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History of two means of egress requirement in the US

axonapoplectic

I was looking at floor plans for European housing projects and a lot of them have a single staircase on a common corridor (of only a handful of units per floor. Even if a project in the US had a few units, my understanding is that we would still be required to provide two means of egress from the common corridor, or directly from the units.

Does anyone know why this is? Is this something we could work to change - as it might be a holdover from before sprinklers?

 
May 10, 21 11:17 pm
axonapoplectic

https://www.treehugger.com/single-stair-buildings-united-states-5180808

Apparently fire rescue is considered the second means of egress. 

May 10, 21 11:33 pm  · 
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Either you're a spammer or you linked the wrong article.

May 11, 21 10:46 am  · 
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So the spammer was deleted, now it looks like I'm dissing AXO. ;)

May 11, 21 11:02 am  · 
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midlander

the provision of balconies specifically for assisted egress is interesting.

May 11, 21 7:18 pm  · 
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midlander

japan also depends on balconies for egress and has very clear regulations on keeping them accessible, providing operable partitions, and installing operable descent hatches.

May 11, 21 7:55 pm  · 
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midlander

china allows a single stair in residential buildings under six floors of non combustible construction. the stairs must be on an exterior wall with sufficient operable windows to avoid smoke buildup. all buildings have fire truck access along the long side - which is a big difference from the condition in most US cities.

May 11, 21 7:59 pm  · 
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RJ87

I think most of these types of codes sprung from the response to the Great Chicago Fire in 1871. People got trapped in their apartments & died. I don't know why we would ever want to be reliant on one way in & out. A second means of egress seams like a good idea for a number of reasons, not just fire.

May 11, 21 9:43 am  · 
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I wouldn't want only one means of egress from a floor. Two means of egress are for more than a fire so adding a sprinkler system won't negate their usefulness. 

May 11, 21 10:48 am  · 
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midlander

https://metropolisny.com/2018/11/why-do-i-need-hallway-i-have-no-neighbors/


specific to NYC but a very thorough explanation.

May 11, 21 10:52 am  · 
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gibbost

I think as architects we tend to only think of egress and how it might affect building occupants.  In an emergency scenario, there is a need for people to ingress the building--(which still seems crazy to me that there are brave people who do this every day).  Having multiple opportunities for horizontal and vertical circulation allows not only for a steady stream of people getting in or out, but also allows for first responders to strategize how best to tackle the emergency.  For instance, firefighters may elect to make the stairwell with the standpipe their 'base camp' where they can store equipment and monitor fire activity in the rest of the building.  A second stair tower would provide clear access for them to safely bring down occupants, while not affecting their operation.

May 11, 21 11:32 am  · 
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The Great Chicago Fire was part of it but actually only 300 folks perished which is remarkable considering the speed and size of the fire. It was the Iroquois Theater fire in 1903, also in Chicago that lead to a lot of the modern fire safety regulations we have now where 602 folks died.  Then in living memory also in Chicago in 2003 there was the E2 night club disaster where 21 folks died and this gave rise to the increase in egress capacity and the exist as you entered regulations for public spaces.


The Chicago and Boston Fires lead to brick exterior walls being required for almost all construction until the 1960s in Chicago and other cities. The concept of fire separation and fire walls also started at this time.

Almost all life safety codes are a reaction to some kind of disaster in an effort to prevent a future disaster.

Over and OUT

Peter N

May 11, 21 11:41 am  · 
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I'm not sure if people are intentionally missing the point of the article axonapopletic posted, or just reverting to the same thing they've always been told ... but the point of the article is that there are developed nations where single-stair buildings are not causing any significant issues while potentially addressing other issues that we sometimes struggle with in this country.

I get that the firefighters use the stairwells and hallways as staging areas because that's how they've been trained, but it doesn't have to be that way as it seems that other nations have figured it out just fine. NYC also has regulations that require an indirect hung ceiling grid using "black iron" rather than direct hung for fire fighting concerns (as well as labor union pressures based on my research), but it doesn't seem to be a problem that the rest of the nation is struggling with. Does this mean the NYC code is wrong? No, not necessarily. It does indicate that they might be able to rethink their approach to suspended ceilings without catastrophic loss of life though. I think the article does a good job of showing a similar thing for single-stair buildings.

