AS 1657:2018 Fixed platforms, walkways, stairways and ladders- Design, construction and installation
7.4.8.1 Step-through ladders
Where it is necessary for a person to step through a ladder, the stiles shall extend not less than 1000 mm above the top landing. The width between the extended stiles at the top shall be not less than 525 mm and not greater than 675 mm.
NOTE: For typical stiles for step-through ladder, see Figure 7.10.
Stile strength and load capacity shall be consistent with the ladder. The maximum deflection of the extended stiles shall be limited to Ls/50, where Ls is the length of the extended stile and the imposed action is a force of 600 N acting outwards at 90° to the slope of the ladder and positioned at the top of the extended stile. The max imum lateral deflection of the extended stiles shall be limited to Ls/15, where Ls is the length of the extended stile and the imposed action is a force of 350 N acting laterally in the plane of the ladder and positioned at the top of the extended stile. Except at points where a ladder cage and other brackets are attached, hand clearances around the stiles shall be maintained at 50 mm.
NOTE: For stile clearance, see Clause 7.4.5.
7.4.8.2 Side access ladders
Where it is necessary for a person to step sideways from a ladder, the ladder stiles and rungs shall extend not less than 1000 mm above the top landing. The horizontal distance from the ladder stile to the landing shall be 90 mm to 175 mm.
NOTES: 1 For typical stiles and rungs for side access ladders, see Figure 7.11.
2. Figure 7.11 shows a typical arrangement for side access from a ladder to a landing. The design of such installations should consider the adequacy of the space between the ladder stile and adjacent edge protection railing to allow safe access, and also the size of the gap between the ladder stile and the adjacent landing, where an infill section or extension to the landing may be appropriate.