(a) Scope, application and purpose -
This standard covers the servicing and maintenance of
machines and equipment in which the unexpected energization
or start up of the machines or equipment, or release
of stored energy could cause injury to employees. This
standard establishes minimum performance requirements
for the control of such hazardous energy.
This standard does not cover the following:
Construction, agriculture and maritime employment;
Installations under the exclusive control of electric
utilities for the purpose of power generation, transmission
and distribution, including related equipment for communication
or metering; and
Exposure to electrical hazards from work on, near, or
with conductors or equipment in electric utilization
installations, which is covered by Subpart S of this
Oil and gas well drilling and servicing.
This standard applies to the control of energy during
servicing and/or maintenance of machines and equipment.
Normal production operations are not covered by this
standard (See Subpart O of this Part). Servicing and/or
maintenance which takes place during normal production
operations is covered by this standard only if:
An employee is required to remove or bypass a guard
or other safety device; or
An employee is required to place any part of his or
her body into an area on a machine or piece of equipment
where work is actually performed upon the material being
processed (point of operation) or where an associated
danger zone exists during a machine operating cycle.
Note: Exception to paragraph (a)(2)(ii): Minor tool
changes and adjustments, and other minor servicing activities,
which take place during normal production operations,
are not covered by this standard if they are routine,
repetitive, and integral to the use of the equipment
for production, provided that the work is performed
using alternative measures which provide effective protection
(See Subpart O of this Part).
This standard does not apply to the following:
Work on cord and plug connected electric equipment for
which exposure to the hazards of unexpected energization
or start up of the equipment is controlled by the unplugging
of the equipment from the energy source and by the plug
being under the exclusive control of the employee performing
the servicing or maintenance.
Hot tap operations involving transmission and distribution
systems for substances such as gas, steam, water or
petroleum products when they are performed on pressurized
pipelines, provided that the employer demonstrates that-
continuity of service is essential;
shutdown of the system is impractical; and
documented procedures are followed, and special equipment
is used which will provide proven effective protection
This section requires employers to establish a program
and utilize procedures for affixing appropriate lockout
devices or tagout devices to energy isolating devices,
and to otherwise disable machines or equipment to prevent
unexpected energization, start up or release of stored
energy in order to prevent injury to employees.
When other standards in this part require the use of
lockout or tagout, they shall be used and supplemented
by the procedural and training requirements of this
Definitions applicable to this section.
Affected employee. An employee whose job requires him/her
to operate or use a machine or equipment on which servicing
or maintenance is being performed under lockout or tagout,
or whose job requires him/her to work in an area in
which such servicing or maintenance is being performed.
Authorized employee. A person who locks out or tags
out machines or equipment in order to perform servicing
or maintenance on that machine or equipment. An affected
employee becomes an authorized employee when that employee's
duties include performing servicing or maintenance covered
under this section.
Capable of being locked out. An energy isolating device
is capable of being locked out if it has a hasp or other
means of attachment to which, or through which, a lock
can be affixed, or it has a locking mechanism built
into it. Other energy isolating devices are capable
of being locked out, if lockout can be achieved without
the need to dismantle, rebuild, or replace the energy
isolating device or permanently alter its energy control
Energized. Connected to an energy source or containing
residual or stored energy.
Energy isolating device. A mechanical device that physically
prevents the transmission or release of energy, including
but not limited to the following: A manually operated
electrical circuit breaker; a disconnect switch; a manually
operated switch by which the conductors of a circuit
can be disconnected from all ungrounded supply conductors,
and, in addition, no pole can be operated independently;
a line valve; a block; and any similar device used to
block or isolate energy. Push buttons, selector switches
and other control circuit type devices are not energy
Energy source. Any source of electrical, mechanical,
hydraulic, pneumatic, chemical, thermal, or other energy.
Hot tap. A procedure used in the repair, maintenance
and services activities which involves welding on a
piece of equipment (pipelines, vessels or tanks) under
pressure, in order to install connections or appurtenances.
it is commonly used to replace or add sections of pipeline
without the interruption of service for air, gas, water,
steam, and petrochemical distribution systems.