Look, I'm skeptical that anything meaningful changes in the code with regard to this in the next 30 years, but at least we could entertain the thought rather than just dismiss it as outlandish. "This is the way it's always been done," as an excuse is just tired and silly. But that's what this thread sounds like so far. 

May 11, 21 12:05 pm  · 
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t a z

Only tangentially related to the actual discussion, but your comment on NYC "black iron" made me think of LA where the FD by code requires helicopter pads for hi-rise aerial firefighting operations. A few recent buildings with code exemptions have gotten their foot in the door, but otherwise that code provision is the reason most LA towers have flat tops without any signature crowns commonly seen in other cites.

May 11, 21 12:29 pm  · 
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The main reason is the use of wood framing and combustible finishes inside units and for common areas. I think you can have small single stair buildings in some US cities if they are non combustible, have sprinklers and the city has ladder rescue capabilities for all occupied floors. Wood frame construction, even with recent prices, is still cheaper in the US than masonry or concrete, even if you still have to build two sets of masonry stair towers and an elevator shaft. In Chicago we typically have and interior stair and and exterior stair and we also have alleys which makes fire rescue and fire fighting much easier than in places like New York where there is often no access to the rear of the building. I think in Chicago a 2 flat no longer must have 2 stairs but needs higher levels of fire separation between the units, this often is not as economical as having an interior and exterior stair.

May 11, 21 12:41 pm  · 
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Hmm, you are almost making the case that if a developer could lease out the space otherwise taken up for stairs and corridors they might be able to use more expensive construction methods if the return on investment is there. Does it pencil out? No idea, but it would be worth looking into in a hypothetical scenario.

The article also talks about compartmentalization and the firefighting access and apparatuses used in areas that allow for single-stair buildings and how they seem to be much more regulated than in the US which in part allows for this to be feasible. This also means that you might be able to change the development patterns we've been forced to rely on that are wasteful and harmful environmentally. If you haven't read the article, you should.

May 11, 21 1:23 pm  · 
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newguy

"Hmm, you are almost making the case that if a developer could lease out the space otherwise taken up for stairs and corridors they might be able to use more expensive construction methods if the return on investment is there. Does it pencil out?"

This is a VERY generous interpretation into the motives that drive developer's financial decisions.

May 11, 21 1:56 pm  · 
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Nothing generous about it. I'm saying they do the math to see if there is money there or not. If not, they don't do it. If there is money to be made, they'd do it.

You're saying if a developer could find a better ROI they would turn it down? Seems to be about the only think that drives their financial decisions.

The problem right now is the code doesn't let them even get to the math part because the whole concept is a non-starter. If it can be done safely and the code allows for it, I'd like to see how it pencils out. I've got developers looking at using mass timber for multi-family housing. If it allows for the compartmentalization as the author says it does, and the code would allow them to recoup some leasable space, I think the developer would want to know if they can make some money that way.

May 11, 21 2:36 pm  · 
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newguy

I'm saying we shouldn't leave the decision on whether or not to provide adequate life safety measures into the hands of developers. A safe building should be mandated by appropriate jurisdictions, not left into the hands of private entities who will only make the safe choice or use safer materials only "if it pencils out."

The needs/desires of developers should be wholly immaterial to the development of life-safety code measures.  They should not even be participants in the discussion

May 11, 21 2:52 pm  · 
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Look, I could make a quip about your reading skills but I won't. I'm not really trying to be antagonistic, but it is frustrating that you keep jumping in when you've already indicated you've made up your mind and don't really care to devote more than superficial thought toward this. Again, that's fine ... but maybe sit it out and enjoy from the sidelines.

For anyone else following along that missed it, I did say that this would all be contingent on the code allowing for it. That indicates that it would be regulated to be safe by the appropriate jurisdictions and not simply left up to the hands of private entities and their bottom lines.

