Learn about confined space safety, the hazards involved, permit-required confined spaces, and safety tips to stay safe in confined spaces.
Published 25 Aug 2023
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.
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:
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.
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.
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:
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.
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.
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 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:
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:
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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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.
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.
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.
The following items are some precautions to observe to ensure safety in confined spaces:
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.
SafetyCulture (iAuditor) is an award-winning management platform that allows teams to generate real-time reports on mobile devices while onsite. With SafetyCulture, you can easily evaluate confined spaces and capture hazards for immediate resolution. Get started with these free customizable confined space safety checklists:
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.
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