To achieve this, minimum separation distances should be maintained between houses, and in particular, between habitable rooms. Habitable rooms include living rooms, bedrooms, studies and kitchens. They do not include halls, stair landings, passageways and utility rooms. Where two habitable rooms face each other such that direct overlooking is physically possible, the windows should be 22 metres apart. Where a window in a habitable room faces a blank wall, the height of which exceeds the top of that window, there should be a distance measuring a minimum of 13 metres between them. In the case of a kitchen window, these standards may be relaxed provided suitable screening is in place. These standards apply on flat ground.