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Previous by Date: Subject: Re: [DCHAS-L] flammable hazardous waste Date: Wednesday, December 18, 2019 at 8:52:10 AM Author: ILPI Support <info**At_Symbol_Here**ILPI.COM> |
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NFPA 77 Table B.1 lists minimum ignition energies and B.2 lists conductive, semi-conductive and non-conductive liquids.
Britton, L. (1999). Avoiding static ignition hazards in chemical operations (CCPS concept book). New York: Center for Chemical Process Safety of the American Institute of Chemical Engineers.
Adapted from CCPS text - Plastic wrap is removed from a plastic container, this induced a static charge on the container. A conductive liquid, like acetone, is poured into the charged plastic container. The acetone takes on this charge. A metal funnel is inserted into the container. A spark goes from the charged acetone to the funnel. Or if the charged acetone is poured out a spark may also occur then. In either case the spark could ignite the flammable liquid.
http://www.srbrowne.com/booklet/page03.html
The use of nonconductive, plastic containers in potentially flammable locations may be an ignition hazard in plants. Static charge accumulations on such containers, caused by the transfer of poorly- =ADconductive liquids or solids, or by contact charging, cannot be dissi =ADpated by the bonding/grounding system.
Contact ("triboelectric") charging of a nonconductive container in a low humidity environment creates a spark ignition hazard by inducing charges in the liquid in the container. These induced charges may cause sparking, e.g., when the liquid is poured into a grounded safety can. Surprisingly, this hazard of charge induction is greatest when the liquid is "conductive".
https://www.paint.org/wp-content/uploads/2015/09/ACA_cc_static_guide.pdf
Removal of plastic bottles from plastic bags may cause high contact charging. Electric field intensities greater than 5 kV/cm (12.5 kV/inch) at the surface of the bottle or liner should be neutralized before a conductive flammable liquid is put into the bottle (21). It is also important to avoid charging a plastic bottle that contains even a small quantity of a conductive, flammable liquid.
--- For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchasA common tactic to ground plastic containers is to simply place a metal (conductive) rod or bar inside the container and ground it. Then you just need to train people to make any pours onto the bar.
You can also do a calculation based on the material to determine the potential static build up. Most times you need to transfer at least about a liter of hydrocarbon to build up any appreciable charge. However, this is dependent on a lot of factors and most organizations are reluctant to give too much weight to this type calculation due to the many potentials for someone doing something that was never considered in the analysis. And, of course, some liquids and some situations can develop a higher charge with much lower rates.
Richard Palluzi
PE, CSP
Pilot plant and laboratory consulting, safety, design,reviews, and training
www.linkedin.com/in/richardppalluzillc/
Richard P Palluzi LLC
72 Summit Drive
Basking Ridge, NJ 07920
rpalluzi**At_Symbol_Here**verizon.net
908-285-3782
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU> On Behalf Of Harold Ingmire
Sent: Wednesday, December 18, 2019 7:36 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] flammable hazardous waste
I found this OSHA link https://www.osha.gov/laws-regs/standardinterpretations/1999-03-29 This may be of some help, but note it is dated.
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU> On Behalf Of Melissa Ballard
Sent: Wednesday, December 18, 2019 6:27 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: [DCHAS-L] flammable hazardous waste
I would appreciate your feedback on my situation. We have recently replaced our single satellite accumulation container that was a 5-gallon metal drum to 2 separate plastic (UN approved) translucent "drums". This was at the suggestion of one of the environmental coordinators at the site. Now the other environmental coordinator & the "fire guy" are saying this is unacceptable because we cannot ground the plastic containers. We only use glass beakers or flasks to pour waste into these containers or it is waste going directly into a container from a HPLC (essentially a closed system).
Is this really a "fire risk"? I recognize that there may be a small potential for static to build in a plastic container, but we are not really "transferring or dispensing" from these containers in the traditional sense. The original starting materials are purchased in plastic 4L containers or glass containers which cannot be grounded when pouring out of either. I am having a hard time understanding the push to go back to a metal container just so we can ground it. I will add that the plastic gives us the ability to see the volume of liquid in the container so we will not over-fill it.
Thoughts on how to handle this? The plastic containers meet the requirements for the waste as per NFPA/DOT so it is just a question of fire risk.
Thanks for your input!
Melissa BALLARD - MSPH, CIH, CSP, CCHO
Industrial Hygienist / Industrial Hygiene Chemist
melissa.ballard**At_Symbol_Here**michelin.com
--- For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchas
--- For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchas
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