Hi, folks:

Annex C of NFPA 69, Standard on Explosion Prevention Systems, includes a
list of materials with their limiting O2 concentrations.

You can view (but cannot copy) NFPA 69 by going to the following web
page:

http://www.nfpa.org/aboutthecodes/list_of_codes_and_standards.asp

Scroll down to and select the desired document.  Scroll to the bottom of
the next screen and select "Preview this document". Follow the
instructions.  Because the "on-line" documents are located on an
external server, expect system loading and response to take some time.

Bob Benedetti
National Fire Protection Association

-----Original Message-----
From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**LIST.UVM.EDU] On Behalf Of
Dan Crowl
Sent: Tuesday, December 04, 2007 1:38 PM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: Re: [DCHAS-L] Flammables in Inert Atmosphere Glove Box

Hi Jay,

The 10 ppm of oxygen is probably OK with respect to flammability.  The 
limiting oxygen concentration from many hydrocarbons is in the 10%
range.

However, the nitrogen gas containing the flammables might become 
flammable when they are discharged from the glove box and mixed with
air.

That is a bigger problem.

Dan Crowl
Michigan Tech University

Saldivar, Jay wrote:
> One of our scientists has asked for guidance in the use of inert (N2)
> atmosphere glove boxes for processes utilizing flammable liquids and
> electrical appliances. Details of the process of concern follow:
> *	Dispersed (in xylenes) silicon nanoparticles are to be further
> dispersed using a SS ultrasonic wand (20 kHz)
> *	Process to be performed in a N2 atmosphere glove box
> *	Monitored O2 levels will not exceed 10ppm in the box
> *	All power to the glove box (including the wand) is cut upon
> exceeding 10ppm O2 concentration in the box
> *	The lab bldg is provided with a fire sprinkler system as well as
> CO2 extinguishers within 10 ft
> 
> Questions:
> *	Is there a (any) concern regarding the use of a wand-type
> ultrasonic to agitate a flammable solvent in an inert atmosphere?
> *	Should this level of O2 ( flammability perspective?
> *	Under this scenario, at what O2 levels should fire reasonably be
> a concern?
> 
> I appreciate any and all feedback on this topic.
> Regards,
> 
> I Jay Saldivar
> Sr Safety Administrator
> Sharp Microelectronics of the Americas
> NW Pacific Rim Blvd
> Camas, WA  98607
>  
> 360/834-8734 (o)
> 360/772-4502 (c)
> saldivarj**At_Symbol_Here**sharpsec.com
> 

Previous post   |  Top of Page   |   Next post