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Subject: [DCHAS-L] Chemistry World: Four children injured after another chemistry demonstration goes wrong in Spain

Date: Jul 18, 2023 10:23 UTC

Author: Ralph Stuart <ralph**At_Symbol_Here**RSTUARTCIH.ORG>

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Subject: [DCHAS-L] SURVEY: CHAS Chats and Communities

Date: Jul 18, 2023 19:47 UTC

Author: Robin M. Izzo <rmizzo**At_Symbol_Here**PRINCETON.EDU>

From: Daniel Crowl <crowl**At_Symbol_Here**MTU.EDU>

Subject: Re: [DCHAS-L] Filling balloons with hydrogen gas

Date: Jul 18, 2023 17:01 UTC

Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>

Message-ID: <CAPEgXxzfuXe6H+LYZ57rCXfe78LnANmX-WT_F6c6q2+v+74GDg**At_Symbol_Here**mail.gmail.com>

In-Reply-To: <CA+U9Xi3mhOeWwN+nis7ZkbcPxEDA9HSvj1_9khXtH6EqcrCgpw**At_Symbol_Here**mail.gmail.com>

Demystify: 
The real problem with hydrogen is that its reported minimum ignition energy (MIE) is very low with a published value of 0.018 mJoule.  A mJ is the equivalent energy of dropping a penny a few mm.  Also, ignition sources are very elusive and frequently difficult to identify and control.  Methane has a minimum ignition energy of 0.280 mJ.  These MIE's are in air.  If the oxygen is increased the values go lower.

Charge can accumulate due to flow or handling (rubbing, etc.)  I remember rubbing a filled balloon on my pants and then sticking it to my head.  It stayed attached to my head due to its static charge.  

I think for this case the primary method to prevent a combustion is to prevent a flammable mixture anywhere during the filling.  This is actually an industrial standard:  NO FLAMMABLE MIXTURES, EVER!  If you have a flammable mixture it is not an issue of IF it will ignite but WHEN it will ignite.  

The lower flammable limit for hydrogen is 4 vol. % in air, which is lower than methane which is 5 vol. %.    The upper flammable limit for hydrogen is 75% and for methane 15 vol %.  This is also a problem since hydrogen has a very wide concentration for flammability. 

The second method is to make an effort to ground everything.  Including the balloon, if possible.  I think the balloon is non-conductive so this creates a problem with grounding and bonding the balloon.  However, this also reduces the ability of the charge to move across the balloon to a grounded object to create a spark.

Based on my experience with all these issues, I would not fill balloons with hydrogen .  The risk is a function of the consequences AND the probability.  In this case the probability is likely low, but the consequences would be high if the balloon did ignite during filling.

Another problem:  how do you know that the hydrogen in the balloon is pure hydrogen?  The balloon might have some initial air in it.

I suggest using metal tubing, ground everything and flush the tubing with pure hydrogen initially into a hood to remove air.  

Dan Crowl



On Tue, Jul 18, 2023 at 10:29 AM Sarah Zinn <szinn**At_Symbol_Here**ucla.edu> wrote:
In general, the accumulation of charge on a balloon or other insulator can be dissipated/prevented through contact with something that can balance the charges once generated and/or lubricate to protect against frictional charge generation in the first place. But, it would likely have to encompass the entire insulator (like humid air or some type of antistatic coating) since the charges aren't able to commute on the balloon. It is not necessarily wrong to say that you can ground an insulator through contact with a conductor—but the caveat is that you need full coverage contact (or at least many more contact points depending on the insulating properties) because the insulator can't do very much of the transport work itself. So likely, you'd need a fluid conductor or charge donor... Note that I am not advocating for the practicality or robustness of this—just continuing the discussion of grounding insulators.

Remember also that hydrogen molecules are very tiny and can even permeate metals—so be thoughtful if planning to use porous materials (I believe this was already said).

Ιn cases like these where low molar amounts are needed, I think the filling/emptying mechanisms and the surroundings are potentially more important to consider than dissipating static charge during active usestatic will be a problem when filling at a pressurized source, though, and charge generated from the friction of shuffling the balloon around to the filling station shouldn't be ignored. Once filled and set up, ignition of this little hydrogen would be a quick (and surprising) pop, but the real danger would be having other flammables or combustible materials nearby, the user nearby, or things that could break and/or launch. If you're going to use a hydrogen balloon, I think I'd say make sure the area is clear, consider using some sort of physical containment, and think very hard about how to control all aspects of filling/emptying. 

