Archive Notice - OSHA Archive

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

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" as a synonym.

Using these definitions, therefore, OSHA concludes that a skylight should be regarded as a hatchway, i.e., an opening in the roof of a building through which persons may fall. 29 CFR 1910.23(a)(4), therefore, requires that skylights in the roof of buildings through which persons may fall while walking or working shall be guarded by a standard skylight screen or a fixed standard railing on all exposed sides.

When a skylight screen is selected for safeguarding the opening, and in the event the skylight is constructed of plastic material subject to fracture (as glass would be), then the skylight must at a minimum be provided with a skylight screen capable of withstanding a load of at least 200 pounds applied perpendicularly at any one area on the screen. On the other hand, a plastic skylight which can provide the necessary structural integrity to support the 200-pound load would not be required to be further safeguarded, since it would meet the intended function of a screen as well.

As expressed in 29 CFR 1910.23(e)(8), the primary function of the screen is to support at least a 200-pound load such as a person may place upon it. This provision further relates that the screen shall provide a minimum deflection so as not to break the glass; but that portion of the requirement may be inapplicable when no glass is present. (The concern for breaking the glass results from the possible fragment exposure to persons beneath the skylight.)

We hope this information is helpful to you. If we may be of further assistance, please contact us.



John B. Miles, Jr., Director
Directorate of Field Operations

[Corrected 8/14/2007]