Working Safely in Confined Spaces

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Published December 8th, 2020

What is a Confined Space?

OSHA defines a confined space across 3 criteria: (1) an area large enough to fully enter or perform certain jobs, (2) has limited or restricted means of entry or exit (e.g portals, hatches, manholes, ladders, spiral stairways, crawl spaces or long distance to exit); and (3) Not designed for continuous occupancy. Examples of 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 include maintenance, inspection, repair and cleaning.

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. It is characterized as a high-risk workplace and requires regulatory permits and strict entry and safety procedures.

Statistics show that an average of 90 people dies 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.

This article will help you understand the dangers of confined spaces and how to be safe when working inside them. You can also browse our free collection of iAuditor confined space safety checklists to help streamline your inspection process and go paperless.

Confined Space Hazards

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 that may result in oxygen deficiency or asphyxiation.

Outside the confined space, 21 percent oxygen 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.

Other common confined space hazards include unguarded machinery, exposed live wires, and heat stress.

5 Safety Tips for Working in Confined Spaces

Confined spaces, particularly permit spaces must be areas only accessible by trained professionals. Here are some general safety tips to help you stay safe in confined spaces:

  1. Area must be free from hazards – Before entering a confined space, ensure that it has a permit prior to entry and the area is free from harmful materials and substances.
  2. Test the atmosphere – A trained worker must conduct a series of atmosphere tests (oxygen, hydrogen, and explosive gas tests) which need to be recorded or included on the work permit.
  3. Ventilate – Never use the ventilator as a vacuum to draw the air outside. Make sure your fan is safe and grounded. Also, test the atmosphere as much as possible. If the atmosphere is within limits, it is recommended to ventilate again.
  4. Watch one another – When someone is working on a confined space, always ensure a workaround watch who can call rescue teams for emergencies or is capable and equipped to conduct a rescue.
  5. Use PPE – Use harness, lifeline, or continuous gas monitoring devices. Also, use a self-contained breathing apparatus if needed.

Confined Space Risk Assessment With iAuditor

Working in a confined space requires deep knowledge about safety procedures and protocols to secure all entrants from known hazards. iAuditor by SafetyCulture 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 iAuditor, 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.


Carlo Sheen Escano

SafetyCulture staff writer

Carlo Sheen Escano is a contributing writer for SafetyCulture based in Makati City, Philippines. Sheen has experience in digital marketing and has been writing for SafetyCulture since 2018. His articles mainly discuss risks in the workplace and well-known safety and quality processes used to mitigate them. Furthermore, Sheen is passionate about providing insights to global customers on how technology can help them to do the best work of their lives.