Best,
Sarah

____________
Dr. Sarah R. Zinn
Postdoctoral Scholar

On Sat, Jul 15, 2023, 1:22 PM Richard Palluzi <000006c59248530b-dmarc-request**At_Symbol_Here**lists.princeton.edu> wrote:

Thank you as I would be very interested in seeing it. I cannot understand how grounding an insulator can work as the insulation, like on a wire, is the barrier itself.

 

Richard Palluzi

BE(ChE), ME(ChE), PE, CSP,FAIChE

 

Pilot plant and laboratory consulting, safety, design, reviews, and training

www.linkedin.com/in/richardppalluzillc/

www.pilotplants.us

 

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 James Kaufman
Sent: Friday, July 14, 2023 1:37 PM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] Filling balloons with hydrogen gas

 

These were the three methods presented by an expert on static electricity in his book on the subject.  He testified in the 1985 Dartmouth College lab explosion the injured a second year grad student.  I will see if I can dig out his name and the book title.  ... Jim

 

PS.  LSI now has virtual lab inspections, safety program evaluations, document reviews, plus courses and seminars ... all virtual.  And, a complimentary,  updated version of our classic Laboratory Safety Guidelines is now available on our website ... https://www.labsafety.org/product/lab-safety-rules

 

James A. Kaufman, PhD

Founder/President Emeritus

 

The Laboratory Safety Institute (LSI)

A Non-profit Educational Organization

  for Safety in Science, Industry, and Education

192 Worcester Street, Natick, MA 01760-2252

(O) 508-647-1900   (F) 508-647-0062   (C) 508-574-6264  

Skype: labsafe; 508-401-7406  jkaufman**At_Symbol_Here**labsafety.org  www.labsafety.org 

 

Teach, Learn, and Practice Science Safely

 

 

 

 

On Fri, Jul 14, 2023 at 10:23 AM Richard Palluzi <000006c59248530b-dmarc-request**At_Symbol_Here**lists.princeton.edu> wrote:

With respect to Jim, neither #1 nor #2 grounds the container if the glass or plastic is, as usual, an insulator. Only placing a conductive rod contacting the liquid is effective.

 

Recognize that small liquid transfers, common in laboratory operations, are usually too slow and too little to generate much charge build up. Larger transfers (over 2 L) can easily generate ignitable discharges. Flowing streams through insulting tubing is a major problem.

 

Richard Palluzi

BE(ChE), ME(ChE), PE, CSP,FAIChE

 

Pilot plant and laboratory consulting, safety, design, reviews, and training

www.linkedin.com/in/richardppalluzillc/

www.pilotplants.us

 

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 James Kaufman
Sent: Thursday, July 13, 2023 4:30 PM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] Filling balloons with hydrogen gas

 

There are three major ways to ground glass and plastic containers:

 

1. Put a metal band around the container and run the ground wire off of it.

2. Rest the container on a grounded mat.

3. If chemical compatibility is not an issue, stick a metal rod with a ground wire on one end into the container.

 

It can also be a good idea to ground yourself.

 

PS.  LSI now has virtual lab inspections, safety program evaluations, document reviews, plus courses and seminars ... all virtual.  And, a complimentary,  updated version of our classic Laboratory Safety Guidelines is now available on our website ... https://www.labsafety.org/product/lab-safety-rules

 

James A. Kaufman, PhD

Founder/President Emeritus

 

The Laboratory Safety Institute (LSI)

A Non-profit Educational Organization

  for Safety in Science, Industry, and Education

192 Worcester Street, Natick, MA 01760-2252

(O) 508-647-1900   (F) 508-647-0062   (C) 508-574-6264  

Skype: labsafe; 508-401-7406  jkaufman**At_Symbol_Here**labsafety.org  www.labsafety.org 

 

Teach, Learn, and Practice Science Safely

 

 

 

 

On Thu, Jul 13, 2023 at 4:12 PM davivid <davivid**At_Symbol_Here**well.com> wrote:

Hi James

I hadn't heard that it was possible to ground/bond non-conductors. How
is this done?

