Remember theGraf Hindenburg Zeppelin disaster?

That's why today's blimps use helium instead. It had 4 x less lifting power than hydrogen, but it's basically inert.

Alan

Ol' USAFR Flight Surgeon and sometimes pilot

On Fri, Apr 5, 2019 at 10:47 AM Richard Palluzi <000006c59248530b-dmarc-request**At_Symbol_Here**lists.princeton.edu> wrote:

I find it difficult to believe that anyone benefits from this type of incredibly risky demonstration. I call to everyone's attention that NFPA 45 Fire Protection for Laboratories Using Chemicals in Chapter 12 requires

12.2* Instructor Responsibilities. Where instructors are performing

demonstrations or students are conducting experiments

using hazardous materials, the instructor shall be required

to perform a documented hazard risk assessment,

provide a safety briefing to students, provide adequate personal

protective equipment (PPE), and place a safety barrier

(as required) between students and the demonstration or experiment

to prevent personal injury.

12.2.1* Instructors in teaching labs shall be trained and

knowledgeable in fire safety procedures, emergency plans, the hazards present in the lab, the appropriate use of PPE, and

how to properly conduct a hazard risk assessment.

I think few, if any, of these types of experiments would survive a real hazard assessment.

I also mention that there is an entire section 12.3.2 on Performance of Experiments or Demonstrations.

12.3.2.1 Experiments or demonstrations for students involving

open flames; fire; or the use of flammable, reactive, toxic

or corrosive chemicals shall be performed in accordance with

12.3.2.1.1, and 12.3.2.1.2, 12.3.2.1.3, or 12.3.2.1.4.

12.3.2.1.1 Experiments or demonstrations shall be performed

in a location that does not block access to the primary

means of egress from the laboratory work area.

12.3.2.1.2* Experiments or demonstrations that involve or

produce hazardous quantities of fumes, vapors, particulates,

or gases shall be performed in a chemical fume hood or other

ventilation device adequate to capture the materials being

evolved. This includes demonstration hoods or other devices

that meet the requirements of ANSI/AIHA Z9.5 2.1.1.

12.3.2.1.3 Experiments or demonstrations involving chemicals

that are performed outside a fume hood where the separation

distance in 12.3.2.1.4 is not possible shall be performed behind

an impact-resistant plastic or tempered-glass safety shield.

(1) The shield shall be at least 0.610 m (24 in.) high and shall

wrap 180 degrees around the hazard or extend at least

0.305 m (12 in.) beyond the hazard in both directions.

(2) The shield shall be secured to the work surface with bolts

or clamps to keep it in place.

12.3.2.1.4 Experiments or demonstrations involving chemicals

that are performed outside a fume hood where a shield is not

utilized shall be performed in a location that is at least 3.05 m

(10 ft.) from students.

12.3.2.2 Experiments or demonstrations using flammable

liquids and open flames shall be performed by a knowledgeable

instructor.

12.3.2.3 In educational and instructional laboratories where

experiments are conducted by students, the instructor shall be

responsible for conducting a safety briefing prior to the start

of each experiment to review the hazards of the chemicals

used, the personal protective equipment required for

This section was specifically added by the committee due to the number of accidents, near misses, and incredibly lucky incidents that keep occurring in schools during well meaning but incredibly poorly planned and implemented demonstrations.

I encourage all members to seriously read these requirements and carefully reconsider any type of demonstration that has significant risk. We can teach a chemistry without having to make students stand in front of an explosive mixture.

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 DAVID Katz
Sent: Friday, April 5, 2019 4:55 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] Safety with Hydrogen-Filled Balloons

As a demonstrator, I have used hydrogen and hydrogen-oxygen filled balloons. They are always filled right before use and kept away from any ignition source or possible source of static electricity. I would also use lecture bottles of hydrogen so I could fill the balloons in class.. The cost of the lecture bottles, as opposed to standard cylinders, was minimal in view of the safety of not having to move the filled balloons from the lab to the classroom. For anyone using hydrogen-filled balloons for demonstrations, one or two balloons, of reasonable size, are sufficient. Although, I perfer a large test tube filled with as close to 100% hydrogen hydrogen as possible. I can reduce the lighting in the classroom and we can watch the hydrogen burn slowly and then observe the condensation formed on the walls of the test tube.

When I did my research, I used lecture bottles of reactive or flammable gases attached to the reaction apparatus when needed. Proper stands and clamping were used for the lecture bottles.. Again, the cost of the lecture bottles was minimal for the increased safety.

David

_________________________________________________________________________

David A. Katz
Chemist, Educator, Expert Demonstrator, Science Communicator, and Consultant
Programs and workshops for teachers, schools, museums, and the public
5003 Canby Dr. * Wilmington, DE 19808-1102 * USA
voice/fax: (302) 509-3282 * email: dakatz45**At_Symbol_Here**msn.com
Visit my web site: http://www.chymist.com
_________________________________________________________________________

----- Original Message -----

From: Wilhelm, Monique

To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU

Sent: Thursday, April 4, 2019 2:49 PM

Subject: Re: [DCHAS-L] Safety with Hydrogen-Filled Balloons

I was always taught to only use balloons for inert gases and that is what we follow where I am.

Monique Wilhelm

Laboratory Manager

Department of Chemistry & Biochemistry

University of Michigan - Flint

From: ACS Division of Chemical Health and Safety [mailto:DCHAS-L**At_Symbol_Here**PRINCETON.EDU] On Behalf Of Craig Merlic
Sent: Thursday, April 04, 2019 1:39 PM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: [DCHAS-L] Safety with Hydrogen-Filled Balloons

Colleagues,

Following up on the explosion at IIT-Bombay which injured a professor and 2 interns:

https://www.hindustantimes.com/mumbai-news/explosion-at-iit-bombay-injures-professor-2-interns/story-i8UkvjMhnKnDeLyjKUj8iM.html

And the dramatic acetylene balloon explosion:

http://www.esdjournal.com/static/Kansas/dauer%20truck.htm

This raises questions about the very common synthetic technique used in research labs of using hydrogen-filled party balloons for small scale reduction reactions at atmospheric pressure. Researchers often fill party balloons with 1-5 liters of hydrogen at a regular gas cylinder, sometimes walk through the lab to their hood, and then connect the balloon to a reaction flask. (All that in contrast with hydrogenation under pressure in a Parr reactor using fixed high pressure lines.)

1. Have there been reports of explosions when using hydrogen-filled balloons for lab reduction reactions?
2. What safety precautions should be followed when balloons are used?

I can envision a number of things to do to avoid or discharge static electricity, but wonder if others have experience in this.

Thanks,

Craig Merlic

Professor of Chemistry

UCLA Department of Chemistry and Biochemistry

Executive Director

UC Center for Laboratory Safety

http://cls.ucla.edu

Los Angeles, CA 90095-1569

Voice: 310-825-5466

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