From the Trusses and Fires thread, it’s clear that we have a few active fire department experts on the board at the moment. So, here’s a new thread to tap that resource more broadly. For new construction and for remodeling, what would you recommend to make the building and occupants safer from fire? Coatings, alarms, sprinklers, blocking, fire rated sheetrock, other materials — what are the most cost effective things to do?
— J.S.
From building boxes and fitting face frames to installing doors and drawers, these techniques could be used for lots of cabinet projects.
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Replies
Hi John,
A very cool question to ask! Without a doubt, sprinklers are the number 1 best choice available. No person has ever died in a fully sprinklered building, where the sprinkler system was functioning properly. That says quite a bit.
The mechanics of a sprinkler system are quite simple, so there isn't a whole lot to go wrong to keep them working fine. Residential sprinklers are finally gaining acceptance, but still most builders (at least on the east coast) don't even offer them as an upgrade.
The bottom line with sprinklers is that the fire is detected and water is applied at the fire's earliest stages. This keeps smoke and fire damage to a minimum. When the sprinkler is activated, the local alarms are activated, and an automatic notification can be sent to the FD, starting their response. The only issue that may become a factor of reliability is in the case of an explosion that knocks the system out altogether. I have been told that even in the boonies, sprinklers can function off of low GPM wells. They may not be 100% effective, but some H2O is better than none.
For the fear of heads popping, they usually only go (outside of fire conditions) from freezing (and thawing), or if they are struck by something - which is found more in the industrial community.
I don't have any experience with fire resistive coatings, but I have read about some that were working well in the west to stop the involvement of a house from a wildland fire. They were using some sort of chemical compound that is used to make baby diapers I think. I'll have to go look that up. Instead of housewrap, maybe we should start using Huggies! <G>
Another huge thing is open voids. Pretty much, codes all cover that now after the removal of balloon construction, but in remodeling - many voids still could be found.
I like the idea somebody mentioned about incorporating fire extinuishers into the design of a home. They could be easily concealed in decorative cabinets in areas of hazard such as the laundry room, kitchen, garage, etc.
Hard wired smoke detectors are critical. If they report to a fire dept. or central station - great, but they need to at least be able to wake the occupants.
One thing I did in building my house - I stood in every room and asked myself what I would do if the way I use to go in and out of a room was blocked by fire. Is there an easy way out? If not, put one in. A window is usually regarded as secondary means of egress. I see many basement conversions (that were obviously not inspected by a building official) that do not afford the occupants a secondary way out. That's not cool.
My personal preference (and probably that of most firefighters) about construction is to use a stick framed roof as opposed to trusses, but that horse has been beat to 1000 deaths elsewhere on this board.
Thanks again for posing the question.
Have a great day,
Tony
Edited 7/23/2003 4:45:44 PM ET by anthonydante
My personal preference (and probably that of most firefighters) about construction is to use a stick framed roof as opposed to trusses,
Tony,
I agree with that a 100%.
I've been doing fire jobs for 13 years and the ones that were trusses were a nightmare and very dangerous.
Let it be beaten to death because the truth is, when a truss roof is burnt it is deffinetly not as safe as opposed to stick framed roofs. You know it and anyone else who I 've talked to over the years who does fire jobs like I do can tell you the same thing.
Like in one of my examples in the other thread about the bottom chord of a truss burning out, It will fail the rest of the truss. A stick frmed roof when just the ceiling beam burns and not the rafter, it's ok for you and any other Firefighter and myself to walk on.
The Point of this whole thing is that a Trussed Roof is deffinetly more dangerous for a Firefighter and a construction worker who both have to walk around on these things when compared to a Stick Framed Roof.
Can we do something to stop them from failing when burnt, I'm sure they can.
Maybe sheetrock both sides of the truss with fire rated sheetrock but what builder would want to pay for that.
There's alot of ways it can be done.
Floor trusses are the worst. I'm sure you no that. You don't just loose some floor joists like you would with 2x10's, you'll loose the whole house, there one big open shaft.
This is just me talking from working fire jobs and what I've seen over the years.
There was a fire that started in a basement a couple years ago but there was a shaft that went from the basement all the way to the third floor for a waste line. The fire went right up the shaft and burt the first second and half of the third floor floor beams. Kitchen and all the bathrooms were gone. This job was 2xs10's, had they have been open web trusses, forget about it.
