I read the October issue Q&A entitled "Are Guardrails Needed if Workers Wear Harnesses?" The provided answer needs to be supplemented with additional OSHA requirements for holes that have fall heights of less than 6 feet. Specifically, 29 CFR 1926.501(b)(4)(ii) requires all holes regardless of depth to be protected such that employees cannot trip or stumble into them. A personal fall arrest system (PFAS) does not meet OSHA's requirements for such holes. In such cases, holes must be either covered or guarded. If the question involved a deck with a fall exposure of less than 6 feet, a PFAS is not permitted and the hole must be either guarded or covered.
OSHA clarified this in an 11/17/98 letter of interpretation regarding an elevator pit, as follows:
The fall protection standard, at 29 CFR 1926.500(b), defines a hole as "a gap or void 2 inches … or more in its least dimension, in a floor, roof, or other walking/working surface." The standard has two requirements with respect to holes. First, 1926.501(b)(4)(i) requires that employees be protected from falling through holes more than 6 feet by fall arrest systems, guardrails, or covers. So, if a hole is more than 6 feet deep, one of these protection systems must be used.
Second, 1926.501(b)(4)(ii) requires that employees be protected from tripping or stepping into holes by placing covers over them. This provision does not specify a minimum depth for the requirement to apply.
The first issue is whether the pit is a "hole." The pit you describe is located in and surrounded by a floor, roof, or other walking/working surface of a significantly larger dimension than the pit. This pit would be considered a hole under the standard. Since the fall distance is less than 6 feet, the applicable requirement is 1926.501(b)(4)(ii), which requires a cover to protect against the tripping/stepping-into hazard. Alternatively, a guardrail could be used to prevent employee exposure to this hazard.
Timothy Carlsen, PE