If you are planning to enter a ceiling via a manhole, you will need to make the manhole a minimum width of 715mm for the Ladders and 750mm for Stairs with hand rail mechanism but wider than 750mm if the upper floor to lower ceiling thickness is extraneously large E.G. Between 250-400mm thick (Without hand rail Mech. Stair product will also be 715mm).
To benefit the most from the flat folding mechanism, ceiling opening will need to as close to attaching wall as possible, this also provides the best stability.
Depending on the inclination of the chosen product, manhole will also need to be lengthened accordingly to avoid head collision with ceiling when climbing.
The widths will also need to be the same for accessing a landing/Mezzanine if there is some kind of alcove or restricted entry point at the landing where the products are attached to, but no length requirement needed.