Ironically, you bring up another point the author made in passing about how the code in the US is largely authored by a private entity rather than a government entity as they are in Canada and Europe. So for the vast majority of jurisdictions that just accept the ICC codes without amendment, you actually are leaving the safe choice and safe materials in the hands of private entities. Just thought it would be interesting to point that out as I know some people only skimmed the article. Oops, I did make a quip about your reading skills. Sorry.

May 11, 21 3:05 pm  · 
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newguy

You said, "The problem right now is the code doesn't let them even get to the math part because the whole concept is a non-starter." Which implies that the developer would only entertain using certain materials if they could save money elsewhere (presumably by eliminating other life-safety measures). But this is a false dilemma. They can use more robust/safer materials in addition to providing other life safety measures, they are just choosing not to.

This implies what we all know to be true: Developers will only use safe building materials and follow life-safety measures because they are mandated to do so.

Which is why I took initial issue with your initial statement: "Hmm, you are almost making the case that if a developer could lease out the space otherwise taken up for stairs and corridors they might be able to use more expensive construction methods if the return on investment is there" because it admits that developers will only do the bare minimum requirement toward building safe buildings, and that they should therefore be entitled to breaks and re-examinations of entire building codes to ensure their profit margins because they can't be assed with doing two things.  It is a faulty assumption that presumes that in order for one thing to be added, another thing must be cut.  This isn't always the case.

If you want to take further issue with me not fawning over and radically changing my stance toward protecting the wellbeing of the general public because I failed to sufficiently absorb the opinion article you posted from treehugger.com, you can keep it in the relevant thread

May 11, 21 3:30 pm  · 
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A few things:

1) It's not all that radical if it is safe and allowable in other developed nations with fewer deaths due to fires than we currently have. The article makes a pretty detailed case for why it could be allowable in the states, and it's not just a free-for-all.

2) My statement about the case to be made for a developer is based on it being first allowable (ergo, safe and legal), and second feasible economically. I realize I may not have made this as clear as I could have. Peter pointed out that with more expensive construction materials (non-combustible ones in particular) it might already be allowed in some jurisdictions, but it isn't being done because everyone is building in wood. I don't know what circumstances it was in reference to, but I'm speculating that there might be a point where the ROI flips. Or maybe not. I'd like to see the math as a hypothetical. If that point happens to be in a place where the size of the development and the increase in leasable SF regained is within the realm of current possibility in other countries ... maybe there is some incentive to make changes to our codes to allow it. I'm assuming people aren't doing it more at the moment because the ROI isn't there as it is currently allowed. The article makes the case that we can probably be more lenient in what we allow, and so it might actually pencil out for the developer if we were closer to what is allowable in Europe.

3) It's not a zero sum change where if one thing gets added another must be cut. No one is going to change the code to say you cannot build two staircases in your building. Instead, what would likely happen is they code would outline or expand the circumstances under which one staircase would be allowable (spitballing here: not Type V, less than 75 feet, balconies that can be used as an area of refuge, not more than 4-8 units per floor or served by the staircase per floor, fire separations between adjacent units, etc. ... I don't know what those circumstances would be, but I'd be open to hearing what people's ideas are). Then, if you want to use two staircases, fine. But if you want to use one because it pencils out better for the developer under the allowable circumstances, also fine.

4) I didn't post the article. The OP did because they found the answer they were looking for in it.

May 11, 21 4:11 pm  · 
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t a z

.

May 11, 21 12:10 pm  · 
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newguy

Here is a typical plan of Grenfell Tower:

72 people died in this fire.  No idea why anyone would ever advocate for relying on one single means of egress that could be blocked for any number of reasons

May 11, 21 12:33 pm  · 
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Economics rule.

May 11, 21 1:16 pm  · 
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The author of the article axonapoplectic posted addresses this in the first paragraphs and points out that a lot of things went wrong with Grenfell that weren't necessarily related to the single stair. You should read the article.

