Stacks and services should be located outside of the grey shaded clear access zones shown for both Category 2 and Category 3 bathrooms to ensure that a wheelchair is able to use the bathroom effectively. In Category 3 wheelchair accessible bathrooms and WC/ Cloakrooms, the access zone extends to the rear of the cistern to enable assistive devices to move up to the surface of the wall. Wheelchair adaptable layouts will need to be capable of simple alteration to also meet this requirement.