Hi! Our project has highefficient toilets with 3.5/2 ltr/flush. Unfortunately the manufacturer doesn't provide these toilets for disabled restrooms. So in disabled restrooms common toilets with 6/3 ltr/flush were installed. Is it allowed to exclude the disabled restrooms from the calculation? If not, is it possible to create a separate fixture group assuming hat e.g. 5 % of employees are handicapped?
I don't think you can exclude them. A separate fixture group is the way to go, but you cannot base it on an assumption of the number of employees that are handicapped unless there is some way to prohibit non-handicapped people from using them. (Some people who are not handicapped prefer using these toilets for various reasons, while others do not, so they will likely get used just as any other toilet in the project.)
I think the best you can do is take the total number of toilets in the project (by gender) and assign a percentage to the separate fixture group for the number of handicapped toilets divided by the total number of toilets. (Ex. 10 toilets total, 2 of which are handicapped accessible. Therefore 2/10 = 20% of building users use that fixture.)