Replies

1. 
   David_Clark | Feb 02, 2000 05:23am | #11

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   I'd like to contribute some thoughts to your discussion.

   Several years ago we at the Illinois Fire Service Institute at the University of Illinois,which is the state fire academy, conducted a series of tests of various floor systems. These included conventional 2" X 10"s, wooden I-beams,and assorted wooden and metal trusses. See "Testing Floor Systems" in the June 1988 issue of Fire Command magazine. Over the years we have held numerous discussions with the wood/truss industry.

   To summarize our tests in general, the 2" X 10's held the floor's integrity. Even though a couple joists burned through, the system held, and confined the fire.

   The wooden I-beam system failed catistrophically without warning in less than 5 minutes from ignition of the fire.

   The various truss systems eventually fell apart after about 6-10 minutes, though some did not have catistrophic failures of the entire system.

   After our tests we asked representatives of the industry who were in attendance what they thought. They replied that the results were the same thing that happened when they tested them.

   Experience from fires for years, plus common sense, tells us that the more mass of the materials, the better it is in a fire.

   However this is only one of the problems with the various lightweight systems. Another major problem is the fact that the entire system is wide open, and allows a fire to quickly spread from one spot to involve the entire under floor area. This is true with the wooden I-beams not just open web trusses, because the wooden webs of the I-beams burn completely away very rapidly. Conversely, with solid conventional lumber we tend to end up with channalized spot fires in one or two joist bays, not throughout the entire floor system. These fires do not generally quickly dump the entire system, nor endanger the whole structure. We have time to find, expose, and extinguish them.

   One comment indicated that most every building, steel or wood, will burn down, so why worry. I disagree. Most fires in conventional construction take much longer to make the building unsafe to work in or on than do fires in lightweight construction. This time factor is critical not only for fire suppression, but also for search and rescue to remove victims.

   Protecting the structural members, of whatever type, by drywall or other means is a positive step. However that does not protect against a fire that starts within or penetrates into the structure of the system. It helps, but is not a cure-all, since we all know that drywall for example is frequently penetrated or not totally sealed, allowing for rapid concealed fire spread.

   As a firefighter, fire chief, and instructor for over 30 years I think that we must recognize that today's buildings, and the fires in them, are different than yesterday's. We must change our tactics and thinking to anticipate more rapid fire spead, and quicker collapse once the fire enters the structure of the building. As another firefighter said earlier in these discussions, we must play the hand we are dealt. We must recognize that the rules have changed, and the clock is running much faster.

1. 
   Couper_San | Feb 06, 2000 07:47pm | #12

   *I was involved with fire test for Jagger's WoodI's at the UL in Toronto a bunch of years ago.I built the frame with the plywood floor and a taper boarded and taped the underside.It failed. We did it again with a new taper and it passed.I think the issue is that these type of products are going to become the standard as the dimentional wood becomes crappier and the span tables get shorter.

2. 
   Guest_ | Feb 08, 2000 10:59am | #13

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   Builders BE CAREFUL too, and keep an eye on your plumber when using I-joists! I was checking out a tract going up in Reno when I-joist were just getting to be popular. One house's garage was completly gutted by a fire during the sheathing stage. It wasn't hard to see where it started: the plumber was sweating a copper pipe from the water heater in the garage at the point where it passes through the wall into the living space. Working from the interior side of the wall, he flared up the OSB sheathing on the garage side and ignited the I-joist cieling before he even realized a fire started. It took only minutes for the fire department to arrive once a crewman noticed the smoke but by then the garage was a total loss.

   It's pretty obvious that a kindling thin joist loaded with fuel of resins and glue is readily flamable. However, since we are using wood faster than we can grow trees we have to find some alternative.

1. 
   Guest_ | Feb 08, 2000 05:05pm | #14

   *teo - Just for the record, we'reb not "using wood faster than we can grow trees". Growth of new lumber exceeds demand everywhere in the U.S, with the possible exception of the south. Down there it's about even, as best as I can tell.

1. 
   Guest_ | Feb 08, 2000 07:05pm | #15

   *"keep an eye on plumbers when using I-joists", Hell keep an eye on them anytime they're on your site. There's not a building material known to man that these guys can't chop, burn, hack or booger.I saw one crew that burned a 3" hole in the web of a wide flange beam (W8x10) to run a water line through, "cause we didn't bring enough fittings to run around it". Unf***ing believable!EB

1. 
   Guest_ | Feb 09, 2000 12:59pm | #16

   *Ron,I should avoid making flippant statements like that. I am very concerned over logging of old-growth forest here in the West, often tax-payer subsidized by national forest programs. Old growth trees offer more easily attainable wider dimensional lumber needed for floor joists than second or third growths. I-joists offer at least an alternative to ease the demand for this product. (Granted, too many acres of virgin forests are lost every day just for paper pulp) I would like to know your source of information. Hard to find the truth between the two hard lines taken by industry and presevationalists.

1. 
   Guest_ | Feb 10, 2000 03:33am | #17

   *teo - I'm afraid I can't come up with any specific sources for my comments. I've been at several trade shows where they talked about the lumber supply. Many of them talked about harvest rates vs. planting rates, and I talked with some of the forrestry folks from time to time. So my statements are based loosly on what they've told me over the years. A side point that might interest you - Remember the spotted owl thing ? That's basically why cutting is about the same as growth in the south. When logging was shut off in the northwest, harvesting in part shifted to the south and Canada. This also resulted in huge price swings in 1994, which cost the consumers millions of dollars, while doing nothing but shifting timber harvests to a different part of the country. So what exactly was accomplished ?

