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Previous by Date: Subject: [DCHAS-L] Lab Safety Teams article Date: Thursday, January 27, 2022 at 2:15:50 PM Author: "Gmurczyk, Marta" <M_Gmurczyk**At_Symbol_Here**acs.org> |
Next by Date: Subject: [DCHAS-L] NYCOSH Webinar on masks and respirators, Fri. February 11th 2pm-5pm Date: Thu, 27 Jan 2022 15:37:15 -0500 Author: Ralph Stuart |
I'm have been on ISO 10156 and 10298 for 20 years. In 2005 there was significant debate over what system is acceptable, US uses a 25 mm diameter glass tube which was based on Zabetakis, M. G., 1965, Flammability Characteristics of Combustible Gases and Vapors, U.S. Bureau of Mines Bulletin 627 while the Europeans were using a 50 mm tube with a lot of updated data from BAM. Both methods relied on visual observation of flame propagation. The ASTM method using a 5 liter stainless steel sphere is more precise and relies on temperature and pressure rise.
The significance of this is that the DOT uses the Bureau of Mines method and data while the UN for transportation and Global Harmonized Standards uses the BAM data for classification of gas flammability. In addition the definition of a flammable gas for transportation is flammable in concentrations of <13% in air or has a flammability range wider than 12% regardless of lower flammability concentration. This may not identify some gases which are flammable under certain conditions, ammonia is a good example of this. It has a LFL of 16% which is difficult to achieve in an open air release. In confinement however it can easily reach this in a room. Ammonia has been involved in numerous explosions some fatal. Many of the new refrigerants are flammable in a very narrow range making them non flammable for transportation. Many users are not aware of this and have gotten into trouble. This is why GHS now has a Flammable 2 classification for these
Eugene Ngai
Chemically Speaking LLC
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Daniel Crowl
Sent: Thursday, January 27, 2022 1:08 PM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] Chemical Safety headlines (10 articles)
The US mostly uses ASTM - American Society for Testing and Materials. I was on the ASTM E27 committee for a number of years which deals with Hazard Potential of Chemicals. This includes flammability.
We did pay attention to ISO standards, but we never had complete consensus. There was always a huge amount of debate on the E27 committee on the various methods. Of course, the testing methods were never perfect and always had flaws.
Dan
On Thu, Jan 27, 2022 at 10:38 AM Eugene Ngai <eugene_ngai**At_Symbol_Here**comcast.net> wrote:
I realized I made a mistake. The US is always higher than ISO 10156 which is the accepted International standard for flammable gases. Sorry for the error
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Eugene Ngai
Sent: Thursday, January 27, 2022 11:33 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] Chemical Safety headlines (10 articles)
Yes, I agree. There are significant differences in gas LFL values between the US and Europe because of the test apparatus. The US is always lower due to the smaller diameter tube used as well the requirement to see a flame propagation downward. In addition LFL for a pyrophoric gas is a significant challenge due to ignition while it is being introduced and prior to mixing.
In recent testing on disilane we had to use a special test apparatus that was custom designed for silane testing to determine the LFL. This was summarized in a recent article
Nguyen, T. T. ,Cao, K. Q., Yang, M. H., Chen, J.R , Tsai, H.Y., Gordon, M., Ngai, E., "Experimental Studies on Ignition Behavior of Pure Disilane and Its Lower Flammability Limit", CHEMICAL ENGINEERING TRANSACTIONS, VOL. 90, 2022
Eugene Ngai
Chemically Speaking LLC
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Daniel Crowl
Sent: Thursday, January 27, 2022 10:50 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] Chemical Safety headlines (10 articles)
HI All,
One needs to realize that the flammability "properties" of chemicals are not fundamental properties such as density, heat capacity, etc.
They are only values derived from a particular apparatus and procedure. This includes flammable limits, flashpoint temperatures, ignition energies and AITs.
Thus, one needs to be careful in applying these "properties" to real situations.
The AIT values for dusts are empirically derived from an apparatus that suspends the dust in air - not dust piles.
Thus, it is not clear how the AIT applies to the sulfur dust piles.