Lockout. The placement of a lockout device on an energy
isolating device, in accordance with an established
procedure, ensuring that the energy isolating device
and the equipment being controlled cannot be operated
until the lockout device is removed.
Lockout device. A device that utilizes a positive means
such as a lock, either key or combination type, to hold
an energy isolating device in the safe position and
prevent the energizing of a machine or equipment. Included
are blank flanges and bolted slip blinds.
Normal production operations. The utilization of a machine
or equipment to perform its intended production function.
Servicing and/or maintenance. Workplace activities such
as constructing, installing, setting up, adjusting,
inspecting, modifying, and maintaining and/or servicing
machines or equipment. These activities include lubrication,
cleaning or unjamming of machines or equipment and making
adjustments or tool changes, where the employee may
be exposed to the unexpected energization or startup
of the equipment or release of hazardous energy.
Setting up. Any work performed to prepare a machine
or equipment to perform its normal production operation.
Tagout. The placement of a tagout device on an energy
isolating device, in accordance with an established
procedure, to indicate that the energy isolating device
and the equipment being controlled may not be operated
until the tagout device is removed.
Tagout device. A prominent warning device, such as a
tag and a means of attachment, which can be securely
fastened to an energy isolating device in accordance
with an established procedure, to indicate that the
energy isolating device and the equipment being controlled
may not be operated until the tagout device is removed.
(c) General -
Energy control program. The employer shall establish
a program consisting of energy control procedures, employee
training and periodic inspections to ensure that before
any employee performs any servicing or maintenance on
a machine or equipment where the unexpected energizing,
startup or release of stored energy could occur and
cause injury, the machine or equipment shall be isolated
from the energy source and rendered inoperative.
If an energy isolating device is not capable of being
locked out, the employer's energy control program under
paragraph (c)(1) of this section shall utilize a tagout
If an energy isolating device is capable of being locked
out, the employer's energy control program under paragraph
(c)(1) of this section shall utilize lockout, unless
the employer can demonstrate that the utilization of
a tagout system will provide full employee protection
as set forth in paragraph (c)(3) of this section.
After January 2, 1990, whenever replacement or major
repair, renovation or modification of a machine or equipment
is performed, and whenever new machines or equipment
are installed, energy isolating devices for such machine
or equipment shall be designed to accept a lockout device.
(c)(3) Full employee protection.
When a tagout device is used on an energy isolating
device which is capable of being locked out, the tagout
device shall be attached at the same location that the
lockout device would have been attached, and the employer
shall demonstrate that the tagout program will provide
a level of safety equivalent to that obtained by using
a lockout program.
In demonstrating that a level of safety is achieved
in the tagout program which is equivalent to the level
of safety obtained by using a lockout program, the employer
shall demonstrate full compliance with all tagout-related
provisions of this standard together with such additional
elements as are necessary to provide the equivalent
safety available from the use of a lockout device. Additional
means to be considered as part of the demonstration
of full employee protection shall include the implementation
of additional safety measures such as the removal of
an isolating circuit element, blocking of a controlling
switch, opening of an extra disconnecting device, or
the removal of a valve handle to reduce the likelihood
of inadvertent energization.
(c)(4) Energy control procedure.
Procedures shall be developed, documented and utilized
for the control of potentially hazardous energy when
employees are engaged in the activities covered by this
Note: Exception: The employer need not document the
required procedure for a particular machine or equipment,
when all of the following elements exist: (1) The machine
or equipment has no potential for stored or residual
energy or reaccumulation of stored energy after shut
down which could endanger employees; (2) the machine
or equipment has a single energy source which can be
readily identified and isolated; (3) the isolation and
locking out of that energy source will completely deenergize
and deactivate the machine or equipment; (4) the machine
or equipment is isolated from that energy source and
locked out during servicing or maintenance; (5) a single
lockout device will achieve a locker-out condition;
(6) the lockout device is under the exclusive control
of the authorized employee performing the servicing
or maintenance; (7) the servicing or maintenance does
not create hazards for other employees; and (8) the
employer, in utilizing this exception, has had no accidents
involving the unexpected activation or reenergization
of the machine or equipment during servicing or maintenance.
