[Hallb-engineering] Fwd: Lesson Learned "Steam Trap Lid Falls from Vise and Strikes Foot Resulting in a Fractured Metatarsal - Argonne National Laboratory "

[Douglas Tilles]

----- Forwarded Message -----
From: mbailey at jlab.org
To: mbailey at jlab.org
Cc: robertl at jlab.org
Sent: Tuesday, August 26, 2014 10:01:35 AM
Subject: Lesson Learned "Steam Trap Lid Falls from Vise and Strikes Foot Resulting in a Fractured Metatarsal - Argonne National Laboratory "






	Steam Trap Lid Falls from Vise and Strikes Foot Resulting in a Fractured Metatarsal - Argonne National Laboratory 	
Statement of Lessons Learned 
For a copy of the original report, see �Attachments� on Lessons Learned page. 

The decision to use equipment and/or processes based solely on past successes does not always guarantee the best results. Discussion of Activities 
On May 23, 2014, a Facilities Management and Services (FMS) -Utilities Systems (US) maintenance mechanic placed a steam trap lid, weighing approximately 65 pounds, into a heavy-duty vise mounted on the corner edge of a workbench.  While the mechanic used a three-foot long wrench to apply torque to install a center nut on the lid, the vise loosened and the lid rolled out.  It fell approximately four feet to the ground striking the mechanic on the left foot resulting in a 1st metatarsal fracture which required surgical repair. Analysis 
The mechanic had twenty-eight years� experience working with similar vises and torque wrenches; however, this was the first time this particular task had been performed at Argonne.  The mechanic had been instructed by another mechanic as to the proper work procedure.  It was verified that the instructions were the procedure that has been used by others without incident..  No further instruction or guidance was provided prior to the commencement of work.

The investigation team inspected the vise that was used and found it to be in good working condition.  It was noted, however, that the surface area of the lid, when placed in contact with the vise jaws, was minimal due to the curved/rounded surface. 

Based on this information, it was concluded that the wrench used to tighten the center nut was almost three times as long, providing three times the torque as the torque provided by the vise handle.  The difference, between the vise jaws (with minimal surface area contact between the jaws and the lid surface) versus the torqueing motion on the lid explains how the vise loosened allowing the lid to fall. Recommended Actions 
The mechanic had twenty-eight years� experience working with similar vises and torque wrenches; however, this was the first time this particular task had been performed at Argonne.  The mechanic had been instructed by another mechanic as to the proper work procedure.  It was verified that the instructions were the procedure that has been used by others without incident..  No further instruction or guidance was provided prior to the commencement of work.

The investigation team inspected the vise that was used and found it to be in good working condition.  It was noted, however, that the surface area of the lid, when placed in contact with the vise jaws, was minimal due to the curved/rounded surface. 

Based on this information, it was concluded that the wrench used to tighten the center nut was almost three times as long, providing three times the torque as the torque provided by the vise handle.  Thr difference, between the vise jaws (with minimal surface area contact between the jaws and the lid surface) versus the torqueing motion on the lid explains how the vise loosened allowing the lid to fall. 
Comments 
8/26/2014 9:28:32 AM by Bailey, Mary Jo 
Submitted to those current in 
�SAF502: FORKLIFT OPERATOR 	
Summary 	Lesson ID: 	843 
	Status: 	OK 
	Doc ID: 	2014-JLAB-843 
	Priority: 	Info 
	Safety Related: 	YES 
	Originator: 	Bailey, Mary Jo 
	Issued: 	8/26/2014 9:27:08 AM 
	Approved By: 	Bailey, Mary Jo 
	Approved On: 	8/26/2014 9:28:32 AM 
	Source: 	DOECRD 
	Location: 	ANL 
	Cost Savings: 	
	Contact: 	Tad Jesionowski, tjesionowski at anl.gov, (630) 252-6883 
	Queued Emails: 	0 
	Sent Emails: 	0 
	Viewings: 	3 times Attachments 

    * M:\wcd\LessonsLearned\Machine Tools\DOE - Yellow - VisePic.pdf 
    * M:\wcd\LessonsLearned\Machine Tools\DOE - Yellow - Vise.pdf 
Hazard Issues 

    * Tools - Machine & Portable 
Skills 

    * SAF502: FORKLIFT OPERATOR 
Distribution/Notification 

    * *Division Safety Officers (DSOs) 
    * *Safety Wardens 
    * *DOE Notification 
    * *ESH&Q Liaisons