Overview of the Permit-Required Confined Spaces Standard
The Final Rule for Permit-Required Confined Spaces was published in the Federal Register on
January 14, 1993, and became effective on April 15, 1993. The standard is based on years of
gathering information on confined space fatalities and on testimony about the hazards of
confined spaces from all sectors of industry and labor. Because it applies to all of general
industry, a performance-oriented standard was developed rather than a specification standard.
The rule citation is 29CFR1910.146.
Many workplaces contain spaces which are considered "confined" because their configurations
hinder the activities of any employees who must enter, work in, and exit them. For example,
employees who work in process vessels generally must squeeze in and out through narrow
openings and perform their tasks while cramped or contorted. For the purposes of this
rulemaking, OSHA is using the term "confined space" to describe such spaces.
In addition, there are many instances where employees who work in confined spaces face
increased risk of exposure to serious hazards. In some cases, confinement itself poses
entrapment hazards. In other cases, confined space work keeps employees closer to hazards,
such as asphyxiating atmospheres or the moving parts of a mixer, than they would be
OSHA uses the term "permit-required confined space" (permit space) to describe those spaces
which both meet the definition of "confined space" and pose health or safety hazards.
Asphyxiation is the leading cause of death in confined spaces. The asphyxiation that have
occurred in permit spaces have generally resulted from oxygen deficiency or from exposure to
toxic atmospheres. In addition, there have been cases where employees who were working in
water towers and bulk material hoppers slipped or fell into narrow, tapering, discharge pipes
and died of asphyxiation due to compression of the torso. Also, employees working in silos
have been asphyxiated as the result of engulfment in finely divided particulate matter (such
as sawdust) that blocks the breathing passages.
OSHA has, in addition, documented confined space incidents in which victims were burned,
ground-up by auger type conveyors, or crushed or battered by rotating or moving parts inside
mixers. Failure to deenergize equipment inside the space prior to employee entry was a
factor in many of those accidents.
Many employers have not appreciated the degree to which the conditions of permit space work
can compound the risks of exposure to atmospheric or other serious hazards. Further, the
elements of confinement, limited access, and restricted air flow, can result in hazardous
conditions which would not arise in an open workplace. For example, vapors which might
otherwise be released into the open air can generate a highly toxic or otherwise harmful
atmosphere within a confined space. Unfortunately, in many cases, employees have died
because employers improvised or followed "traditional methods" rather than following existing
OSHA standards, recognized safe industry practice, or common sense.
The failure to take proper precautions for permit space entry operations has resulted in
fatalities, as opposed to injuries, more frequently than would be predicted using the
applicable Bureau of Labor Statistics models. OSHA notes that, by their very nature and
configuration, many permit spaces contain atmospheres which, unless adequate precautions are
taken, are immediately dangerous to life and health (IDLH). For example, many confined
spaces are poorly ventilated - a condition that is favorable to the creation of an oxygen
deficient atmosphere and to the accumulation of toxic gases.
Furthermore, by definition, a confined space is not designed for continuous employee
occupancy; hence little consideration has been given to the preservation of human life within
the confined space when employees need to enter it.
It is your obligation as an employer to evaluate your workplace to determine if any spaces
are permit-required confined spaces. Based on your answers during this session Confined
Spaces Advisor has concluded that the specific space in question is such a space.
REMINDER: A confined space is characterized by restricted means of entry/exit, size
sufficient to contain a worker, and not specifically designed for worker occupancy. A
permit-required space is a confined space that has a hazard to health or life associated with
it. Hazards may be the result of atmosphere or materials in the space or the result of the
shape of the space.
In general, the Permit-Required Confined Spaces standard requires that you, the employer,
evaluate the workplace to determine if any spaces are permit-required confined spaces. If
permit spaces are present, and your workers are ever authorized to enter such spaces (you
said they do) you must develop and implement a comprehensive permit spaces program, which
is a an overall plan/policy for protecting employees form permit space hazards and for
regulating employee entry into permit spaces. The OSHA standard includes detailed
specification of the elements of an acceptable permit spaces program (29CFR1910.146(d)).