The procedures shall clearly and specifically outline
the scope, purpose, authorization, rules, and techniques
to be utilized for the control of hazardous energy,
and the means to enforce compliance including, but not
limited to, the following:
A specific statement of the intended use of the procedure;
Specific procedural steps for shutting down, isolating,
blocking and securing machines or equipment to control
Specific procedural steps for the placement, removal
and transfer of lockout devices or tagout devices and
the responsibility for them; and
Specific requirements for testing a machine or equipment
to determine and verify the effectiveness of lockout
devices, tagout devices, and other energy control measures.
(c)(5) Protective materials and hardware.
Locks, tags, chains, wedges, key blocks, adapter pins,
self-locking fasteners, or other hardware shall be provided
by the employer for isolating, securing or blocking
of machines or equipment from energy sources.
Lockout devices and tagout devices shall be singularly
identified; shall be the only devices(s) used for controlling
energy; shall not be used for other purposes; and shall
meet the following requirements:
Lockout and tagout devices shall be capable of withstanding
the environment to which they are exposed for the maximum
period of time that exposure is expected.
Tagout devices shall be constructed and printed so that
exposure to weather conditions or wet and damp locations
will not cause the tag to deteriorate or the message
on the tag to become illegible.
Tags shall not deteriorate when used in corrosive environments
such as areas where acid and alkali chemicals are handled
Standardized. Lockout and tagout devices shall be standardized
within the facility in at least one of the following
criteria: Color; shape; or size; and additionally, in
the case of tagout devices, print and format shall be
Lockout devices. Lockout devices shall be substantial
enough to prevent removal without the use of excessive
force or unusual techniques, such as with the use of
bolt cutters or other metal cutting tools.
Tagout devices. Tagout devices, including their means
of attachment, shall be substantial enough to prevent
inadvertent or accidental removal. Tagout device attachment
means shall be of a non-reusable type, attachable by
hand, self-locking, and non-releasable with a minimum
unlocking strength of no less than 50 pounds and having
the general design and basic characteristics of being
at least equivalent to a one-piece, all environment-tolerant
nylon cable tie.
Identifiable. Lockout devices and tagout devices shall
indicate the identity of the employee applying the device(s).
Tagout devices shall warn against hazardous conditions
if the machine or equipment is energized and shall include
a legend such as the following: Do Not Start. Do Not
Open. Do Not Close. Do Not Energize. Do Not Operate.
(c)(6) Periodic inspection.
The employer shall conduct a periodic inspection of
the energy control procedure at least annually to ensure
that the procedure and the requirements of this standard
are being followed.
The periodic inspection shall be performed by an authorized
employee other than the ones(s) utilizing the energy
control procedure being inspected.
The periodic inspection shall be conducted to correct
any deviations or inadequacies identified.
Where lockout is used for energy control, the periodic
inspection shall include a review, between the inspector
and each authorized employee, of that employee's responsibilities
under the energy control procedure being inspected.
Where tagout is used for energy control, the periodic
inspection shall include a review, between the inspector
and each authorized and affected employee, of that employee's
responsibilities under the energy control procedure
being inspected, and the elements set forth in paragraph
(c)(7)(ii) of this section.
The employer shall certify that the periodic inspections
have been performed. The certification shall identify
the machine or equipment on which the energy control
procedure was being utilized, the date of the inspection,
the employees included in the inspection, and the person
performing the inspection.
(c)(7) Training and communication.
The employer shall provide training to ensure that the
purpose and function of the energy control program are
understood by employees and that the knowledge and skills
required for the safe application, usage, and removal
of the energy controls are acquired by employees. The
training shall include the following:
Each authorized employee shall receive training in the
recognition of applicable hazardous energy sources,
the type and magnitude of the energy available in the
workplace, and the methods and means necessary for energy
isolation and control.
Each affected employee shall be instructed in the purpose
and use of the energy control procedure.
