fireproof construction seminar

[davidj]

For folks in the SF Bay Area, Truitt and White have a seminar tomorrow on the new CA "Wildland Urban Interface Building Code".  I think this is mostly concerned with fire resistance and probably applies to anyone trying to build a cabin in CA as of this year:

http://www.truittandwhite.com/sem_event/index.cfm?fuseaction=eventarticle&rowid=141

Hopefully I'll be there and I'll try and post a summary if they come up with anything interesting.

[MountainDon]

It would be interesting to all, not just those building in CA at present. Many things, good and bad, begin in CA and migrate.

[glenn kangiser]

Yup -- that and the economy is what has pretty well stopped building around here.  Only about 4 new home permits issued in the first 5 months this year in our area.

If you get to go watch to see how it steers builders to buy certain corporate produced products - generally these new codes and laws have angles besides safety in mind.

[davidj]

Finally time to jot down a few notes on the fireproof building seminar.  I'll chop this up into smaller chunks so something makes it out even if I get distracted.  Note that I often can't read my own handwriting, let alone understand it, so I wouldn't make any important decision based on these postings...

The part of the California Building Code that covers the fireproof stuff is apparently "chapter 7A".  It applies to:
- all "state responsibility areas" (where the state handles fire protection - basically county-permitted construction)
- areas with a very high fire risk in "local responsibility areas" (places where someone other than the state provides fire protection and they are likely to be subject to wildfires)

There's no good computer map yet of the high risk local responsibility areas, but it sounded like it's obvious for a lot of places - e.g. downtown Berkeley is not very high fire risk, the East Bay Hills are.  I'm guessing a lot of cabins will be in state responsibility areas so it applies regardless of the level of risk.

It applies to new construction from Jan 1 2008 in state responsibility areas, whereas some local responsibility areas may hold off until July 2008.  The code applies based on the date of new construction, e.g. if you built your house last year then you can ignore it for remodels but if you built it this year then all remodels are covered too.  However, some local codes (e.g. Marin, San Diego County) are tighter and may insist on compliance for major remodels.

[davidj]

One interesting point was that most structures don't burn down during the main fire, which typically passes through in just a few minutes.  Most get destroyed because of a small fire that starts during the pre-fire or post-fire phase, which lasts much longer.  If you are not fortunate enough to have Glenn as a neighbor, then the small fire grows over a period of time and eventually burns the place down, primarily because there's no one around to put it out.  Lots of the code seems to be addressing this issue.

There was one other point where my guess at what happened was completely wrong.  I thought they'd rushed this out because of the fires in LA last year.  Turns out they started on this in earnest in 1995!

The areas that are affected by the code are:
- roofing
- vents
- siding
- eaves
- windows
- doors
- decks
- vegetation

The Calfire Wildland Urban Interface Products guide seems to be the definitive reference on what products can be used and it is supposedly updated regularly.

[MountainDon]

they started on this in earnest in 1995!

Good to see they're on top of this issue...

[davidj]

For roofing, very high fire risk areas need class A roofing materials, lower risk need class B etc.  Metal is class A.  Some other points:
- opening at edges of roof, e.g. under clay tiles, must be plugged with e.g. a "birdstop"
- exposed metal valleys must have roll roofing underneath them
- gutters must have some way of minimizing debris, e.g. a gutter cover

No eave or soffit vents are allowed unless proven to resist the intrusion of embers or flame.  This is problematic right now - regular vents with a mesh large enough to pass the existing vent code have a mesh that's too big to stop embers!  Some products are on the way to fix this ("Brandguard", "Vulcan vent"), although apparently you might get away with 1/8" mesh if you're lucky.  Through roof, ridge and gable vents are _not_ covered by the code (yet!) and are fine.

Eaves themselves also need to be non-combustible.  There's a penetration test that's used, but there were no good examples of what might pass the test (although a boxed-in soffit of cement board would seem to be fine!).

For windows, you essentially need dual pane with at least one pane tempered (which can be either the inside or outside pane).  Window frames aren't covered by the code.

There are also some requirements on doors - the advice was to check the product literature (although I think tempered glass was implied).

Siding needs to be one of:
- non-combustible
- ignition-resistant
- 6" diameter logs
- certain types of wood siding with specified joints
The WUIP guide (see previous post) has a bunch of info on approved siding.  It was emphasized that it's just the siding/sheathing setup that matters - e.g. straw bale underneath is fine.

The part of an attached deck that you walk on is also covered (I guess this means hand rails aren't covered!).  Again, non-combustible decking is fine and untreated redwood/cedar is okay (note the "untreated" applies to its state at inspection - adding stain doesn't void this and apparently, after just a few weeks, doesn't significantly affect it's fire retardant properties).  Interestingly many existing plastic-like deck materials (e.g. trex, evergrain) burn pretty well and are definitely not approved.  There is a new type of trex - "Accents Fire Defense" that is covered, but there are only a couple of styles and there's a 10-15% pricing premium.

Vegetation needs to be clear out to 30' and reduced out to 100' (except at property lines).

[MountainDon]

For windows, you essentially need dual pane with at least one pane tempered (which can be either the inside or outside pane).  Window frames aren't covered by the code.

So vinyl frames are oaky as long as there's one pane of tempered glass... the frame can melt and allow the tempered glass to fall in or out of the structure leaving a big hole in the wall.....   



