Permit-Required Confined Spaces

Tanks, vaults, pits, and silos can hold a hazardous atmosphere, engulfing material, or other serious hazards, and they are hard to get out of. 29 CFR 1910.146 asks you to find those spaces, warn employees, and either keep employees out or control entry with a written program, permits, training, and rescue.

Who it applies to

The standard covers general industry and does not apply to agriculture, construction, or shipyard employment (parts 1928, 1926, and 1915) (1910.146(a)).

A confined space is a space that (1910.146(b)):

• Is large enough and so configured that an employee can bodily enter and perform assigned work; and
• Has limited or restricted means for entry or exit; and
• Is not designed for continuous employee occupancy.

A permit-required confined space (permit space) is a confined space with one or more of these characteristics (1910.146(b)):

• Contains or has a potential to contain a hazardous atmosphere.
• Contains a material that has the potential for engulfing an entrant.
• Has an internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls or by a floor that slopes downward and tapers to a smaller cross-section.
• Contains any other recognized serious safety or health hazard.

What the standard requires

Evaluate, warn, and decide

• You must evaluate the workplace to determine if any spaces are permit spaces (1910.146(c)(1)).
• If there are, you must inform exposed employees of their existence, location, and danger by posting danger signs or by any other equally effective means (1910.146(c)(2)).
• If you decide employees will not enter, you must take effective measures to prevent entry and comply with (c)(1), (c)(2), (c)(6), and (c)(8) (1910.146(c)(3)).
• If you decide employees will enter, you must develop and implement a written permit space program (1910.146(c)(4)).

Alternate procedures

You need not comply with paragraphs (d) through (f) and (h) through (k) provided that (1910.146(c)(5)(i)):

• You can demonstrate that the only hazard is an actual or potential hazardous atmosphere, and that continuous forced air ventilation alone is sufficient to keep the space safe for entry.
• You develop monitoring and inspection data supporting both points. Any initial entry to get that data follows (d) through (k).
• You document the determinations and data and make them available to each employee who enters or that employee's authorized representative.
• Entry follows the procedures in (c)(5)(ii).

Reclassifying a permit space

A permit space may be reclassified as a non-permit confined space if:

• It poses no actual or potential atmospheric hazards and all hazards are eliminated without entry, for as long as the non-atmospheric hazards remain eliminated (1910.146(c)(7)(i)); or
• Entry to eliminate hazards is performed under (d) through (k), and testing and inspection during that entry demonstrate the hazards have been eliminated, for as long as they remain eliminated (1910.146(c)(7)(ii)).

If hazards arise in the declassified space, each employee must exit and you must then reevaluate it (1910.146(c)(7)(iv)).

Host employers and contractors

When you arrange for a contractor's employees to do work that involves permit space entry, you must inform the contractor that the workplace contains permit spaces and that entry is allowed only through compliance with a permit space program meeting the requirements of the standard, apprise it of the hazards identified and your precautions, coordinate entry when both workforces will be working in or near permit spaces, and debrief the contractor afterward (1910.146(c)(8)). The contractor must obtain available information from you, coordinate entry with you under that same condition, and inform you of its program and any hazards confronted or created (1910.146(c)(9)).

The permit space program

Among other things, you must:

• Implement the measures necessary to prevent unauthorized entry (1910.146(d)(1)).
• Identify and evaluate permit space hazards before employees enter (1910.146(d)(2)).
• Test conditions in the permit space to determine if acceptable entry conditions exist before entry is authorized to begin. Exception: 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 must be performed to the extent feasible before entry is authorized and, if entry is authorized, entry conditions must be continuously monitored in the areas where authorized entrants are working (1910.146(d)(5)(i)).
• When testing for atmospheric hazards, test first for oxygen, then for combustible gases and vapors, and then for toxic gases and vapors (1910.146(d)(5)(iii)).
• Provide at least one attendant outside the permit space for the duration of entry operations (1910.146(d)(6)).

Entry permits

Before entry is authorized, you must prepare an entry permit, and the entry supervisor must sign it before entry begins (1910.146(e)(1), (e)(2)). The permit must identify 15 items, including the space, the purpose, the hazards, the acceptable entry conditions, test results, and the rescue services that can be summoned (1910.146(f)(1) through (f)(15)).

Entrants, attendants, and entry supervisors

• Authorized entrants must exit as quickly as possible when ordered to evacuate, when they recognize a warning sign or symptom of exposure or detect a prohibited condition, or when an evacuation alarm is activated (1910.146(h)(5)).
• Attendants must remain outside the permit space during entry operations until relieved by another attendant (1910.146(i)(4)).
• Entry supervisors must terminate entry and cancel the permit when operations are completed or a condition not allowed under the permit arises (1910.146(j)(3), (e)(5)).

Rescue and emergency services

If you designate a rescue service, you must evaluate its ability to respond in a timely manner and its proficiency with rescue-related tasks and equipment, select one that can reach victims within an appropriate time frame and is equipped and proficient, inform it of the hazards, and give it access to the permit spaces to plan and practice (1910.146(k)(1)).

Retrieval systems or methods must 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 (1910.146(k)(3)).

• Each entrant must use a chest or full body harness with a retrieval line attached at the center of the back near shoulder level, above the head, or at another point you can establish presents a profile small enough for successful removal. Wristlets may be used instead if you can demonstrate that a harness is infeasible or creates a greater hazard and wristlets are the safest and most effective alternative (1910.146(k)(3)(i)).
• The other end of the line must be attached to a mechanical device or fixed point outside the space in such a manner that rescue can begin as soon as the rescuer becomes aware that rescue is necessary. A mechanical device must be available to retrieve personnel from vertical type permit spaces more than 5 feet (1.52 m) deep (1910.146(k)(3)(ii)).

Training

You must train all employees whose work is regulated by the standard (1910.146(g)(1)). Training must be provided before an employee is first assigned duties, before a change in assigned duties, whenever a change in permit space operations presents a hazard the employee has not previously been trained on, and whenever you have reason to believe there are deviations from the entry procedures or inadequacies in the employee's knowledge or use of them (1910.146(g)(2)).

Written programs and records

• Written permit space program (1910.146(c)(4)).
• Training certification with each employee's name, the trainers' signatures or initials, and the dates of training (1910.146(g)(4)).
• Canceled entry permits, retained for at least 1 year (1910.146(e)(6)).
• Certifications for alternate procedure entries and for reclassification, each containing the date, the location of the space, and a signature (1910.146(c)(5)(ii)(H), (c)(7)(iii)).

Easy-to-miss requirements

• Control of atmospheric hazards through forced air ventilation does not constitute elimination of the hazards for reclassification (Note following 1910.146(c)(7)(ii)).
• When changes in the use or configuration of a non-permit confined space might increase the hazards to entrants, you must reevaluate it and, if necessary, reclassify it (1910.146(c)(6)).
• Employees you designate as rescuers must practice permit space rescues at least once every 12 months, by simulated rescue operations from the actual permit spaces or from representative permit spaces (1910.146(k)(2)(iv)).

Related guides

• Lockout/tagout
• Respiratory protection

Source

This guide is based on the text of 29 CFR 1910.146 as published on osha.gov. The regulation itself always controls. States that run their own OSHA-approved State Plans may have additional or stricter rules.