A Brief Guide to OSHA’s Confined Spaces and Risk Factors

Confined Space Rescue Services

A Brief Guide to OSHA’s Confined Spaces and Risk Factors

Although the term Confined Space seems self explanatory, it’s not always obvious when someone is actually working in a confined space that can pose a potential risk to their health and safety. 

Confined Spaces are hazardous places, and people can be severely injured or die if precautions are not taken, and regulations are not followed.

OSHA (the Occupational Safety and Health Administration) provides guidance on how to define Confined Spaces, how to identify them, and if a Confined Space requires a permit. Let’s take a deeper look.

Definition of a Confined Space

Confined Space Rescue Services - PROS Services
Confined Space Rescue – PROS Services

A Confined Space is any space that’s partially or fully enclosed and has limited access to allow a person to enter and perform their work. This kind of restricted access can, therefore, increase the risk of not being able to exit when necessary, or communicate when help is needed.

OSHA looks at 3 factors in a Confined Space:

1. Is the space large enough for a person to fit?

The important piece here is that a person should not only be able to enter into the space, but also be able to bodily fit into the space, and have enough room to perform his or her work inside. 

2. Does the space have limited or restricted entry and exit?

Limited or restricted access refers to a person’s ability to escape the space in an emergency. If a person trapped in a space needs to crawl, climb, twist or be obstructed in some way when trying to exit, then it is considered a Confined Space.

3. Is the space designed for continuous occupancy? 

If a space is designed and configured to allow continuous occupancy, then it would not be considered a Confined Space. 

Examples of Confined Spaces


Large containers used to hold potentially hazardous liquids and gases

Silos/Storage Bins

Granaries or structures that store bulk, loose materials like grain and fodder

Air Handlers

Large metal boxes used in regulating heating, ventilating and air conditioning systems


Conduits and pipe systems, also used in regulating heating, ventilating and air conditioning systems


Large cylindrical pipes or structures designed to escape smoke or gases during combustion

Escalator Pits

Narrow, enclosed spaces housing an escalator or a bank of escalators


Large mixers, such as concrete mixing drums


Boilers and boiler rooms in commercial or industrial buildings 


Industrial applications of furnaces and associated equipment

Truck Tankers

Tanks attached to truck trailers, semi trailers and rail cars


Trash compactors and material bailers used in recycling and waste management facilities

Crawl Spaces

Any space or area in a building to access wiring, plumbing, storage


Underground pipes and tunnels used to carry sewage, water and waste matter

Lift Stations/Digesters

Pumping stations that move water between different elevations 

Storm Drains/Culverts

Pipes and tunnel systems used to carry excess rain from paved surfaces

Septic Tanks

Large holding tanks to decompose and purify organic sewage  

Utility Vaults

Underground (or enclosed) storage areas accessed by a maintenance portal


Cylindrical pipes to move liquids (or gases) from one area to another

Dock Leveler Pits

Loading dock equipment used during loading and unloading and cargo transfers

Utility Tunnels

Underground (or aboveground) passageways or corridors used to carry electricity, water, steam or sewage

Attic Spaces

Low height rooms or spaces directly under a roof in a house or building

Open Top Pits

Pits used during vehicle inspections, mining and industrial applications

Conveyor Tunnels

Conduits that can transport materials or vehicles

Elevator Pits

Vertical shafts that can be above ground or below ground designed to hold an elevator or a bank of elevators

More Information and Get Help

Confined Spaces are not designed or intended for human occupancy, and are only used for maintenance, transportation or other such activities. Due to the high risk nature of operating within Confined Spaces, it is advisable to seek professional help to avoid hazardous situations.

Refer to OSHA’s website for more info about their standards and resources for Confined Spaces.