Permit vs Non-Permit Confined Spaces: Key Differences

Everyone likes to work in an open space with all amenities nearby. However, this may not always be possible. A lot of people even today work in confined and potentially harmful spaces. A report from the Occupational Safety and Hazard Administration (OSHA) states that over 1,030 fatalities occurred due to occupational injuries in confined spaces between 2011 and 2018. This figure highlights the dangers of these work environments when proper precautions are not taken.

While some of these spaces require a formal permit due to the presence of serious hazards, others are classified as non-permit confined spaces. In this guide, we will explore the differences between permit and non-permit confined spaces.

Read More: What Is OSHA Confined Space Training

What Is a Confined Space?

According to OSHA, a confined space is an area large enough for a worker to enter and perform tasks but not designed for continuous occupancy. These spaces often lack natural airflow and may trap hazardous substances. Being confined increases the risk of harm even from mundane sources, such as poor ventilation or temperature extremes.

Confined spaces are often characterized by limited entry or exit, inadequate ventilation, and a configuration that wasn't meant for regular work. Entry can include manholes, storage tanks, tunnels, and utility vaults. It's the combination of these characteristics that triggers safety assessment.

The most common examples of confined spaces include silos, pipelines, crawl spaces, septic tanks, and sewers. These are areas you may encounter in construction, maintenance, utilities, and manufacturing. They require a thorough hazard evaluation before someone enters.

Read More: OSHA Heat Regulations in 2025

What is a Permit-Required Confined Space (PRCS)?

A permit-required confined space represents the highest level of risk and demands careful oversight and documentation before entry. According to OSHA standard 29 CFR 1910.146, this particular space contains, or has the potential to contain, one or more serious hazards. 

A formal written permit must approve entry and must list hazards and safety systems in place. The factors affecting these spaces include: 

Qualifying Hazards That Trigger PRCS Classification

Atmospheric dangers, such as low oxygen levels, flammable vapors, toxins, engulfment risks, entrapment hazards, and any other recognized safety threats, are reasons to categorize a space as permit-required.

Components of the Entry Permit

A valid permit must detail the qualifications of entrants, emergency plans, hazard controls, and measures such as respiratory protection. It must be authorized by a trained individual and posted at the worksite until all activities are complete.

Safety Systems Required for PRCS

Atmospheric testing, mechanical ventilation, lockout/tagout procedures, and rescue arrangements are mandatory before and during entry into confined workplaces. You and your colleagues must work only after verifying safe conditions.

Read More: What is Asphyxiation and How to Avoid in Confined Space

What is a Non‑Permit Confined Space? 

A non‑permit confined space may have multiple hazards, but can be controlled without a formal permit. These spaces often meet confined space criteria but lack serious hazards. In other words, those hazards can be safely controlled without formal processes. 

Meanwhile, here’s an overview of OSHA non-permit confined space requirements: 

Hazard Evaluation and Mitigation

A risk assessment must show that adequate controls effectively eliminate hazards. These may include ventilation and isolation of energy sources. Continued entry is permitted without repeated permits as long as controls remain in place.

Ongoing Monitoring Requirements

Even without a permit, employers must monitor conditions regularly to ensure the space remains safe. If new hazards emerge, it must be reclassified as a permit-required confined space. Sometimes, employers can also seek help from an OSHA inspector to monitor the premises precisely. 

Read More: What are OSHA Toolbox Talks?

What Are the Differences Between Permit and Non‑Permit Confined Spaces?

However, there are multiple differences between confined and non-confined spaces, depending on the work requirements. Let’s explore the key differences below: 

How to Recognize Hazards in Confined Spaces?

You must be able to identify and control hazards before your entry into the workplace, irrespective of whether permits are available or not. Worker safety is of utmost importance and you can ensure the same by recognizing the following hazards in confined spaces: 

Atmospheric Hazards

Low oxygen, toxic vapors, flammable gases, and oxygen-rich atmospheres are common risks in confined spaces. These hazards can be easily overcome through extensive testing, ventilation, or other interventions.

