ISO 14122-4 Fixed Ladders

[sajk14]

Hello All,

I am designing a fixed cage vertical ladder that will be attached to a large storage tank to provide access to the roof of the tank. The usage of the vertical ladder will be very minimal and ideally will be used for emergency only ( once or twice a year ). The height of the storage tank is approx 24m and so I will be using fixed intermediate rest platforms in the design.

I have designed the vertical ladder so that as you climb up the ladder you are facing the main wall of the tank ( or building ) and as you come to the intermediate platform you have to make a side step off the ladder rung onto the intermediate platform.

For the very top flight as you get to the top of the ladder you just walk forwards and onto the roof of the tank ( or building ).

However I have been challenged by a colleague that the ‘side step’ between the actual ladder and the intermediate platform is not in accordance with the ISO 14122-4 standard and that the examples in the standard show the only way to exit from a vertical ladder is by stepping off forwards from the ladder onto a platform.

I disagree with my colleagues interpretation of the standard and I believe that a side step is acceptable and allowed and this is shown in Fig 1b and also mentioned in clause 4.7.3.1

Please could anyone provide me with any advice or assistance with regards to this.

Many thanks for your time and your help is greatly appreciated.

 

[Ussuri]

Stepping of the side is common on scaffolding.

You need to make sure the the ladder extends through the floor by a couple of metres so the individuals feet are above floor level when still on the ladder.

If you look at EEMUA 105, figure 16 on page 65 shows a detail for a side access through a floor.

http://www.eemua.org/p_general.htm