Permit spaces must be identified by signs, and entry must be controlled and limited to
authorized persons. An important element of the requirements is that entry be regulated by a
written entry permit system, and that entry permits be recorded and issued for each entry in
to a permit space. The standard specifies strict procedures for evaluation and atmospheric
testing of a space before and during an entry by workers. The standard requires that entry
be monitored by an attendant outside the space and that provisions be made for rescue in the
event of an emergency. The standard specifies training requirements and specific duties for
authorized entrants, attendants, and supervisors. Rescue service provisions are required,
and where feasible rescue must be facilitated by a non-entry retrieval system, such as a
harness and cable attached to a mechanical hoist.
The OSHA Permit-Required Spaces Standard provides for alternative (less stringent than full
permit procedures) entry procedures in cases where the only hazard in a space is atmospheric
and the hazard can be controlled by forced air. The alternative procedure is allowed only in
cases where specified requirements for substantiation and notification are met. Your answers
during this session with the Confined Spaces Advisor indicated that you are not eligible to
apply the alternative procedures to the space in question.
Special requirements apply to contractors whose employees work in spaces controlled by
others. Employers who engage contractors to work in their permit-required confined spaces
also have special obligations pertaining to that arrangement.
If certain kinds of work are done in a permit space, then additional OSHA rules may apply.
These kinds of work include telecommunications, electrical (underground), paper/pulp milling,
shipbuilding, longshoring, and sewer work. Confined Spaces Advisor asked you to identify
applicable kinds of work done in the permit space, and has appended additional guidance at
the end of this report if you indicated any of the critical kinds of work.
Construction, ship yard or marine terminal employment, and agriculture are not subject to the
OSHA General Industry Permit-required Confined Spaces regulation (29CFR1910.146). However,
employers in those industries should be aware that their workers are covered when they do
work that falls under the general industry category. For example, maintenance, repair, and
refurbishing work is covered under general industry rules even though done by "construction"
You may be able to reclassify a permit-required confined space to non-permit space status if
you can permanently eliminate the hazards affecting the space.
The following twenty five items describe provisions of the Permit-required Confined Spaces
rule that apply to operations involving the space in question. The text follows closely the
language of 29CFR1910.146, but has been edited to present only material relevant to the case
described and to organize material in a useful sequence. Use Confined Spaces Advisor Option
6 to view the official text of 29CFR1910.146.
- The employer shall evaluate the workplace to determine if any spaces are permit-required
- If the workplace contains permit spaces, the employer shall inform exposed employees, by
posting danger signs or by any other equally effective means, of the existence and location
of and the danger posed by the permit spaces.
NOTE: A sign reading DANGER -- PERMIT-REQUIRED CONFINED SPACE, DO NOT ENTER or using other
similar language would satisfy the requirement for a sign.
- If the employer decides that its employees will enter permit spaces, the employer shall
develop and implement a written permit space program that complies with this section. The
written program shall be available for inspection by employees and their authorized
representatives. The permit space program must include the fourteen elements specified in
29CFR1910.146(d). These elements correspond to items 4 through 17 in this guidance
- The employer shall implement the measures necessary to prevent unauthorized entry;
- The employer shall identify and evaluate the hazards of permit spaces before employees
- The employer shall develop and implement the means, procedures, and practices necessary
for safe permit space entry operations, including, but not limited to, the following:
- Specifying acceptable entry conditions;
- Isolating the permit space;
inerting, flushing, or ventilating the permit space as necessary to eliminate or control
- Providing pedestrian, vehicle, or other barriers as necessary to
protect entrants from external hazards; and
- Verifying that conditions in the permit
space are acceptable for entry throughout the duration of an authorized entry.
