What Is A Permit Required Confined Space?

permit required confined space

A Permit Required Confined Space (PRCS) is a designated area that possesses specific characteristics, requiring proper precautions and protocols for entry. This space is defined by limited openings for entry and exit, unfavorable atmospheric conditions, and potential hazards that can endanger the health and safety of individuals.

Understanding the importance of PRCS awareness and compliance is paramount in ensuring the well-being of workers and preventing accidents. By being aware of PRCS and its associated risks, employers and employees can implement necessary safety measures, conduct thorough risk assessments, and adhere to regulatory guidelines to minimize the occurrence of incidents. Compliance with PRCS regulations not only safeguards individuals from harm but also protects organizations from legal liabilities and reputational damage.

Read the full article to learn about permit required confined spaces - their definition, guidelines, key considerations, and best practices for safe entry.

Understanding Confined Spaces

Confined spaces are areas with limited means of entry and exit, making them challenging to navigate and potentially hazardous. These spaces may have restricted ventilation, leading to poor air quality and an increased risk of asphyxiation or exposure to toxic gases. Confined spaces can vary in size and shape, including storage tanks, crawl spaces, tunnels, and silos. They often have limited visibility, making it difficult to identify potential hazards or escape routes. Common examples of confined spaces include utility vaults, manholes, boilers, and storage bins.

Key Differences Between a Confined Space and a Permit-Required Confined Space

The main distinction between confined spaces and permit required confined spaces lies in the presence of additional hazards within a PRCS that require specific safety measures and permits for entry. PRCS are distinguished by factors such as atmospheric hazards, engulfment risks, or the potential for an internal configuration that could trap individuals. While all PRCS are confined spaces, not all confined spaces are PRCS.

According to OSHA, a confined space is defined as a space large enough for an employee to enter and perform assigned work, has limited means for entry and exit, and is not designed for continuous employee occupancy. They stated examples such as tanks, vessels, silos, storage bins, hoppers, vaults, and pits. On the other hand, a permit-required confined space is defined by OSHA as a confined space that contains (or has a potential to contain) a hazardous atmosphere, contains a material that has the potential for engulfing an entrant (for example, a space containing an internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls or by a floor which slopes downward and tapers to a smaller cross-section), or a space that contains any recognized health or safety hazard.

Identifying Permit Required Confined Spaces

Learning how to recognize environments, industries, and common locations where a permit required confined space may be present is crucial for effective compliance and worker safety.

  • Construction Sites: Trenches, excavations (dug-out areas for construction or utility work), underground utility access points (tunnels, underground passages, and crawl spaces), building sites, and underground construction projects can all pose PRCS hazards.
  • Mining and Extraction Operations: Underground mines, shafts, and confined areas within extraction facilities are common PRCS environments.
  • Utilities Sector: Water treatment facilities, electrical substations, wastewater plants, power stations, and telecommunications vaults frequently have PRCS due to equipment installation and maintenance requirements.
  • Transportation and Shipping: Aircraft maintenance facilities, railway maintenance yards, cargo holds, tanks (storage tanks, silos, and enclosed vessels), and engine compartments on ships, as well as tunnels and underground transportation systems, can be PRCS.
  • Manufacturing Industry: Factories, chemical plants, food processing facilities, metalworking shops, and refineries often have PRCS due to the presence of tanks, vessels, and confined storage areas. Confined storage areas (rooms or spaces designed for storage, such as vaults or storage bins) and enclosed machinery compartments (equipment or machinery with limited access points, such as engine rooms or mechanical enclosures) are common in different industries.
confined space hazard assessment form

Legal and Regulatory Framework

Occupational Safety and Health Administration (OSHA) sets guidelines and standards for PRCS safety (29 CFR 1910.146). According to the standard, employers are responsible for identifying PRCS, assessing hazards, implementing control measures, providing proper training, and ensuring compliance with regulations. If they find that their workplace contains permit spaces, they are required to inform exposed employees of their existence, location and the hazards they pose. Installing danger signs is one way to do so.

