We’ve seen an uptick in applications for 4-story residential structures that are classified as R-3 (single-family or duplex) because of increased demand for density and additional housing in the city. The Seattle Residential Code (SRC) currently only applies to buildings that are 3 stories or less, so these projects are reviewed under the Seattle Building Code (SBC). According to the SBC, a residential building with 4 stories must be protected with sprinklers complying with NFPA 13R, not NFPA 13D system commonly applicable in SRC buildings.
Our technical leads have determined the allowance of a NFPA 13D system may be acceptable to be used in these 4 story structures, with an approved Code Modification Request after consultation with the Seattle Fire Department. This change in policy is based on the understanding that for these types of buildings, the NFPA 13D system provides a cost-effective solution to life safety and improves the chance for occupants to escape or be evacuated in case of a fire. The allowance of the NFPA 13D systems versus the NFPA 13R in these structures helps reduce the cost of built-in fire protection, at the same time mitigates the more severe impacts such as loss of residential structures and occupant displacement resulting from fire.
If you have a project under review and would like to pursue this option, please contact your assigned Ordinance reviewer for more information.
For general information contact:
Amy Barnett
(206) 684-3965
amy.barnett@seattle.gov
Mariko Blessing
Mariko.blessing@seattle.gov