Confined Space Safety

Learn about confined space safety, the hazards involved, permit-required confined spaces, and safety tips to stay safe in confined spaces.

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What is Confined Space Safety?

Confined space safety is the practice of ensuring safe work conditions in fully or partially enclosed areas such as manholes, pipelines, boilers, utility vaults, and storage bins. Confined space safety precautions should be undertaken accordingly to comply with health and safety regulations and prevent work-related injuries, illnesses, or even deaths.

confined space safety

What is a Confined Space?

According to the U.S. Occupational Safety and Health Administration (OSHA), a confined space is an area large enough to fully enter or perform certain jobs. A confined space also has limited or restricted means of entry or exit (e.g. portals, hatches, manholes, ladders, spiral stairways, crawl spaces, or long distances to exit) and is not designed for continuous occupancy. Apart from the OSHA criteria, confined spaces are defined across countries or regions as follows:

NIOSH Confined Space

Based on the definition of the National Institute for Occupational Safety and Health (NIOSH), a confined space refers to a space that, by design, has limited openings for entry and exit, unfavorable natural ventilation which could contain or produce dangerous air contaminants, and which is not intended for continuous worker occupancy.

While OSHA enforces regulations, NIOSH provides research-based recommendations to prevent work-related injuries. Therefore, it is empirical that NIOSH includes the element of “unfavorable natural ventilation” in its definition of a confined space.

HSE Confined Space

As the regulator of occupational health and safety legislation in the U.K, the Health and Safety Executive (HSE) explains that a confined space is a place which is substantially enclosed (though not always entirely), and where serious injury can occur from substances or conditions within the space or nearby (e.g., lack of oxygen).

While OSHA and NIOSH specify that a confined space is not designed or intended for continuous worker occupancy, the HSE emphasizes that a confined space safety does not only include substances or conditions within the area but also nearby or around it.

CCOHS Confined Space

The Canadian Centre for Occupational Health and Safety (CCOHS) probably offers the most detailed description of a confined space. CCOHS elaborates that a confined is a fully or partially enclosed space that is not primarily designed or intended for continuous human occupancy and has limited or restricted entrance or exit, or a configuration that can complicate first aid, rescue, evacuation, or other emergency response activities.

However, the CCOHS adds that a confined space is a fully or partially enclosed space that can represent a risk for the health and safety of anyone who enters, due to one or more of the following factors:

  • its design, construction, location, or atmosphere;
  • the materials or substances in it;
  • work activities being carried out in it; or
  • the mechanical, process, and safety hazards present.

WorkSafeBC Confined Space

As a statutory agency based in the Canadian province of British Columbia, WorkSafeBC simply states that a confined space is an enclosed or partially enclosed area that is big enough for a worker to enter.

Nevertheless, they gave examples of a confined space that is enclosed on all sides such as a tank, or as few as two sides such as an enclosed conveyor. WorkSafeBC concurs that confined spaces are not designed for someone to work in regularly.

Safe Work Australia Confined Space

According to the definition of Safe Work Australia (SWA), a confined space is determined by the hazards associated with the specific situation—not just because work is performed in a small space.

As the Australian government statutory body for developing national policy relating to work health and safety (WHS) and workers’ compensation, SWA stresses that hazards in a confined space are not always obvious and may change from one entry point to the next.

What is a Permit-Required Confined Space?

A permit-required confined space also known as a “permit space” contains or has the potential to contain a hazardous atmosphere or any other serious safety or health hazards. Permit-required confined spaces are characterized as a high-risk workplace, requiring regulatory permits and strict entry and safety procedures.

OSHA Standard and Requirements

OSHA 1910.146 is the standard for confined spaces. It is found in Title 29 (Labor) Subtitle B (Regulations Relating to Labor) Part 1910 (Occupational Safety and Health Standards) Subpart J (General Environmental Controls). The OSHA confined space standard explains the requirements for permit-required confined spaces in detail. Generally, listed below are some OSHA confined space requirements:

  • Evaluate the workplace to determine if any spaces are permit-required confined spaces.
  • Inform exposed employees if the workplace contains permit spaces.
  • Take effective measures to prevent employees from entering the permit spaces if employers decide that employees will not enter permit spaces.
  • Develop and implement a written permit space program if employers decide that employees will enter permit spaces.
  • Use alternate procedures for entering a permit space under certain conditions.
  • When there are changes in the use or configuration of a non-permit confined space that might increase the hazards to entrants, reevaluate that space and, if necessary, reclassify it as a permit-required confined space.
  • A space classified by the employer as a permit-required confined space may be reclassified as a non-permit confined space under specific procedures.
  • When an employer (host employer) arranges to have employees of another employer (contractor) perform work that involves permit space entry, the host employer should follow the established protocol.
  • In addition to complying with the permit space requirements that apply to all employers, each contractor who is retained to perform permit space entry operations should adhere to the given process.

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What is a Rescue Plan in Confined Space Safety?

