Health, Safety, Security and Environment

Permit-Required Confined Spaces

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Many workplaces contain spaces that are considered to be “confined” because their configurations hinder the activities of any employees who must enter into, work in, and exit from them. In many instances, employees who work in confined spaces also face increased risk of exposure to serious physical injury from hazards such as entrapment, engulfment, and hazardous atmospheric conditions. Confinement itself may pose entrapment hazards, and work in confined spaces may keep employees closer to hazards, such as an asphyxiating atmosphere, than they would be otherwise. For example, confinement, limited access, and restricted airflow can result in hazardous conditions that would not arise in an open workplace.   

The term “permit-required confined space” (i.e., permit space) refers to those spaces that meet the definition of a “confined space” and pose health or safety hazards, thereby requiring a permit for entry. 

A confined space has limited or restricted means of entry or exit, is large enough for an employee to enter and perform assigned work, and is not designed for continuous occupancy by the employee. These spaces may include but are not limited to, underground vaults, tanks, storage bins, pits, and diked areas, vessels, and silos.  

A permit-required confined space is one that meets the definition of a confined space and has one or more of these characteristics: 

  • contains or has the potential to contain a hazardous atmosphere, 
  • contains a material that has the potential for engulfing an entrant,
  • has an internal configuration that might cause an entrant to be trapped or asphyxiated by inwardly converging walls or by a floor that slopes downward and tapers to a smaller cross-section, and/or 
  • contains any other recognized serious safety or health hazards.

Who is Covered?    

OSHA’s standard for confined spaces, Title 29 Code of Federal Regulations Part 1910.146, effective April 15, 1993, contains the requirements for practices and procedures to protect employees in general industry from the hazards of entry into permit-required confined spaces (i.e., permit spaces).

OSHA estimates that about 224,000 establishments have permit spaces; 7.2 million production workers are employed at these establishments, and about 2.1 million workers enter permit spaces annually.

OSHA anticipates that compliance with these regulations will avoid 53 worker deaths and injuries, 4,900 lost-workday cases, and 5,700 non-lost-time accidents annually. 

Requirements of the Standard


In general, employers must evaluate the workplace to determine if spaces are permit-required confined spaces. (See flow chart). If there are permit spaces in the workplace, the employer must inform exposed employees of the existence, location, and danger posed by the spaces.

This can be accomplished by posting danger signs or by another equally effective means.  The following language would satisfy the requirements for such a sign: 


If employees are not to enter and work in permit spaces, employers must take effective measures to prevent their employees from entering the permit spaces.

If employees are to enter permit spaces, the employer must develop a written permit space program, which shall be made available to employees or their representatives.   Under certain conditions, the employer may use alternate procedures for worker entry into a permit space.  For example, if employers can demonstrate with monitoring and inspection data that the only hazard is an actual or potentially hazardous atmosphere, which can be made safe for entry by the use of continuous forced air ventilation alone, they may be exempted from some requirements, such as permits and attendants.  Even in such circumstances, however, the internal atmosphere of the space must be tested first for oxygen content, second for flammable gases and vapors, and third for potential toxic air contaminants before any employee enters.

(Learn How to combat confined space hazards with the right PPE).

Written Program  

The employer who allows employee entry must develop and implement a written program for permit-required confined spaces. Among other things, the OSHA standard requires the employer’s program to: 

  • identify and evaluate permit space hazards before allowing employee entry.
  • test conditions in the permit space before entry operations and monitor the space during entry.    
  • perform, in the following sequence, appropriate testing for atmospheric hazards:
    • oxygen, combustible gases or vapors, and toxic gases or vapors;
  • implement necessary measures to prevent unauthorized entry. 
  • establish and implement the means, procedures, and practices such as:
    • specifying acceptable entry conditions,
    • isolating the permit space,
    • providing barriers,
    • verifying acceptable entry conditions,
    • purging, making inert, flushing, or ventilating the permit space to eliminate or control hazards necessary for safe permit space entry operations.      
  • identify employee job duties. 
  • provide, maintain, and require, at no cost to the employee, the use of personal protective equipment and any other equipment necessary for safe entry (e.g., testing, monitoring, ventilating, communications, and lighting equipment; barriers, shields, and ladders);
  • ensure that at least one attendant is stationed outside the permit space for the duration of entry operations.
  • coordinate entry operations when employees of more than one employer are to be working in the permit space. 
  • implement appropriate procedures for summoning rescue and emergency services.
  • establish, in writing, and implement a system for the preparation, issuance, use, and cancellation of entry permits.
  • review established entry operations and annually revise the permit-space entry program.
  • when an attendant is required to monitor multiple spaces, implement the procedures to be followed during an emergency in one or more of the permit spaces being monitored.

If hazardous conditions are detected during entry, employees must immediately leave the space, and the employer must evaluate the space to determine the cause of the hazardous atmospheres.

When entry to permit spaces is prohibited, the employer must take effective measures to prevent unauthorized entry.  Non-permit confined spaces must be reevaluated when there are changes in their use or configuration and, where appropriate, must be reclassified.

If testing and inspection data prove that a permit-required confined space no longer poses hazards, that space may be reclassified as a non-permit confined space.  If entry is required to eliminate hazards and to obtain the data, the employer must follow procedures as set forth under sections (d) through (k) of the standard.  A certificate documenting the data must be made available to employees entering the space.  The certificate must include the date, location of the space, and the signature of the person making the certification.

Contractors also must be informed of permit spaces and permit space entry requirements, any identified hazards, the employer’s experience with space (i.e., the knowledge of hazardous conditions), and precautions or procedures to be followed when in or near permit spaces. 

