Sewerage Manual Part 1 v4 (with Eurocodes) - deletion of SM3

1 Part 1 Sewerage Manual (with Eurocodes incorporated) contents related to Eurocodes highlighted in green Key Planning Issues and Gravity Collection system Third Edition, May 2013 drainage SERVICES DEPARTMENT Government of the Hong Kong Special Administrative Region 2 CONTENTS 1. INTRODUCTION SCOPE ABBREVIATIONS DESIGN STANDARDS Planning, Investigation and Materials of Sewerage system Sewerage Structures REQUIREMENT OF SUSTAINABILITY HARBOURFRONT ENHANCEMENT REQUIREMENTS 2.

2 Sewerage IN HONG KONG THE HONG KONG SITUATION 3. GENERAL PLANNING AND INVESTIGATION INTRODUCTION INFORMATION FOR system PLANNING Previous Studies Planning of Sewerage Catchment Areas Maps, Town Plans and drainage Records Location of Utilities IMPLEMENTATION PROGRAMMES DESIGN LIFE LAND ENVIRONMENTAL CONSIDERATIONS Environmental Standard and Legislative Control Environmental Assessment Mitigating Measures SITE INVESTIGATIONS HYDROGRAPHIC STUDIES 3 4.

3 FLOW AND LOAD ESTIMATION FLOW ESTIMATION LOAD ESTIMATION Loads Existing Data Sources Load Estimation Unit Load Factors 5. DESIGN OF SEWERS DESIGN CRITERIA Capacity (gravity pipelines) Minimum Velocity Maximum Velocity Levels Alignment Minimum Pipes Size Septicity Large Deep Sewer Planting in the Vicinity of Sewers Sewerage Works in Conjunction with Roadworks HYDRAULICS OF GRAVITY PIPELINES Basic Equations Local Losses Water Surface Profiles Design Tools PIPELINE MATERIALS Choice of pipe Material Corrosion Protection pipe Joints 6.

4 STRUCTURAL DESIGN OF GRAVITY PIPELINES INTRODUCTION DESIGN PROCEDURE FOR RIGID PIPES FILL LOADS Narrow trench condition Embankment condition SUPERIMPOSED LOADS 4 WATER LOAD BEDDING FACTORS DESIGN STRENGTH EFFECT OF VARIATION IN pipe OUTSIDE DIAMETERS 7. MANHOLES AND SPECIAL STRUCTURES MANHOLES Location Access Openings Access Shafts Working Chambers Intermediate Platform Inverts and Benching Covers Step-irons and Ladders Backdrop Manholes INVERTED SIPHONS MUTLIPLE pipe CROSSINGS Introduction Number of pipe Crossings and Size Control Structures Level of pipe Crossings DRY WEATHER FLOW INTERCEPTION Pollution Sources Abatement of Pollution Problems Design Considerations for DWF interceptors 8.

5 OPERATION AND MAINTENANCE OF Sewerage SYSTEMS GENERAL Maintenance Objectives TAKING OVER OF COMPLETED WORKS Procedures for Handing Over Handing Over in Dry Conditions Documents to be Submitted INSPECTION AND GENERAL MAINTENANCE OPERATIONS 5 Inspection Programmes Closed Circuit Television Surveys Inspection within Red Routes, Pink Routes and Expressways Inspection of Drains behind Slopes Desilting Programmes Methods for Desilting/Cleansing Sewerage REHABILITATION pipe Replacement Trenchless Methods for Repairing Pipes DRY WEATHER FLOW INTERCEPTORS Inspection Cleansing INVERTED SIPHONS Flushing Inspection and Desilting CONNECTIONS TO EXISTING Sewerage system Existing Capacity Terminal Manholes Provision of Manholes drainage RECORDS SAFETY PROCEDURES General Working

6 In Sewers Safety Requirements for Working in Confined Space Working under Adverse Weather Conditions and During Flooding 9. TUNNEL SEWERS GENERAL TUNNEL SEWERS Introduction Flow Control in Tunnel Sewers Monitoring of Hydraulic Performance Inspections Maintenance Potential Problems and Remedial Actions DEEP SEWAGE TUNNEL system Introduction Choice of Deep Sewage Tunnel system Tunnel Construction Methods 6

7 Site Investigation (SI) Land Requirements Protection of Deep Sewage Tunnels Geotechnical Control for Tunnel Works Sizing of Deep Sewage Tunnels Gradient of Deep Sewage Tunnels Operation and Maintenance Considerations 10. TRENCHLESS CONSTRUCTION INTRODUCTION NON-MAN-ENTRY TYPE Slurry Pressure Balance Method Earth Pressure Balance (EPB) Method MAN-ENTRY TYPE Heading Method Hand-dug Tunnel Method MAJOR CONSIDERATIONS Planning & Design Stage Construction Stage Environmental Issue Cost Consideration REFERENCES TABLES LIST OF TABLES TABLES FIGURES LIST OF FIGURES FIGURES 7 1.

8 INTRODUCTION SCOPE Part 1 of this Manual offers guidance on the planning, design, construction, operation and maintenance of public gravity Sewerage systems in Hong Kong. For guidance on sewage pumping stations & rising mains, please refer to Part 2 of this Manual . DSD has also promulgated Practice Note No. 1/2011 Design Checklists on Operation & Maintenance Requirements and Practice Note No. 3/2010 Design Consideration for Large Deep Gravity Sewers which can be reached on DSD s internet home page : Readers are requested to go through the Practice Notes, or their latest versions, when designing sewers to ensure that the final products satisfy the operation and maintenance requirements of the maintenance authority.

9 ABBREVIATIONS The following abbreviations are used throughout this Part 1: ADWF Average Dry Weather Flow ArchSD Architectural Services Department APCO Air Pollution Control Ordinance BD Buildings Department BS British Standard BSI British Standards Institution BS EN European Standards adopted as British Standards CEDD Civil Engineering and Development Department CIRIA Construction Industry Research and Information Association DSD drainage Services Department DWF Dry

10 Weather Flow DWFI Dry Weather Flow Interceptor E&M Electrical & Mechanical EMSD Electrical and Mechanical Services Department EC Eurocodes ( European Standards EN1990 to EN1999) EN European Standard EPD Environmental Protection Department EIAO Environmental Impact Assessment Ordinance FRP Fibreglass Reinforced Plastic GEO Geotechnical Engineering Office GRP Glass Reinforced Plastic HATS Harbour Area Treatment Scheme HDPE High Density Polyethylene HyD Highways Department ISO International Organisation for Standardisation IWA International Water Association MDPE Medium Density Polyethylene NCO Noise