I've done jobs where the roofs had trusses but the house was burnt so bad that we had to frame a new one but stick framed the roofs.
Joe Carola
Tony --
Thanks for the answers, which of course have led me to more questions.
Sprinklers may be simple to you, but I'd need to learn the basics before installing them. So how do I learn to do sprinklers?
At the moment I have the downstairs ceiling down in one room, and the upstairs floor up in a couple others, so it's the ideal time to plumb for sprinklers there. Upstairs I have access from the whole attic. So I can do most of the place without adding to the scope of ceiling work. Is it possible to do a 15' x 25' room with wall mounted sprinklers? I'll be opening walls everywhere for electrical work.
The sprinklers I've seen all appear to be plumbed in of all things steel black pipe. Doesn't that rust and fill up with crud? Would copper be better? There must be things like pipe size tables and length of run considerations to learn.
As for voids, I'm blocking them off as I go. There are big cornices all around which create an opening between the upstairs wall cavities and the attic. These are getting blocks at the bottom of the cornice, which also provides solid nailing for a picture rail. I'm going to fit plywood around the pipes top and bottom of the plumbing and electrical chases.
Extinguishers are only good if the homeowner knows to keep them up to date, and that they're only an escape aid, not a substitute for the whole fire department.
My plan already includes hard wired interconnected smoke detectors on a dedicated circuit. I see now that it would be a good idea to provide a way for that yellow wire to interface to an alarm system.
As for two easy ways out of every room, I have that except for the master bath. So I'll have to reconsider that second door to the back hall that my wife wants.....
Thanks for a lot of useful info ---
-- J.S.
John
There are now PVC sprinkler systems that are allowed.
And the codes are starting to realize that residenctial systems don't need all of the bells and whistles of commercial systems.
And Wisbro has out PEX plumbed system.
http://www.wirsbo.com/main.php?pm=1&mm=3&sm=0&pc=homeowner/ho_mm3sm0.php
I'd have to hear more to be convinced that a sprinkllered system will function off a low GPM well. I'm no 'spert on hydraulics but the local guys who checked this out found that they were not likely to have sufficient flow to be worth doing, without a large reservoir to pressurize the flow from.
The local firefighters had suggested an ordinance requireing sprinklers in all new houses over 2500 sq ft or remo's involving some certain percentage of the house. Sounds like a good idea until you try to figutre out where that water is going to come from. One house might have a well that produces 80 GPM while the one down the street has only 3GPM or even a third of that.
And it is not only the well output that you have to consider, Delivery to end point is a function of pipe size, distance, and pressure.
For example, I know of a well that makes 80 GPM but it is 120 feet from the house and 188 feet down to water with the pump hanging at 200. The house is about 120 feet long and is three stories high. That means you need a delivery system that can go nearly five hundred feet with a head lift of over 220 feet and still deliver more than a drizzle. You are talking about a larger pump, line, and a tank in the attic to do that. The owner could certainly handle the cost, especially when weighted against the value of his children's lives, but is it doable in the first place?.
Excellence is its own reward!
I'm curious about something along the line of sprinklers -
Seems with all the technology out there these days, it would be possible to develop directional sprinklers. For instance - If a fire started north of a sprinkler head, the water could be directed north instead of 360°.
Heck, they might even be able to detect if the fire goes out, and then shut off the water flow to minimize damage to the structure.
Do you know if anyone has attempted anything like that? Did you hear about the dyslexic guy who walked into a bra?
John: I'm sorry I forgot to mention about the piping material. In residential, PVC is most often used. It works great. Ceiling mounted sprinklers will provide the best coverage, but wall mounted can be used in areas where ceiling mounts are not possible. I notice wall mounts in hotels quite a bit where they retrofitted spriklers. (On a side note, I always ask if a hotel is sprinklered when making reservations - if they say no, I move on. Paranoid? Maybe, but there have been some tragic fires in hotels.)
I believe NFPA 13 talks about possibilities of up to 400 square feet of coverage from a residential head now, which would satisfy your 15x25 room, providing that wall coverage was met. I'm going off the top of my head here, so don't take this as law. I'll have to look it up when I get back to work.
