A safety professional was designing multiple offset ladder sections for the exterior of an 80-plus-foot grain silo, with 3-foot by 3-foot rest platforms with guardrails at each offset. Some individual ladder sections were under 24 feet. He asked whether each section above 24 feet from the ground needs a ladder safety system, or whether the 24 feet is measured platform to platform.
OSHA explained that under 29 CFR 1910.28(b)(9)(i)(B), fixed ladders extending more than 24 feet above a lower level require a personal fall arrest system or ladder safety system, and that the distance a ladder section sits above the ground or a rest platform determines whether one is required. Crucially, the measurement must account for falls past the platform: because a worker could fall past a 3-foot by 3-foot platform, the measurement extends from ground level, not from the platform.
The second question was whether marking the ladder for emergency use would trigger the exception in 29 CFR 1910.23(a)(1). OSHA said no: that exception applies exclusively to ladders used in emergency operations such as firefighting, rescue, and tactical law enforcement operations, or training. However, as an enforcement matter, OSHA will not cite violations where fixed ladders on grain silos lack safety devices if the ladders are exclusively for emergency egress and carry visible "Emergency Use Only" signage at both ends.