Dan Crowl
On Wed, Jan 26, 2022 at 3:54 PM Jeffrey Lewin <jclewin**At_Symbol_Here**mtu.edu> wrote:
Photos from other news sources (but nothing spectacular)
Decon after entry https://www.cerescourier.com/news/local/sulphur-fire/
On Wed, Jan 26, 2022 at 4:13 PM Monona Rossol <0000030664c37427-dmarc-request**At_Symbol_Here**lists.princeton.edu> wrote:
The autoignition temp is probably related, but I wouldn't know how. Most deflagration accidents have occurred at ordinary outdoor/indoor temperatures. For deflagration the most relevant data is the deflagration index (Kst) value which is dependent in part on particle size. We are now requiring Kst values for special effects dusts used in entertainment venues. It's an expensive test, but once it's determined, the data can go right on the SDS for all future customers.
There was an interesting deflagration of walnut shell dust thrown into the air to look like conditions after a mine collapse on a set in 2003. The set was in a major arena and the deflagration and subsequent fire did $5 Million in damage. That'll teach them to rent out to a film company.
This Kst value is another bit of data that should be on all SDSs for anything in powder form. It would be easy in the case of inert minerals because the Kst would be zero since they can't deflagrate. But powdered sugar, starch, dyes, or any other organic chemical powder or metal powder in bulk should be accompanied by a Kst value. Some of the metals, like aluminum, have a particularly nasty punch, and we've seen these go off even when aluminum pigment powders were transferred from container to container where friction causes a static discharge as the initiator.
So I teach about deflagration with containment such as wood shop explosions where the building collapses, and deflagration without containment which there is a flash over and subsequent fire such as the Holi powder (starch and dye powder) flashover and fire in the Tiawan pool party fire that put over 500 in the hospital and killed 15.
And now, thanks to Ralph, I have a sulfur example. The pictures, of course, are no fun, since the warehouse was not closed up and it didn't explode. The best I can do is show a picture of the fire trucks and wisps of smoke coming out of the warehouse from the pile of sulfur that the flash over set on fire.
So Ralph, get one with a mushroom cloud and flames next time, OK?
Monona
-----Original Message-----
From: davivid <davivid**At_Symbol_Here**WELL.COM>
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Sent: Wed, Jan 26, 2022 2:52 pm
Subject: Re: [DCHAS-L] Chemical Safety headlines (10 articles)Turns out the reported autoignition temperature for sulfur is as low as
168C. The dust is quite sensitive and hydrocarbon impurities are known
to decrease the autoignition temp.
http://www.sulphuric-acid.com/techmanual/Plant_Safety/safety_sulphur.htm
This is lower than that of red phosphorus at 260C.
https://web.stanford.edu/dept/EHS/cgi-bin/lcst/lcss/lcss72.html
Regards
Dave Lane
Principal
Clavis Technology Development
On 1/26/22 7:45 AM, Monona Rossol wrote:
> At last. My ppt has examples of all kinds of deflagration substances, but I haven't had a good one on sulfur. Monona
> CAUSE DETERMINED OF SULFUR FIRE AT CERES FARM COMPANY
> https://www.modbee.com/news/local/article257699048.html
> Tags: us_CA, industrial, follow-up, environmental, ag_chems
>
> The source of a hazardous materials fire that prompted a 12-hour shelter in place advisory for some Ceres residents on Monday was determined to be a light bulb.
>
> An employee at Stanislaus Farm Supply on East Service Road was changing a light bulb inside a 40,000-square-foot warehouse that contained a large amount of fertilizer-grade sulfur, said Dustin Bruley, supervisor of the Stanislaus Regional Fire Investigation Unit.
>
> "In those warehouses they have a lot of dust floating in the air attributed to that product and when you change out a light bulb the simplest spark or static electricity can set off the particulate that floats in the air," Burley said. In this case the particulate was flammable sulfur.
>
> He said the spark caused flash fire, "The air around it has this matter floating so when it ignites, anything in that room has the potential to ignite as well."
>
> A 500-ton pile of fertilizer sulfur began smoldering. Employees tried to put it out but the fire grew larger than they could handle.
>
>
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Jeff Lewin
Director of Chemical Laboratory Operations
Research Integrity Office
Laboratory Operations
205 Lakeshore Center
Michigan Technological University
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