Confined Space versus Permit Required Confined Space | Major Safety Skip to content

What Is A Confined Space?

The term "confined space" has become a catch-all phrase with a lot of misconceptions around its definition. We want to clear those misconceptions up and bring some clarity to your understanding of what a "confined space" is.

OSHA on Confined Spaces

OSHA provides the definition of a confined space in 29 CFR 1910.146. They stipulate three conditions for identifying a space a confined space.

  1. It must be large enough and so configured that it is possible for a person to bodily enter and perform work.
  2. It has limited or restricted means for entry and exit.
  3. It is not designed for continuous employee occupancy.

We can make a few helpful observations about this definition. First, this definition helps us to quickly grasp the variety of confined spaces that might be present in a work place. Some examples are fuel storage tanks, manholes, railroad tank cars, sewers, a variety of vaults, boilers, elevator pits, and open topped pits.

The second observation is that it doesn't follow that a confined space will always be designated a permit-required confined space. In some cases, these spaces might be deemed non-permit confined spaces. If they are non-permit spaces, then no special considerations are needed to work in them. But this begs the question: what is a permit-required confined space?

Permit-Required Confined Space

Obviously, it is not unusual for any of the above cited confined spaces to contain conditions that could be hazardous to the life and health of a worker. In such cases, special procedures would be required to enter and work in the space. Such confined spaces are called permit-required confined spaces.

OSHA puts it like this: a permit-required confined space is "a confined space that contains hazards capable of causing death or serious physical harm." To be more precise, a permit-required confined space contains at least one of the following hazards (cited from GFG).

  1. The potential to contain or generate a hazardous atmosphere, (such as oxygen deficiency from rusting metal, combustible methane from decomposing leaves or debris, or hydrogen sulfide from sewage).
  2. The space contains a material that has the potential for engulfing an entrant, (anything from water, to mud, to wood chips, to molasses).
  3. An internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls or by a floor which slopes downward and tapers to a smaller cross-section, (such as many bins, chutes and dust collectors).
  4. Or any other recognized serious safety or health hazard, (from rotating blades or vanes, to poisonous snakes).
  5. Temporary work, such as welding or painting, that will itself introduce a hazard into a confined space thereby making it a permit-required confined space.

When any one of these conditions is present, the confined space is a permit-required confined space. At this point, entry and work in the space must follow OSHA 29 CFR 1910.146 regulations. This will include testing of the atmosphere with an appropriate gas detector, providing means of confined space entry and rescue, and providing proper ventilation--among other things.

If you have a confined space and are unsure whether it should be designated a permit-required confined space, please give us a call. We'd be glad to assist any way we can.


Previous article A Step-by-Step Guide to Using a Confined Space Ventilation Blower Purge Chart
Next article Fall Protection Rescue Plan