Section R313 of the International Residential Code is amended by adding the following section:

Section R313.4. Approved automatic sprinkler systems shall be installed in any structure containing five or more townhouse units. A voluntarily installed automatic fire sprinkler system in townhouses or one- and two-family dwellings shall be in accordance with Appendix R, Dwelling Unit Fire Sprinkler Systems found in WAC 51-51-60105.