Modern Materials on Fire: "The Man Trap"

[ChrWright]

The longer you work on homes, the more you understand how the various trades affect one another during a project. The more care you give at each stage, the easier it is on the guy who has to come in after you. But how many of you have thought about the guys and girls who may have to enter your project if it catches fire sometime during its lifetime?

Building codes in many cases are based on life safety and exist for the benefit of occupant and firefighter alike. In a house fire, the few minutes you slow down the fire with proper stopping might be the difference between life and death.

But advances in lightweight construction methods have brought new challenges to fighting house fires. A few links:


http://images.pennnet.com/articles/fe/thm/th_kirsh1.jpg

http://www.nfpa.org/assets/images//journal/JA09/lightweight_210x3.jpg http://www.cdc.gov/niosh/docs/wp-solutions/2009-114/images/Figure3.png



http://tinyurl.com/yaay4e9

The finished product will be attractive and will completely conceal the former stairway opening. This is not a problem under “ordinary” conditions. However, if there is a fire in the lower level with the exposed floor joists, the floor over the former stairway will become a “man-trap”:


http://www.nfpa.org/publicJournalDetail.asp?categoryID=1857&itemID=43878&src=NFPAJournal&cookie_test=1

Two recent studies detail the relationship between fire and engineered wood construction assemblies—notably, that they burn quicker and fail faster than their dimensional lumber counterparts. What do the findings mean for the fire service, builders, consumers, and NFPA codes?

[OGStilts]

Our building codes say that if we use TJI floor joists that they must have 5/8" drywall or a fire sprinkler system protecting them for this reason and has been that way for many years. I thought that was standard across the country, are you saying it isn't?

[framer55]

So do you advocate the elimination of engeneered wood products?

[Silvertree]

When I was in trade school we had fire studies as part of our structural building processes education.

Surprised to find out that a steel truss failed before a glulam, and other interesting things came up also.

Steel makes a great floor joist but its slow to work with. We no longer build for a long life, we build for efficiency. If building a new home I would consider floor joists as one thing I would spend more money on, also I would use plywood as opposed to OSB.

When I built an addition on my last home I used OSB for the wall sheathing and 1/2" plywood for the roof sheathing, over scissored energy trusses. Added about $1000 total to my home for building beyond code.

I also buiult 2 of the 4 exterior walls with 2x4 rather than 2x6 and insulated with an R-13, careful fitting and insulated corners got me close to what the R-19 walls got.

Interesting article on the fire considerations.:2thumbsup:

[SLS-Construction]

Chad - fire sprinklers were just added to the 09 codes which don't get used until 2011 in states that accept / approve them. As I recall there are up to 20 states, where either the whole state or at least a county / major city in the state requires them.

[Bender]

Why plywood instead of OSB?

[OGStilts]

Well I was refering to where engineered floors are unfinished below. Basically, what I'm saying is that if we want to use engineered lumber and not finish or drywall the basement ceiling they required us to put in the sprinkler system. It has been this way for years around here and I'm surprised it's not that way across the country. The code you are refering to is for the whole house sprinkler system.

And yes there are several villages around here who require whole house sprinkler systems now but those are not the ones I was referring to.

[ChrWright]

So do you advocate the elimination of engeneered wood products?

I'm advocating better awareness of fire issues in the build environment. A lot of guys and girls come up through the trades learning HOW to do things, but not always the WHY. Understanding how fire acts in a wood structure is important knowledge for all of us to have when working on a home.

We all know a lot of work goes on under the radar, without permits and without inspections. Even in those areas with good oversight, things get missed. Something small...like properly stopping a fire at a bulkhead and slowing its spread to another floor can mean the difference between life and death for someone living in your project years from now--or for a firefighter entering the house to protect life and property.

I've heard of whole neighborhoods of track homes being designated as DO NOT ENTER by the fire departments serving them(unless lives are in danger) because they are built to such extreme minimum standards. As someone whose spouse is a firefighter, that notion scares the hell out of me.

[Silvertree]

Why plywood instead of OSB?

It was a 3/12 pitch and 24" OC for the trusses so I added 1x4 cleats on the seams.

I seen too many swelled up bowed in roofs built with OSB.
I read the specs more than once and I know that OSB has some structural properties superior to plywood, but after 25 years in the business (at the time) I understood those properties were less important than plywoods ability to get wet and dry out without delaminating, I just wanted what I thought was a better product.

[PA Woodbutcher]

I attended firefighter training for a the local volunteer fire department 15 years ago. It was know then that trusses have killed more firefighters than any other single cause.

[Bender]

Well I was refering to where engineered floors are unfinished below. Basically, what I'm saying is that if we want to use engineered lumber and not finish or drywall the basement ceiling they required us to put in the sprinkler system. It has been this way for years around here and I'm surprised it's not that way across the country. The code you are refering to is for the whole house sprinkler system.

And yes there are several villages around here who require whole house sprinkler systems now but those are not the ones I was referring to.

I wonder if that has to do with being in a 'union heavy' state as well.

[bconley]

There are also issues with other materials such as plastics.

There is considerable concern regarding the dangers of vinyl siding, particularly its toxicity in a fire. According to The Environmental Magazine, both acid smoke and the carcinogen dioxin are released when vinyl siding burns or melts in a fire. According to firefighters, it is not unusual for people trapped in building fires to die of chemically toxic fumes before the flames actually reach them, and according to documentary reports, fire departments have refused to allow firefighters to put out house fires with vinyl siding because of the dangers.

[afkama]

Great post.
We make a point of studying each job from a fire safety standpoint. We use type X drywall as a standard, although for more reasons than fire. We make sure that the clients have fire extinguishers, and send them reminders when they need to be serviced. We also try to convince the client to build beyond code in regards to egress. Quite often we have opened walls just to fireblock the balloon framing.

