| Author |
Message |
Michael Chusid, RA FCSI CCS
Senior Member
Username: michael_chusid
Post Number: 330
Registered: 10-2003
| | Posted on Monday, October 16, 2017 - 02:30 pm: |    |
1. Have you worked on a building designed to survive the type of wild fires in Northern California?
2. What was done to increase building survivability?
3. Is there a good code or standard for designing non-residential structures to resist wild fire?
4. Other thoughts?
Michael Chusid, RA FCSI CCS 1-818-219-4937
www.chusid.com www.buildingproduct.guru |
Ellis C. Whitby, PE, CSI, AIA, LEED
Senior Member
Username: ecwhitby
Post Number: 340
Registered: 03-2003
| | Posted on Monday, October 16, 2017 - 05:55 pm: | |
Seriously, outside of a concrete bunker or buried structure, what can survive that intense a fire? All masonry construction would greatly improve survivability. You would also need a sloped roof with slate or clay tiles.
I would be very interested to know if there are standards for non-residential construction in that environment. |
Steven Bruneel, AIA, CSI-CDT, LEED-AP, EDAC
Senior Member
Username: redseca2
Post Number: 612
Registered: 12-2006
| | Posted on Monday, October 16, 2017 - 06:10 pm: | |
Michael,
The California Building Code added Chapter 7A, "Materials and Construction Methods for Exterior Wildfire Exposure a couple code cycles ago. This Chapter is triggered when you project site falls within a area considered high hazard as shown on maps at this site: http://www.fire.ca.gov/fire_prevention/fire_prevention_wildland_zones_maps
For actual projects I have used much more detailed maps that breaks this down lot by lot.
Chapter 7A itself has articles covering: "Ignition-Resistant Construction", "Roofing", "Vents", "Exterior Covering", "Exterior Windows and Doors", "Decking", and "Accessory Structures".
Outline requirements include:
Exterior Walls, Roofs, and Decks require either Non-combustible construction, fire-retardant treated wood construction, fire-retardant treated wood shingle construction, heavy timber or log construction. Type X gypsum sheathing or a UL listed One-hour wall assembly underneath the cladding is considered equal and allows you more cladding options.
Gaps, joints, voids behind materials are all addressed. It sounds as if simple wood decks, with gaps between the boards and clearance for kids, dogs and cats to play around under are no longer possible without at least all fire-retardant wood construction.
Vents shall be non-combustible and have 1/16 to 1/8 inch diameter openings. Vents may only be installed into the underside of eaves or cornices if the space being ventilated is fully sprinkled or the exterior cladding is non-combustible.
Soffits, Porch ceilings and other underside surfaces need to conform with the wall requirements for materials.
I have only needed to conform with these requirements for Type I and II projects, which isn't an issue, but I am sure it gets more complicated with Type V projects.
As for effectiveness, I am sure these requirements help in a "simple wild fire". But for a true "Fire storm" like what occurred in some North Bay locations this last week, I am not so sure. With high enough temperatures, buildings just implode into flames. |
Mark Gilligan SE,
Senior Member
Username: mark_gilligan
Post Number: 827
Registered: 10-2007
| | Posted on Monday, October 16, 2017 - 06:13 pm: | |
Am not aware of specific formal criteria but there are some features that help. These include:
Non combustible roofs. My understanding is that wood shingles are not allowed.
Stucco exterior walls or something equally not combustible.
Probably most important is controlling vegetation around the building. |
J. Peter Jordan
Senior Member
Username: jpjordan
Post Number: 998
Registered: 05-2004
| | Posted on Tuesday, October 17, 2017 - 10:05 am: | |
This is essentially a property preservation issue, not a life safety issue. A fire would have to be relatively "cool" in order not to bake the occupants of a fire-proof structure. I think the prescriptive requirements for a fire-resistant structure are relatively straightforward, but a "safe room" in such a structure would probably have to be several stories underground (not a simple basement) with very good recirculating air systems. The nuclear shelters of the 50s and 60s come to mind. The difference is that such safe rooms would not have to support life for a very long term, perhaps a few hours, certainly not the weeks or months required to survive a nuclear event.
J. Peter Jordan, FCSI, AIA, CCS, LEED AP, SCIP
|
Brian E. Trimble, CDT
Senior Member
Username: brian_e_trimble_cdt
Post Number: 96
Registered: 08-2005
| | Posted on Tuesday, October 17, 2017 - 10:07 pm: | |
There is an ICC code, "International Wildland-Urban Interface Code" that addresses these kinds of issues. More information can be found here: https://codes.iccsafe.org/public/document/code/556/9890216. It may be the same as that in the California Building Code. A masonry structure is certainly fireproof, but there are a lot of other things to consider such as windows, eaves, and the temperature of the surrounding fire. |
John Bunzick, CCS, CCCA, LEED AP
Senior Member
Username: bunzick
Post Number: 1728
Registered: 03-2002
| | Posted on Monday, October 23, 2017 - 02:50 pm: | |
Some who died in the recent fires were asphyxiated. Fires that large literally use up all the oxygen in their immediate area. Short of a bunker with oxygen, it seems to me that large fires are best survived by evacuation.
As to type of construction, I've also heard that fire shutters are effective by resisting ignition of building contents by radiant heating. Of course, no building safety or protection system will work for the most extreme events. |
ken hercenberg
Senior Member
Username: khercenberg
Post Number: 1121
Registered: 12-2006
| | Posted on Monday, October 23, 2017 - 04:19 pm: | |
I wonder how effective a continuous insulation system made up of mineral fiber insulation at walls and roof for protection from property damage. You would need to have some means to attach protection at openings. Of course in this case many people had little to no warning.
There were some pretty clever building protection systems utilized by homeowners who used variations of that idea.
I'd still get the heck out if I could and pray I had something to come back to. |
Michael Chusid, RA FCSI CCS
Senior Member
Username: michael_chusid
Post Number: 331
Registered: 10-2003
| | Posted on Monday, October 23, 2017 - 07:30 pm: | |
Several decades ago, I was involved in introducing autoclaved aerated concrete (AAC) in North America. It has amazing fire resistance. I wanted to use it in wildland areas as I believe it could have resisted about any fire that would go up against it. Windows would need fire shutters or blocks of the lightweight AAC that could quickly be lifted into window openings. Doors would be two to four hour rated. Mechanical openings would need rated closures.
There are also active systems to protect buildings, including automatic sprinklers.
In coastal areas subject to storm surge, there are now community-wide programs to encourage resilience. We need to see the same community-wide efforts in wildland adjacent communities.
I live on a hillside in Los Angeles. I get a visit from the Fire Dept almost every year to assure vegetation is cut-back to defensible distances.
Michael Chusid, RA FCSI CCS 1-818-219-4937
www.chusid.com www.buildingproduct.guru |
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