ESD 160 - Design Manual Vol.2.pdf

Engineering Department

Design Manual Volume Two

Facility Design Guide

ESD-160 October 2007

ESD 160 Design Manual

Volume Two: Facility Design Guide

REVISION LOG

Item (Table of Contents, Chapter, or Appendix)

Rev.

No.

Date Entered

Initials

Chapter 2 001 9/21/2012 MEC

Instructions:

After revising your ESD as described in the revision transmittal, enter the item revised, date entered, and initial above.

SDCWA

San Diego County Water Authority Engineering Department

ESD 160

Design Manual: Volume Two

Facility Design Guide

October 2007

Copyright © 2000 The San Diego County Water Authority. The information provided herein is for the convenience and use of the San Diego County Water Authority and its member agencies. Any use of the information by any entity other than the San Diego County Water Authority is at such entity’s own risk, and the San Diego County Water Authority assumes no liability for such use.

Prepared by: Jacobs Engineering, Edited by: Jacobs Engineering Reviewed by: Water Authority Departments

Approved by: Michael T. Stift, Director of Engineering

For additional copies, call Ron Hartnett at 858-522-6878 or vist the Engineering Department offices at the Water Authority, San Diego

SDCWA Design Manual Validation

FACILITY DESIGN GUIDE

October 2007 ii REV 00

ESD 160 Design Manual: Volume Two (Facility Design Guide)

Introduction and use

The ESD 160 Design Manual: Volume Two (Facility Design Guide) documents the practices and standards that are used for design of projects at the San Diego County Water Authority.

Personnel involved in design of Water Authority projects shall adhere to the practices and procedures described in this document.

Engineering management shall be responsible for enforcement of these practices in their respective design management of projects.

Revisions and maintenance

This manual is intended to be a living document that evolves to meet changing San Diego County Water Authority needs.

Engineering management continuously monitors the design activities for its various projects and will identify refinements to or additional practices and procedures.

The Engineering Department is responsible for maintaining this manual, for revising chapters as practices and procedures change, and for issuing manuals and revisions to appropriate personnel.

Users may suggest changes or additions to this document by submitting a Change Request Form to the Manager of the Administration and Controls Group. This form is available at the Water Authority server in the directory I:\0130.00\Resources\Forms&Templates. Comments will be reviewed, and if changes are instituted, the manual will be revised and revisions will be distributed to manual users.

Personnel entrusted with this manual are responsible for maintaining it in a current and update condition as revised chapters are published.

Validation The San Diego County Water Authority Engineering ESD 160 Design

Manual: Volume Two (Facility Design Guide) is hereby accepted and approved.

Michael T. Stift, Director of Engineering San Diego County Water Authority

SDCWA Design Manual TABLE OF CONTENTS

October 2007 iii REV 00

Table of Contents

Chapter 1 Introduction

Chapter 2 Transmission Pipelines

Chapter 3 Pump Stations

Chapter 4 Flow Control Facilities

Chapter 5 Seismic Design Criteria

Chapter 6 SCADA and Instrumentation & Control

Appendix A Supplemental Seismic Design Criteria for Water Facilities

SDCWA Design Manual Chapter 1. Introduction

October 2007 Chapter 1 REV 00

Chapter 1 Introduction

Overview

Purpose This chapter presents an introduction to the purpose, use, and organ-ization of the Facility Design Guide.

Topics This chapter is composed of the following topics:

CHAPTER 1 INTRODUCTION .................................................................................................... 1-1

1.1 FACILITY DESIGN GUIDE IS PART OF THE DESIGN MANUAL ....................................................... 1-1

1.1.1 FACILITY DESIGN GUIDE IS THE SECOND VOLUME OF THE DESIGN MANUAL ........................... 1-1

1.1.2 PURPOSE OF THE FACILITY DESIGN GUIDE ........................................................................... 1-1

1.1.3 DESIGN MANAGER ............................................................................................................... 1-2

1.1.4 INCONSISTENCIES ................................................................................................................ 1-2

1.1.5 REFERENCE TO THE DESIGN CONTRACTOR GUIDE ................................................................ 1-2

1.1.6 HYPERLINKS ........................................................................................................................ 1-2

1.2 USE OF THE FACILITY DESIGN GUIDE ....................................................................................... 1-3

1.2.1 USE BY DESIGN CONTRACTORS ........................................................................................... 1-3

1.2.2 DEVIATIONS FROM THE FACILITY DESIGN GUIDE ................................................................... 1-3

1.3 ORGANIZATION OF THE FACILITY DESIGN GUIDE ...................................................................... 1-4

1.3.1 SIX CHAPTERS IN THE FACILITY DESIGN GUIDE ..................................................................... 1-4

1.3.2 ENGINEERING DISCIPLINES ................................................................................................... 1-4

1.3.3 CHAPTER LAYOUT ................................................................................................................ 1-5

FIGURE 1-1: CHAPTER LAYOUT ....................................................................................................... 1-5

October 2007 Chapter 1 REV 00

This page intentionally left blank

October 2007 1-1 REV 00

1.1 Facility Design Guide is Part of the Design Manual

1.1.1 Facility Design Guide is the Second Volume of the Design Manual

1. The Facility Design Guide is the second volume of a two-volume Design Manual that consists of the following:

1.1. VOLUME 1 – DESIGN CONTRACTOR GUIDE: Provides de-

sign management and administrative procedures, including re-quirements for design schedule and budget control, reporting, QA/QC program, deliverables at different levels of design, con-struction cost estimating, records management, and other top-ics. The Design Contractor Guide also describes the relation-ships between the Design Contractor and the Design Manager.

