In the past osha has required cages for fixed ladders taller than 20 feet but as of january 2017 fall protection is required on fixed ladders.
Fixed ladder cage specifications.
Here are the basics of the requirements.
All wood parts of fixed ladders shall meet the requirements of 1910 25 b.
1917 118 e 2 when a well or cage is used ladders with length of climb exceeding 30 feet 9 14 m shall comply with the following provisions.
A cage or well on a fixed ladder prevents lateral movement containing the individual climbing the ladder and offering the comfort of a surrounding safeguard.
Fixed ladders more than 20 feet 6 1 m in height shall be provided with a cage well or ladder safety device.
Ladders newly installed or altered after november 19 2018 require a ladder safety system or personal fall arrest system.
Fixed ladders provide stability when ascending to an elevated work surface because they are fastened to the building or a secure surface.
The regulations say that if a fixed ladder is taller than 20 feet you are required to have a cage which meets all the requirements of 29 cfr 1910 27 d.
Cages must extend 42 inches above the top of the landing.
American national standards for ladders fixed safety requirements the safety standard for fixed ladders contains an entire section devoted to these enclosures.
For fixed ladders consisting of wood side rails and wood rungs or cleats used at a pitch in the range 75 degrees to 90 degrees and intended for use by no more than one person per section single ladders as described in 1910 25 c 3 ii are acceptable.