Construction sites have specific regulations, such as the Confined Spaces in Construction Standard (29 CFR 1926 Subpart AA). Various countries and regions also have their own regulations, such as the European Union's Directive 92/57/EEC and the Australian/New Zealand Standard AS/NZS 2865:2001.

Penalties for Non-Compliance

Non-compliance can result in penalties such as fines, citations, or even criminal charges. Consequences may also include work stoppages, legal liabilities, damage to reputation, and increased insurance premiums.

Hazards and Risks in PRCS

Hazards and risks associated to a permit required confined space include atmospheric, physical, biological, and psychosocial risks. Learn how to mitigate them for a safer work environment.

Atmospheric Hazards

Atmospheric hazards in PRCS include lack of oxygen. Oxygen-deficient environments can cause dizziness, confusion, and even loss of consciousness.
Toxic gases are another hazard. Presence of gases like carbon monoxide, hydrogen sulfide, or volatile chemicals can lead to respiratory problems, poisoning, or explosions. To mitigate atmospheric hazards in permit-required confined spaces, implement thorough atmospheric testing before entry. Ensure proper ventilation systems are in place to maintain safe oxygen levels and remove toxic gases. Use gas detectors to continuously monitor the atmosphere during work.

Physical Hazards

The configuration of a confined space such as narrow passages, uneven surfaces, or obstacles can impede movement, increasing the risk of falls, entrapment, or injuries is a physical hazard in PRCS. Noise is another one. Excessive noise levels in confined spaces can cause hearing damage and communication difficulties, impacting workers' safety and awareness. To mitigate physical hazards in permit-required confined spaces, implement measures to eliminate or control hazards such as protruding objects, restricted spaces, moving machinery, or loud noises. Provide appropriate personal protective equipment (PPE) for workers' safety.

Biological Hazards

Biological hazards in permit required confined spaces include mold and bacteria. Damp and poorly ventilated confined spaces can harbor mold, which can trigger allergies, respiratory issues, and other health problems. Contaminated PRCS can host harmful bacteria that may cause infections or diseases, particularly in environments like sewers or wastewater treatment plants. To mitigate biological hazards in permit-required confined spaces, implement proper hygiene practices, including regular cleaning and disinfection. Provide workers with appropriate personal protective equipment (PPE) to minimize exposure to biological agents. Establish protocols for safe handling and disposal of biological substances.

Psychosocial Hazards

Stress and claustrophobia are considered to be the top psychosocial hazards in permit re-required confined spaces. The confined nature of PRCS can induce stress due to restricted movement, fear of incidents, or working under pressure. Individuals with claustrophobia may experience severe anxiety or panic attacks in confined spaces, affecting their ability to work effectively. To mitigate psychosocial hazards in permit-required confined spaces, ensure clear communication channels and regular updates on tasks. Provide adequate breaks and support systems to address stress and mental health concerns. Promote teamwork, collaboration, and a positive work environment to reduce psychosocial risks.

Entry Permit System

The entry permit serves as a formal authorization for individuals to enter a permit required confined space safely. It includes essential information such as the location of the PRCS, entry duration, specific hazards, and required safety precautions. The permit may also include a checklist for verifying completion of pre-entry procedures and necessary equipment.

Pre-Entry Procedures and Requirements

Before entering a PRCS, individuals must undergo training on PRCS hazards, safety procedures, and the proper use of personal protective equipment (PPE). A thorough evaluation of the PRCS should be conducted to identify potential hazards and implement appropriate control measures. The permit may require pre-entry tests, such as atmospheric monitoring, to ensure the space is safe for entry.

Roles and Responsibilities of Authorized Entrants, Attendants, and Entry Supervisors

Authorized entrants are responsible for following safety procedures, using PPE, and promptly reporting any changes or hazards observed during entry.
Attendants, on the other hand, monitor the activities inside and outside the PRCS, maintain communication, and initiate emergency response procedures if necessary. Lastly, entry supervisors oversee the entire entry process, ensuring compliance with safety regulations, verifying permits, and coordinating work activities.

