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 https://www.osha.gov.

August 25, 2006

Ms. Donna L. Pierce
Chambliss, Bahner & Stophel, P.C.
1000 Tallan Building
Two Union Square
Chattanooga, TN 37402

Dear Ms. Pierce:

Thank you for your March 9, 2006, letter to the Occupational Safety and Health Administration's (OSHA) Directorate of Enforcement Programs. You stated that you represent a company in the baking industry with production facilities in different states and have questions regarding Federal OSHA's Control of hazardous energy (lockout/tagout or LOTO) and Bakery equipment standards, 29 CFR §§ 1910.147 and 1910.263, respectively.
1 Your scenarios, paraphrased questions and our replies follow.

Scenario 1: The company has a piece of equipment that regulates temperature and humidity. This equipment uses a long serpentine conveyor, approximately 61 feet long, four feet wide and eight feet high with two levels of interlocked doors on each side. The conveyor is composed of many individual chain driven trays that transfer the product through the equipment. Periodically, the doors must be opened to observe whether the equipment is operating properly. When the doors are opened to make this observation, safety interlocks are by-passed, but the observer is trained never to allow a body part to pass the plane where the door would be if closed. The observer only monitors the equipment to ensure it is functioning properly. The observer is prohibited from performing any adjustments, repairs or cleaning until the shutdown/lockout provisions of §1910.147 have been met.

Question 1: Is this procedure appropriate as a minor servicing exception, 29 CFR 1910.147(a)(2)(ii) or otherwise?

Question 2: If this procedure is not acceptable, would it be acceptable to have a safety interlock override the procedure controlled through a mechanic-controlled key or some other procedure?

Question 3: Would it be acceptable to perform the observation if the internal guards were installed [such] that [the barrier] would prevent contact with the internal areas of the equipment?

Reply: While it is not possible to conclusively determine the answer to your question without observing this particular piece of equipment and considering the manner in which it is situated and used, as a result of the employees' positioning with respect to the door opening, it is likely that they would be exposed to hazardous energy, such as moving parts.

The task you describe would involve an employee observing whether the equipment is operating properly. This activity would be considered inspecting the equipment, and therefore would be considered Servicing and/or maintenance as defined at 29 CFR 1910.147(b). Although LOTO applies to servicing and maintenance, minor adjustments may be exempt from the LOTO if the inspection process is routine, repetitive and integral to the use of the conveyor for production purposes provided that the work is performed using alternative measures which provide effective protection. This exemption determination must be made on a case-by-case basis in accordance with the §1910.147(a)(2)(ii) note. As detailed in the inspection procedure you outline,thesafety interlocks are bypassed when the doors are opened. As a result of this bypass, LOTO would apply.

Aside from the minor servicing exception, an employer can avoid the requirements of the LOTO standard through the use of an alternative method which eliminates employee exposure to servicing and maintenance hazards — i.e., through the use of guarding methods that meet the requirements of Machinery and Machine Guarding, 29 CFR Part 1910, Subpart O, and Bakery Equipment, §1910.263. The internal guards you reference would satisfy this exception if they complied with these standards.

With respect to your second question concerning the use of mechanics keys, we do not have enough information to provide a response at this time.

Scenario 2: Another piece of equipment puts two cookies together after depositing a layer of crème between them. This machine has to be timed perfectly to ensure proper assembly of cookies. To successfully adjust the timing of the equipment, it must be operating when the adjustments are made. The doors on the equipment are locked, but do not have safety interlocks. The equipment does have internal guards to prevent insertion of fingers or hands into the hazard area while allowing employees to make the required adjustments. Employees also occasionally use extended air nozzles to blow off excess product. Employees are trained on the timing and cleaning processes, the safety features built into the equipment and processes, and the potential hazards that could be created if they bypass the internal safety features. Employees follow 1910.212, the guarding standard, but not 1910.147.

Question 4: Are these design features and safety practices satisfactory as a minor servicing exception, 29 CFR 1910.147(a)(2)(ii), or otherwise?

Reply: The adjustment of a machine component's timing mechanisms constitutes machine servicing activity, which is covered by the LOTO standard if an employee(s) is exposed to hazardous energy. See §1910.147(a)(2)(ii)(A) and (B). As described in the previous reply, there is an exception for minor servicing activities which take place during normal production operations, provided that the work is performed using alternative measures which provide effective protection. See the 29 CFR 1910.147(a)(2)(ii) note.

In your scenario, the LOTO standard would not apply if the minor servicing exemption applies or if the internal machine guarding method eliminates employee exposure to hazardous mechanical (kinetic) energy. If this is not the case, then employee protection must be provided, as previously described, when energization is essential (e.g., timing adjustment work) — i.e., pursuant to the §1910.147(f)(1) equipment testing and positioning provisions.

Question 5: if these design features and safety practices are not satisfactory, what standards apply?

