From: Jeff Tenney <jtenney46**At_Symbol_Here**ATT.NET>
Subject: Re: [DCHAS-L] Auto-ignition temperatures
Date: Tue, 11 Sep 2018 08:56:44 -0400
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: 201809111256.w8BCulU0028760**At_Symbol_Here**

The issues with powdered aluminum:


• Aluminium powder is combustible and classified as being flammable.

• Mixtures of aluminium powder and air are ignitable over a wide range of concentrations and can cause violent

dust explosions.

• Highly flammable hydrogen can form on contact with water or other chemicals and present an additional risk of

explosion, and possibly be responsible for causing a secondary dust explosion.

=E2=80=A2 The strong electrostatic charge on aluminium powder can lead to electrical discharges, which can possibly ignite

a cloud of aluminium dust.


The above if from:


The above is most likely why no auto ignition temp is listed.

Hope this helps,


From: Debbie M. Decker
Sent: Tuesday, September 11, 2018 5:33 AM
Subject: [DCHAS-L] Auto-ignition temperatures


Hi All:


We're working through a list of materials classified as H250 (pyrophoric) but are having a terrible time finding auto-ignition data to back up that classification.  It appears to have evaporated off Sigma SDS' and other sources (CRC, PubChem, ChemSpider, CAMEO) don't seem to have it either.  Most irritating, to me, is the classification of powdered aluminum as pyrophoric with no auto-ignition data to back it up - just a note "ignites on contact with air."  If that were the case, the entire pyrotechnic and propellant industries would have folded up by now.


Does anyone out there have auto-ignition data in a format they're able/willing to share? Or have any insight into where the data has gone off to?


Thanks mucho,



Debbie M. Decker, CCHO, ACS Fellow

Past Chair, Division of Chemical Health and Safety

Councilor and Programming Co-Chair

University of California, Davis





Birkett's hypothesis: "Any chemical reaction

that proceeds smoothly under normal conditions,

can proceed violently in the presence of an idiot."



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