'). Yet 905.4 is not covered by the sections listed in 905.3.

From this I could read this to say a class 3 is not required in in that 3 story building, but a class I would be if it has a horizontal exit exceeding the 100' + 30' distance. If what Tim says is accurate then this wouldn't be the case. Where is the "where required" language in the NFPA? Reading on free access is painful so maybe I am missing it.

 

[Sifu]

Maybe I found some of it. NFPA 14, 905.2.2 says within 20' of a HE, 905.2.2.1 provides the language about where at the HE. Still nothing on the number of stories or floor level. I'll keep looking.

 

[Tim Mailloux]

FWIW almost of all of my new school projects have fire walls / horizontal exits in them, and these projects almost always go thru extensive independent third party code reviews by guys that really know their stuff and this has never come up. There is a chance it was missed by the 3rd party and the local AHJ, but I doubt it.

 

[Sifu]

I wish I could rely on the fire plans examiners and inspectors but I just can't. They are the people who initially told the DP that an NFPA 13R could be used in this building which was more than twice the allowable area for a 13R system. Their entire design was based on this premise. Now, because the bad old building department poked a hole in it, the response is this fire wall and HE, which made me cringe with the anticipated problems....like this one, and a few more.

This may be simply my ignorance of standpipes, but the language throughout may be pointing me in a direction. Some sections refer to "systems", some to "connections", some use neither term.

The answer to this question may clear it up for me: In a building that requires a sprinkler system, but not a standpipe system per 905.3.1 does 905.4 tell me to install a class 1 hose connection to the sprinkler system at the HE's, but not require a standpipe system? The question is generated by my reading of 905.3.3 which indicates this scenario.

I hope I am getting it, because when I re-read 1026.5 with this in mind it seems to indicate that the standpipe system is required where required by 905.3, and the hose connection is required where required by 905.4.

Using this strategy, my 3 story R2 would not require a standpipe system, but it would require a class 1 hose connection at the HE.

 

[princeofpen]

FWIW almost of all of my new school projects have fire walls / horizontal exits in them, and these projects almost always go thru extensive independent third party code reviews by guys that really know their stuff and this has never come up. There is a chance it was missed by the 3rd party and the local AHJ, but I doubt it.

You could be in a situation where you are exceeding code and your reviewer isn't noting when you do. An exit through a fire wall is just that and only certain exits are HE's

 

[Tim Mailloux]

You could be in a situation where you are exceeding code and your reviewer isn't noting when you do. An exit through a fire wall is just that and only certain exits are HE's

no, they are almost always used as HE's so we dont require an excessive amount of exit stairwys

 

[RBK]

I wish I could rely on the fire plans examiners and inspectors but I just can't. They are the people who initially told the DP that an NFPA 13R could be used in this building which was more than twice the allowable area for a 13R system. Their entire design was based on this premise. Now, because the bad old building department poked a hole in it, the response is this fire wall and HE, which made me cringe with the anticipated problems....like this one, and a few more.

This may be simply my ignorance of standpipes, but the language throughout may be pointing me in a direction. Some sections refer to "systems", some to "connections", some use neither term.

The answer to this question may clear it up for me: In a building that requires a sprinkler system, but not a standpipe system per 905.3.1 does 905.4 tell me to install a class 1 hose connection to the sprinkler system at the HE's, but not require a standpipe system? The question is generated by my reading of 905.3.3 which indicates this scenario.

I hope I am getting it, because when I re-read 1026.5 with this in mind it seems to indicate that the standpipe system is required where required by 905.3, and the hose connection is required where required by 905.4.

Using this strategy, my 3 story R2 would not require a standpipe system, but it would require a class 1 hose connection at the HE.

The IBC could probably use some work to clear this up. 905.3 lists when standpipes (or standpipe systems) are required, then 905.4 addresses where the hose connections on those systems are to be installed. In 905.3, the height is by far the most common trigger, but there are other situations that can require standpipes.

In your example, if the R2 building doesn't reach the height threshold, standpipes aren't required. Once you've established that, the horizontal exits are a non-issue because you aren't required to have standpipes. Hose connections aren't generally allowed to be connected to directly to sprinkler systems. There are instances where "hose stations" are connected to sprinkler systems, but those aren't terribly common, and shouldn't be confused with standpipes. The one exception that I can think of is addressed in 905.3.4 where a standpipe is required for stages. The majority of the time, the stage is sprinklered, and if there's no other reason for a standpipe system in the building, it makes more sense to use the exception and connect the hose & cabinet required by 905.3.4.1 directly to the sprinkler system.

 

[RBK]

FWIW almost of all of my new school projects have fire walls / horizontal exits in them, and these projects almost always go thru extensive independent third party code reviews by guys that really know their stuff and this has never come up. There is a chance it was missed by the 3rd party and the local AHJ, but I doubt it.

I would imagine the school projects don't meet the height requirement to trigger standpipes. In my experience, schools exceeding 4 stories or with a story more 30' above fire department access is not very common. The vast majority of new schools I've seen have been 2 stories.

 

[princeofpen]

no, they are almost always used as HE's so we dont require an excessive amount of exit stairwys

Not sure I'm understanding your design/s but as long as you can move from your location in building "A" and out of building "B" within exit travel distance requirements you don't need an HE . If your travel distance overall from "A" only gets you into "B" in 250 yes it's an HE. HE's require standpipes when required, smoke/fire dampers, and sq ft per person on each side of that wall. I just avoid unless necessary