Reply: The Machinery and machine guarding, Subpart O,standards apply to Normal production operations — i.e., the utilization of a machine or piece of equipment to perform its intended production functions. Activities that are necessary to prepare or maintain a piece of equipment are not considered normal production operations and are defined as Servicing and/or maintenance activities. See §1910.147(b). Section1910.147 applies to the control of hazardous energy during servicing and/or maintenance of the equipment. However, it is important to note that the Bakery equipment standard, §1910.263, also addresses the design, installation, operation, and maintenance of machinery and equipment used within a bakery, including machine guarding requirements contained in paragraph (c).

Scenario 3: The company has a third piece of equipment with a flight chain with ears every four or five links to ensure proper spacing and movement of the product. The chain runs in a channel across the top of the machine and then returns back into the underside of the machine. There are chain adjustments in the underside of the machine that require monitoring or adjusting occasionally. The company has trained its personnel to override the safety switch and observe the equipment while it is running in order to determine whether the equipment is working properly. When repairs or adjustments are actually made, lockout/tagout (energy control procedure) is applied.

Question 6: Is this an acceptable practice?

Reply: Refer to the first reply.

Question 7: Does it make a difference how the safety switch on the guard is overridden or if the guard is bolted shut without electrical interlocks
3 that would require the employee to use a tool to remove the door?

Reply: With respect to performance-oriented machine guarding requirements, guard design and construction must be of such design and strength to protect workers from the machine hazards. Guards must be affixed to the machine, where possible, and they may be fastened by any method (e.g., bolts) that prevents the guard from being inadvertently dislodged or removed. See §§ 1910.212(a)(2) and 1910.219(m)(1).

Scenario 4: A conveyor consists of several rollers that are four feet long and three inches in diameter that are covered by sheet metal guards. To properly clean these rollers, the equipment must be running. The guards are removed, and the rollers are sprayed using a water hose as an extended tool.

Question 8: Is this an acceptable practice?

Reply: No, if the guard removal exposes the employee(s) to hazardous energy associated with machine operation, such as moving gears, sprockets, V-belts or ingoing nip points.

Question 9: Does it matter if the equipment remains on the production line while it is cleaned or removed to a different location for the cleaning process?

Reply: It is difficult to answer this question with the information you provided. However, the options discussed above apply. Another option would be to lock out or tag out the conveyor, remove the rollers and clean them in a safe area. Thereafter, the clean rollers could then be re-installed, LOTO removed and the conveyor returned to normal production operation.

Scenario 5: Standard 1910.263(l)(9)(ii) provides that all safety devices on ovens shall be inspected at intervals of not less than twice a month by an especially appointed, properly instructed bakery employee, and not less than once a year by representatives of the oven manufacturers.

Question 10: Does the bi-weekly inspection mean that the employee must test the safety devices in order to ensure each is functioning properly or may the employee visually inspect the safety devices for changes from the previous inspection?

Reply: OSHA's present Bakery equipment requirements are based upon the American Standard Safety Code for Bakery equipment (ANSI Z50.1-1947), which included most of the source standard's Safety Device Testing provisions (Section 13.9.2). The OSHA standard retained many of the source standard's inspection requirements; however the Agency did not include any specific testing requirements in this provision. See §1910.263(l)(9)(i) and (ii). Therefore, the current OSHA standard does not explicitly require safety device testing.

However, these §1910.263(l)(9) general provisions for bakery oven inspections and maintenance are performance-oriented requirements that are intended to ensure the proper operation of safety devices (controls). In order to prescribe a procedure that is necessary to keep the oven safety devices functioning properly, an employer needs to base their inspection program (e.g., visual inspection requirements) on recognized and generally accepted engineering experience, such as, but not limited to, the:

  • Original equipment manufacturer (OEM) specifications/instructions; and
  • Recognized and good engineering practice — e.g., Standard for Ovens and Furnaces, ANSI/NFPA 86-2003.

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 www.osha.gov. If you have any further questions, please feel free to contact the Office of General Industry Enforcement at (202) 693-1850.


Richard E. Fairfax, Director
Directorate of Enforcement Programs



1 Twenty-six (26) states have OSHA-approved State Plans and have adopted their own standards and enforcement policies. For the most part, these States adopt standards that are identical to Federal OSHA. However, some States may have adopted different standards applicable to this topic or may have different enforcement policies that are more specific and/or more stringent. [ back to text ]





2 Simply training the employee to stay away from hazardous machine components is not effective alternative employee protection. [ back to text ]





3 While properly designed and maintained interlocks generally provide effective machine guarding, §1910.212 does not require the use of interlocks. [ back to text ]





4 The OSHA bakery equipment standard, §1910.263(l)(9)(ii), specifies that the annual inspections of ovens shall be conducted by representatives of the oven manufacturer. OSHA considers representatives of the oven manufacturer to be qualified persons who are knowledgeable of the various safety considerations and of the safe operational characteristics of the equipment. They may or may not be employees for the oven manufacturer. Refer to the April 24, 1998, letter to the American Bakers Cooperative, Inc. that is posted on the OSHA public webpage for details: http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=22573 [ back to text ]