All other employees whose work operations are or may
be in an area where energy control procedures may be
utilized, shall be instructed about the procedure, and
about the prohibition relating to attempts to restart
or reenergize machines or equipment which are locked
out or tagged out.
When tagout systems are used, employees shall also be
trained in the following limitations of tags:
Tags are essentially warning devices affixed to energy
isolating devices, and do not provide the physical restraint
on those devices that is provided by a lock.
When a tag is attached to an energy isolating means,
it is not to be removed without authorization of the
authorized person responsible for it, and it is never
to be bypassed, ignored, or otherwise defeated.
Tags must be legible and understandable by all authorized
employees, affected employees, and all other employees
whose work operations are or may be in the area, in
order to be effective.
Tags and their means of attachment must be made of materials
which will withstand the environmental conditions encountered
in the workplace.
Tags may evoke a false sense of security, and their
meaning needs to be understood as part of the overall
energy control program.
Tags must be securely attached to energy isolating devices
so that they cannot be inadvertently or accidentally
detached during use.
(c)(7)(iii) Employee retraining.
Retraining shall be provided for all authorized and
affected employees whenever there is a change in their
job assignments, a change in machines, equipment or
processes that present a new hazard, or when there is
a change in the energy control procedures.
Additional retraining shall also be conducted whenever
a periodic inspection under paragraph (c)(6) of this
section reveals, or whenever the employer has reason
to believe that there are deviations from or inadequacies
in the employee's knowledge or use of the energy control
The retraining shall reestablish employee proficiency
and introduce new or revised control methods and procedures,
The employer shall certify that employee training has
been accomplished and is being kept up to date. The
certification shall contain each employee's name and
dates of training.
Energy isolation. Lockout or tagout shall be performed
only by the authorized employees who are performing
the servicing or maintenance.
Notification of employees. Affected employees shall
be notified by the employer or authorized employee of
the application and removal of lockout devices or tagout
devices. Notification shall be given before the controls
are applied, and after they are removed from the machine
Application of control. The established procedures for
the application of energy control (the lockout or tagout
procedures) shall cover the following elements and actions
and shall be done in the following sequence:
Preparation for shutdown. Before an authorized or affected
employee turns off a machine or equipment, the authorized
employee shall have knowledge of the type and magnitude
of the energy, the hazards of the energy to be controlled,
and the method or means to control the energy.
Machine or equipment shutdown. The machine or equipment
shall be turned off or shut down using the procedures
established for the machine or equipment. An orderly
shutdown must be utilized to avoid any additional or
increased hazard(s) to employees as a result of the
Machine or equipment isolation. All energy isolating
devices that are needed to control the energy to the
machine or equipment shall be physically located and
operated in such a manner as to isolate the machine
or equipment from the energy source(s).
Lockout or tagout device application.
Lockout or tagout devices shall be affixed to each energy
isolating device by authorized employees.
Lockout devices, where used, shall be affixed in a manner
to that will hold the energy isolating devices in a
"safe" or "off" position.
Tagout devices, where used, shall be affixed in such
a manner as will clearly indicate that the operation
or movement of energy isolating devices from the "safe"
or "off" position is prohibited.
Where tagout devices are used with energy isolating
devices designed with the capability of being locked,
the tag attachment shall be fastened at the same point
at which the lock would have been attached.
Where a tag cannot be affixed directly to the energy
isolating device, the tag shall be located as close
as safely possible to the device, in a position that
will be immediately obvious to anyone attempting to
operate the device.
Following the application of lockout or tagout devices
to energy isolating devices, all potentially hazardous
stored or residual energy shall be relieved, disconnected,
restrained, and otherwise rendered safe.
If there is a possibility of reaccumulation of stored
energy to a hazardous level, verification of isolation
shall be continued until the servicing or maintenance
is completed, or until the possibility of such accumulation
no longer exists.
Verification of isolation. Prior to starting work on
machines or equipment that have been locked out or tagged
out, the authorized employee shall verify that isolation
and deenergization of the machine or equipment have
Release from lockout or tagout. Before lockout or tagout
devices are removed and energy is restored to the machine
or equipment, procedures shall be followed and actions
taken by the authorized employee(s) to ensure the following:
The machine or equipment. The work area shall be inspected
to ensure that nonessential items have been removed
and to ensure that machine or equipment components are
The work area shall be checked to ensure that all employees
have been safely positioned or removed.
