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Dust Collection Q&A

  •   Why does NFPA 484 require a dedicated dust collector for an aluminum polishing operation? Have you ever experienced having a stainless steel part polished causing an aluminum dust collector explosion? I read an old “ask the experts” question “(…We had a community college install a dust collection system inside a room next to their welding area. There are 32 welding stations and three grinding stations (with aluminum, carbon, and stainless steel dust)…” and you never said “don’t do that”.

    Answered February 19th, 2016 by Expert: Diane Cave, P.Eng

    Aluminum dust is very reactive, not only with water but with other dusts.  This is why a dedicated dust collector is required.  Depending on the metals it is reacting with depends on the resultant reaction.  For instance, when  aluminum dust reacts with certain oxides (rusts) a thermite reaction can occur, this can create great amounts of hydrogen gas and heat.  In extreme cases combustion can occur, which is very dangerous in the presence of hydrogen gas.  For this reason aluminum is to have a dedicated dust collector.
    I personally have not experienced or heard of a dust collector exploding with an aluminum/stainless steel combination, but that does not mean that it cannot happen.  But I have experienced a aluminum/copper combination dust collector having reactions in it, that lead to excessive gas formation and small fires.  This was all caused by chemical reactions in the dust collector, and was solved when dedicated dust collectors for each product were used.
    The dust collectors that are used for welding applications are used to collect fuse and smoke, not dust.  Therefore it does not matter what type of welding you are doing.  Grinder or other hot work application are not to be connected to dust collector and are to follow proper hot work permitting systems in accordance with NFPA 51B.  If you are doing hot work and using the dust collector to collect the spark you run the risk of setting the bags on fire.

    I’m not familiar with the other question it is you are making reference too, who wrote it or who answered it.