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Previous by Date: Subject: Re: [DCHAS-L] Thirteen people hurt in chemical explosion at Nevada museum Date: Friday, September 5, 2014 1:03:28 PM Author: larry.tirri**At_Symbol_Here**UNLV.EDU |
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I finally saw a good view of the Reno demo accident last night. What it and the "rainbow" demo accident have in common, among other things, is the unfortunate pouring of flammable solvent onto an ongoing fire. In the case of methanol, the ambient temperature vapor pressure is well between the upper and lower ignition limits. In the latter case the bottle was a 4 liter that was at the time 4/5th headspace. In the video you could easily see the flame advance into the headspace and propel the liquid out like a rocket motor. The bottle replenishing the former demo (rainbow) was also a 4 liter of methanol, with the same unfortunate result. Pouring flammable solvent onto a fire is obviously in general a bad idea, but those solvents with vapor pressure in between the flammable limits are guaranteed unwanted excitement.
The container failure concern is a good one though. In receiving surplus chemicals into our facility at the University of Wisconsin, I've seen way too many cases of inappropriate use of containers for some waste mixture. Plastic with seams, that fail, is one that people just don't see coming.
I'm all for exciting chemistry demos but planning ahead, learned insights and staying with the exact protocol saves it.
-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of David Roberts
Sent: Friday, September 05, 2014 10:53 AM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: Re: [DCHAS-L] Thirteen people hurt in chemical explosion at Nevada museum
My 0.02 on these demos - including what I pass on to members of my department who participate in outreach events. I've seen a lot of these types of accidents/incidents over the years. None personally, just in terms of reading about them. I feel that many of these events have happened due to container failure. That is, using the same container over and over, eventually developing some sort crack in the container that leads to some sort of catastrophic container failure.
Many people have done the same demo for years, and suddenly have issues, leading to a news report and hospital visits and whatever. I do feel it's often something simple like container failure due to overuse, though I don't have any real evidence for this. Personally, I have seen many containers fail over the years, and often times it is from something like this happening.
Be safe all
Dave
On Sep 5, 2014, at 10:36 AM, CHANDRA, Tilak > There are many conflicting reports about the incident and we need to wait for the final scientific report, if done correctly. Rainbow, NY High school and other recent incidents are almost same (methanol and salts) and keep happening. All these incidents are mainly caused by human errors or not having the hands-on training and instrument failure. We need to know the scale of the DEMO/reaction (qty. used of Boric aacid, MeOH, H+), SOP, training, containment etc.
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>
> Tilak
>
> -----Original Message-----
> From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of Ralph Stuart
> Sent: Friday, September 05, 2014 8:29 AM
> To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
> Subject: Re: [DCHAS-L] Thirteen people hurt in chemical explosion at Nevada museum
>
>> When I used to climb and mountaineer more I used to read a yearly accident report.
>
> I was talking to a Cornell faculty member who was also a skydiver and she reported that there is a similar system in that sector. There has been a precipitous decline in accidents over the last few decades as a result.
>
> I guess when your business involves clear risks to your customers, you develop a proactive safety system. It will be interesting to see when the lab management community moves beyond surprise that there is risk to acknowledging and managing that list.
>
> - Ralph
>
> Ralph Stuart, CIH
> rstuartcih**At_Symbol_Here**me.com