In order to accommodate a wide variety of spaces, including open office plans, please use the following calculation method: All areas within 15 FT of the perimeter wall are to be considered perimeter areas. All areas greater than 15 FT from the perimeter wall are to be considered non-perimeter areas. For rooms that are intersected by a line offset 15 FT from the perimer wall, the area of the entire room can be included as perimeter area if 75% or more of the room is within 15 FT of the perimeter wall. For such rooms, the designer must decide whether perimeter or non-perimeter controls are more appropriate for the remaining 25% of the room. Please include project assumptions in the credit. Applicable internationally.