May 11, 21 1:18 pm  · 
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newguy

I'll admit that I didn't read the article....But I have a nervous response to the excuse that "a lot of things went wrong." When it comes to life safety measures, built-in redundancy should be viewed as a good thing, not something to be streamlined. The second means of egress is one of those things.  A lot of things can and will go wrong during an emergency event, which is why it's important to have multiple measures in place for preserving life.

I could have just as easily used the example of night clubs in other countries that are notorious death traps when they rely on only one means of egress (perhaps the article references this as well, I don't know). Sorry, I just can't get on board with this. If I have to choose between making a safe building, vs maximizing the net saleable square footage for a developer, I'm choosing the safe building every time.

May 11, 21 1:22 pm  · 
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Just read the article before you make up your mind is all I'm saying. It's not saying this is something we should do for high-rises, or night clubs. It's in addition to other more heavily regulated passive and active safety measures, not as a means to simply cut corners to save a buck. It's a niche scenario which could help the fabric of our cities.

May 11, 21 1:26 pm  · 
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newguy

I just skimmed it. It appears to be saying, Europe has buildings with one means of egress (except Germany, which has tailored its fire department equipment to work in conjunction with their code) and is using the absence of large scale fires in old historic buildings to justify the absence of 2nd means of egress, which is faulty logic. Just because it hasn't happened doesn't mean it won't.

The article also hand waves away the Grenfell Tower fire by claiming "multiple factors" went wrong without addressing how those other factors would need to be maintained and enforced to prevent this from happening. It's using a sort of "perfect storm" fallacy where it just assumes the other contributing factors would be addressed somehow without stating how.

The main motivator seems to be a desire to introduce diversity of architecture typologies by making a vague appeal to urbanism, but that's hardly a convincing argument as life safety and urban architectural diversity are not diametrically opposed to one another.

I dunno man, I'm not swayed by the article.

May 11, 21 1:37 pm  · 
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Ok, now *read* the article

May 11, 21 1:40 pm  · 
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newguy

naw, I'm good. I've addressed my concerns on how the article fails to provide meaningful solutions, but rather just gestures broadly toward "Europe" and assumes the reader will make the leap. If you want to fight the battle of reducing life safety measures on behalf of developers, have at it. I would hope that would turn out to be a lonely battle, though

May 11, 21 2:02 pm  · 
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In other words, you made up your mind before you opened the article, went to the article looking for something you could use to justify that opinion, and then stopped as soon as you felt satisfied. Cool, that's fine. But that's exactly what I'm pointing out is the problem. You don't want to do the bare minimum to participate in a meaningful discussion. That's fine. Maybe next time try sitting it out instead.

May 11, 21 2:31 pm  · 
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newguy

The article was pretty slim in ideas and proposals. Not sure why you're defending it the way you are, to be honest. I've since read it and found it utterly unconvincing and something that would probably be refuted by a qualified fire professional quite easily. Apparently you don't see any issues with the article. Fine, whatever. You wanna go to the mat to defend an article that wasn't critically examined, go on ahead.

May 11, 21 2:36 pm  · 
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cheers

May 11, 21 2:38 pm  · 
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EA - The article states that in countries that allow single stair buildings have less deaths than in the US who requires double stairs and fire sprinklers. What the article glosses over and only mentions in passing is that those countries that allow single stair buildings the construction of those buildings are all non combustible. The buildings also use 2 hour fire partitions to separate the building into smaller areas.

I'm not convinced that creating such buildings with one stairway are just as safe as a building with two stairs.  

May 11, 21 3:48 pm  · 
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I didn't think those points were glossed over in the article at all. He outlines the history of the construction types in the countries he references (comparing it to the US), and comes back to compartmentalization multiple times throughout.

I'm curious to hear what you think would be the minimum acceptable conditions for a building with one stairway. Height, fire separation distances, construction type, sprinklers, compartmentalization requirements, etc.

Perhaps another question would be, is two stairs the absolute bare minimum level of safety in buildings? If other countries can do it without additional deaths due to fires, why do we need to be so conservative in our approach?