My other concern is freezing. Obviously you don't want to run a sprinkler line anywhere you wouldn't put a water pipe. I haven't seen a residential dry system, but they may exist. A dry system is usually used in warehouses and anywhere subject to freezing. A compressor is used to fill the lines wih air, the water is held below the riser clapper since the air pressure exceeds that of the water's exertion on the clapper. When a head trips, the air expels, the clapper opens and charges the system.
Here is a link to NISTIR 6941 for your reading pleasure:http://fire.nist.gov/bfrlpubs/fire02/PDF/f02137.pdf
Here is some info from the USFA:http://www.usfa.fema.gov/public/sprinklers.cfm
I know that there is a residential sprinkler association that would probably be a great help to your planning, but I can't find a link. Also, in your design, call your fire marshal's office. Ask them to come out to provide some thoughts on your specific requirements.
For egress, I do have one room where there is only 1 way in and out. The guest bathroom off of the center hallway upstairs. 5' wide bathrooms are tricky when they have full showers across the back wall. There are no other options for egress. Naturally, this isn't a room of long-term occupancy, so egress concerns are important here, but not vital. I wanted to keep an ax in the room so our guests could easily breach the wall to safety, but my wife had some sort of decorating ideas that didn't include tools of destruction. Women! <G>
Wrecked Angle: Thanks for even more info on these. I've read about 'em, seen 'em on TV, but haven't been able to see one being built yet. Hopefully I'll come across one that I can see while it's being built. The more I know about a building, the better I'll know how it's going to burn.
Piffin: I'm with you...I don't see how a low GPM well could do it. The only explanation I can think of is that a sprinkler head is meant to stop a fire in it's earliest stages. That being said, in a residential application, only one head should be needed to control a fire since fire loads in homes are lower than that of industry. The big thing I see, as you mentioned, is elevation. I'll go visit the FMO when I get back to work and see what they can tell me.
Boss: the idea behind a 360 degree pattern is more about keeping the room's thermal layer in check. By keeping the ceiling area cool, it eliminates the possibility of flashover. All of the water droplets are designed to absorb heat as they fall. Sprinklers, by design, will not stop after activation. Because of the possibility of hidden fire, or fire getting inside a void space, the system keeps flowing until the FD shuts it down. Fire is tricky if it isn't overhauled properly. While this may add to excess water damage, it sure beats what would happen if it was fire damage!
I also think there has not been a very strong push to incorporate too much technology into sprinkers. The system works great without too many bells and whistles. Too much technology might mess that up. Last week we went o a waterflow alarm in an old mill building. There had been a fire in a storage area. The 60 year old sprinkler system kept the fire in check until we got there. We overhauled (ripped things apart looking for hidden fire or embers that may relight) it a bit, wet it down, and were back in the firehouse in under an hour. If there were no sprinklers, we'd probably still be there!
Edited 7/24/2003 9:21:44 AM ET by anthonydante
Any links on where or how most home fires start?
Non-smoking related, that is.
Electrical? Cooking gone bad? Besement utilities?
Curious...
Thanks, Mongo
http://www.nfpa.org/PressRoom/NewsReleases/FireDeaths/FireDeaths.aspbobl Volo Non Voleo
I searched the site, but the only information I could find was that smoking is the leading cause of home fires.
since I don't smoke I wonder what the second and third and fourth biggest causes are .... (besides fireplaces and candles, neither of which do I have).
Anyone?
Careless cooking is a real big one. We have several projects in my district. There is a great deal of alcoholism and drug abuse in these projects. We go to numerous small fires because people (in a chemically altered condition) put some food on and then usually pass out. If the cooking flares up to get the cabinets, fire spread is usually pretty fast from there. Many cultures in these housing developments use oil to cook everything, which lights up pretty fast.
I feel sorry for the innocent people that live in these complexes. They didn't pick their neighbors, but they oftentimes lose their belongings and have their lives disrupted by the stupid actions of others.
