Mr. Clark,

 

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

 

 

We had a cable f ail at the counterweight a few months ago.  That particular fume hood had onl y a single counterweight rather than one for each side of the sash.  Fortunately, no one was using the hood at the time.  The sash drop was not far and there was no glass breakage.  The hood is nearly twenty years old.  It would've caused injury; it took two people to raise the sash afterwards.

 

One quick soluti on we've implemented is 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 stoppe d by the block before crushing an arm.

 

Inspection can b e problematic depending upon where the counterweight is located.  There can be access and confined space issues.  Also, the failure occurred where the cable was stressed (crimped).  It may be more practical to replace cables regularly 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 Behal f 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 ide as on hood sash cables:

We inspect all our hood sas h cables quarterly by a visually inspecting the cable and running a finger al ong the cable to feel for any bumps or frayed wire.  We use 3/32” st ainless steel “aircraft grade” cables with a rating of 900 pounds.  ; We have found wire that has frayed in the middle of the twist and it is not visible witho ut a magnifying glass, and if it were to give away while someone was in the hood , we would have a serious injury.  We are thinking about instituting a chan ge schedule for all the cables. Does anyone have any ideas or comments?    

Does anyone have any inform ation 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 t hey would be willing to share?

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

R.J. Wolcik

Environmental Health and Safety

Strem Chemicals, Inc.

7 Mulliken Way, Dexter Industrial Park

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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