"Accessible threshold" compliance - drainage detail

[Hastings]

I cannot find online the document pdf recommended in the building regulations on how to do this:

"Accessible thresholds in new housing – Guidance for house builders and designers".

 

All the door manufacturers' cross section detail drawings of accessible thresholds show some form of drain just in front of the door but in the diagram in the building regulations guidance (Scotland) no such drain is shown.

 

Is the drain simply good practice or is it mandatory (in a new build)?

 

I was planning on having the door entrance platt area (concrete) slope away to a drain (already in place serving a rainwater downpipe) that is 2.8m away from the door.

 

Thanks.

Edited March 20, 2022 by Hastings
added image

[Russell griffiths]

Not mandatory, just good practice. 

My accessible door is under a roof area, so no need for drainage.