We have numerous arson fires as well. While most people think of arson usually for insurance, in my district it is usually from a mentally incorrect person with a fetish for fire, or a revenge tactic. I've been to 2 arson fires already this summer that were set by women whose boyfriends/husbands cheated on or divroced them. What's that saying about a woman scorned? <G>
Here are some facts from the USFA that may help answer some questions:
http://usfa.fema.gov/public/facts.cfm
Tony
Edited 7/24/2003 3:42:43 PM ET by anthonydante
You are right about careless cooking. The only fire I've been involved with was caused by a family member putting a deep pan of oil on the stove top to bring it up to temperature, then going upstairs to do a few quick things. I was a young teenager at the time, sitting in the living room in a recliner, watching TV, when I heard the WHOOF sound of the pan of oil bursting into flame. I sat there watching TV for maybe about 10-15 seconds before it registered what I had just heard. So I got up and went into the kitchen. I saw the fire, and it looked big. By then, the curtains behind the stove, which were covered with years of cooking oil spatters, were going up in flames.
I remember standing there for about 5-10 seconds, just looking at the fire, thinking something along the lines of "Hey the kitchen's on fire. That's not right. Get out of here, fire. Boy, this could be pretty bad. Someone should do something. There's noone here. I suppose I should do something. What should I do?" Not my finest moment, but I wasn't expecting to see a fire. I'm pretty sure my reaction would be a lot faster today, but who knows? A 5-10 second reaction time isn't that bad.
We had a fire extinguisher in the kitchen at that time, sitting on the window sill behind the stove. I had to reach behind the flames to get it. Not the best place to put an extinguisher. Lucky I have long arms. It was a small extinguisher, with only enough charge to take care of the stove top fire, not the curtains. Once it ran out, I used the spray wand in the sink to put the curtains out. The flames had been licking the ceiling and the cabinets on the neighboring wall, but fortunately, they didn't have time to catch.
I figure I started fighting the fire within about 30 seconds of it starting. It might have taken as long as a minute to put it out. And maybe 2-3 minutes after I put it out, the only smoke detector in the house, on the second floor, started to beep. Smoke detectors are great, but a fire can get pretty big before a detector goes off.
After that fire, my Dad bought large industrial sized fire extinguishers for each floor, and they are sitting right out in the open. They look ugly, but they are very accesible. Permanent damage to the house was minimal. Paint took care of most of it. We didn't replace the oil soaked curtains behind the stove. Learned that lesson. Bare walls now. That was a long time ago and we ate a lot more fried food then. We never deep fry stuff anymore, and if we ever did, we would be present the whole time.
I can only imagine what would have happened if I hadn't been there to put it out right away. The oily curtains burned fast and might have been able to catch the cabinets on fire, or maybe not. The large deep pan of oil would have burned for a while and heated that whole room, possibly catching the wooden cabinets on fire near the ceiling.
As far as building tips go, I think the area around the stovetop should be as fireproof as possible. Maybe an island stovetop with a huge metal hood over it is the ideal way to go when you have the space. There really shouldn't be any wooden cabinets near the stovetop if you want to prevent a stovetop fire from spreading. Not sure how realistic this is though. In a small kitchen, people want to cram as many cabinets in as possible. Metal hoods and metal back splash/walls are probably the best idea in those situations.
When I was about 20 I nearly did the same thing. Started some oil heating to make some french fries. About 2 quarts of oil. Forgot about it for awhile. Remembered and ran into the room.
Nothing happening. Turn the stove off, and whoosh it starts on fire. Fortunately, the lid for the pan was right there, so I put it on. Then carefully took the pan outside onto the driveway (probably not smart). For over an hour if I removed the lid it would instantly shoot flames up.
Really amazed me how once the oil got hot enough it would burn as soon as there was an oxygen supply.
Frankly, I got really really lucky, as I was renting an old dump. Probably over 100 years old, total wood construction. That wood was so dry, that the whole place would have gone up in minutes if the fire had had a chance to spread.
I don't heat up oil except in a deep fat fryer nowadays.
It sounds like a good experience for you. Nothing got damaged. Nobody got hurt. And you learned a lesson that you will never forget.
That's how I view the fire that I experienced. After school, I moved in with a bunch of buddies for a couple years. They all kind of looked at me funny when I insisted that we buy a decent fire extinguisher for the house. At that point in life, money was for buying fun things. I'm pretty anal now about stuff like that. Especially now that I have a family of my own.