May 11, 21 4:17 pm  · 
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newguy

For high rise, many stairs discharge you into the lobby with a clear line of sight to the exit (one stair to the lobby, the other to the right-of-way). Seems it would be an issue if a single stair discharged you into a lobby that was on fire. I'm very much two stair minimum. Doors to stairwells can be blocked, sight could be impaired, smoke could be in front of the exit.....far too many factors to rely on only one exit. If its blocked for any reason you just killed a lot of people

May 11, 21 4:22 pm  · 
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IBC and Seattle be killing a lot of people then.

"Despite what we have been led to believe over the years, single stair multifamily buildings are legal even in some U.S. jurisdictions. The International Building Code allows for up to four floors, but with stringent regulations including a max of four units per floor, and requirements for sprinklers. Seattle allows up to six floors plus a mezzanine with a single stair configuration."

But yeah, high rises are a different animal and have their own unique requirements.

May 11, 21 4:32 pm  · 
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newguy

Pretty sure those code requirements stop at those heights because that's how high a firefighter truck ladder can typically reach (along with requiring other mitigating factors like sprinklers, unit count, construction type, etc), so occupants could theoretically egress from their windows/balconies or wait at an area of refuge. That ability goes away once a building is high-rise (and firefighters will need to go UP the stairs while occupants go DOWN) which is why any discussion of having only one exit is crazy-town.

May 11, 21 5:19 pm  · 
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That's essentially my question for Chad, and you too if you want to play along, under what conditions would you be ok with a single stair? Obviously, high rise is a step too far in your opinion, but it seems like you're ok with it under some conditions (within reach of fire truck ladder, sprinklers, unit count, construction type, egress from windows/balconies, area of refuge, etc.). What are those conditions?

May 11, 21 5:30 pm  · 
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newguy

I guess I don't understand your question, then. The IBC currently already allows for some instances of single stair occupancy (you just posted an example)....so what exactly are you asking? Are you trying to expand when it could be applied? Re-work the tables in chapter 10 of the code? I'd think that's a question best left to fire fighting professionals and not architects.

May 11, 21 5:45 pm  · 
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EA - I do think the the author glosses over the fire resistant construction and area separation with fire portions. The author only mentions those things twice - once in reference to older masonry buildings, and and the second time is when dealing with modern construction in Germany where dividing a building up into units is mentioned. There is no further explanation of the construction types and fire resistant construction required to accomplish a single exit from each floor. This article was written for the layman - not architects. Without understanding building codes and construction the article makes it seem that it is easy to only have one exit per floor.

May 11, 21 5:52 pm  · 
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EA - for your main question - what would be my minimum acceptable conditions for a building with one stairway? 

No A, E, or I occupancies. 

 Four stories or less. 

 Fire area limited to 3,000 sf each floor. 

 Automatic sprinkler required. 

 Type IIb or heavy timber construction.

The single stairway must contain an area of refuge.

May 11, 21 5:56 pm  · 
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Cool, thanks for thinking it through. I'm curious as to how you came to that criteria, like 3,000 SF for example.

I think the article is exclusively talking about multi-family residential (though I don't think that's made clear) ... I don't see references to anything but residential in the article so that's what I'm assuming anyway. 2018 IBC is something like 200 gross SF per occupant for residential occupant load calcs, so you can get up to 9,800 gross SF before you'd be at 50 occupants which if in a single room would trigger a second exit. Is it conceivable that you'd allow more than 3,000 SF, or are you sticking with 3,000 because of the added complexity of exiting a multi-room unit compared to a single room? We allow 49 people to use one exit out of a room, why not a building? I'm not suggesting you're wrong or I disagree with you, I'm just wondering how you came up with the number and your other criteria and thought I might use this as an example.

May 11, 21 6:33 pm  · 
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The 3,000 sf came about because of the fire partitions that would be around each area. Using 3,000 sf allows 2-3 apartments, decent sized neighborhood retail, or a small business.  Not all on one floor but one use per floor. The size also reduces the complexity and cost of having to deal with MEP issues and fire partitions.