Thanks for the info davidj

[davidj]

No eave or soffit vents are allowed unless proven to resist the intrusion of embers or flame.  This is problematic right now - regular vents with a mesh large enough to pass the existing vent code have a mesh that's too big to stop embers!  Some products are on the way to fix this ("Brandguard", "Vulcan vent"), although apparently you might get away with 1/8" mesh if you're lucky.  Through roof, ridge and gable vents are _not_ covered by the code (yet!) and are fine.

I noticed a display of the "Vulcan Vent" ember-proof vents at one of the local lumber yards.  They had a price of $18 on the 2" round vents.  I assumed this was for a box of vents, but it turned out that it was for one vent!  Even my little 20x30 has 20 rafter bays - put a couple of these in each one and you're looking at almost $1000 of vent!!  This starts to make spray foam insulation look like the cheap option...

[cordwood]

No eave or soffit vents are allowed unless proven to resist the intrusion of embers or flame.  This is problematic right now - regular vents with a mesh large enough to pass the existing vent code have a mesh that's too big to stop embers!  Some products are on the way to fix this ("Brandguard", "Vulcan vent"), although apparently you might get away with 1/8" mesh if you're lucky.  Through roof, ridge and gable vents are _not_ covered by the code (yet!) and are fine.

I noticed a display of the "Vulcan Vent" ember-proof vents at one of the local lumber yards.  They had a price of $18 on the 2" round vents.  I assumed this was for a box of vents, but it turned out that it was for one vent!  Even my little 20x30 has 20 rafter bays - put a couple of these in each one and you're looking at almost $1000 of vent!!  This starts to make spray foam insulation look like the cheap option...

See Glens post above!

[Don_P]

The pictures I've seen after wildfires speak for themselves though. The new houses are weathering the storm, the old ones are just foundations. The intent is good.

[rick91351]

A lot of 'fireproofing' is just common sense which I see a lot of on this form.  If you are going to have wide eves and overhangs you have to cut the trees and brush back.  In effect give yourself a safety zone.  Wide eves and overhangs are wonderful at keeping snow and ice away from a dwelling but they are also wonderful heat sinks.  You simply must take fuel away fuel from those areas.  If trees that surround your dwelling have dead limbs remove them.  If a tree is showing signs of getting sick don't wait until it is a lighting rod waiting to happen, best just get it out of there.

If you have a load of needles and leaves laying in valleys on the roof get up there and remove them.  If they don't catch fire at an opportune time they certainly will shorten the life of the roof.  Once again get them off there.

Truly and very seriously this is one area that a ounce of prevention is a lot better than a pound of cure.  One can not depend on the BLM or the Forest Service to be there quickly.  Remember they are not your city nor the county rural fire department.  When they do arrive often times they call in the retardant drops.  They are very exciting and fun to watch and should be because around here from an C-130 it is now over $10,000 a drop.  If the fire starts on your property and you are found at fault guess who pays?  I will give you a hint; it is not your Uncle Sammy.  I also hate to inform you but your kids roasting marshmallows and starting a forest fire is not considered an act of God by the Forest Service.  Even if you and your attorney can get the USDA to settle for a few cents on the dollar you are often time still out thousands of dollars in legal fees and settlement costs not to mention your time way from work.  And the ill feelings that have now 'heated up' with all the cabin neighbors. 
   
A great example is Mountain Don's fire a fire that crossed on to his property.  That structure was saved really because they had taken time to remove fuel from around the structure.  If you look at the pictures around Mountian Don's Cabin you do not see any limbs hanging to the ground.  Very few limbs are even hanging close to the ground.  These do in fact act as a conduit pulling the fire from the ground to the trees.  Nor have I ever noticed in the pictures that Don has posted in the past a lot of fuel laying on the ground anywhere around his cabin or his property.  If there is no fuel there is no burn; it is that simple. 

A certain amount of fire is not detrimental to Ponderosa pine trees, nor Douglas Fir trees if you can keep it out of the tops of the trees of course.  Certainly it has been noted in many publications and papers the benefits and use of these types of low grade fires to control insect populations and to thin out certain types of vegetation grow that rob water and nutrients from trees.  Alpine Fir and many of the higher Alpine verities you will find the bark to be is very thin and 'pitchy'.  This make their bark is very sustainable to blistering and susceptible to transferring heat and fire from the ground to the tree.  In effect making a real neat roman candle.

I feel what saves this verity in nature really is the fact they grow in the cooler damper climes of the higher altitudes.  Very seldom do you ever find them in thick forest situations.  Granted they do grow in thick groups and groves but for the most part not the like the huge pine and fir forests that can run for miles and miles.  However if you ever are fortunate enough build around them remember in very dry drought years they can be extremely volatile.  Because of the pitch and the slow growth they carry a huge amount of fuel.

Probably nothing that has not been already posted and already rode to death but just a little common sense goes a long way.

rlr                       

[waggin]

For a very good basic illustration of some (but definitely not all) site considerations for fire safety/defense zones:

http://your.kingcounty.gov/ddes/fire/pdfs/FirewiseBrochure.pdf

It's an illustrated, printable brochure packed with tips on making your property and buildings safer.

This was part of a forest stewardship class I took, and I feel like I learned a lot from it.  There are a lot of things that most or all of us have done over the years that probably weren't ideal.