I definately respect fire. Have numerous small fire extinguishers mounted throughout the house. Used one once in the garage and replaced it.
Have installed hard wired interconnected detectors in the house. Even put one in the attic and one in the garage, and with the info about trusses in another thread, seems like I really made a good call here.
Need to get some new ones for the cars. Still, there never seems to be a good place to store them in a car. Wish they'd design a fire extiguisher compartment into cars.
> Have numerous small fire extinguishers mounted throughout the house. Used one once in the garage and replaced it.
Note that the dry chemical "ABC" extinguishers should be recharged or replaced annually. The powder packs down and cakes over time, so old ones might not work when you need them. They're nice to have for practice, though.
Another point worth noting for oil fires, or any combustible liquid, is that you have to get it 100% out in one pass. If you put out 99.99% of the fire and the extinguisher runs out, all of a sudden it goes FOOMP and you're right back where you started.
-- J.S.
I suppose it'd be nice to replace extinguishers or recharge them that regularly, though that's the most frequent I've ever heard recommended. But, I simply am not gonna spend the money to do so. I have 5 in the house, and plan to add one more by the other garage door.
I've been told before that taking them down and thumping them helps shake free the clumps and ensure they work when used. I do that on occassion, but only replace if the gauge says to.
Took one in to refill once. A big one. It was old enough they said they had to run a bunch of tests on it before they could refill it. Bottom line, it was more expensive to test then fill then to just replace. Seems crazy to me, but it really seems that even the expensive ones are disposable anymore.
Your point on flammable liquids is well taken. You gotta totally get those or you've done nothing.
When in the navy I got a chance to attend firefighting instructors school in San Francisco . Talk about a blast.. we used to go into raging fires armed with nothing more than frightened 18 year old kids and put them out. after a fire or two to calm them down we'd sit inside a locked up room and dump a couple of hundred gallons of Jet fuel (JP5) light it off and let it get really raging.. Those kids were sometimes wetting their pants but we had frightened them earlier about what would happen if they dropped the hose and they hung on to it with a death grip..
when you would just about pass out from the smoke we'd charge the hose and let them fight it..
by the end of the week even the scared ones could walk into a room full of fire and calmly put it out.. Teach them the basics and have them experiance a few really big fires and they learn that fire is simple.. it needs three things to be dangerous.. Fuel/air and heat remove anyone of the three and the fire is out..
build houses where the fuel is contained or the required heat too high or you can cut off the source of air and you have a fire proof house.
bobl & Tony,
Thanks for the links. Much appreciated.
Mongo's question is a major interest of mine. What are the most common sources of home fires (besides smoking and fireplaces, which probably are the biggest).
A few years ago TOH's Tom Silva's Brother's house burned down and they featured the construction of the replacement home for the whole year, but NEVER did talk about the cause of the fire. I was quite dissapointed by that omission.
Norm (not "that" Norm)
:o)
The did discuss the cause of the fire or at least hinted at it.
It started in the heating system. It has been a while, so I don't remember the details, but I think that part of it was an "unconvential" heating system. Maybe wood burning boiler.
Also there was some lawsuites hinted at. I think by his insurance company trying to subrogate against the suppliers and/or maintiners of the heating equipment.
Gallant's next project made history. It was the first time in the show's 23-year-run that the show took on a new construction project. Gallant said the team rebuilt a home for Dick Silva, Tom Silva's older brother, shortly after his house caught fire and burned to the ground.
“‘This Old House,’ for the first time ever, decided to show people what's involved with a new house,” Gallant said. “It's a totally different process to remodel compared to a new home. There are fewer restrictions on what you can do.”
Gallant said since he did a lot of electrical work on Dick Silva's house, he was concerned about the cause of the fire.
“When they said it was an electrical fire, I thought the worst,” he said. “Luckily, it wasn't me, it was the motor. They think they have it narrowed down to a problem with the heating system, which has nothing to do with me. Thank the good Lord, because I did a lot of work on that house.”
During the construction of the new home, Dick, his wife and his two daughters were living in a 50 ft trailer right on the job site. Gallant said the homeowners were dealing with a lot of different emotions because of the house fire.
“They were really sad,” he said. “They have a beautiful house now, but they had a beautiful house beforehand.”
