From: "Stuart, Ralph" <Ralph.Stuart**At_Symbol_Here**KEENE.EDU>
Subject: Re: [DCHAS-L] 'Large fireball' injures students in chemistry experiment gone wrong
Date: Mon, 27 Nov 2017 13:08:20 +0000
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: E63E2F1D-6061-4864-A348-59C5572FCDBE**At_Symbol_Here**

> I also tell my teachers that it is appropriate (and highly recommended) that student lab reports also include a section on safety precautions. This is how we foster a culture of safety.
I agree that this is an important learning opportunity. The ACS's chemical safety program is developing some support materials for this aspect of student lab work. We have hopes that these will be available in 2018.

Thanks to everyone for the contributions to this discussion. You may be interested in an effort that the Consumer Product Safety Commission is developing around "flame-jetting". I hadn't heard of this phenomenon until a meeting last year, but it could be related to the rainbow demo instances as well as other fire events in public settings.

An NFPA article on flame-jetting can be found at

Of particular interest is the paragraph that states
"Flame jetting was only observed when the container was being tilted and the vapors were pouring from the mouth of the container. It is hypothesized that initially, when the container is upright, the head space above the liquid is too fuel-rich and above the upper flammability limit, meaning that combustion is not supported within the container. As the container is tilted and vapors begin to pour from the open mouth, however, air is entrained into the head space and the fuel-rich mixture eventually falls within the flammable limits; if an ignition source is present and combustion occurs, the flame propagation condition inside the container can lead to flame jetting."
I think that this means that, depending on how full the solvent container is, someone could conduct the same demonstration several times without incident before the flame jet occurs.

- Ralph

Ralph Stuart, CIH, CCHO
Environmental Safety Manager
Keene State College
603 358-2859


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