accessibility standards for Federal outdoor developed areas 53 may be constructed of a number of different types of materials. Some of these materials, such as heavy timbers, may be quite thick and must allow for knee and toe clearance under the table at the wheelchair spaces. In addition to the clear ground space for each wheelchair space, a clear ground space 36 inches wide must be provided on all usable sides of a table. This allows a person using a mobility device to maneuver around all usable sides of the table. The clear ground space is measured from the back edge of the benches. Fire Rings, Grills, Fireplaces, andWoodstoves [10112, 10113, and 10115] A minimum of 48 by 48 inches of clear ground space must be provided on all usable sides of fire rings, grills, fireplaces, and woodstoves. The usable sides of these elements are the sides that can be used for building a fire or for cooking. All sides of fire rings and grills are generally usable, unless a wall or other struc- ture on a side renders that side unusable. At least 48 inches of clear ground space must be provided around the entire fire ring or grill (figure 19). The front sides of fireplaces and woodstoves are generally the usable sides. 48" ALL AROUND 2% TO 5% MAX SLOPE IN ALL (380 TO 865 mm) 15" TO 34" (1220 mm) DIRECTIONS Figure 19—Requirements for clear ground space at a pedestal grill.