The house was antiques galore, Gallant said.
“If you're an antiques person, you'd go ga-ga in this house,” he said. “He collected Coca-Cola and Hershey antiques, and they lost everything in the fire. It's amazing. You think they would be able to stop a fire eventually, but they didn't stop this one. It burnt right straight down to the ground.”
In addition to rewiring the new house, Gallant also installed an automatic standby generator. The homeowner previously had a manual generator to deal with the several power outages in his area. Gallant sat down with Dick Silva and looked at the budget and the cost of the generator. Because the generator was donated, the homeowner only had to cover the cost of labor and installation.carpenter in transition
One more plug for SIPs from me - The total lack of air cavities in Structural Insulated Panels, coupled with the tightness of SIP houses in general, helps them perform exceptionally well in fires. No air, no fire. The interior side of all SIPs must be covered with a min. of 1/2" of sheet rock for adequate fire resistance.
Kevin Halliburton
"I believe that architecture is a pragmatic art. To become art it must be built on a foundation of necessity." - I.M. Pei -
I've never worked a fire in a SIP home. I'm curious if they'll get much hotter inside faster. I assume they would.
Knowing that, I'll need to be sure my crew takes out all the glass in the house pronto to avoid a possible flashover condition.
Thanks for opening my eyes to a new angle!
Have a good one,Tony
Out gassing from burning styrofoam?
In the UL fire test the SIP Model flashed to about 2000 degrees, as most forms of construction do in that test, but then it quickly died out on its own with no damage to the SIP Panels at all. The tightness of SIP construction starved the fire of oxygen and put it out. Yes, I can see a backdraft situation developing under those circumstances but the test models in UL fire tests are pretty small and the openings are minimal. I imagine a full sized home would pull enough air from the exterior fenestration, as well as the hvac system, to keep it from becoming a real issue.
As to IMERC's concern about offgassing, by the time the panels have been breached enough to start melting the foam, the home has already progressed to the point of total loss and is full of dangerous carcinogens from countless other sources as well. No firefighter should be inside the home at that point at all.Kevin Halliburton
"I believe that architecture is a pragmatic art. To become art it must be built on a foundation of necessity." - I.M. Pei -
I second the point about SIP's from a fire standpoint they are tested by lighting a fire in the corner and then checked for thermal transmission after 15 minutes..
too low to start a fire..
If the world trade center had been built of SIP's it would still be standing..
If the world trade center had been built of SIP's it would still be standing..
He, he, he... Spoken like a true panelhead frenchy. :-)>
SAVE THE PLANET, BUILD WITH SIP's
PANELHEADS EVERYWHERE SPOUTIN' OFF LIP!!!
IF IT'S STARVING CHILDREN WITH TERMINAL CANCER
WE'RE PRETTY SURE THAT SIP's ARE THE ANSWER!!!
GOOOOOOOO SIP'S!!!
Kevin Halliburton
"I believe that architecture is a pragmatic art. To become art it must be built on a foundation of necessity." - I.M. Pei -
What caused the world trade center to fail was the fire which heated the steal past its capcity which caused it to buckle and leading to additional failures..
(OK now nit pickers can point out the terrorists who flew the planes into the building.. )
steal while strong per pound is weak when heated.. Panels would be heavier and probably not the solution to building extremely tall buildings out of but certainly would have provided a stronger , more energy dispersant, thermally stronger bulding..
As for children with cancer, I rather doubt panels could help..
I don't believe that panels are always the answer.. In certain climates they will be of little benefit.. However in climates with high energy demands (either heating or cooling) they do offer many advantages, those advantages should be analized to decide what method to use when building..
I can seldom accept that stick built is the correct answer even if it is the cheapest method of construction.. If cheapest were always best we'd all be driving Yugo's (OK maybe that dates me too much,, Kia's better?)
Well, in all fairness to SIP's, Maybe SIPs aren't the answer to starving kids with cancer - but stick framing would be even less effective in helping starving kids with cancer than SIPs! :~)>Kevin Halliburton
"I believe that architecture is a pragmatic art. To become art it must be built on a foundation of necessity." - I.M. Pei -
As far as the WTC. I read a couple real interesting articles about the fire proofing insullation used. The original design called for insullating with wet sprayed asbestos. They got this done up to the 60 something floor, and the environmental laws changed. The floors above that were insullated a different way (forget how). The asbestos was suppossed to be able to sustain the building through 4 hours of a serious fire.
