Accessible home design - flooring question

by Brenda
(Edinburgh)

In building a home for an elderly person what would be the maximum acceptable height for the change in level between two rooms in order to avoid a tripping hazard?

I am aware that it is possible to 'get used to' level changes up to 40mm, but worry about the number of broken arms (or worse) whilst getting used - and what about visitors?

The case in question will be between vinyl in the utility room and a thick layer of tiling, plywood and screed in the kitchen.