CITY OF SPOKANE DEPARTMENT OF ENGINEERING SERVICES DESIGN STANDARDS FEBRUARY, 2007 with edits to Chapter 3 JANUARY, 2021 CITY OF SPOKANE ENGINEERING SERVICES DESIGN STANDARDS TABLE OF CONTENTS 1.0 OVERVIEW........................................................................................................... 1-1 1.1 Purpose and Scope........................................................................................................1-1 1.2 Definitions ......................................................................................................................1-1 1.3 References.....................................................................................................................1-2 1.4 Variance Requests.........................................................................................................1-3 1.5 Environmental Checklist.................................................................................................1-3 1.6 Design Coordination/Technical Assistance....................................................................1-3 1.7 Permits and Licenses.....................................................................................................1-4 1.8 Material Acceptance.......................................................................................................1-4 1.9 Amendments; Process and Authority.............................................................................1-4 2.0 DEVELOPER/CONSULTANT SERVICES ........................................................... 2-1 2.1 Definitions ......................................................................................................................2-1 2.2 Preliminary Procedures..................................................................................................2-1 2.3 Design Review Submittals..............................................................................................2-1 2.4 Penalties ........................................................................................................................2-6 3.0 STREETS, ALLEYS, BIKEWAYS and SIDEWALKS https://static.spokanecity.org/documents/projects/street-design-standards-update/spokane- design-standards-v13-2020-11-03.pdf City of Spokane Design Standards TABLE OF CONTENTS January 2021 Page i 3.0 STREETS, ALLEYS, BIKEWAYS and SIDEWALKS https://static.spokanecity.org/documents/projects/street-design-standards-update/spokane- design-standards-v13-2020-11-03.pdf 4.0 SANITARY SEWERS ........................................................................................... 4-1 4.1 Definitions ......................................................................................................................4-1 4.2 Public Sewers.................................................................................................................4-3 4.2-1 Pipe Sizes ..............................................................................................................4-3 4.2-2 Pipe Slopes ............................................................................................................4-4 4.2-3 Pipe Depth..............................................................................................................4-4 4.2-4 Roughness Coefficient ...........................................................................................4-5 4.2-5 Horizontal Alignment ..............................................................................................4-5 4.2-6 Vertical Alignment ..................................................................................................4-5 4.2-7 Manholes................................................................................................................4-5 4.2-8 Temporary Manholes .............................................................................................4-5 4.2-9 Combined Sewers ..................................................................................................4-6 4.2-10 Separation of Sewers and Other Utilities .............................................................4-6 4.2-11 Easements ...........................................................................................................4-6 4.3 Side Sewers ...................................................................................................................4-6 4.3-1 Pipe Size and Alignment ........................................................................................4-6 4.3-2 Pipe Depth..............................................................................................................4-6 4.3-3 Connection to Manholes and Catch Basins ...........................................................4-6 4.3-4 Connection to Public Sewer Main ..........................................................................4-6 4.3-5 Cleanouts ...............................................................................................................4-6 4.4 Private Sewers ...............................................................................................................4-7 4.5 Tables and Figures.........................................................................................................4-8 5.0 WASTEWATER PUMP STATIONS...................................................................... 5-1 5.1 Definitions ......................................................................................................................5-1 5.2 General Requirements ...................................................................................................5-2 5.2-1 Minimal Pump Station Design Requirements.........................................................5-2 5.3 Site Selection and Plan ..................................................................................................5-3 5.3-1 Location..................................................................................................................5-3 5.3-2 Security/Equipment Protection ...............................................................................5-3 5.3-3 Temporary Lift Stations ..........................................................................................5-3 5.4 Station Access................................................................................................................5-4 5.5 Wet Pit/Dry Pit Station Design........................................................................................5-4 5.5-1 Wet Pit Layout ........................................................................................................5-4 TABLE OF CONTENTS City of Spokane Design Standards Page ii January 2021 5.5-2 Wet Pit Storage Volume .........................................................................................5-4 5.5-3 Wet Pit Detention Time ..........................................................................................5-5 5.5-4 Odor Control...........................................................................................................5-5 5.5-5 Dry Pit Design ........................................................................................................5-5 5.6 Submersible Station Design...........................................................................................5-5 5.7 Pumps ............................................................................................................................5-6 5.7-1 Cycle Time .............................................................................................................5-6 5.7-2 Pump Control Staging ............................................................................................5-6 5.7-3 Number of Pumps ..................................................................................................5-6 5.7-4 Net Positive Suction Head (NPSH) ........................................................................5-7 5.7-5 Head Loss Curves..................................................................................................5-7 5.7-6 Additional Pump Design Parameters .....................................................................5-7 5.7-7 Bypass Piping.........................................................................................................5-8 5.8 Force Mains....................................................................................................................5-8 5.9 Power Supply .................................................................................................................5-9 5.10 Emergency Operation ..................................................................................................5-9 5.10-1 Emergency Power ................................................................................................5-9 5.10-2 Emergency Storage..............................................................................................5-9 5.11 Miscellaneous Equipment and Appurtenances ............................................................5-9 5.11-1 Screens, Racks and Traps ...................................................................................5-9 5.11-2 Controls/Flow Monitoring......................................................................................5-9 5.11-3 Valves.................................................................................................................5-10 5.11-4 Ventilation...........................................................................................................5-10