[GSBN] Strawbale Classroom in Cork Ireland (Fire Resistance) (+SB code)

Thu Mar 15 22:12:47 UTC 2012

While it isn't a direct answer to your questions, Art and Tom, there are three factors that make strawbale buildings a little different than most structures, in the case of fire.  1) While plastered strawbale walls are quite fire resistant, they comprise a super-insultated envelope that, in the case of a significant fire inside the building, can result in much higher internal temperatures than would occur in a similar fire within a less-well insulated and less robust building, such as a stick-framed or steel-framed residence.  2) Due to the insulative properties, and the dense, thick, low-oxygen interior of the walls, smoldering hot spots can be created inside a strawbale wall exposed to a significant fire.  These hot spots can last for a long time after the initial fire is extinguished.  They may be hard to locate, and if not dealt with, could possibly be the source for ignition of subsequent fires.  3) Few firefighters have any experience with putting out a fire in a strawbale building.  This may lead to using techniques which are less effective for strawbale structures, unnecessary destruction of the walls, the possibility of turning the fire-resistant plastered walls into an additional fuel source, by breaching the walls and breaking them up, scattering and decompressing the straw bales.  

A few years ago, Martin was working with a person very experienced in fire fighting techniques and technology.  This led, among other things, to a prototype device that could be carried by firefighters, which used a piercing nozzle to make small holes in the plaster, and then inject liquid carbon dioxide into the wall at strategic locations to suppress fire and extinguish hot spots within strawbale walls.  Perhaps Martin can update us on what advances he is aware of, relating to firefighting in SB structures.  

Derelict

Derek Roff
derek at unm.edu

On Mar 15, 2012, at 2:50 PM, Oasis Design wrote:

