Standard Interpretations - Table of Contents
• Standard Number: 1910.23(a)(1); 1910.23(e)(8)

OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at

February 16, 1984

Mr. Joseph P. Stanton
Iovine & Woods, P.C.
Suite 200
7908 Frankford Avenue
Philadelphia, PA 19136

Dear Mr. Stanton:

This is in response to your letter of December 21, 1983, regarding skylights as regulated by the Occupational Safety and Health Administration (OSHA). This response provides an interpretation and clarification of the General Industry Standard 29 CFR 1910.23(a)(4) and 1910.23(e)(8).

These regulations are included in 29 CFR 1910, Subpart D—Walking-Working Surfaces. 29 CFR 1910.21(a)(1) of the same Subpart defines floor opening as: An opening measuring 12 inches or more in its least dimension, in any floor, platform, pavement, or yard through which persons may fall, such as a hatchway, stair or ladder opening, pit, or large manhole.

Moreover, a definition given in Webster's New Collegiate Dictionary (1977 edition) for "hatch" is "an opening in the...floor or roof of a building;" the same entry gives "hatchway"