Physical Hazards

Physical hazards usually include sudden flooding, collapsing materials, mechanical entrapment, or temperature extremes. These dangers often demand engineering or procedural controls. OSHA mandates learning more about physical hazards and their effects through various certifications. 

Engulfment and Structural Hazards

Materials like sand or grain can easily trap or suffocate workers. Confined spaces with such risks should always be deemed permit required until someone rigorously inspects them. This safeguards workers from all kinds of structural hazards. 

Are There Any Safe Entry Procedures for PRCS?

Permit-required spaces require a sequential approach to ensure safe access and operations. You can do it easily by following some safe entry procedures, specifically for PRCS: 

Pre‑Entry Planning

Entry plans include identifying hazards, defining roles, securing tools, and planning rescues. A competent supervisor must sign off before entry begins.

Isolation Techniques

Lockout/tagout, process shutdown, or physical barriers may be needed to isolate hazards. These measures must be tested before anyone enters.

Atmospheric Testing and Ventilation

Continuous monitoring and use of fresh air systems are mandatory for permit-required spaces. Testing is also a mandate for these spaces before entry and throughout operations.

Entry Execution and Attendant Duties

Designated attendants must remain outside to monitor entry, initiate rescue, and maintain communication. They must never enter the space to ensure no one is contaminated by any hidden danger. 

Rescue Protocols

Rescue plans should use non-entry methods first. If workers must enter the confined space for any reason, they must have breathing protection and appropriate support systems compulsorily.

What Are the Safe Practices in Non‑Permit Confined Spaces?

A non-permit space may be safer, but it may still require safety planning and hazard mitigation. On that note, here is a list of the safe practices that you must follow when dealing with these confined spaces: 

Initial Hazard Assessment

Before entering, you must evaluate all potential risks and confirm that no permit-level hazard exists. Controls such as natural ventilation or ensuring the absence of energy sources may suffice. These methods must be employed consistently for safe entry.

Periodic Reviews and Re‑Assessment

Conditions inside confined spaces can change depending on specific situations. Regular checks across non-permit spaces should confirm whether the hazards have emerged or evolved.

Training and Awareness Requirements

Employees must be trained on recognizing hazards and reporting changes. This applies specifically if you are working within a non-permit space. Awareness training promotes vigilance and early problem identification.

What are the Best Practices for Confined Space Safety?

The decision of being employed in permit or non-permit spaces may not be in your hands. However, you can still take some proactive measures to help save lives and improve compliance. These include: 

Conduct Regular Risk Assessments

Periodical audits, inspections, and hazard reviews help you maintain a safe environment and correct classification. They also ensure no new risks emerge and that all control measures work effectively. 

Implement Rigorous Communication

Documented procedures and standardized checklists ensure all team members know everything about hazards and safeguards. This ensures everyone is aligned on safety expectations before, during, and after the entry.

Invest in Ongoing Training

Refresher courses and drills reinforce awareness. They explain all responsibilities that must be followed by every personnel. This is beneficial for making quick decisions and proper techniques which can also prevent major incidents.

Review and Update Rescue Protocols

Rescue plans must be practiced regularly so that you can implement them correctly in emergency conditions. This ensures that any gaps in planning, equipment availability, or response time are addressed before a real crisis occurs.

Get Certified to Know About Confined Spaces

You must understand the key differences between permit-required and non-permit confined space to ensure workplace safety.

Permit-required spaces demand formal entry procedure and hazard controls. Non‑permit spaces may also prevent hazards, but are usually managed through well-documented controls.

You can easily evaluate both spaces and apply safety measures based on their requirements. This often involves conducting some hazard assessments and detailed rescue planning.

Still unsure about the proper safety measures? Enroll in an OSHA certification course to learn more!

References

• https://www.osha.com/blog/permit-required-confined-space

• https://etraintoday.com/blog/permit-required-confined-space-vs-non-permit-required-what-are-differences/

• https://www.uscompliance.com/blog/confined-space-entry-permit-or-non-permit/