- The employer shall provide the following equipment at no cost to employees, maintain that
equipment properly, and ensure that employees use that equipment properly:
- Testing and
monitoring equipment needed to comply with requirements of this section;
equipment needed to obtain acceptable entry conditions;
- Communications equipment
necessary to allow entrants and attendants to communicate and monitor conditions in the space
(see 29CFR1910.146(h)(3) and (i)(5) regarding the duties of attendants and entrants to
- Personal protective equipment insofar as feasible engineering and work
practice controls do not adequately protect employees;
- Lighting equipment needed to
enable employees to see well enough to work safely and to exit the space quickly in an
- Barriers and shields as required by 29CFR1910.146(d)(3)
(see item v,
- Equipment, such as ladders, needed for safe ingress and egress by authorized
- Rescue and emergency equipment needed to comply with 29CFR1910.146(d)(9),
except to the extent that the equipment is provided by rescue services; and
- Any other
equipment necessary for safe entry into and rescue from permit spaces.
- The program shall evaluate permit space conditions as follows when entry operations are
- Test conditions in the permit space to determine if acceptable entry
conditions exist before entry is authorized to begin, except that, if isolation of the space
is infeasible because the space is large or is part of a continuous system (such as a sewer),
pre-entry testing shall be performed to the extent feasible before entry is authorized and,
if entry is authorized, entry conditions shall be continuously monitored in the areas where
authorized entrants are working;
- Test or monitor the permit space as necessary to
determine if acceptable entry conditions are being maintained during the course of entry
- When testing for atmospheric hazards, test first for oxygen, then for
combustible gases and vapors, and then for toxic gases and vapors.
testing conducted in accordance with Appendix B to section 1910.146 would be considered as
satisfying the requirements of this paragraph. For permit space operations in sewers,
atmospheric testing conducted in accordance with Appendix B, as supplemented by Appendix E to
section 1910.146, would be considered as satisfying the requirements of this paragraph.
- The program shall provide at least one attendant outside the permit space into which
entry is authorized for the duration of entry operations; NOTE: Attendants may be assigned
to monitor more than one permit space provided the duties described in paragraph (i) of this
section can be effectively performed for each permit space that is monitored. Likewise,
attendants may be stationed at any location outside the permit space to be monitored as long
as the duties described in paragraph (i) of this section can be effectively performed for
each permit space that is monitored.
- If multiple spaces are to be monitored by a
single attendant, include in the permit program the means and procedures to enable the
attendant to respond to an emergency affecting one or more of the permit spaces being
monitored without distraction from the attendant's responsibilities under paragraph (i) of
- Designate the persons who are to have active roles (as, for example, authorized
entrants, attendants, entry supervisors, or persons who test or monitor the atmosphere in a
permit space) in entry operations, identify the duties of each such employee, and provide
each such employee with the training required by paragraph (g) of this section;
- Develop and implement procedures for summoning rescue and emergency services, for
rescuing entrants from permit spaces, for providing necessary emergency services to rescued
employees, and for preventing unauthorized personnel from attempting a rescue;
- Develop and implement a system for the preparation, issuance, use, and cancellation of
entry permits as required by this section;
- Develop and implement procedures to coordinate entry operations when employees of more
than one employer are working simultaneously as authorized entrants in a permit space, so
that employees of one employer do not endanger the employees of any other employer;
- Develop and implement procedures (such as closing off a permit space and canceling the
permit) necessary for concluding the entry after entry operations have been completed;
- Review entry operations when the employer has reason to believe that the measures taken
under the permit space program may not protect employees and revise the program to correct
deficiencies found to exist before subsequent entries are authorized; NOTE: Examples of
circumstances requiring the review of the permit space program are: any unauthorized entry
of a permit space, the detection of a permit space hazard not covered by the permit, the
detection of a condition prohibited by the permit, the occurrence of an injury or near-miss
during entry, a change in the use or configuration of a permit space, and employee complaints
about the effectiveness of the program.
- Review the permit space program, using the canceled permits retained (as provided by
29CFR1910.146 (e)(6)), within 1 year after each entry and revise the program as necessary, to
ensure that employees participating in entry operations are protected from permit space
hazards. NOTE: Employers may perform a single annual review covering all entries performed
during a 12-monthperiod. If no entry is performed during a 12-month period, no review is
necessary. Appendix C to section 1910.146 presents examples of permit space programs that
are considered to comply with the requirements of paragraph (d) of this section.
