A Guide To Confined Spaces Safety Standards

confined space signage

What Is A Confined Space?

A confined space is an enclosed or partially enclosed area with limited entry and exit points. It is not designed for continuous occupancy and may pose risks to workers due to hazards like restricted access, poor ventilation, or the potential for the accumulation of hazardous substances.

To ensure the safety of individuals working in such environments, various safety standards have been established. This article aims to provide an in-depth understanding of the safety standards for confined spaces, addressing key questions and concerns surrounding this topic.

The 3 Types of Confined Spaces

Confined spaces can be classified into 3 categories based on their characteristics and the level of risk they present. Understanding these classifications helps in determining the appropriate safety measures for each type of confined space. The 3 classifications are as follows:

Non-Permit Required Confined Space

These spaces do not possess atmospheric or physical hazards that could potentially endanger workers. Entry into non-permit required confined spaces does not require a written permit, but caution is still necessary.

Permit-Required Confined Space (PRCS)

PRCS are confined spaces that contain actual or potential hazards, such as a hazardous atmosphere, engulfment hazards, or internal configuration hazards. Entry into PRCS requires a written permit specifying the precautions and safety measures to be taken.

Alternate Procedure Confined Space

Some confined spaces may have unique characteristics or risks that differ from typical PRCS. In such cases, an alternate procedure may be established to address the specific hazards, ensuring worker safety.

Types of Hazards in Confined Spaces

Working in confined spaces exposes individuals to various types of hazards that can jeopardize their safety. It is crucial to identify and understand these hazards to implement appropriate control measures. The following are some common types of hazards found in confined spaces:

Atmospheric Hazards: Confined spaces can have an atmosphere that is deficient in oxygen or contains toxic gases, vapors, or dust. These atmospheric hazards can lead to asphyxiation, respiratory problems, or chemical exposures.

Engulfment Hazards: Some confined spaces, such as grain silos or tanks, pose a risk of engulfment. Workers can be buried or trapped by materials such as grain, sand, or water, resulting in suffocation or crushing injuries.

Physical Hazards: Physical hazards in confined spaces include restricted spaces, sharp edges, protruding objects, or moving machinery. These hazards can cause injuries such as cuts, bruises, or fractures.

Temperature Extremes: Confined spaces may have extreme temperatures, either excessively hot or cold. Exposure to extreme temperatures can lead to heat exhaustion, heatstroke, frostbite, or hypothermia.

Noise and Vibrations: Some confined spaces may have high noise levels or vibrations from machinery or equipment. Prolonged exposure to these factors can result in hearing loss or other health issues.

Electrical Hazards: Confined spaces may contain electrical equipment or wiring that poses a risk of electric shock or electrocution.

What Are the Safety Standards for Confined Spaces?

When it comes to confined spaces safety, there are specific standards in place to safeguard workers' well-being and prevent accidents. These standards encompass regulations, training requirements, and best practices designed to address the unique hazards associated with confined spaces. Some prominent regulatory standards include:

OSHA's Confined Spaces in Construction Standard

The Confined Spaces in Construction (1926 Subpart AA standard), introduced by the Occupational Safety and Health Administration (OSHA), outlines requirements for identifying and assessing hazards, implementing control measures, and conducting rescue operations in confined spaces within the construction industry.

OSHA's General Industry Standard for Permit-Required Confined Spaces

OSHA's Permit Required Confined Spaces standard (29 CFR 1910.146) focuses on permit-required confined spaces and addresses procedures for atmospheric testing, permits, training, and rescue operations.

EU Directive 92/57/EEC

Within the European Union, the EU Directive 92/57/EEC sets forth measures for protecting workers' health and safety when working in confined spaces. It covers risk assessment, control measures, and training requirements.

