AAI Stainless Steel Access Ladders - Type AA520
Stainless Steel Access Ladders
AA520 Access ladders are designed for access to platforms and structures where use of a stair is not suitable.
Ladders are 380mm min between stringers, complete with rungs at 300 max ctrs.
For the AA520 ladder type, the stringers are opened out to 700mm to a walk-through and is complete with a three rung step section. For ease of transport / installation, ladders can be spliced.
Ladders are secured with stays at generally 2500 ctrs, although this may increase if larger stringer sections are used.
Safety cages or fall arrest systems are an essential requirement for ladders where a user could fall 3m or more or come into contact with dangerous equipment. Safety cages should start 2400mm from FFL and have hoops in line with the handrail ctrs to the head and 900mm max spacing there-after.
Inclined ladders should be set at 75 ̊ or steeper. Landings where required should not be less than 840mm square complete with handrails and toe plates to protect open sides.
Material: Stainless steel grade 316L to provide the best possible corrosion resistance. Grade 304 could be used for less aggressive environments.
Ladders stringers and walk-through: Generally 65x13 flat bar minimum, c/w 20mm dia solid rungs. Stringers can be manufactured from larger flat bar or angle sections, if fixing ctrs are limited.
Safety Cage, (hoops & straps): 50x8 flat bar.
Ladder stays: Generally flat bar of the same section as the ladder stringers.
Safety chains should be provided to ladders with walk-through's, to guard against falls.
All fixings to be stainless steel grade 316 (A4)
Finishes include: Self-colour, pickle and passivate and electro polished.
Direct contact with materials such as aluminium or copper should be avoided, however use of suitable isolating gaskets should eliminate any problems with this.