> Martin, 
> 
> I'm working on the hydrant water supply as part of the integrated design for a project with at least two straw bale buildings. The required hydrant flow in this jurisdiction is determined by the Insurance Service Office procedure for needed fire flow.
> 
> Can anyone help me figure out the Construction Class number for earth plastered straw bale for purposes of this calculation?
> 
> Here's a table from the document linked above that is sort of a Rosetta Stone for translating amongst the various standards that you all might be familiar with:
> 
> <Picture 23.png>
> This calculation is non-critical; we can get it to work with ISO class 1 (the worst) but I feel like we'd have more credibility if we had an idea what actual class the building fit in...
> 
> Thanks, 
> 
> Art
> 
> 
> On 3/15/12 1:24 PM, martin hammer wrote:
>> 
>> Tom -
>> 
>> First a note re: the second EBNet link Derek listed.  This is the repository page for all supporting documentation for the proposed Strawbale Construction chapter of  the International Building Code.  It includes the 2006 ASTM fire tests reports and the fire test video.  It also includes the other documents that support the proposed SB code, as well as the proposed chapter and appendix as published by ICC on March 13.  (note, ICC did not include a few final revisions I requested, for example potentially allowing baled materials other than the 5 cereal straws.  But I will pursue including them in the longer review process.)
>> 
>> In addition to the excellent 2006 fire tests conducted by D. Eisenberg, B. King, and B. Obregon of this list, there is the excellent 2004 German fire test by FASBA and Dirk Scharmer (of this list).  Here is a summary of this test by Dietmar Lorenz (of Dan Smith’s office) from the Fall 2006 Last Straw:
>> 
>> “A major step toward Code recognition was accomplished in February 2006 with the General Approval (“Allgemeine bauaufsichtliche Zulassung” or AbZ) of “Construction Straw Bales” as insulating infill within certain wall assemblies. As part of the application the Fachverband Strohballenbau had to show compliance with the following criteria:
>>  
>> 1. Flammability:
>> In a standardized test straw passed as “Normalentflammbar B2”, i.e. it is not considered an easily flammable material, but of normal or regular risk regarding combustion and flame spread.
>>  
>> 2. Fire Resistance:
>> An unplastered 18" wide bale wall was tested to achieve 30-minute fire resistance (F-30), and 90-minute fire resistance (F-90) with 3 cm of earth plaster on each side. A minimum of F-30 is required, except in single-family residences with at least 5m of separation from adjacent structures. Fire resistance is technically not part of the AbZ, but included as a general prerequisite.”
>> 
>> You can go to www.fasba.de (click on English) and you can find a link to the fire test (in German) and see a poster on SB Fire Resistance that gives a good summary.
>> 
>> Martin
>> 
>> 
>> 
>> On 3/15/12 10:33 AM, "Derek Roff" <derek at unm.edu> wrote:
>> 
>> Seeing the videos of fire tests may be useful in convincing the council, in appealing to the "seeing is believing" tendency of our brains.  Catherine Wanek documented the New Mexico fire test in the 90's, and could probably send you a copy of the video.  Bruce King has a 10-minute video on his website of the fire test done a few years ago in Texas.  
>> 
>> http://www.ecobuildnetwork.org/resources/straw-bale-fire-test-video
>> 
>> There are many other useful documents on Bruce's site, including PDFs of the ASTM testing reports for the one-hour and two-hour fire tests.  Scroll down to Fire Resistance on this page:
>> 
>> http://www.ecobuildnetwork.org/strawbale-construction-code-supporting-documentation
>> 
>> Good luck,
>> Derelict
>> 
>> Derek Roff
>> derek at unm.edu
>> 
>> On Mar 13, 2012, at 4:03 AM, Tom Woolley wrote:
>> 
>> Dear friends
>> 
>> here is the old chestnut about strawbale and fire!
>> I would be most grateful if anyone willing to help with this could email Alan Wiseman directly
>> I am sure that Alan is aware that properly plastered strawbale walls are not a fire risk, 
>> however he needs some official looking documents to give to his local authority to convince them to issue a fire certificate
>> 
>> The situation in Ireland is different from the UK ...
>> we were able to convince building control in Northern Ireland that we complied with one of the US Building Codes and that was sufficient to get approval!
>> Irish Regs
>> http://www.environ.ie/en/DevelopmentHousing/BuildingStandards/
>> 
>> many thanks to anyone who can assist
>> 
>> Tom Woolley
>> 
>> Begin forwarded message:
>> 
>> From: alan wiseman <wisemandesigns at gmail.com>
>> Date: 13 March 2012 09:46:47 GMT
>> To: <tom.woolley at btconnect.com>
>> Subject: Strawbale Classroom
>> 
>>  
>> Dear Tom,
>> 
>> I have received planning permission for a strawbale classroom .This is located in a built up area, next to a large block creche on one side and 2m away from a dwelling on the other side, a couples of miles from Cork city. But now comes the awkward part. As it is a commercial building we need to get a Fire Certificate This will be difficult as there is no precedent here in Ireland for this (there are plenty of structures, mainly dwellings, as you are aware, but none commercial that needed a Fire Safety Certificate).
>>  
>>  I am aware of commercial structures in the UK that have been built with strawbales.I would like to find out how they managed to persuade the fire department. I have test results from North America but precedents in Europe, particularly in the UK would better strengthen our case.  I am hoping you might have some insight or indeed contact on this. Any help is greatly appreciated.
>> 
>> 
>> Thanking you.
>> 
>> Kind regards,
>> 
>> 
>> Alan. 
>> 
>>  
>> 
>> 
>> 
>> 
>> 
>> 13 Amberley Lawn
>>  
>> Grange
>>  
>> Cork
>>  
>> 
>>  
>> Tel: 021 489 99 79
>>  
>> Mob: 086 877 6564
>>  
>> www.wisemandesigns.net <http://www.wisemandesigns.net/> 
>> 
>> 
>>  
>> Tom Woolley
>> 
>> Rachel Bevan Architects
>> 80 Church Road
>> Crossgar
>> Downpatrick
>> BT30 9HR
>> tom.woolley at btconnect.com
>> 028 44 830988
>> www.bevanarchitects.com <http://www.bevanarchitects.com/> 
>> 

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