Explanation from OSHA of the "not designed for continuous human occupancy" component if the definition of the term "confined space".

Standard Number: 1910.146(b)

June 22, 1995

Mr. Dan Freeman
c/o Safety Management, L.C.
# 4 Deerwood Drive
Blue Grass, Iowa 52726

Dear Mr. Freeman:

This is in response to your letter of April 25, 1994, seeking an explanation from the Occupational Safety and Health Administration (OSHA) of the "not designed for continuous human occupancy" component in the definition of the term "confined space." Please accept our apology for the delay in this response.

The proposed rule (F.R., Vol. 54, No. 106, June 5, 1989, pg. 24089) provided the initial clarification of OSHA's intent on this subject when we stated "In addition, OSHA proposes paragraph (b)(10)(iii) to make it clear that the work areas covered by this standard are unsuitable, by nature for continuous employee occupancy, because those spaces were created to contain such things as degreasers, sawdust, and sewage, not to accommodate people."

In the preamble of the final rule (F.R., Vol. 58, No. 9, January 14, 1993, pg. 4478), OSHA discusses comments sent to the docket and the slight differences between our definition of confined space and that of the American National Standards Institute (ANSI) definition. Although the distinction between the "primary function" (ANSI) and the "design" (OSHA) of a space may seem inconsequential, OSHA believes that the final rule's definition properly places the focus on the design of the space, which is the key to whether a human can occupy the space under normal operating conditions. Thus, if a space is truly designed for human occupancy, then the primary function of the space is irrelevant.

If you have further questions on this response please contact Mr. Don Kallstrom in the Office of General Industry Compliance Assistance (202) 219-8031. Again please accept our apology for the delay.

Sincerely,

John B. Miles, Jr., Director
Directorate of Compliance Assistance