Forget the guys name, but the main designer of the framework repeatedly claimed that if a serious fire erupted above that level the buildings would collapse. He wrote about it in his book about building the buildings and spoke about it many times.
Later skyscrapers were designed from the ground up with different systems to protect the steel framing. But, the WTC was cobbled together in mid-stream and wasn't effectively insulated against fire. This possibly cost many people their lives, and possibly the buildings themselves.
I'm sure the highjackers knew this, and deliberately hit the buildings above those floors to exploit this weakness.
> Forget the guys name, but the main designer of the framework repeatedly claimed that if a serious fire erupted above that level the buildings would collapse.
Leslie Robertson. The impact knocked much of the gunnite off of the steel, which exposed it to heat. The steel floor joists expanded due to the heat, causing an outward thrust on the external frame. The weak link was the joint between the joists and the outside walls, when some of those failed, the column length suddenly became two stories instead of one, and right in the area where the steel columns were weakened by heat. Those columns buckled outward, and the upper floors became a giant hammer, crushing each of the floors below. Finally, the tops of the buildings were moving downward quite fast, IIRC close to 100 MPH, when they hit the ground. From buckling of the columns to total collapse took about 11 seconds.
-- J.S.
Thanks for filling in the details. It would be interesting to know if the asbestos would have been more inpact resistant then the gunnite.
What I read said that the designer didn't think the gunnite was up to the task even if undamaged. If that was correct, then the buildings were doomed to come down just from the fire.
Perhaps I should see if I can find a copy of his book, it'd be interesting to see exactly what he said. I know too well that relying on what a columnist says someone said often leaves you being decieved and only thinking you've learned something factual.
Seems to me I have read that dense packed cellulose has a similar fire retardant effect as SIP's. Since no air can move through this insulation (unlike FG), the fire does not spread. Cells as loose-packed ceiling insulation has also been found to supress fire better than FG as well. Seems like cheap fire insurance with other benefits as well.
My two firefighter cousins said they never saw a fully involved building with complete drywall. If a room had drywall everywhere (excepting solid wood and code-approved junction boxes) then the fire was still in one room when they showed up to put it out. But if a DIY bookcase project or an attic access panel or a remodel in progress opened up the envelope, those were the houses that were completely destroyed.
Up here, you not only have to survive the fire, but also the winter weather afterwards. Hopefully you run outside in enough warm clothes to make it to the neighbors house, however far that is. I have three insulated, heated structures (house, detached garage and cabin) on my lot, Each separated by 40 or 100 feet of mineral soils. So I've got options.
Just had a thought I'd like to pass along.
Last time we replaced out smoke detectors we found some with permenant batteries instead of 9 volt ones. That way you don't have to try to remember to replace them. When the battery eventually runs down, it's time to replace the unit anyway.
Seems like it was a bit more expensive - Maybe $20 or so. But it would probably end up being just about as cheap over 10 years if you add in the cost of replacing the 9 volt batteries every few months.
Two guys are shooting the breeze. One asks, "How many wives have you had?"
The other thinks for a moment and replies, "Only one—of my own."
John,
Great thread. I've been a volunteer firefighter for a while now. Doing some research for our fire company I've noticed, in my area, that the number of structure fires has declined considerably in the last 10 years all of it due to better building practices. Along with sprinklers, every family must have an escape plan and meet in a predetermined location. This way they can tell arriving firefighters that everyone is out of the house. There's nothing worse than going into a fully involved structure, and not knowing the floor plan, crawling around in heat you simply cannot imagine, loaded down with gear, on a search and rescue (hopefully not recovery), to find out later that the place was empty.
If sheetrocking trusses is cost-prohibitive, what about pre-treating them with a fire-retardant paint? How might those material and labor costs compare?
I believe someone did a test on them to see just how much fire could be slowed and the paint did help. Perhaps the coating would buy some time and structural strength, improving safety margins for all involved - resident or fireman.
BJ
(I'm a finagler at heart.)