The have published a series of guides called "Building for Everyone: A Universal Design Approach." This series provides a comprehensive best practice guide for how to design, build, and manage spaces so they may be easily accessible for all people.
Section five, "Sanitary Facilities" provides recommendations for unisex and single sex toilets, showers, and changing areas, and more detailed issues including grab rails, dispensers, heating, lighting, surfaces, and waste disposal.
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