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Borates Used In Cellulose Insulation Don’t Deteriorate Metal

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Dan R. asked:

Looking for some recommendations on blown in cellulose – do you know of any reps in the Pacific Northwest who could help answer some questions? There seems to be a concern that the boric acid used to fire-treat cellulose may deteriorate metal studs with our client and I’m looking to talk to someone who could help! Thanks

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We can answer that for you right here. This is an unusual question though, because expressed corrosiveness concerns always center on ammonium sulfate (AS), which is also used as a fire retardant in cellulose insulation, not the extremely benign boric acid (BA). Many buyers will specify all borate cellulose insulation because corrosion is not an issue under any and all circumstances.  BA/AS chemistries are also noncorrosive when correctly formulated and applied.  ASTM material standards for cellulose and fiber glass insulation contain corrosiveness tests the materials must meet.  In addition, the CPSC Interim Safety Standard for cellulose insulation contains a corrosion test required for insulation to be legally sold.

The industry-wide EPD for cellulose insulation in North America provides more helpful information. Also check this webinar that provides more answers about cellulose insulation and its environmental benefits.

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