May 11, 21 7:00 pm  · 
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I think we are told "YOU NEED TWO STAIRS!!!" so frequently from so early on in our training that it sticks and it's very, very hard to let go of it. 

But as Mike points out in the article: Grenfell was a rehab of an existing building that was built with one stair, and it was essentiallty clad in fireworks as a "refresh" so people lookign *at* it wouldn't feel bad for it, the cladding material was chosen based on falsified test data, and it's 24 stories tall.

The single stair buildings Mike is talkgin about are, s he sayds int he article, less than 10 sotires, and new builds. it's entirely possible to build safe housing with one stair.

I know when Grenfell happened my immediate knee-jerk reaction was to be appaled that anoyone would suggest a single-stair building. but i;ve been following Mike on Twitter for years and he's got me convinced. - michael eliason on Twitter: "5 story apartment building partially set in a basel courtyard, by itten brechbuehl. and guess what? it's a single stair! https://t.co/Rog8EKj3u8 https://t.co/3sVV4FSmSs" / Twitter 

May 11, 21 2:36 pm  · 
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bowling_ball

Sorry, and I know this is pedantic, but he didn't even spell "storey" correctly, so how am I to trust that source? It would seem an expert would know such things. But again, I'm a pedant...

May 11, 21 5:34 pm  · 
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bowling_ball

Also, since when is pointing out that something was done, make that thing safe? People do dumb things all the time. Doesn't make it safe or smart.

May 11, 21 5:35 pm  · 
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midlander

i think in this case, from reading the link on nyc codes i posted above - it doesn't seem like there was a single original reason residential buildings required two egress routes. it seems to have evolved through a series of code revisions with heavy influence from the fire departments and little coordinated thought on the overall fire safety approach.

May 11, 21 8:03 pm  · 
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midlander

most of the american codes evolved from regulations in nyc, chicago, and boston where major fires in the 19th century showed obvious hazards. but fire protection systems, fire department technologies and practices, and most importantly building construction and site planning have changed enormously since then.

May 11, 21 8:05 pm  · 
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midlander

it really would make sense to look at regulations from a neutral standpoint balancing effective safety with practical limitations according according to current practice in development and life safety technology. but i don't know who would initiate that. for all the prestige of architecture universities, they don't conduct research on practical topics.

May 11, 21 8:07 pm  · 
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Well stated midlander. It seems like we are taught that most (significant) code changes come about because of failures or disasters where we find out that the codes may not be addressing something that could better protect HSW. It's a reactionary cycle ... failures happen, we conduct forensic examinations to determine issues, we correct issues with new code provisions. Nothing wrong with that, but perhaps there is room to be more proactive.

I like the idea of universities conducting research to identify areas where the code might be on the conservative side and proactively changing things in the codes to allow for more options. At the moment, the only people I know or can think of that might be close to doing this is Straube, et al. with Univ. of Waterloo in regards to building science. Even then, a lot of what they are doing is still reactionary based on what they see from failures and forensic investigations. Perhaps the furring attached through layers of continuous insulation and cladding weights and insulation compression might be the most proactive thing they are looking at that isn't directly tied to building failures (it's still tangentially related because of moisture- and mold- related failures within wall cavities prompting the use of CI in the codes though). Even then, I don't know if that has made it into any particular code as a prescriptive option, or if they've just confirmed the application can work under the right conditions.

May 12, 21 1:54 pm  · 
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SneakyPete

At least one overseas firm (working in the US market) in my experience is challenging assumptions in the prescriptive code by promoting the use of performance approaches. We have had success in getting things built that would otherwise been impossible due to existing conditions and the rigid prescriptive requirements. It necessitates knowledgeable and receptive building and fire departments, but when it works it's a breath of fresh air. It does, however, run the risk of creating yet ANOTHER cottage industry biting off a chunk of our fee.

May 12, 21 1:59 pm  · 
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