The nursing home must ensure that minimum usable room space exclusive of toilet rooms, closets, lockers, wardrobes, must:

(1) In existing facilities, be at least eighty square feet per bed in each multibed room and at least one hundred square feet for each single bed room;

(2) In a new building or addition, be one-hundred and ten square feet per bed in multibed rooms, and one-hundred square feet in single bed rooms;

(3) In new construction, ensure that the minimum usable room space is also exclusive of vestibules; and

(4) For exceptions to room size requirements refer to WAC 388-97-2180.