After lockout or tagout devices have been removed and
before a machine or equipment is started, affected employees
shall be notified that the lockout or tagout device(s)
have been removed.
Lockout or tagout devices removal. Each lockout or tagout
device shall be removed from each energy isolating device
by the employee who applied the device. Exception to
paragraph (e)(3): When the authorized employee who applied
the lockout or tagout device is not available to remove
it, that device may be removed under the direction of
the employer, provided that specific procedures and
training for such removal have been developed, documented
and incorporated into the employer's energy control
program. The employer shall demonstrate that the specific
procedure provides equivalent safety to the removal
of the device by the authorized employee who applied
it. The specific procedure shall include at least the
Verification by the employer that the authorized employee
who applied the device is not at the facility:
Making all reasonable efforts to contact the authorized
employee to inform him/her that his/her lockout or tagout
device has been removed; and
Ensuring that the authorized employee has this knowledge
before he/she resumes work at that facility.
(f) Additional requirements.
Testing or positioning of machines, equipment or components
thereof. In situations in which lockout or tagout devices
must be temporarily removed from the energy isolating
device and the machine or equipment energized to test
or position the machine, equipment or component thereof,
the following sequence of actions shall be followed:
Clear the machine or equipment of tools and materials
in accordance with paragraph (e)(1) of this section;
Remove employees from the machine or equipment area
in accordance with paragraph (e)(2) of this section;
Remove the lockout or tagout devices as specified in
paragraph (e)(3) of this section;
Energize and proceed with testing or positioning;
Deenergize all systems and reapply energy control measures
in accordance with paragraph (d) of this section to
continue the servicing and/or maintenance.
Outside personnel (contractors, etc.).
Whenever outside servicing personnel are to be engaged
in activities covered by the scope and application of
this standard, the on-site employer and the outside
employer shall inform each other of their respective
lockout or tagout procedures.
The on-site employer shall ensure that his/her employees
understand and comply with the restrictions and prohibitions
of the outside employer's energy control program.
(f)(3) Group lockout or tagout.
When servicing and/or maintenance is performed by a
crew, craft, department or other group, they shall utilize
a procedure which affords the employees a level of protection
equivalent to that provided by the implementation of
a personal lockout or tagout device.
Group lockout or tagout devices shall be used in accordance
with the procedures required by paragraph (c)(4) of
this section including, but not necessarily limited
to, the following specific requirements:
Primary responsibility is vested in an authorized employee
for a set number of employees working under the protection
of a group lockout or tagout device (such as an operations
Provision for the authorized employee to ascertain the
exposure status of individual group members with regard
to the lockout or tagout of the machine or equipment
When more than one crew, craft, department, etc. is
involved, assignment of overall job-associated lockout
or tagout control responsibility to an authorized employee
designated to coordinate affected work forces and ensure
continuity of protection; and
Each authorized employee shall affix a personal lockout
or tagout device to the group lockout device, group
lockbox, or comparable mechanism when he or she begins
work, and shall remove those devices when he or she
stops working on the machine or equipment being serviced
Shift or personnel changes. Specific procedures shall
be utilized during shift or personnel changes to ensure
the continuity of lockout or tagout protection, including
provision for the orderly transfer of lockout or tagout
device protection between off-going and oncoming employees,
to minimize exposure to hazards from the unexpected
energization or start-up of the machine or equipment,
or the release of stored energy.
Note: The following appendix to §1910.147 services as
a non-mandatory guideline to assist employers and employees
in complying with the requirements of this section,
as well as to provide other helpful information. Nothing
in the appendix adds to or detracts from any of the
requirements of this section.
[54 FR 36687, Sept. 1, 1989, as amended at 54 FR 42498,
Oct. 17, 1989; 55 FR 38685, 38686, Sept. 20, 1990; 61
FR 5507, Feb. 13, 1996]