2This comprehensive code comprises all building, plumbing, mechanical, fuel gas and electrical requirements for one- and two-family dwellings and townhouses up to three stories. The IRC contains many important changes such as: An updated seismic map reflects the most conservative Seismic Design Category (SDC) based on any soil type and a new map reflects less conservative SDCs when Site Class A, B or D is applicable. The townhouse separation provisions now include options for using two separate fire-resistant-rated walls or a common wall. An emergency escape and rescue opening is no longer required in basement sleeping rooms where the dwelling has an automatic fire sprinkler system and the basement has a second means of egress or an emergency escape opening. The exemption for interconnection of smoke alarms in existing areas has been deleted. New girder/header tables have been revised to incorporate the use of #2 Southern Pine in lieu of #1 Southern Pine. New tables address alternative wood stud heights and the required number of full height studs in high wind areas.