Encourages the use and reuse of existing buildings. This code covers repair, alteration, addition and change of occupancy for existing buildings. and historic buildings, while achieving appropriate levels of safety without requiring full compliance with the new construction requirements contained in the other I-Codes. Key changes in the 2021 IEBC include: For storm shelters, the required occupant capacity is now limited to the total occupant load of the classrooms, vocational rooms and offices in the school while the maximum distance of travel was deleted. When significant portions of a building�s exterior wall coverings or exterior wall envelope are added or replaced, they must comply with the requirements of Chapters 14 and 26 of the IBC. Snow loads must be addressed during repair of substantial structural damage regardless of whether the damage was a result of snow. Additions, Level 3 alterations and Changes of occupancy in Educational occupancies are now required to meet the enhanced classroom acoustic requirements of Section 808 of ICC A117.1. Additional equipment may be added to a roof without a full structural analysis when the equipment weighs less than 400 pounds and is less than 10 percent of the total roof dead load. With a change of occupancy, a seismic analysis is required for a Group S or Group U occupancy changing to a new occupancy. Furniture, such as office cubicles, reception desks or smaller bookcases, are exempt from a permit and not intended to be a Level 2 alteration. Sprinkler requirements for Level 2 and Level 3 alterations are revised for higher hazard areas.