- Permit system (see 29CFR1910.146 (e)). The following six-step procedure must be followed
for each entry into the permit space.
- Before entry is authorized, the employer shall
document the completion of measures, procedures, and practices necessary for safe permit
space entry (listed under item (6) of this guidance report and in 29CFR1910.146(d)(3)) by
preparing an entry permit. NOTE: Appendix D to section 1910.146 (Accessible through the
Advisor system options) presents examples of permits whose elements are considered to comply
with the requirements of this section.
- Before entry begins, the entry supervisor
identified on the permit shall sign the entry permit to authorize entry.
- The completed
permit shall be made available at the time of entry to all authorized entrants, by posting it
at the entry portal or by any other equally effective means, so that the entrants can confirm
that pre-entry preparations have been completed.
- The duration of the permit may not
exceed the time required to complete the assigned task or job identified on the permit.
- The entry supervisor shall terminate entry and cancel the entry permit when the entry
operations covered by the entry permit have been completed; or when a condition that is not
allowed under the entry permit arises in or near the permit space.
- The employer shall
retain each canceled entry permit for at least 1 year to facilitate the review of the permit
-required confined space program required by 29CFR1910.146(d)(14). Any problems encountered
during an entry operation shall be noted on the pertinent permit so that appropriate
revisions to the permit space program can be made.
- Entry Permit Requirements (as specified in 29CFR1910.146(f)). The entry permit that
documents compliance with the permit-required confined spaces standard and authorizes entry
to a permit space shall identify the following fifteen items:
- The permit space to be
- The purpose of the entry;
- The date and the authorized duration of
the entry permit;
- The authorized entrants within the permit space, by name or by such
other means (for example, through the use of rosters or tracking systems) as will enable the
attendant to determine quickly and accurately, for the duration of the permit, which
authorized entrants are inside the permit space; NOTE: This requirement may be met by
inserting a reference on the entry permit as to the means used, such as a roster or tracking
system, to keep track of the authorized entrants within the permit space.
personnel, by name, currently serving as attendants;
- The individual, by name,
currently serving as entry supervisor, with a space for the signature or initials of the
entry supervisor who originally authorized entry;
- The hazards of the permit space
to be entered;
- The measures used to isolate the permit space and to eliminate or
control permit space hazards before entry; NOTE: Those measures can include the lockout or
tagging of equipment and procedures for purging, inerting, ventilating, and flushing permit
- The acceptable entry conditions;
- The results of initial and periodic
tests performed under 29CFR1910.146(d)(5) (see prior item (8) of this report), accompanied by
the names or initials of the testers and by an indication of when the tests were performed;
- The rescue and emergency services that can be summoned and the means (such as the
equipment to use and the numbers to call) for summoning those services;
communication procedures used by authorized entrants and attendants to maintain contact
during the entry;
- Equipment, such as personal protective equipment, testing
equipment, communications equipment, alarm systems, and rescue equipment, to be provided for
compliance with this section; Note: equipment must be provided to insure communication
between the attendant outside the space and workers within the space;
- Any other
information whose inclusion is necessary, given the circumstances of the particular confined
space, in order to ensure employee safety; and
- Any additional permits, such as for hot
work, that have been issued to authorize work in the permit space.