Training Requirements for Confined Space Work

To ensure workers are adequately prepared to address the unique challenges of confined spaces, training programs play a crucial role. Proper training equips individuals with the knowledge and skills necessary to identify hazards, implement safety protocols, and respond to emergencies. Key training requirements include:

Confined Space Entry Training: This training provides workers with an understanding of confined space hazards, control measures, and safe entry and exit procedures. It covers topics such as atmospheric monitoring, lockout/tagout procedures, and the proper use of personal protective equipment.

Rescue Training: Workers who may need to perform rescue operations in confined spaces must receive specialized rescue training. This training focuses on techniques for safely extricating individuals from confined spaces while minimizing risks to both rescuers and victims.

Supervisor Training: Supervisors responsible for overseeing confined space work should receive additional training to effectively manage and mitigate risks.

Best Practices for Working in Confined Spaces

In addition to regulatory standards and training requirements, there are several best practices that individuals and organizations should follow when working in confined spaces. These practices help to minimize risks and create a safer work environment. Here are some essential best practices:

  • Thorough Risk Assessment: Before entering a confined space, it is crucial to conduct a thorough risk assessment. This assessment should identify potential hazards such as toxic gases, lack of oxygen, or physical obstructions. By understanding the risks, appropriate control measures can be implemented.
  • Proper Ventilation: Adequate ventilation is essential in confined spaces to maintain a safe atmosphere. Ventilation systems should be used to remove hazardous substances or fumes and ensure a constant supply of fresh air.
  • Regular Equipment Inspection: All equipment used in confined spaces, including gas detectors, personal protective equipment (PPE), and communication devices, should be regularly inspected and maintained. Faulty equipment can pose serious risks to workers.
  • Continuous Monitoring: Continuous monitoring of the atmosphere within confined spaces is vital to detect any changes in gas levels or oxygen concentration. Gas detectors and monitoring devices should be used to alert workers of hazardous conditions.
  • Appropriate PPE Usage: Personal protective equipment plays a crucial role in confined spaces. Workers should wear PPE such as respirators, gloves, and protective clothing to protect themselves from hazards.
  • Effective Communication: Communication is essential for ensuring the safety of workers in confined spaces. Establishing reliable communication methods, such as two-way radios or signaling systems, can help in case of emergencies or when assistance is required.


1. What are some examples of confined spaces?
Confined spaces can include storage tanks, pipelines, sewers, silos, tunnels, and underground vaults, among others. These spaces are typically limited in size and have restricted entry and exit points.

2. Do all confined spaces require a permit?
No, not all confined spaces require a permit. Permit requirements typically depend on the specific hazards present in the space. If the space poses a significant risk to workers' safety, a permit is usually required.

3. Who is responsible for ensuring safety in confined spaces?
Both employers and employees share the responsibility of ensuring safety in confined spaces. Employers must provide proper training, equipment, and a safe working environment, while employees must follow established safety protocols and use the provided equipment correctly.

4. What should be included in a confined space rescue plan?
A confined space rescue plan should include procedures for quickly and safely removing individuals from a confined space in case of an emergency. It should address communication methods, equipment requirements, and coordination with emergency services.

5. Are there any specific requirements for ventilation in confined spaces?
Yes, confined spaces must be adequately ventilated to ensure a safe working environment. Ventilation systems should be designed to provide fresh air, remove hazardous substances, and maintain appropriate oxygen levels.

6. How often should confined space entry training be conducted?
Confined space entry training should be conducted initially for all workers who may enter confined spaces as part of their job duties. Refresher training should be provided periodically to reinforce knowledge and address any updates in regulations or procedures.

7. What is the golden rule of confined space entry?
The golden rule of confined space entry is to follow the principle of "No Entry without Proper Precautions." This rule emphasizes that no worker should enter a confined space without taking appropriate safety precautions and following established procedures. It highlights the importance of thorough risk assessment, proper training, and the use of necessary safety equipment. Adhering to this rule helps to ensure that workers are adequately protected and reduces the risk of accidents and injuries in confined spaces.

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.