ECN Forum Forums Code Related Discussion Building Codes for Electricians Fire stopping / Draft stopping

Florida is revisiting this as I said upthread. They have changed the wording of the code for plate penetrations fron "draftstopping" to 'fireblocking" which will eliminate foam in wood construction.
This is still not the same as "firestopping".
I can see that this will be another year of trying to decide what 67 counties and 500 cities will consider appropriate. They seem to be as interested in smoke as they are fire. I suppose red caulk will always work but it is probably more than you need.

You've got to admit, the whole idea of "fire rated" cauking in wood frame construction is pretty silly... especially in view of all the other combustible materials like insulation, carpeting, drapes, furniture, etc.

Using fire stopping on wood frame construction is kind of like putting a steering wheel lock on Rolls Royce and parking in the South Bronx... a lot of good it'll do.

If we're truly serious about fire safety and protection, we'd stop using wood framing and construction altoghether. If I were to build a new home for myself from scratch, I'd go steel and concrete.

At minimum, the newer fire resistant paint and wood treatments should be applied with all new construction. By the way, anybody have any opinions on these treatments?

Joe

That is why they say "fire blocking". It just blocks the rapid spread of fire products (smoke) and delays the actual spread of the fire so you have time to get out. If the wall cavity is really fairly well sealed the fire might choke itself out before it ever really gets loose. It is not really that easy to light the side of a 2x4. If you have foam in there the foam itself may be the biggest accelerant for the fire. It certainly will not help the smoke problem.

As I understand it, fire behaves in ways that sometimes seem to be the opposite of "what common sense would tell you."

In actual fire tests, wood framed walls perform identically as walls with light steel framing. Indeed, contrary to popular expectations, the wood members don't burn, so much as slowly char away.

This all changes if there is active airflow across the wood. That's why draft stops and fire blocks are so critical. Again, testing showed the old practice of blocking every 4 ft was no more effective than blocking every 8 ft, so the requirement was dropped. We now 'block' only at each floor level.

It is correct to note that the vast amount of fuel is in the contents, rather than the building itself.

It is also quite correct that we need to know more than just the electrical code!

Are any jurisdictions still on the UBC?
California recently made the switch to the International Code. I thought we were the last to do so.
(The need to know Codes other than the NEC is the reason that this forum area is here)

[quote=JJM]At minimum, the newer fire resistant paint and wood treatments should be applied with all new construction. By the way, anybody have any opinions on these treatments?[quote/]

Out here at Sequoyah Nuclear, the carpenters apply a chemical to all wood used inside the plant. The chemical makes the wood fire resistant. Not sure for how long, but it turns the wood blue. It also weakens the wood also... not sure on the specifics though. Any one else heard of this?

Luke, I am not familiar with the exact product / method you describe, but....

It sounds like a bromate (bromine salt) solution is applied. I don't see how it would 'weaken' the wood, but it might make the surface softer.

Any treatment applied to wood, to make it "fire resistant", has only been evaluated to reduce the surface flammability of the wood. That is, the ability of a flame to catch on the face of the wood, then spread along the surface. There is absolutely no reason to think that the wood will, ultimately, burn any differently than "normal" wood.

AFAIK, all 'fire' and 'rot' treatments applied to wood are based upon some sort of salt (though not necessarily table salt!). Keep this in mind, especially in moist areas; those same salts will corrode metal just as well.

Reno you bring up a good point about corrosion. I assume you guys know if you are shooting fasteners or attaching galvanized boxes to the new PT lumber it will rust off your nails, screws and straps. This stuff is tough on anything steel, galvanized or not. The green fasteners are OK but stainless is better. They originally said double hot dipped galvanized will work but I am hearing, "not so much", from my lumber supplier.