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Standard Interpretations - (Archived) Table of Contents
• Standard Number: 1910.147; 1910.147(a)(2)(ii)
• Status: Archived

Archive Notice - OSHA Archive

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.
This letter constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any situation not delineated within the original correspondence.

October 20, 2004

Mr. Mark Kaster
Dorsey and Whitney LLP
50 South Sixth Street, Suite 1500
Minneapolis, Minnesota 55402

Dear Mr. Kaster:

Thank you for your May 12, 2004 letter to the Occupational Safety and Health Administration's (OSHA) Directorate of Enforcement Programs. You had questions regarding the application of the Lockout/Tagout standard's minor servicing exception and the use of a lockable on/off switch as an alternative measure to provide effective employee protection from hazardous energy associated with a particular machine or piece of equipment. Your paraphrased scenario, question, and our response follow.

Scenario: Our client manufactures machines for the corrugated industry, such as a high-speed feed machine for rotary die cutter production lines (see attached diagram). When in operation, the machine's extendo (telescoping conveyor and front sheet feeder), waste gate, belts, and other moving parts can be in operation during minor servicing work.

A customer wishes our client to install a lockable on/off switch on this machine to be used as a safeguard during routine minor service that might be needed during production runs. The switch would be a control circuit device that could be locked in the "off" position by use of a key that can be removed by the operator to prevent another individual from inadvertently starting the equipment. The switch would be designed to meet the control reliability criteria of American National Standard, ANSI B11.19-1997. This switch would be used with the following four tasks that the machine's operator would perform routinely:

  1. Set-up: The operator must raise and go under the extendo to adjust the settings on the Finishing Machine Hopper (the finishing machine is downstream of the machine in question) and preload the hopper with material;

  2. Interim access: The operator may raise and go under the extendo to adjust the settings on the Finishing Machine Hopper, straighten sheets, add or remove sheets, or clear a jam;

  3. Waste sheet removal: The operator may go under the extendo to remove waste sheets; and

  4. Feed interrupt: The operator may interrupt the feed to reach into the Finishing Machine Hopper area or over the extendo to straighten, add, or remove sheets.
During normal operations, and depending on the size of the orders and the quality of the incoming material, any and/or all of these tasks could occur one or more times per hour during the work shift.

To perform these tasks during a production run, the operator could lock the on/off switch in the "off" position, remove the switch key, and then proceed to access the machine for the minor servicing work. The machine could not be turned back on until the operator returned to the normal operating position with his switch key.

Question: Would the use of the aforementioned lockable on/off switch be appropriate for use as an alternative measure to provide effective employee protection, as required by the minor servicing exception found at 29 CFR 1910.147(a)(2)(ii)?

Response: The minor servicing exception applies only to minor servicing activities that must be performed during normal production operations (i.e., the utilization of a machine for its intended production function) and that are necessary to allow production to proceed without interruption. The minor servicing activity must be:

  • Routine — performed as part of a regular, basic course of procedure;
  • Repetitive — repeated regularly as part of the production process or cycle; and
  • Integral — inherent to, and be performed as part of, the production process.
The exception applies only if the employer provides effective alternative protection from hazardous energy.

OSHA has determined that a reliable control circuit is an acceptable method for protecting employees who are performing activities that fall within the minor servicing exception to the Lockout/Tagout standard. In our
July 15, 2003 letter to David Teague (see enclosed copy), we stated that "a circuit that meets the control reliability and control-component-failure-protection requirements of the American National Standards for machine tools (ANSI B11.19-1990) would provide alternative safeguarding measures with respect to the minor servicing exception contained in 1910.147(a)(2)(ii)."

However, as stated in the letter to Mr. Teague, please be aware that mechanisms such as the one you mention can be used to control hazardous energy only in situations when the other provisions of the minor servicing exception apply. In regard to your enclosed machine design diagrams and task descriptions, you include some activities that may be servicing and maintenance activities covered by the standard (e.g. adding sheets, preloading the hopper), rather than the minor servicing activities contemplated in the exception to the standard.
1 Without direct observation of these tasks, it is not possible for us to determine with certainty whether they would fall under the minor servicing exception. Your client's customers may contact OSHA's free On-Site Consultation Service for assistance in performing a case-by-case hazard analysis to determine the applicability of the minor servicing exception for these activities.

In your scenario, you stated that machine parts such as the extendo, waste gates, and belts can be in operation during minor servicing work. It is assumed that locking the proposed on/off switch in the "off" position would deactivate the machine and prevent all movement in the machine's parts. If this is not the case, and employees are still exposed to hazards created by the action of the machinery when performing activities under the minor servicing exception, then additional safeguarding measures for effective employee protection must be undertaken. One such method would be effectively guarding the hazardous areas of the machinery, as required by Subpart O - Machinery and Machine Guarding of Part 1910. Under no circumstances is an employee ever permitted to place any part of his or her body within a hazardous area (such as the point-of-operation, ingoing nip points, or around power transmission apparatus), unless all hazardous energy is effectively controlled.

As you may know, the State of Minnesota administers its own occupational safety and health program, with approval and monitoring by federal OSHA. States that administer their own OSH plans must promulgate regulations that are "at least as effective" as the federal regulations, although they may be more stringent. As a result, Minnesota and other State-plan states may have safety and health laws that are more restrictive than the federal laws; therefore, if the equipment is installed in one of these State-plan states, then the customer would need to be aware that state occupational safety and health laws may be applicable. For more information specific to the State of Minnesota, you may contact the Minnesota Department of Labor and Industry at:
Mr. Scott Brener, Commissioner
Minnesota Department of Labor and Industry
443 Lafayette Road North
St. Paul, Minnesota 55155-4307
(651) 284-5050
(651) 282-5405 FAX
Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA requirements are set by statute, standards, and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at http://www.osha.gov.


Richard E. Fairfax, Director
Directorate of Enforcement Programs

Enclosure - July 15, 2003 letter to David Teague

1 In Westvaco Corp. 16 (BNA) OSHRC 1374 (90-1341, 1993), the Occupational Safety and Health Review Commission (OSHRC) rejected an employer's assertion that set-up activities associated with a printer/slotter machine constituted servicing and maintenance within the scope of the exception. While not reaching the questions of whether the activities were "minor" or whether the alternative protection was effective, the OSHRC concluded that adjustments made while the machine was being set-up according to unique specifications to produce corrugated paperboard containers were not adjustments made during "normal production operations." [ back to text ]
Archive Notice - OSHA Archive

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

Standard Interpretations - (Archived) Table of Contents

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