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I am working on a project that has Fire-Retardant-Treated (FRT) wood that is over 50-years old.
The wood is installed in a conditioned space (not subjected to sunlight or rain, heated and cooled with moisture levels maintained like any building). The wood had different manufacturers with varying labels, but two did list the chemical used as PROTEXOL. I'm struggling to find information for the efficacy of the FRT wood after so many years. Do you have any information or recommendations for recertifying FRT wood with lab testing for the presence of the correct chemicals or subjecting samples to ASTM/UL/NFPA? Any help is greatly appreciated. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
5 Comments
Dan Wilder
11/21/2023 08:59:29 am
Depending on how it was applied will play into its lifespan. Surface applied, dipped, pressure treated....also the location..was it near heavy humidity and/or heat areas (boilers, steam lines, pipe chases, heaters, southern exposure vs northern, snow/ice loading). Conditioned spaces aside, there will still be variations so providing a solid test sample criteria will be important, also assuming that the pieces can be removed without impacting the structure.
Conrad
11/21/2023 11:56:15 am
If the intent is to avoid adding sprinklers to an existing combustible concealed space (or to prove it is limited combustible), it may be more cost effective to clad the 50 year old wood in something acceptable to the AHJ like a layer or two of drywall.
Jack G
11/21/2023 01:00:59 pm
I ve found that “ fire treated wood “ shrinks thru the years causing weakened structural strength fasteners popping. Lasalle Library in Philadelphia they had to rip the roof off and replace it with normal wood and fire sprinklers. Have an engineer check it out before doing anything to it.
Greg
11/27/2023 11:08:30 am
As it happens, I was observing some construction in my home town that was using d-blaze plywood. Thinking about the full lifecycle of the commercial-residential building, I looked up the manufacturer's cut sheet to understand how long the treatment would last. Basically, the same question you are asking but at the beginning of the building's life. A bit of reverse engineering in comparing the old product to a similar new product may be useful. In other words, a comparison to the pressure impregnation process and the chemical used in that treatment to the chemicals used today and treatment process. Also, was there any UL testing that covered the product then, and is it similar to the testing of today. Interestingly, the fact sheet for d-blaze is not stating any period of ineffectiveness, assuming all conditions are maintained.
Greg
11/27/2023 11:18:08 am
this might help in your efforts to backtrack across listings. d-blaze is stated as listed on this webpage from California. Possibly, there is a trail to follow to previous similar listings. Leave a Reply. |
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