Apart from rapidly losing the strength to engage in ‘what if’ scenarios, I will answer this. Because of the clarity of FWS and the HSE I think you can not have a toilet that is used by both sexes and maintains the safer single sex design in cubicles in a single sex environment with washbasins.
From Document T:
Cubicle: A ventilated compartment, not self-
contained, usually formed by the assembly of
partition panels and located within a room.
Universal toilet: Toilet facilities provided in a fully enclosed room which contains a water-closet and washbasin and hand-drying facilities, and is intended for individual use by persons of either sex.
Single-sex toilet: Toilet facilities intended for the exclusive use of persons of the same sex, and with washbasins and hand-drying facilities in either the toilet room or cubicle, or in a separate area intended for use only by persons of that sex.
It can be seen in Document T for England, that cubicles are not rooms and that single sex toilet cubicles must be in a single sex environment.
eg. 1.22 The layout when entering, exiting and using a toilet room or cubicle should cater for the safety, privacy and dignity of users. Cubicle doors should only open into single-sex toilet accommodation.
The HSE have said to me directly in relation to Document T when I have had discussions with them over the years. There is also another Document M that is clear about single sex toilets within single sex washrooms for accessibility. For Scotland, Wales and Northern Ireland you need to look at their regulations. All of them mention women and men in different varieties of non domestic provision. Doc T and Doc M are England’s Approved Documents providing guidance on ways to meet the building regulations which is under Ministry of Housing, Communities & Local Government so they will be looking at this as well. They’ll be aware of all the weird and wacky designs as they tried to rein it in with Document T. Document T is based on Building Standards BS6465 which cost a fortune to own. Recently owners of buildings have been doing their own thing often in the name of ‘inclusivity’ and not referring to British Standards. If they had, they would have such a problem now.
When I discussed the legalities of the situation with regards to toilet design, the HSE referred me to the Ministry of Housing, Communities & Local Government.
The only real design test so far was the (non-service) Kelly tribunal case which (unbelievably and bizarrely) was lost. I was glad to see the judge in this GLP case looked at the Kelly case and came to the same conclusion as me and common sense - the verdict was wrong on the workplace regs.
When I was discussing unsafe school toilets with the DfE, which don’t fall under 1992 legislation, they told me they do fall under 1974 legislation. Now this one talks about keeping everyone safe (visitors etc).
The GLP judge also made a distinction between a room and a cubicle. This is something that is relevant and was also relevant in the British Standards at the time of 1992 legislation. I have the relevant section here from BS6465 from 1984:
“WC compartments should be self contained, but where a range of WCs is provided, each in a separate cubicle within a single room, e.g. in schools, offices, factories, public buildings and public conveniences, it simplifies ventilation, cleaning and, to some extent, supervision and prevention of wilful misuse, if the cubicle walls terminate above the floor as well as below the ceiling. These advantages are gained only at the expense of a certain degree of privacy. Where cubicles are used, the whole room in which they are situated may be regarded as a single unit for the purposes of ventilation.
Where partition walls and doors of WC cubicles are kept clear of the floor, the clearance should be not less than 100 mm and not more than 150 mm. Partitions and doors that terminate below ceiling level should be not less than 2 m in height from the floor.”
Sorry if that’s a bit jumbled and long. I am really so weary about all of this.