- Training (as specified in 29CFR1910.146(g)). The employer shall provide training so
that all employees whose work is regulated by this section acquire the understanding,
knowledge, and skills necessary for the safe performance of the duties assigned under the
permit spaces standard. Training shall be provided to each affected employee:
- Before the
employee is first assigned duties under this section;
- Before there is a change in
- Whenever there is a change in permit spaceoperations that presents a
hazard about which anemployee has not previously been trained;
- Whenever the employer
has reason to believe either that there are deviations from the permit space entry procedures
required by the permits spaces program (see 29CFR1910.146(d)(3) or prior item (6) of this
report) or that there are inadequacies in the employee's knowledge or use of these
procedures. The training shall establish employee proficiency in the duties required by the
29CFR1910.146 standard and shall introduce new or revised procedures, as necessary, for
compliance with the permit spaces standard. The employer shall certify that the training
required the standard (described in this section) has been accomplished. The certification
shall contain each employee's name, the signatures or initials of the trainers, and the dates
of training. The certification shall be available for inspection by employees and their
- The Five Duties of Authorized Entrants (as specified in 29CFR1910.146(h)). The employer
shall ensure that all authorized entrants:
- Know the hazards that may be faced during
entry, including information on the mode, signs or symptoms, and consequences of the
- Properly use equipment (see prior item (7) or 29CFR1910.146 (d)(4) for the
list of equipment);
- Communicate with the attendant as necessary to enable the
attendant to monitor entrant status and to enable the attendant to alert entrants of the need
to evacuate the space (see also duties of attendants described in item 22, below, or in
29CFR1910.146(i)(6) of the standard);
- Alert the attendant whenever: The entrant
recognizes any warning sign or symptom of exposure to a dangerous situation, or the entrant
detects a prohibited condition; and
- Exit from the permit space as quickly as possible
whenever: An order to evacuate is given by the attendant or the entry supervisor; the
entrant recognizes any warning sign or symptom of exposure to a dangerous situation; the
entrant detects a prohibited condition, or an evacuation alarm is activated.
- The Ten Duties of Attendants (as specified in 29CFR1910.146(i)). The employer shall
ensure that each attendant:
- Knows the hazards that may be faced during entry, including
information on the mode, signs or symptoms, and consequences of the exposure;
- Is aware
of possible behavioral effects of hazard exposure in authorized entrants;
- Continuously maintains an accurate count of authorized entrants in the permit space and
ensures that the means used to identify authorized entrants accurately identifies who is in
the permit space;
- Remains outside the permit space during entry operations until
relieved by another attendant; NOTE: When the employer's permit entry program allows
attendant entry for rescue, attendants may enter a permit space to attempt a rescue if they
have been trained and equipped for rescue operations (see rescue requirements below or
29CFR1910.146 (k)(1) for details) and if they have been relieved as required by this section;
- Communicates with authorized entrants as necessary to monitor entrant status and to
alert entrants of the need to evacuate the space;
- Monitors activities inside and
outside the space to determine if it is safe for entrants to remain in the space and orders
the authorized entrants to evacuate the permit space immediately under any of the following
conditions: If the attendant detects a prohibited condition; If the attendant detects
the behavioral effects of hazard exposure in an authorized entrant; If the attendant
detects a situation outside the space that could endanger the authorized entrants; or If
the attendant cannot effectively and safely perform all the duties required of entrants (see
item 21 above);
- Summon rescue and other emergency services as soon as the attendant
determines that authorized entrants may need assistance to escape from permit space hazards;
- Takes the following actions when unauthorized persons approach or enter a permit
space while entry is underway: Warn the unauthorized persons that they must stay away from
the permit space; Advise the unauthorized persons that they must exit immediately if they
have entered the permit space; and Inform the authorized entrants and the entry supervisor
if unauthorized persons have entered the permit space;
- Performs non-entry rescues as
specified by the employer's rescue procedure; and
- Performs no duties that might
interfere with the attendant's primary duty to monitor and protect the authorized entrants.
- The Six Duties of Entry Supervisors (29CRF1910.146(j). The employer shall ensure that
each entry supervisor:
- Knows the hazards that may be faced during entry, including information on the mode,
signs or symptoms, and consequences of the exposure;
- Verifies, by checking that the appropriate entries have been made on the permit, that
all tests specified by the permit have been conducted and that all procedures and equipment
specified by the permit are in place before endorsing the permit and allowing entry to begin;
- Terminates the entry and cancels the permit as required by paragraph (e)(5) of this
- Verifies that rescue services are available and that the means for summoning them are
- Removes unauthorized individuals who enter or who attempt to enter the permit space
during entry operations; and
- Determines, whenever responsibility for a permit space entry operation is transferred
and at intervals dictated by the hazards and operations performed within the space, that
entry operations remain consistent with terms of the entry permit and that acceptable entry
conditions are maintained.
