[The caller asked for help in interpreting the definition of a confined space. Although the spaces in question are large enough for entry and are not designed for continuous employee occupancy, there is a question as to whether the single "submarine style" door constitutes a limited or restricted means for entry or exit under the definition of a confined space in 1910.146(b).

Each space is a filter plenum that measures approximately 40 x 40 x 20 feet. The only means of entry or exit is the submarine style door that is an airlock. It allows upright entry, but requires 15-20 pounds of pressure to open because of the negative pressure in the space. There is a 6 inch high door ledge that one must step over, which helps make the seal. When closed, it is air-tight and virtually sound proof. Workers enter the space to change out filters or take readings. Workers are required to wear PPE, including respirators, inside this space because the filters contain alpha emitters.]

OSHA notes in the in the preamble of the confined space standard (54 FR 24089) that doorways and other portals through which a person can walk are not considered to be limited means for entry or exit. However a technical amendment was published (59 FR 55208-55209) that revised the Preamble description of restricted access. Under the new description, the caller's space may be a confined space because the door may be an obstruction which makes entry into or exit from the space difficult, even though the portal is a standard size doorway. This clarification by OSHA is effective immediately. In light of this revision, the space in question should be re-evaluated under these revised criteria to determine if it is a permit-required confined space.

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Last modified: 04/18/96 08:50:32