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May 2025 4 City of Pleasanton <br />5859 Owens Drive <br />Fire Flow Analysis <br />INDIVIDUAL HYDRANT LIMITATIONS <br />The fire flow analysis in this report includes results simulated by the hydraulic model <br />along distribution mains and does not account for individual hydrant limitations. <br />The hydraulic model predicts the capability of the distribution system to deliver water at <br />the selected hydrant “location” and does not limit the flow based on the individual <br />hydrant capacity nor lateral limitation. Most hydrants with 4-inch connections typically <br />extract water at a rate of 1,500-2,000 gpm depending on their size, length, and hydrant <br />type. Fire engine trucks can also impact water flow based on the size of their water <br />tank and pump. Fire marshals indicate that individual fire engines can pump up to 2,000 <br />gpm. <br />When the required fire flow water extraction value exceeds 1,500-2,000 gpm, multiple <br />hydrants become necessary to meet the demand. There is a maximum spacing <br />requirement between hydrants that is based on the prescribed flow, where a higher flow <br />requirement (industrial/commercial/institutional) necessitates more hydrants with <br />reduced spacing between them. Maximum hydrant spacing is documented in the <br />International Fire Code (ICC IFC-2021). <br />CONCLUSIONS AND RECOMMENDATIONS <br />The hydrant closest to 5859 Owens Drive was able to supply the commercial fire flow <br />requirement of 2,500 gpm for 2 hours while maintaining a residual pressure above 20 <br />psi. The distribution system can supply up to 5,408 gpm while maintaining a residual <br />pressure of 20 psi, however pipeline velocities will exceed the 10 ft/s criteria. Figure 1 <br />documents the available fire flows under each scenario and also identifies the pipe that <br />exceeds the maximum velocity constraint of 10 ft/s during a 2,500 gpm (Scenario 2) <br />and 5,408 gpm (Scenario 3) fire flow. The maximum available fire flow while <br />maintaining a 20-psi residual pressure and pipeline velocities under 10 ft/s is 2,447 <br />gpm. <br />It should be noted that since the fire flow requirement is larger than a single fire <br />hydrant’s limitation of 1,500-2,000 gpm, multiple hydrants are needed to supply this fire <br />flow requirement. <br />Sincerely, <br />AKEL ENGINEERING GROUP, INC. <br />Tony Akel, P.E. <br />Senior Principal