Mr. Clark,

With the steel block in place, can you still fully close the sash?

We had a cable fail at the counterweig ht a few months ago.  That particular fume hood had only a single counterwe ight rather than one for each side of the sash.  Fortunately, no one was us ing the hood at the time.  The sash drop was not far and there was no glas s breakage.  The hood is nearly twenty years old.  It would've caus ed injury; it took two people to raise the sash afterwards.

 

One quick solution we've implemented i s to tip a rectangular steel block (approx. 1"x1"x3 1/2"; longer would be better) on end and place it in the sash path next to the deflector shield.  If the sash is released, it will fall and be stopped by the b lock before crushing an arm.

 

Inspection can be problematic dependin g upon where the counterweight is located.  There can be access and conf ined space issues.  Also, the failure occurred where the cable was stressed (crimped).  It may be more practical to replace cables regul arly rather than attempt an inspection for defects that may not be visible.

 

Rick Clark

Sr. Research Chemist

Curwood, Inc.

From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**list.uvm.edu] On Behalf Of RJ Wolcik
Sent: Wednesday, November 11 , 2009 12:26 PM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: [DCHAS-L] Hood Sash Cables

We are looking for some ideas on hood sash cables:

We inspect all our hood sash cables quarterly by a visually inspecting the cable and running a finger along the cable to feel for any bumps or frayed wire.  We use 3/32” stainless steel “a ircraft grade” cables with a rating of 900 pounds.  We have found wire that has frayed in th e middle of the twist and it is not visible without a magnifying glass, and i f it were to give away while someone was in the hood, we would have a serious injury.  We are thinking about instituting a change schedule for all t he cables. Does anyone have any ideas or comments?    

Does anyone have any information on cable breakage, or has anyone heard of an incident of both sash cables breaking at the same time causing the sash to completely fall?

Does anyone have a policy they would be willing to sha re?

---------------------------------------------------

R.J. Wolcik

Environmental Health and Safety

Strem Chemicals, Inc.

7 Mul liken Way, Dexter Industrial P ark

Newburyport, MA 01950-4098, U.S.A.

Telephone: 978.499.1660

Fax: 978.499.1661

Email: rj**At_Symbol_Here**strem.com

www.strem.com

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