Thank you
Dave Lane

On 7/13/23 6:45 AM, James Kaufman wrote:
> There are several ways to ground and bond plastic and glass containers
>
> Please contact me directly for more information ... Jim
>
>
> PS.  LSI now has virtual lab inspections, safety program evaluations,
> document reviews, plus courses and seminars ... all virtual.  And, a
> complimentary,  updated version of our classic Laboratory Safety Guidelines
> is now available on our website ...
> https://www.labsafety.org/product/lab-safety-rules
>
>
>
> *James A. Kaufman, PhD*
>
> Founder/President Emeritus
>
>
>
> *The Laboratory Safety Institute (LSI)*
>
> A Non-profit Educational Organization
>
>    for Safety in Science, Industry, and Education
>
> 192 Worcester Street, Natick, MA 01760-2252
>
> (O) 508-647-1900   (F) 508-647-0062   (C) 508-574-6264
>
> Skype: labsafe; 508-401-7406  jkaufman**At_Symbol_Here**labsafety.org  www.labsafety.org
>
>
> *Teach, Learn, and Practice Science Safely*
>
>
>
>
>
>
>
> On Wed, Jul 12, 2023 at 1:31 PM Alyssa Brand <abrand**At_Symbol_Here**lbl.gov> wrote:
>
>> Let me preface this with: I am no expert in the safe use of hydrogen gas.
>> But I wonder why a balloon would be used rather than a dedicated, regulated
>> gas line. My main concern with this would be the potential for ignition of
>> the hydrogen due to a static electricity discharge, and I would think that
>> using plastic components might not only increase the risk of a static
>> discharge occurring, but prevent the use of bonding and grounding. If I'm
>> entirely off base, feel free to ignore me. As I said, not an expert.
>>
>> Alyssa
>>
>> On Fri, Jul 7, 2023 at 10:54 AM davivid <davivid**At_Symbol_Here**well.com> wrote:
>>
>>> We do hydrogenations and hydrogenolysis in our lab in quantities of up
>>> to several moles. The equipment is assembled in a hood. Hydrogen is
>>> plumbed into the hood via 1/4" polyethylene tubing cable tied to the
>>> drop ceiling from tanks located elsewhere in the lab. The hydrogen
>>> regulator is set to deliver the lowest feasible pressure and the outlet
>>> valve set to deliver the lowest feasible flow.
>>>
>>> The assembled equipment is charged with the reactants and solvents then
>>> evacuated using a small diaphragm pump in the hood through a stopcock. A
>>> two-way stopcock can be used but a three-way stopcock is preferred as it
>>> does not require disconnection of the tubing from the system when
>>> switching between evacuation and fill. Hydrogen is then let into the
>>> evacuated system via the stopcock and fills the balloon. The hydrogen
>>> flow can be shut off at the system using the stopcock. If desired, the
>>> evacuation and fill procedure can be repeated multiple times to flush
>>> residual air from the system
>>>
>>> We use mylar balloons from the Dollar Store as they are more capacious,
>>> stronger, less permeable, and more solvent resistant than rubber
>>> balloons. If you go this route you will need to fit the tubing several
>>> inches into the mouth of the balloon to reach past the internal valve.
>>>
>>> The attached photo shows the method we use to connect the balloons to
>>> the system. A gas inlet adapter is fitted with Tygon tubing which then
>>> connects to 1/4" polyethylene tubing. The joint between the two types of
>>> tubing is secured by two wraps of cable tie and sealed with grease. The
>>> tubing extends into the balloon to the point indicated by the arrow. The
>>> joint between the balloon and the 1/4" line is sealed with grease and
>>> fastened by wrapping several times with the ribbon from the balloon.
>>>
>>> Best regards
>>> Dave Lane
>>> Chief Science Officer
>>> Artisyn Laboratories
>>>
>>>
>>>
>>> On 7/6/23 12:27 PM, Laura Cunningham wrote:
>>>> Hi all,
>>>>
>>>> Does anyone have recommendations on how to *safely* fill a balloon with
>>> hydrogen? The hydrogen tank in this scenario is in an open lab, and the
>>> hydrogen filled balloon is for a hydrogenation reaction. The gas tank is
>>> located close enough to a fume hood that piping the hydrogen into the fume
>>> hood might be feasible. Wondering what other people’s experiences have been
>>> with this.
>>>>
>>>> Thanks,
>>>> Laura
>>>>
>>>> Sent from Proton Mail for iOS
>>>>
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>>
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>> Divisional membership chair at membership**At_Symbol_Here**dchas.org
>
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