[Eieio]

OSB is a product of the Devil..

[orson]

Interesting thread.

I know from working on and occasionaly supervising wood framed commercial building projects where the building is not sprinklered it is extremely difficult if not in some occasions impossible to comply with building codes in regard to fire ratings and fire blocking, particularly in complex framing assemblies.

In my opinion the cases where designers and architects do work arounds or occupancy limits are low enough that a sprinkler system is not required, there is so much added cost and difficulty in the framing and drywall stages with regard to maintaining fire ratings in ceiling/floor assemblies and bearing walls, as well as 2 hour fire ratings on certain rooms in cases where the architect is doing an occupancy limit work around to fall below the sprinklered SF requirement, it all becomes very senseless, not to mention short sighted and frought with liability.

Although I don't have experience with residential sprinkler systems my understanding is they can be plumbed in materials that will make the increased cost much more bearable than a commercial cast iron installation.

If at the same time they decrease the framing and drywall costs, eliminate the possibility or probability of catastrophic mistakes(in regard to fires) during construction and allow builders to choose building products that are superior in every respect other than fire safety, perhaps the cost is justified?

[afkama]

Although I don't have experience with residential sprinkler systems my understanding is they can be plumbed in materials that will make the increased cost much more bearable than a commercial cast iron installation.



About ten years ago I was doing a complete gut on a house I had bought for myself. I needed to upgrade the service anyway so I thought I might as well go the extra mile and size it for a sprinkler system. I was curious what my ROI would be in regards to my insurance. My agent told me that if I sprinklered the house they would have to increase my rate- said they had more claims for water damage than fire damage.

[OGStilts]

About ten years ago I was doing a complete gut on a house I had bought for myself. I needed to upgrade the service anyway so I thought I might as well go the extra mile and size it for a sprinkler system. I was curious what my ROI would be in regards to my insurance. My agent told me that if I sprinklered the house they would have to increase my rate- said they had more claims for water damage than fire damage.

Yes this is true. In fact I've gotten insurance companies to pay for the installation of water alarm systems like flowlogic and also they reduced the homeowners insurance rates on top of that for installing it just because all of the water damage claims they get. Unfortunately, those units won't be affective for sprinkler system houses.


I've installed sprinkler systems on 2 new construction houses, one was approx 6,000 sf (including unfinished basement) and one was 10,000 sf (including unfinished basement) and the sprinkler systems cost between $10,000 - $15,000. They used an orange plastic pipe (can't remember the name of it). It adds a couple of days to the schedule, and it's a pain in the arse submitting plans and getting the fire department to sign off on it as well as the coordinating of the tie-in with the plumber and inspector. The whole thing sucks on our end but if it saves lives it's worth it.

[Winchester]

In The city of Vancouver sprinklers are required, but not in the surrounding areas.

From my remodeling/reno stand-point, there isn't really a whole lot in regards to fire codes here until you get into multi-unit stuff.

I do think it would be good for all of us to be educated in this area though.

I wish there were classes offered by someone that were required for contractors to take, as well as lots of optional ones. I know the VRCA offers classes on estimating and other stuff, but they are all geared towards very large projects that involve tendering.

[WarnerConstInc.]

I actually prefer OSB, I have seen too many roofs that the plywood has delaminated. That gets to be dangerous when walking up there. I always use 5/8 rock on ceilings. I know it is not always required but, it makes me feel warm and fuzzy.

[afkama]

In The city of Vancouver sprinklers are required, but not in the surrounding areas.

From my remodeling/reno stand-point, there isn't really a whole lot in regards to fire codes here until you get into multi-unit stuff.

We did a job a few years ago in Marin County. They've had some very bad brush fires in the past so they are pretty intense on fire codes. A lot of homes are built on hillsides and if you can't put a turn around at the top of the drive, which of course we rarely have the room to do- the fire dept requires us to install a standpipe and a tram at street level to get men and equip up there. This is in case another fire breaks out they can send the trucks there. We didn't have a local vendor for the tram so we brought in an outfit from the midwest. We were required to have the tram in before we could start framing.

City gets bent because the engineer isn't licensed in CA and on top of that they decide this thing has to meet elevator code. Building dept tells me that if I can get a temporary variance from the fire dept they will let us start framing while they sort it all out.

I meet with the fire marshal who tells me that he doesn't want to step on the building dept's toes.

Then he tells me that's too bad because they won't use this thing anyway- it will only hold two men and it takes 10 min round trip. They will just load their guys and equip in pickups and run them up there that way.

I point out that the client is paying $60,000 plus yearly maintenance plus the emergency generator for this butt ugly thing at the entry to his property.

For something that will never get used????

I realized then that at some point in the past someone got the bright idea to do this. when they figured out that it wasn't going to work- they kept requiring it anyway because they were afraid of lawsuits from those who had already been dinged.

[Mike(VA)]

Recently looked at a potential job that was fire damage. Pics are of the ceiling above the island in the kitchen where the fire started. Took out the drywall and surrounding area pretty quick.

[afkama]

Recently looked at a potential job that was fire damage. Pics are of the ceiling above the island in the kitchen where the fire started. Took out the drywall and surrounding area pretty quick.

In the second photo- does that show a stairway without fireblocking in the wall at the stringer?

[bconley]

I have seen too many roofs that the plywood has delaminated.
If the plywood was delaminated, then what do you think the OSB would have looked like?

[Eieio]

I have a fire restoration to look at again tomorrow took a glimpse a few days ago. I will try to take some pics

[WarnerConstInc.]

If the plywood was delaminated, then what do you think the OSB would have looked like?

Never seen it delaminate, just swell to twice its normal thickness.