A confined space rescue plan is a system of steps undertaken by designated personnel to rescue employees from permit spaces. The rescue and emergency services often use a retrieval system or the equipment used for non-entry rescue of persons from permit spaces, among other equipment and assets necessary for safe entry into and rescue from permit spaces. The OSHA requirements related to a confined space rescue plan is as follows:

  • Develop and implement procedures for summoning rescue and emergency services, for rescuing entrants from permit spaces, for providing necessary emergency services to rescued employees, and for preventing unauthorized personnel from attempting a rescue.
  • Evaluate a prospective rescuer’s ability to respond to a rescue summons in a timely manner, considering the hazard(s) identified.
  • Evaluate a prospective rescue service’s ability, in terms of proficiency with rescue-related tasks and equipment, to function appropriately while rescuing entrants from the particular permit space or types of permit spaces identified.
  • Select a rescue team or service from those evaluated.
  • Inform each rescue team or service of the hazards they may confront when called on to perform rescue at the site.
  • Provide the rescue team or service selected with access to all permit spaces from which rescue may be necessary so that the rescue service can develop appropriate rescue plans and practice rescue operations.
  • Provide affected employees with the personal protective equipment (PPE) needed to conduct permit space rescues safely and train affected employees so they are proficient in the use of that PPE, at no cost to those employees.
  • Train affected employees to perform assigned rescue duties.
  • Train affected employees in basic first-aid and cardiopulmonary resuscitation (CPR).
  • Ensure that affected employees practice making permit space rescues at least once every 12 months.
  • To facilitate non-entry rescue, retrieval systems or methods shall 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 of the entrant.
  • 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 written information shall be made available to the medical facility treating the exposed entrant.

Why is Working Safely in a Confined Space Important?

Statistics show that an average of 90 people died each year while working in confined spaces in the United States alone. Most of these incidents are caused by asphyxiation or oxygen deficiency due to the presence of deadly gases while performing certain jobs.

Detailed safety procedures must be thoroughly conducted to ensure all entrants will be provided adequate protection while performing their job inside the confined space. Moreover, employers are responsible for educating and reinforcing their workers about safety rules.

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What are the Oxygen Levels in Confined Spaces?

Outside the confined space, 21 percent oxygen is necessary to sustain life. Oxygen in confined spaces tends to go low. It might be used for rust, bacterial growth, and slime. Other gas may enter the confined space and displace the oxygen. Operations like heating will consume oxygen.

If oxygen is reduced to 12 to 16 percent, workers will increase pulse and respiration and experience loss of coordination. If the oxygen decreases to 6 to 10 percent, they will experience nausea, vomiting, loss of consciousness, and even death.

Prepare your employees for workspace operational risks with confined spaces training

Risks that are associated with working in the construction or mining industry are inevitable as that’s just the nature of manual work. Naturally, when working in enclosed spaces that have limited access and entry or exit points, appropriate training must be provided to workers prior to deployment. This covers the protective equipment they should use on-site and the safety practices the workers should observe the entire duration of their shifts. Most importantly, they should also be given an exit plan in the case of accidents such as the obstruction of the entry or exit access and the collapse of any areas where they’re working. It’s always ideal to train the workers on what they can do when faced with compromising situations so they’ll know what to anticipate when working on-site. Moreover, it will help your staff improve their knowledge and skills to effectively mitigate the dangers connected with working in limited spaces.

We’ve compiled a selection of confined spaces training that your workers can take to ensure safe operations when working in confined spaces. These specialized training courses address topics including entrance permit systems, atmospheric monitoring, emergency protocols, and more, all to provide your employees with a fundamental understanding of confined space regulations and procedures.

Risk Assessment with SafetyCulture

Working in a confined space requires deep knowledge of safety procedures and protocols to secure all entrants from known hazards. SafetyCulture (formerly iAuditor) is a mobile app and cloud-based solution that empowers teams to collect consistent data to ensure adequate protection was provided to all entrants while performing their job inside a confined space.

With SafetyCulture, safety officers can perform confined space risk assessments on mobile devices anytime, anywhere—even while offline. They can easily capture, annotate, and attach photos of non-compliant items for more accurate reports. Confined space risk assessments can be sent immediately right after the inspection to any member of the organization with a single tap of a finger.

FAQs About Confined Space Safety

The following items are some precautions to observe to ensure safety in confined spaces:

  • Provide proper training and certification for all workers entering the confined space
  • Perform a hazard assessment or regular inspection of the space before entry
  • Monitor air quality and ensure adequate ventilation 
  • Use appropriate PPEs such as respirators, gloves, and safety harnesses
  • Secure communication with workers inside and outside the confined space and have a worker on standby outside at all times
  • Implement lockout/tagout procedures to prevent accidental activation of equipment or machinery
  • Establish emergency response and rescue plan procedures and make sure that all workers are aware of them
  • Utilize tools such as digital checklists in conducting confined space risk assessments and inspections

The main hazard when working in a confined space is the deadly atmosphere due to the presence of carbon monoxide, hydrogen sulfide, and methane gas which may result in oxygen deficiency or asphyxiation. Other common confined space hazards include unguarded machinery, exposed live wires, and heat stress.

PPEs for confined spaces include respiratory protection items such as self-contained breathing apparatus (SCBA) and air-purifying respirators, Protective clothing such as coveralls, chemical-resistant suits, gloves, hard hats, and boots are also necessary. Eye and face protective gear should also be worn, which includes safety glasses and goggles. For hearing protection, earmuffs and earplugs are recommended.

Confined spaces include tanks, vaults, pits, manholes, tunnels, equipment housings, pipelines, boilers, furnaces, compactors, sewers, attic spaces, and elevator pits. Common work performed in confined spaces includes maintenance, inspection, repair, and cleaning.

Jona Tarlengco
Article by
Jona Tarlengco
Jona Tarlengco is a content writer and researcher for SafetyCulture since 2018. She usually writes about safety and quality topics, contributing to the creation of well-researched articles. Her 5-year experience in one of the world’s leading business news organisations helps enrich the quality of the information in her work.