I would like to clarify that while we do not particularly encourage pouring from larger containers, we do not necessarily discourage gravity dispensing.  Well-planned gravity dispensing can be safe and might arguable be more efficient when dispensing larger volumes or for particular materials that do not pump well.

 

I suppose I could point to a few reasons why I generally like pumped dispensing over pouring when these larger container reside in the laboratories. 

 

•         Most recently involving a graduate student offering to help procure some ether for a demo while visiting a lab and proceeding to create an ether puddle while attempting to pour from a flex-spout can to a small 100 or 250ml beaker.  Though in fairness, the same puddle could have been created with the poor use of a solvent pump (or poor quality pump).  But generally a pump gives the dispenser a bit more control and is less dependent on a steady hand.

 

•         The worry of can slipping out of a user's hands and rolling across the lab sloshing solvent.  (which is also a motivator for the use of a tilt stand or transiently used cradle)

 

•         The spectre of a flashback from the vapor plume spilled out from the inverted container.  While we encourage consistency in practice (If you would use a fume hood to dispense from a 4L bottle - shouldn't you use a hood or equivalent LEV when dispensing from a larger container?), these pourings tend to happen where they are most convenient - at the foot of their flammable cabinets (or within).  A big plus for a well-designed solvent pump is that it will help keep the head-space vapors in the can.

 

•         A cross-threaded or failing safety faucet, which will help produce a bigger puddle than a sloppy pour, especially when used with a cradle to store horizontally.

 

Of course, what I really like is when the realization is made that 1 or 2  of the 4-L bottles would provide an adequate supply and that the 5-gal can is not really needed.

 

With regards to bonding and grounding, I would be remiss if I did not point out that Goat Throat has a line of flammable solvent pumps with built-in B/G wires and have the option of conductive plastic components.  The metal body/dip-tube of the before-mentioned BŸrkle pumps similarly make B/G fairly easy and have an accessory B/G kit.  Shortly before starting here, this campus had a fire involving pentane poured from a can.  Given the eye-witness account, no discernable ignition source, and the absence of B/G, the cause of this incident was attributed to ignition via static discharge - so B/G is definitely not worth overlooking.

 

Regards,

 

 

This is a very interesting topic to us as well, thanks to Linda for asking it.

 

We are nearing completion of our bulk storage area. It is designed to handle bulk container no larger than 20L (5 gal.) - outside the rated storage room is an ante room with a fume hood. The idea is that the 5 gallon drums can be dispensed in the hood. I see the first ergonomic issue here is lifting the 5 gallon pail into the hood.

 

It was my thought that researchers could use a tipper inside the fume hood for dispensing into smaller containers using stainless funnels - this would eliminate the contamination concerns of degraded polymer pump parts.

 

Many graduate students and research associates are just fine with pouring by hand into their container right on the floor in the storage area and dealing with the exposure (provided it's not toxic - ideally using spill pads and secondary containment). It laziness -  we discourage that practice when we observe it, even if it is methanol or acetone. We will ask them to put it on a cart, go back to their lab and move the pail from the cart to the hood and dispense there.

 

So I am wondering É.Stanley, why do you discourage gravity dispensing?

 

Be well,

James Saccardo, CHMM, MPH

Environmental Health and Safety Officer

 

From: ACS Division of Chemical Health and Safety [mailto:DCHAS-L**At_Symbol_Here**PRINCETON.EDU] On Behalf Of Olmsted, Linda
Sent: Wednesday, September 26, 2018 8:56 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] bulk solvent storage room information

 

--- 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