When employees of more than one employer are conducting entry operations, the affected employers must coordinate entry operations to ensure that affected employees are appropriately protected from permit space hazards.  Contractors also must be given any other pertinent information regarding hazards and operations in permit spaces and be debriefed at the conclusion of entry operations.

(Find out: Templates confined-space-program)

Permit System

A permit, signed by the entry supervisor and verifying that re-entry preparations have been completed and that the space is safe to enter, must be posted at entrances or otherwise made available to entrants before they enter a permit space.  

The duration of entry permits must not exceed the time required to complete an assignment. Also, the entry supervisor must terminate entry and cancel permits when an assignment has been completed or when new conditions exist. New conditions must be noted on the canceled permit and used in revising the permit space program.  The standard also requires the employer to keep all canceled entry permits for at least 1 year.

Entry Permits
  • Entry permits must include the following information:  
  • test results. 
  • tester’s initials or signature. 
  • name and signature of a supervisor who authorizes entry.
  • name of permit space to be entered, authorized entrant(s), eligible attendants, and individual(s) authorized to be entry supervisor(s);
  • purpose of entry and known space hazards. 
  • measures, to be taken, to isolate permit spaces and to eliminate or control space hazards i.e., locking out or tagging of equipment and procedures for purging, making inert, ventilating, and flushing permit spaces.   
  • name and telephone numbers of rescue and emergency services.
  • date and authorized duration of the entry. 
  • acceptable entry conditions. 
  • communication procedures and equipment to maintain contact during entry;
  • additional permit(s), such as for hot work, that have been issued to authorize work in       the permit space;
  • special equipment and procedures, including personal protective equipment and alarm systems; and any other information needed to ensure employee safety. 
Training and Education

Before the initial work assignment begins, the employer must provide proper training for all workers who are required to work in permit spaces. Upon completing this training, employers must ensure that employees have acquired the understanding, knowledge, and skills necessary for the safe performance of their duties. Additional training is required when

  • the job duties change,
  • there is a change in the permit space program, or the permit space operation presents a new hazard, and 
  • when an employee’s job performance shows deficiencies. 

Training also is required for rescue team members, including cardiopulmonary resuscitation (CPR) and first-aid training (see Emergencies). Employers must certify that training has been accomplished.

Upon completion of training, employees must receive a certificate of training that includes the employee’s name, signature or initials of trainer(s), and dates of training. The certification must be made available for inspection by employees and their authorized representatives.  

In addition, the employer also must ensure that employees are trained in their assigned duties.

Authorized Entrant’s Duties
  • know space hazards, including information on the mode of exposure (e.g., inhalation   or dermal absorption), signs or symptoms, and consequences of the exposure;
  • use appropriate personal protective equipment properly (e.g., face and eye protection, and other forms of barrier protection such as gloves, aprons, and coveralls);
  • as necessary, maintain communication (i.e., telephone, radio, visual observation) with attendants to enable the attendant to
  • monitor the entrant’s status as well as to alert the entrant to evacuate.
  • exit from permit space as soon as possible when ordered by an authorized person,      when the entrant recognizes the warning signs or symptoms of exposure exists, when a prohibited condition exists, or when an automatic alarm is activated; and
  • alert the attendant when a prohibited condition exists or when warning signs or symptoms of exposure exist. 

Attendant’s Duties

  • remain outside permit space during entry operations unless relieved by another authorized attendant.
  • perform non-entry rescues when specified by the employer’s rescue procedure.
  • know existing and potential hazards, including information on the mode of exposure, signs or symptoms, consequences of the exposure, and their physiological effects; 
  • maintain communication with and keep an accurate account of those workers entering the permit-required space. 
  • order evacuation of the permit space when a prohibited condition exists, when a worker shows signs of physiological effects of hazard exposure when an emergency outside the confined space exists, and when the attendant cannot effectively and safely perform required duties.
  • summon rescue and other services during an emergency. 
  • ensure that unauthorized persons stay away from permit spaces or exit immediately if they have entered the permit space.  
  • inform authorized entrants and entry supervisor of entry by unauthorized persons, and perform no other duties that interfere with the attendant’s primary duties.
Entry Supervisor’s Duties
  • know space hazards including information on the mode of exposure, signs, or symptoms and consequences of exposure.
  • verify emergency plans and specified entry conditions such as permits, tests, procedures, and equipment before allowing entry.
  • terminate entry and cancel permits when entry operations are completed or if a new condition exists.
  • take appropriate measures to remove unauthorized entrants, and ensure that entry operations remain consistent with the entry permit and that acceptable entry conditions are maintained.

The standard requires the employer to ensure that rescue service personnel are provided with and trained in the proper use of personal protective and rescue equipment, including respirators; trained to perform assigned rescue duties, and have had authorized entrants training. The standard also requires that all rescuers are trained in first aid and CPR and, at a minimum, one rescue team member be currently certified in first aid and in CPR.  The employer also must ensure that practice rescue exercises are performed yearly and that rescue services are provided access to permit spaces so that they can practice rescue operations.  Rescuers also must be informed of the hazards of the permit space. 

Also, where appropriate, authorized entrants who enter a permit space must wear a chest or full-body harness with a retrieval line attached to the center of their backs near shoulder level, or above their heads.  Wristlets may be used if the employer can demonstrate that the use of a chest or full-body harness is infeasible or creates a greater hazard.  Also, the employer must ensure that the other end of the retrieval line is attached to a mechanical device or to a fixed point outside the permit space.  A mechanical device must be available to retrieve personnel from vertical type permit spaces more than 5 feet deep. 

In addition, 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 other written information must be made available to the medical facility treating the exposed entrant.

(Learn How to Rescue someone from a confined space ).


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