Figure 30(b) Alternate Stalls. Two alternate stalls are permitted for alterations only; one alternate stall is required to be 36 inches (915 mm) wide. The other alternate stall is required to be a minimum of 48 inches (1220 mm) wide. In either alternate stall, if a wall mounted water closet is used, the depth of the stall is required to be a minimum of 66 inches (1675 mm). If a floor mounted water closet is used, the depth of the stall is required to be a minimum of 69 inches (1745 mm). The 36 inches (915 mm) wide stall shall have parallel grab bars on the side walls. The 48 inches (1220 mm) minimum stall shall have a grab bar behind the water closet and one on the side wall next to the water closet. Grab bars are mounted 33-36 inches (840-915 mm) above the finish floor. In both alternate stalls, the centerline of the water closet is 18 inches (455 mm) from a side wall. In both alternate stalls, the grab bars along the sides of the water closets shall extend at least 54 inches (1370 mm) from the back wall and shall have one end no farther than 12 inches (305 mm) from the back wall.