Connecting to Collections Care

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  • 1.  Intumescent coatings

    Posted 5 days ago

    Hi, Everyone,

    My organization is looking for ways to protect isolated covered bridges (made entirely or mostly of wood) from fire.  Most of these structures are many thousands of dollars away from a water system for sprinklers and are located a good distance from volunteer fire stations.  In other words, it won't take long for an arsonist or a lightning strike to destroy one of our bridges.

    We are looking at intumescent paint/coatings as a possible treatment for the bridges.  What we have read so far is encouraging, but not necessarily written from a conservation professional's point of view.  Is there anything out there written by conservators about intumescent coatings?  Alternately, does anyone have opinions about using intumescent products on historic structures?  We know that repeated applications of the coatings will be needed over the life of the structures, but are there other concerns about this treatment we should consider?

    Thanks in advance for your consideration!



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    Kim Dillon
    Cultural Resource Support Section
    Missouri State Parks
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  • 2.  RE: Intumescent coatings

    Posted 4 days ago

    Hi Kim,

    Thank you for the inquiry! I don't have expertise in architectural conservation materials.

    I reached out to someone on the Connecting to Collections Care expert list whose specialty aligns with your question to see if they have any experience with this specific type of paint/coat or know of any relevant guidance. If I hear back, I'll share in another reply.

    In the meantime, I'm interested to see if others have used or heard of this paint/coating before and can speak from firsthand experience.



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    Sky-Lyn Munoz
    Connecting to Collections Care Monitor
    Preventive Conservator
    Victoria and Albert Museum (V&A)
    London
    United Kingdom
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  • 3.  RE: Intumescent coatings

    Posted 3 days ago

    Good morning! Consider having your local fire chief/inspector come in for a consult. I realize you want to approach this from an artifact conservation view, but first and foremost, you have to protect the structure from fire (as much as you can), and that's your fire department's wheelhouse. I am the Director of the Edison Birthplace in Milan, Ohio and am married to our fire chief. I've brought the local fire department in several times to discuss fire strategies and also to troubleshoot. Trust me, they will be only too happy to help!



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    Cindi Rospert
    Director
    Edison Birthplace Museum
    Milan
    United States
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    Original Message


  • 4.  RE: Intumescent coatings

    Posted 3 days ago
    We found intumescent paint at the Nevelson Chapel in New York. While this is indoors, you may find the research helpful - it was published in Heritage in April of 2025


    You might also contact our lead author, Lora Angelova, who's now at the Getty.






    Original Message


  • 5.  RE: Intumescent coatings

    Posted 2 days ago
    In Lora's bibliography, this article is on fire-retardant coatings used in cultural heritage:
    1. Soares, I.; Ferreira, J.L.; Silva, H.; Rodrigues, M.P. Fire-Retardant and Fire-Resistant Coatings: From Industry to the Potential Use on Cultural Heritage. J. Cult. Herit. 2024, 68, 316–327. [Google Scholar] [CrossRef]


    Martha Singer

    Material Whisperer/Art Conservation Services

    http://www.materialwhisperer.com

    martha@materialwhisperer.com

    Tel: 973.943.9224




    Original Message


  • 6.  RE: Intumescent coatings

    Posted 3 days ago

    Having lost one of our most impressive and accessible covered bridges to fire a few decades ago, this seems a great question.

    Have you considered the least expensive possible sprinkler system - I suspect that would be a deluge system with just open heads and no local activation heads?

    Have you considered an economic analysis including expected time to bridge replacement due to deterioration rather than sudden loss, frequency at which any one bridge is expected to be lost to fire, costs and expected reliability of maintenance or replacement of intumescent coatings, etc.?

    Such a good question to have posed, thanks,
    Rob



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    Robert Waller
    President
    Protect Heritage Corp.
    Ottawa
    Canada
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    Original Message


  • 7.  RE: Intumescent coatings

    Posted 3 days ago

    There are some articles written regarding intumescent paint and historic buildings, although some are older documents.  I have attached a few links below. Please take my thoughts as just one opinion and consult with a fire protection engineer about the best intumescent coatings for your structures. <u1:p></u1:p>

    I have evaluated intumescent products for archives and museum facilities, but these are all new build facilities, so I don't have direct experience with historic structures. On new interiors, especially in or near collections storage rooms, we strive to use a water based intumescent coating that is durable, abrasion resistant, no dust output, and with low VOCs.  With that, we always advise that the building off gas at least 4 weeks before moving in collections, and in reality, it is usually a much longer off gas period. <u1:p></u1:p>

    Some of the intumescent paints have chemical compositions that we try to avoid as they degrade collections, but I have not evaluated them for the long-term effects on historic wood or outdoor use.  Additionally, some of the most durable intumescent coatings may not have the texture or finish that you would like for an historic structure. Some products can be painted.  Many wooden structures prefer transparent coatings and there are some specific products for timber systems. You can ask for samples, run your own scratch and abrasion tests, check the color, and evaluate how it will look over time. <u1:p></u1:p>

    Note that the intumescent must be applied correctly or it can crack and fail.<u1:p></u1:p><u2:p></u2:p>

    The fire ratings of the intumescent coating are very important, and I usually review those with a 3-hour rating or a 4-hour rating. It is best to check with your fire protection engineer the best application and rating for your particular use. <u1:p></u1:p>

    I have reviewed a variety of intumescent products, listing the pros and cons from a preservation perspective. I do not make the final recommendation. My review then goes to the staff, architect and fire protection engineer for evaluation and decision. Some coatings have no or low VOC's, while some are more durable with acceptable higher VOCs or with small quantities of problematic chemicals that should dissipate with off-gassing. Application, specific requested properties, fire rating, cost, and location also play into consideration.   <u1:p></u1:p><u2:p></u2:p>

    https://www.buildingconservation.com/articles/intumescent-products/intumescent-products.htm<u1:p></u1:p><u1:p> </u1:p>

    https://www.environment.nsw.gov.au/sites/default/files/heritage-maintenance-intumescent-paint-systems-and-heritage-buildings-2021.pdf<u1:p></u1:p>

    https://natfire.com/blog/fireproofing-historic-wooden-bridges/

    NPS may be able to provide guidance. 



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    Michele Pacifico
    Archival Facilities Consultant
    Jackson
    United States
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    Original Message


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