- Record Type: Interpretation
- Standard Number: 1910.147
- Subject: Control of Hazardous
Energy Source (Lockout/Tagout) standard.
- Information Date:1994
August 12, 1994
Ms. Joanne B. Linhard Consultant Organizational
Resources Counselors, Inc. 1910 Sunderland Place, N.W. Washington,
Dear Ms. Linhard:
This is in response to your December 20,
1993 letter, requesting interpretation of the Control of Hazardous
Energy Source (Lockout/Tagout) standard, 29 CFR 1910.147. Please
accept our apology for the delay in responding. Your questions and
our replies follow:
Question 1: At one location there are over
energy sources and different
procedures for controlling hazardous energy. Would each machine
require a specific, written procedure?
Reply: With the following exceptions, energy
control procedures specified by 1910.147(c)(4) must be developed,
documented and utilized for the control of potentially hazardous
energy when employees are performing servicing and/or maintenance
on machines or equipment:
1. The 1910.147 standard
does not apply to work on cord and plug connected electrically powered
equipment under the conditions specified by 1910.147(a)(2)(iii)(A).
2. Employers need not document
the required energy control procedures for a particular machine
or equipment when all of the elements of the note following 1910.147(c)(4)(i)
3. Please note that employees
interact with machines and equipment either when they are in the
normal production operations mode or in the servicing and/or maintenance
mode. By the Note following 1910.147(a)(2)(ii)(B), minor tool changes
and adjustments and other minor servicing activities, which take
place during normal production operations, are not covered by the
1910.147 standard if they are routine, repetitive, and integral
to the use of the machine or equipment for production provided that
the work is performed using alternative measures which provide effective
protection (See 1910 Subpart O - Machine Guarding). If an employee
cannot perform minor tool changes and adjustments and other minor
servicing activities during normal production operations without
potential exposure to hazardous energy otherwise protected either
by guarding or by alternative measures providing effective protection,
then the employer must effect the servicing and/or maintenance mode
and comply with applicable provisions of paragraphs (c) through
(f) of the lockout/tagout standard.
4. One energy control procedure
may be used for similar machines and/or equipment if the procedure
adequately addresses the unexpected energization hazards related
to each machine.
Question 2: A group of machines and equipment
which includes a
brush cleaner and associated
cleaner slump, a dryer, a conveyor and a stacker, collectively,
have multiple, including electrical, thermal and mechanical (including
pneumatic and hydraulic), energy sources. All the machines cannot
be completely shut down for servicing and/or maintenance of any
one of these machines or equipment. Can an individual machine or
equipment, for example, the dryer, be locked out separately for
servicing and/or maintenance? Also, is an energy control procedure
required for each machine or equipment on which servicing and/or
maintenance is to be performed?
Reply: An individual machine, for example
the dryer, or individual equipment or a machine and equipment combination,
such as the brush cleaner and associated cleaner slump, may be locked
out by an authorized employee performing servicing and/or maintenance.
Separate energy control procedures would be required, for example,
for the dryer and for the brush cleaner and associated cleaner slump.
These separate energy control procedures must ensure that servicing
and maintenance employees are not exposed to hazards of other interconnected
and nearby machines or equipment including the conveyor and stacker.
Question 3: Do the samples of a work authorization
of energy control procedures
enclosed with my letter meet the documentation requirements of 1910.147?
Reply: A work authorization permit is not
required by the 1910.147 standard. The value of this sample permit
is questionable since it does not identify what work is authorized
on the dryer. Also, the sample does not indicate that lockout in
accordance with an established energy control procedure is a prerequisite
to working on the dryer.
The sample energy control
procedures are deficient. For example, there is no specific statement
in the sample on the intended use of the energy control procedure
as required by 1910.147(c)(4)(ii)(A). Other energy control procedures
requirements are contained in 1910.147(c)(4)(ii). These requirements
are delineated further, for example, 1910.147(d) covers the application
of control, in the lockout/tagout standard.
Please note that the 1910.147 standard
does not cover exposure to electrical hazards from work on, near
or with conductors or equipment in electrical installations. Such
work is covered by Subpart S - Electrical of the 1910 General Industry
standards. Electrical Safety - Related Work Practices, that is,
1910.331 - 335, include lockout and tagging requirements for employees
working on or near exposed deenergized parts. By note 2 following
1910.333(b)(2), lockout and tagging procedures that comply with
paragraph (c) through (f) of 1910.147 will be deemed to comply with
1910.333(b)(2) provided that:
1. The procedures address
the electrical safety hazards covered by Subpart S; and
2. The procedures also incorporate
the requirements of paragraphs 1910.333(b)(2)(iii)(D) and (b)(2)(iv)(B).
Thank you for your interest in Occupational
Safety and Health. If we may be of further assistance, please contact
the Office of General Industry Compliance Assistance, Ronald Davies
on 202-219-8031 extension 110.
John B. Miles, Jr., Director Directorate
of Compliance Programs