Appeal 34947

PFC B105.2

The minimum fire flow and flow duration for one- and two-family dwellings having a fire-flow area that does not exceed 3,600 square feet shall be 1,000 gpm at 20 psi for 1 hour. For one and two-family dwellings exceeding 3,600 square feet, the required fire flow shall be as specified in PFC Appendix B, Table B105.1(1).

Provide alternatives to fire flow requirements on the site as the proposed subdivision will have duplexes on each lot less than 3,600 square feet in area.

Each duplex (each lot) will be constructed with residential sprinklers in order to reduce the allowed fire flow to 500 gpm at 20psi for 1 hour. The owner is also proposing a 5-foot wide hardscape buffer around each duplex unit as the existing hydrant fire flow for the closest hydrant (NE corner of the site on NE Klickitat Street) is 400 gpm at 20 psi.

In discussions Portland Water Bureau and Fire Bureau, each lot will have water services to the existing water main in NE Klickitat Street. A public water main extension or services to the water main in NE Fargo Street are not allowed per PWB. The other option for fire flow is to provide a private water main from the existing water main in NE Fargo through the 20-wide public pedestrian right-of-way. The private water main would also require a private fire hydrant and a back flow preventor. Yearly maintenance would be required for this private water main and hydrant as is cost prohibitive. PWB has determined that a public main extension from the existing water main in NE Klickitat Street into the proposed private street for the subdivision is not feasible due to the existing water main size (4"). Therefore, the applicant is proposing fire sprinklers (as allowed by code) to reduce the required fire flow to 500 gpm at 20psi. The owner is also proposing a 5-foot wide hardscape buffer around each proposed duplex to provide for additional fire safety measures as the available fire flow at the closest hydrant (NE corner of the site) along NE Klickitat only has 400 gpm at 20 psi. The combination of fire suppression systems (sprinklers) in each duplex and a hardscape buffer around each duplex will provide equivalent fire protection to what the code requires.