2. 
   Guest_ | Feb 13, 2000 08:55pm | #19

   *Well we've certainly ruined this thread! However....The spotted owl thing was right in my back yard, and I should not say "was" because that was just a media star of a passionate cause being fought every day here in the Northwest. Have you heard of Julia Butterfly?Obviously the economics are complex, but I think a lot was accomplished. A large part of the population here are intelligent, progressive and motivated people who have used a lot of tools to help reduce dangerous logging practices in their home. In the most patriotic sense, they love their country and are protecting it. The logging may have moved on, but here the Salmon population (and fishing industry) has stopped its decline into extinction as well as dozens of other species. The logging industry is at a more sustainable level, offering longer, more stable employment. Soil erosion and related mud slides, fire danger and ability for forest disease and pests to thrive have been curbed.Most of these "tree huggers" are just people like you and I stopping corrupt corporations with short-gain minded CEOs from raping our country. Let's hope they inspire all of us to learn about and rationalize the industry across the whole continent until it's run at a sustainable level.

3. 
   Guest_ | Feb 13, 2000 08:55pm | #18

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   We've been using I-joists (mostly TJI's and Weyerhauser) here for some time. However, the firefighters say that no building will collapse sooner, since the thin web burns quickly.

   Is there anyone with direct experience with this, and does anyone feel that adding some degree of protection (like Type X drywall) is worth it to compensate?

   Jeff Clarke

1. 
   Guest_ | Jan 25, 2000 09:12am | #1

   *Jeff,This is just one man's opinion but I don't think anyone can save a house once a fire gets to a certain point. Wood burns, steel melts. Fire rated drywall might slow it down though. I never thought about TJI's burning faster, but because they are so thin, it makes sense. Ed. Williams

1. 
   Guest_ | Jan 25, 2000 11:13am | #2

   *My inspector is also one of our volunteer firefighters. The issue came up in one of our conversations years ago. Long story short? He's fine with TJI's.I prefer 5/8ths rock on all exterior walls and ceilings. Nothing really to do with fire, more for stiffness. An added bonus, I suppose.

1. 
   Guest_ | Jan 25, 2000 05:04pm | #3

   *Fire performance of I-joists and floor trusses is a hot topic in many parts of the U.S. Fire services have tried to get them banned in a few cities. I don't know if any of those attempts have been successful. The salesman who sells us our I-joists just told us to avoid talking about fire performance and I-joists. I don't believe that's morally right, though. I generally discuss it openly with anyone who ask me. There have been many reports and/or accusing letters passed back and forth over this issue. I'm sure some of these are posted on the internet if you search for them.

1. 
   Guest_ | Jan 25, 2000 05:22pm | #4

   *Jeff,I do not know how true this is, it was relayed to me by my local rep. TJI tried to have their joists approved by UL for class 5 rating. They passed the test 3 of 5 times. UL had the option of passing them or not, they chose to not pass them. They will be tested again in the next few years. From what he explained to me they failed by less than a couple of seconds. This was passed on by a sales rep so I am only relaying what I was told. But I have no problem with them.Rick TukPS Get a piece and see how fast it burns compared to a piece of wood.

2. 
   Guest_ | Jan 26, 2000 05:49am | #5

   *There are a number of fire retardant paints, coatings, or additives on the market with either a Class A or Class B fire rating. I wonder if slathering some of this stuff on would make a significant difference. Has anyone had any experience using fire retardant paints?

3. 
   Guest_ | Jan 26, 2000 10:04am | #6

   *Ah, the salesman code of ethics! I too have heard the same concerns about I-joists from a firefighter, anecdotal though that is. I imagine falling through a burning floor is a firefighter's worst nightmare.So where are our resident firefighters?

4. 
   Jim_Irish | Jan 26, 2000 10:27am | #7

   *I did the firefighter gig for many years and still am a state instructor. From a firemans point the floor ijoists and truss roofs fall in the same catoragy - the rule of thumb is 10min after the fire starts the building is unsafe to enter. Steel beams will fail at 600degrees that is why you wrap them with drywall. Solid lumber takes a long time to burn thru.and so we do prefer it but will work with the hand thats dealt. All fires will go out when the steam from the water absorbs more btu's than the fire can produce-we call it a conversion

5. 
   Guest_ | Jan 26, 2000 11:26pm | #8

   *I agree with Jim. I've been a professional firefighter for 17 yrs., and spent my first 10 yrs. in our older section of town. Heavy timber commercial buildings, etc. There is no doubt in my mind that heavy timbers are much more fire resistive than lightweight construction. I don't trust I-joists or roof trusses. Its not so much the rate of combustion that is the big concern, but that they rely so much on structural integrity for strength. When they fail, they fail big. It only takes a few minutes for the gang-nail plates to start popping out of roof trusses, and I can't believe I joists would fare much better. The bottom line for the fire service is that we will always be in the business of doing the best we can with a bad situation. I joists aren't going to go away just 'cause we complain about them. The key is to learn about building construction before the fire, adjust your tactics and strategies, and like Jim said, "Play the hand you are dealt."More to the point, I'm currently building a home for my family. and I chose to use 2x10's instead of tji's. I wouldn't have them in MY house. That's my opinion, for what it's worth. Can't back it up with science, just experience.

6. 
   Guest_ | Jan 27, 2000 11:16am | #9

   *A slight digression: residential sprinklers worth it? (Maybe one next to each I-joist?)

7. 
   Guest_ | Jan 27, 2000 07:45pm | #10

   *Residential sprinklers are a rather hot topic. I believe they will someday be as common as another huge lifesaver, the lowly smoke detector. If added during the construction phase they are comparatively cheap, they go unnoticed until needed, and save lives. Something about keeping small fires small. I would have had them in my new home, but there is no way my well would supply them, so I'm stuck.