Federal Register - March 2, 2021
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Source: Federal Register
jbell on DSKJLSW7X2PROD with NOTICES
Federal Register / Vol. 86, No. 39 / Tuesday, March 2, 2021 / Notices laser is considered a Class 4 operation.
Class 4 operations are defined by ANSI
as very dangerous to the eyes and skin, with a risk of fire and explosion.1 No workers are allowed inside the laser cell while the laser is being used. Instead, the operators station is located outside of the laser cell and the operator uses hand controls to activate the laser turntable. The laser cutting system is a fully enclosed structure, with the laser operating similar to a robot. The laser is affixed to the end of arm tooling within this fixed structure. Stamped parts are loaded into the cell and unloaded from the cell structure via a turntable from outside of the laser cell. When actuated, the turntable rotates to the inside of the machine and presents the parts to the laser. The turntable cannot rotate until the operator clears the light curtain, which is used as a safeguard blocking access between the turntable and the operators station.
As noted above, the laser trimming process creates a byproduct of chaff, dust, direct, chips, slugs, and debris, and the laser system must be cleaned to enable the laser to function properly.
The laser cell has access doors to enable cleaning and certain other necessary tasks to be performed inside the cell.
The access doors utilize interlocked switches that disable hazardous motion of the turntable and laser energy when opened.
The machine enclosure of the Trumpf laser cell is protected by two entry/exit points: A far access door and a near access door. Each access door has an interlock switch that is integrated into the laser and machinery motions. When the door to the laser cell is opened, the release of laser energy is inhibited and the machine axes cannot move. Further, Gestamp added red mechanical latches hasps to the external side of each entry door that allow a lock or a group lockout hasp or lock to be affixed, thus locking the hatch in its location.
In addition, Gestamp has implemented procedures to prevent the door from closing during laser cell cleaning activities, which could actuate the system. Gestamp requires all personnel entering the laser cell to individually lockout by placing their individual lock on the slide bar. Each employee entering the laser cell must remove his own personal key from his individual lock or hasp, take the key into the cell, and keep the key in his possession the entire time he is in the laser cell. If more than one employee enters the cell, one of the employees shall be designated the Leader of the cleaning crew. The Leader can only 1 ANSI
B11.21 and ANSI Z136.1
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remove his lock after he has verified that everyone else in the cleaning crew has left the laser cell.
Gestamp contends that the alternative energy control procedures included in the application provide the workers with a place of employment that is at least as safe and healthful as they would obtain under the existing provisions of OSHAs control of hazardous energy lockout/tagout standard. Gestamp certifies that it provided employee representatives of affected workers with a copy of the variance application.
Gestamp also certifies that it notified the workers of the variance application by posting, at prominent locations where it normally posts workplace notices, a summary of the application and information specifying where the workers can examine a copy of the application. In addition, the applicant informed the workers and their representatives of their rights to petition the Assistant Secretary of Labor for Occupational Safety and Health for a hearing on the variance application.
B. Variance From 29 CFR 1910.147d3
As an alternative means of complying with the requirements of 1910.147d3, Gestamp proposed to use a comprehensive engineered system and appropriate administrative procedures.
The applicant referenced ANSI/ASSE
Z244.12016, clause 8, which states that Lockout or tagout shall be used unless the user can demonstrate an alternative method will provide effective protection by persons. When lockout or tagout is not used, then alternative methods shall be used only after the hazards have been assessed and risks documented as the basis for their alternative lockout method. Gestamp asserted in the variance application that the cleaning task within the Trumpf laser cell is one that requires access to the machine in a manner that renders full lockout infeasible. Because the Trumpf laser cell is a Class 4 operation, no one is allowed inside the machine enclosure during laser operations. Gestamp also asserted in the variance application that because the cleaning task occurs on a frequent basis, regular powering down and locking out of the laser to perform the routine cleaning operations could damage the laser over time. Further, full lockout of the laser cell requires the use of auxiliary lighting sources, which could introduce fall and shock hazards into the cleaning operation.
Additionally, the design of the Trumpf laser cell includes advanced control systems that prevent engagement of the laser while the laser cell is occupied. As an alternative energy control procedure, Gestamp has developed an engineered
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system that uses red mechanical latches attached to the external side of each door of the laser cell. The latches are secured to the frame of the machine with two metal screws and have a locking capacity that allows a lock or a group lockout hasp to be affixed; this latch prevents the door from closing and the laser from being able to be energized during laser cell cleaning operations.
Gestamp maintained that use of the proposed latch system provides a level of safety equivalent to what can be achieved by strict compliance with the standard at 1910.147d3. According to Gestamps variance application, equivalent safety is achieved by prohibiting the release of laser energy during cleaning operations utilizing a modified door latch that prevents unintentional re-energization of the laser. In the variance application, Gestamp provided the following stepby-step details of the safety procedures to be followed prior to and following cleaning activities:
Process To Enter Trumpf Laser Cell To Perform Cleaning Activities 1. Communicate to the Operator and coworkers in the area that cleaning will take place. At the Human Machine Interface HMI screen, change the Series Production from Continuous Job to Single Job. Once the turntable has come to a complete stop, open one of the doors on the side of the laser cell by using the handle.
2. After the door is open, communicate the lockout to coworkers and move the red slide bar to prevent the door from being shut while inside.
All personnel entering the laser cell must individually lockout, by placing their individual lock on the slide bar or hasp. If more than one person is to enter on either side, a lockout hasp must be used.
3. After locking out on the laser cell, verify that Feed Hold Through Safety Device Error is displayed on the HMI
screen.
4. To verify that the turntable will not move while working inside of the laser cell, hit the green activation button.
Employees can enter the laser cell only after these four 4 steps are completed.
5. When work is completed inside the laser cell, all employees who entered the cell, except the Leader when more than one employee entered, shall exit and remove their individual locks. Once all other employees are outside of the laser cell, the Leader must verify his location and hit the Danger Zone Acknowledge Button on the inside of the cell door. The Leader must immediately exit the cell, remove his
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