When we hear the term "confined spaces," we tend to envision tight or restrictive quarters as you might find in a cave, underground tank or even a narrow tunnel. The word "confined" easily leads us away from the intended concept.

The OSHA definition for confined spaces relates to a particular configuration that could result in any of the following:

Atmospheric Condition — a condition in which dangerous air contamination, oxygen deficiency, or oxygen enrichment may exist or develop;

Entry/Exit Access — a condition where the emergency removal of a suddenly disabled person is difficult due to the location or size of the access opening; or

Engulfment Condition — a condition where the risk of engulfment exists or could develop.

Basically, a confined space is any area that has a limited means of egress (can't be readily exited), and that it is subject to either a potential for accumulating toxic or flammable contaminants, or it has a potential for an oxygen-deficient or oxygen-rich atmosphere - less than 19.5% oxygen or more than 23% oxygen. A confined space often relates to the possibility of flooding or a cave-in, which obviously would impact egress.

The types of spaces that may fall under the definition of "confined space" can be surprising. For example, storage tanks, process vessels, ventilation exhaust ducts, sewers, utility vaults, tunnels, open bins and even open top trenches can be classified as confined spaces. In short, they do not necessarily have to be confining.

When you want to determine if a particular space is a confined space, you should ask the following questions:

• Is access to the space limited? Is it difficult or unusual to enter or leave the area? How about the potential difficulty in removing an incapacitated worker?

• Was the space not designed for full-time employee occupancy?

• Is the space poorly ventilated?

If your answer is a "yes" or a "maybe" to any of these questions, then you should treat the area as a confined space and proceed accordingly.