That may be true but many other less expensive and well-made models still have the problem. It is the cause of numerous laboratory fires every year.
And it is important the user verify that the control and alarm systems are truly independent. Many share the same sensor, contactor, or microprocessor based controller which means if the shared device fails, both systems will go out.
For more information on this concern see Runaway Heaters at https://www.linkedin.com/pulse/runaway-heaters-richard-palluzi/, Watchdog Timers at https://www.linkedin.com/pulse/watchdog-timers-richard-palluzi/ , and High or Over Temperature Protection In a Research Environment at https://www.linkedin.com/pulse/high-over-temperature-protection-research-environment-richard-palluzi/ ..
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 ILPI Support
Sent: Friday, August 21, 2020 12:13 PM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: [DCHAS-L] Runaway hotplate stirrers Was: [DCHAS-L] Chemical Safety headlines (19 articles)
Technology has evolved to address both of these issues.
Ohaus's Guardian series of hotplate stirrers have two independent safety controls to continuously monitor the electronics and shut off heating before an over temperature condition occurs, drastically reducing the possibility of a runaway situation.
In addition, the higher end models can help reduce unattended operation. They will automatically shut off the heater if no one is detected after a user set "time out" period has passed or if the Bluetooth link between a paired mobile device is broken.
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Safety Emporium - Lab & Safety Supplies featuring brand names
Fax: (856) 553-6154, PO Box 1003, Blackwood, NJ 08012
Regarding the story on the fire at NDSU:
One of the tags on this story says unknown chemicals, but it was a base bath comprised of ethanol and sodium hydroxide. The fact that the kid left it on a pair of stir plates while he went to lunch is the reason it got out of hand. We were not able to definitively nail down the initial cause, but the stir plates were models that have been identified as having a design flaw that has caused other fires and I know that discussion has appeared several times over the years within this group.
Bret Mayo
Associate Director of Environmental Health and Safety
NORTH DAKOTA STATE UNIVERSITY
Office Phone: 701-231-6299
Cell Phone: 701-238-2720
Email Address: bret.mayo**At_Symbol_Here**ndsu.edu
https://www.ndsu.edu/police_safety/
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