Standard Interpretations - Table of Contents Standard Interpretations - Table of Contents
• Standard Number: 1926.500(b); 1926.501(b)(1); 1926.501(b)(4)(i); 1926.501(b)(4)(ii); 1926.502(b)

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

September 30, 2004

Mr. Bob Kersten
Received via e-correspondence

Dear Mr. Kersten:

In your e-correspondence submitted June 28, 2004, and in subsequent telephone conversations with our staff, you asked about OSHA construction standards that pertain to a depression in a finished concrete ground floor.

We have paraphrased your question as follows:

Question: Scenario: There is a depression in a finished concrete ground floor. The ground floor measures approximately 200 feet by 350 feet. The depression is 7 feet wide, 70 feet long, and 33 inches deep. It has concrete walls and a concrete floor. Are guardrails required under 29 CFR Part 1926 Subpart M around this depression?

The answer to your question depends on whether, under the standard, the depression constitutes an unprotected side/edge or a hole.

Section 1926.501(b)(1)(unprotected sides and edges) states:
Each employee on a walking/working surface . . . with an unprotected side or edge which is 6 feet or more above a lower level shall be protected from falling by the use of guardrail systems, safety net systems, or personal fall arrest systems.
Section 1926.501(b)(4)(i) states: Each employee on walking/working surfaces shall be protected from falling through
holes (including skylights) more than 6 feet (1.8 m) above lower levels, by personal fall arrest systems, covers, or guardrail systems erected around such holes. [Emphasis Added.]
Section 1926.501(b)(4)(ii) states:
Each employee on a walking/working surface shall be protected from tripping in or stepping into or through holes (including skylights) by covers.
In §1926.500(b), "hole" is defined as:
a gap or void 2 inches or more in its least dimension, in a floor, roof, or other walking/working surface.
The standard does not set a maximum dimension for a depression to be considered a "hole." Whether a depression is considered a hole or an unprotected side/edge is relevant where the depth of the depression is less than 6 feet. In that case, if it is a "hole," employees must be protected from the tripping/stepping into hazard.

One of the factors that is relevant to distinguishing between a "hole" that is less than 6 feet deep and an "unprotected side or edge" that is less than 6 feet high is the overall size of the walking/working surface in relation to the size of the depression.

This is a factor because it is even more difficult for workers to be cognizant of the specific location of holes than of unprotected sides/edges. The smaller the size of the depression in relation to the over-all walking/working surface, the more likely it is that the workers will loose track (or be unaware) of its location. Conversely, where, for example, a depression takes up most of the walking/working surface, workers will tend to be more aware of its boundaries.

In your scenario, although the depression is large, the walking/working is significantly larger. The total floor is so large that there is an increased possibility a worker could lose track of the location of the depression and either trip or step into it. Therefore, it is considered a hole.

In this case §1926.501(b)(4)(ii) would apply, requiring that employees on walking/working surfaces be protected from tripping or stepping into or though the hole by covers.
1 However, as we explained in the attached letter to Mr. Russell dated November 17, 1998, guardrails may be used instead of covers. If you choose to use guardrails, they must meet the requirements of §1926.502(b).

If you need additional information, please contact us by fax at: U.S. Department of Labor, OSHA, Directorate of Construction, Office of Construction Standards and Guidance, fax # 202-693-1689. You can also contact us by mail at the above office, Room N3468, 200 Constitution Avenue, N.W., Washington, D.C. 20210, although there will be a delay in our receiving correspondence by mail.


Russell B. Swanson, Director
Directorate of Construction

1 Because the hole you described is less than 6 feet deep, §1926.501(b)(4)(i) does not apply.
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