Yes. The entrance at the top of a fixed ladder is considered a ladderway “hole.” Fall protection requirements for holes are found under 1910.28(b)(3). Paragraph (iii) requires that “each employee is protected from tripping into a ladderway floor hole or ladderway platform hole by a guardrail system and toeboards erected on all exposed sides, except at the entrance to the hole, where a self-closing gate or an offset must be used.”
Also, guardrail system requirements specific to holes are found in 1910.29(b)(13) which says, “when guardrail systems are used around holes that serve as points of access (such as ladderways), the guardrail system opening must have a self-closing gate ... or is offset to prevent an employee from walking or falling into the hole.” As such, all fixed ladder entrances, regardless of height, must be guarded in this manner.