Communication Protocols During PRCS Entry

Effective communication is crucial during PRCS entry to maintain safety and respond to emergencies promptly. Communication methods may include two-way radios, visual signals, or predetermined hand signals to facilitate communication between entrants, attendants, and supervisors. Regular check-ins and updates should be established to ensure continuous communication and provide necessary support. Installing warning signages on confined spaces can also enhance protection and help prevent accidents.

confined space sign


1. Is it possible to convert a confined space into a non-permit required space?

Yes, it is possible to convert a confined space into a non-permit required space if all the hazards have been eliminated or controlled. This typically involves reevaluating the space, implementing necessary engineering controls, and ensuring that it meets the criteria outlined by relevant regulations and standards.

2. What does OSHA mean by a "limited or restricted means of entry and exit" in the definition of "confined space"?

OSHA defines "limited or restricted means of entry and exit" as an entrance or exit that is difficult to maneuver through due to its size, location, or other physical obstacles. This could include narrow openings, ladders, tunnels, or other barriers that may hinder easy access or escape from the confined space.

3. Who is responsible for identifying PRCS in a workplace?

Employers are responsible for identifying PRCS in a workplace. They should conduct thorough assessments to determine which spaces meet the criteria for permit-required confined spaces. This involves considering factors such as configuration, hazards, and the potential for employee exposure.

4. How often should PRCS training be conducted?

PRCS training should be conducted initially for all affected employees, and then periodically thereafter. The frequency of training should be determined by the employer, considering factors such as employee turnover, changes in work practices, and the need for refresher training to ensure ongoing awareness and competency.

5. How often should PRCS entry procedures be reviewed and updated?

PRCS entry procedures should be reviewed and updated as necessary, especially when there are changes in the PRCS or the work being conducted. It is essential to ensure that procedures reflect current hazards, control measures, and regulatory requirements. Regular reviews and updates help maintain a safe work environment.

6. Are there any resources or organizations that provide assistance in PRCS compliance?

Yes, there are resources and organizations that provide assistance in PRCS compliance. Occupational Safety and Health Administration (OSHA) offers guidance documents, training materials, and compliance assistance resources. Additionally, industry associations, safety consultants, and specialized training providers can offer expertise and support in achieving PRCS compliance.

7. How does the standard apply when the opening to a space is very small?

The standard still applies when the opening to a space is small. If the space meets the definition of a confined space and has associated hazards, it may still require permits and compliance with PRCS regulations. The size of the opening does not exempt it from the requirements if other criteria are met.

8. Is it a permit space entry if the worker only reaches into the space with his arms?

It depends on the circumstances. If the worker's entry meets the definition of a confined space and there are associated hazards that cannot be controlled from outside the space, it may still be considered a permit space entry. Each situation should be evaluated to determine the need for permits and compliance measures.

9. How long is needed to retain entry permits?

Entry permits should be retained for a specific duration determined by the employer, based on the work being conducted and any applicable regulations or standards. Generally, it is recommended to retain entry permits for a sufficient period to allow for review, reference, and documentation purposes.

10. What is required if we reclassify a permit space as a non-permit confined space?

If a permit space is reclassified as a non-permit confined space, it must meet specific criteria outlined by applicable regulations and standards. This typically involves reassessing and eliminating any existing hazards, implementing appropriate control measures, and documenting the reclassification process.

The material provided in this article is for general information purposes only. It is not intended to replace professional/legal advice or substitute government regulations, industry standards, or other requirements specific to any business/activity. While we made sure to provide accurate and reliable information, we make no representation that the details or sources are up-to-date, complete or remain available. Readers should consult with an industrial safety expert, qualified professional, or attorney for any specific concerns and questions.


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Author: Herbert Post

Born in the Philadelphia area and raised in Houston by a family who was predominately employed in heavy manufacturing. Herb took a liking to factory processes and later safety compliance where he has spent the last 13 years facilitating best practices and teaching updated regulations. He is married with two children and a St Bernard named Jose. Herb is a self-described compliance geek. When he isn’t studying safety reports and regulatory interpretations he enjoys racquetball and watching his favorite football team, the Dallas Cowboys.