- Rescue and emergency services (29CFR1910.146(k)) NOTE: OSHA is has initiated rule
making procedures to clarify certian aspects of rescue requirements and procedures.. There
are two ways in which rescue services may be provided: By employees of the subject employer
or by employees of a second party rescue service. The following requirements apply to
employers who have employees enter permit spaces to perform rescue services.
When an employer (host employer) arranges to have persons other than the host
employer's employees perform permit space rescue, the host employer shall:
- The employer shall ensure that each member of the rescue service is provided with, and
is trained to use properly, the personal protective equipment and rescue equipment necessary
for making rescues from permit spaces.
- Each member of the rescue service shall be trained to perform the assigned rescue
duties. Each member of the rescue service shall also receive the training required of
- Each member of the rescue service shall practice making permit space rescues at least
once every 12 months, by means of simulated rescue operations in which they remove dummies,
manikins, or actual persons from the actual permit spaces or from representative permit
spaces. Representative permit spaces shall, with respect to opening size, configuration, and
accessibility, simulate the types of permit spaces from which rescue is to be performed.
- Each member of the rescue service shall be trained in basic first-aid and in
cardiopulmonary resuscitation (CPR). At least one member of the rescue service holding
current certification in first aid and in CPR shall be available.
To facilitate non-entry rescue, retrieval systems or methods shall be used whenever an
authorized entrant enters a permit space, unless the retrieval equipment would increase the
overall risk of entry or would not contribute to the rescue of the entrant. Retrieval
systems shall meet the following requirements.
- Inform the rescue service of the hazards they may confront when called on to perform
rescue at the host employer's facility, and
- Provide the rescue service with access to all permit spaces from which rescue may be
necessary so that the rescue service can develop appropriate rescue plans and practice rescue
If an injured entrant is exposed to a substance for which a Material Safety Data Sheet
(MSDS) or other similar written information is required to be kept at the worksite, that MSDS
or written information shall be made available to the medical facility treating the exposed
- Each authorized entrant shall use a chest or full body harness, with a retrieval line
attached atthe center of the entrant's back near shoulder level, or above the entrant's head.
Wristlets may be used in lieu of the chest or full body harness if the employer can
demonstrate that the use of a chest or full body harness is infeasible or creates a greater
hazard and that the use of wristlets is the safest and mosteffective alternative.
- The other end of the retrieval line shall beattached to a mechanical device or fixed
point outside the permit space in such a manner that rescue can begin as soon as the rescuer
becomes aware that rescue is necessary. A mechanical device shall be available to retrieve
personnel from vertical type permit spaces more than 5 feet (1.52 m) deep.
- When an employer (host employer) arranges to have employees of another employer
(contractor) perform work that involves permit space entry, the host employer shall:
- Inform the contractor that the workplace contains permit spaces and that permit
space entry is allowed only through compliance with a permit space program meeting the
requirements of this section;
- Apprise the contractor of the elements, including the hazards identified and the
host employer's experience with the space, that make the space in question a permit space;
- Apprise the contractor of any precautions or procedures that the host employer
has implemented for the protection of employees in or near permit spaces where contractor
personnel will be working;
- Coordinate entry operations with the contractor, when both host employer personnel
and contractor personnel will be working in or near permit spaces so that employees of one
employer do not endanger the employees of any other employer; and
- Debrief the contractor at the conclusion of the entry operations regarding the
permit space program followed and regarding any hazards confronted or created in permit
spaces during entry operations.
YOU MAY BE ABLE TO DECLASSIFY THE PERMIT SPACE IF THE HAZARD CAN BE ELIMINATED. USE CONFINED
SPACES ADVISOR'S SPECIAL TOPICS OPTION FOR DETAILED INFORMATION