1.2. VOLUME 2 – FACILITY DESIGN GUIDE: Provides design re-

quirements for different types of facilities, including pipelines, pump stations, and flow control facilities.

1.1.2 Purpose of the Facility Design Guide

1. The Facility Design Guide provides general technical guidelines that shall be followed by Design Contractors selected by the Water Au-thority to prepare engineering reports, construction drawings, speci-fications, and other documents for construction of the facilities nec-essary to implement the CIP and/or to provide services during other project phases. The design of these facilities shall be based on:

1.1. Applicable codes and standards.

1.2. The project-specific scope of work.

1.3. Criteria presented in the project Predesign or Planning Study

Report

1.4. The Water Authority Design Manual

1.5. Documents and other standard manuals referenced in the De-sign Manual

2. The Facility Design Guide is intended to ensure uniformity of design concepts, formats, methodologies, procedures, construction mater-ials, types of equipment, and quality of work products produced for the Water Authority.

3. The Design Contractor shall take full responsibility for the designs produced. This responsibility of the Design Contractor is in no way diluted or absolved by the Design Manual.

October 2007 1-2 REV 00

1.1.3 Design Manager

1. A Design Manager will be assigned to each project and will be the Design Contractor’s point of contact with the Water Authority for the project.

2. The Design Manager will administer the Contract to ensure compli-ance with provisions of the Contract and the Design Manual.

1.1.4 Inconsistencies

1. Inconsistencies may exist between the Design Manual, Predesign Report, project scope of work, and other Water Authority docu-ments. Resolution of such inconsistencies, if any, is discussed in the Design Contractor Guide, Chapter 1, Paragraph 1.4.

1.1.5 Reference to the Design Con-tractor Guide

1. Refer to the Design Contractor Guide for additional information and requirements.

1.1.6 Hyperlinks

1. The Facility Design Guide chapter tables of contents are hyper-linked. Other references are not hyperlinked.

October 2007 1-3 REV 00

1.2 Use of the Facility Design Guide

1.2.1 Use by Design Contractors

1. The Facility Design Guide identifies general design details and ap-proaches to be used for design of Water Authority facilities. The Facility Design Guide is intended to promote uniformity in key de-sign concepts and equipment types.

2. The Facility Design Guide does not limit the responsibility of the Design Contractor, but assists in providing professionally sound, ef-ficient, uniform, and workable facilities, including pipelines, flow control facilities, pump stations, and other facilities. Not all aspects of design are addressed in the Facility Design Guide, and, in all cases, the Design Contractor must use good engineering judgment and practices.

3. The Design Contractor shall incorporate the design criteria pre-sented in the Facility Design Guide into the overall facility design.

Sometimes the criteria are given in ranges, in which case the final criteria shall be selected within the indicated range. In other cases, specific criteria have been given and shall be followed by the De-sign Contractor. However, the Design Contractor may request changes to the criteria presented in the Facility Design Guide to suit the specifics of the project. Refer to Section 1.2.2 below for more information.

4. If documents referenced in the Facility Design Guide have been updated since the original writing of the Facility Design Guide, the Design Contractor shall use the documents current at the time the design is initiated. Such document use shall be referenced in writ-ing to the Design Manager.

1.2.2 Deviations from the Facility De-sign Guide

1. If the Design Contractor desires to deviate from the criteria pre-sented in the Facility Design Guide, the Design Contractor shall propose such modifications, with justifications, to the Design Man-ager as described in Design Manual, Volume 1 - Design Contractor Guide.

October 2007 1-4 REV 00

1.3 Organization of the Facility Design Guide

1.3.1 Six Chapters in the Facility De-sign Guide

1. The Facility Design Guide is presented in six chapters as follows:

1.1. Chapter 1 – Introduction

Describes the purpose, use, and organization of the Facility De-sign Guide. It also describes how the Facility Design Guide coor-dinates with the Design Contractor Guide and other Water Au-thority manuals and documents.

1.2. Chapter 2 – Transmission Pipelines

Describes requirements for design of Water Authority transmis-sion pipelines, including materials, methods of jointing, inline valves and flow meters, venting and draining, instrumentation and control and other appurtenances.

1.3. Chapter 3 – Pump Stations

Describes requirements for design of Water Authority pump sta-tions, including pump types and selection, control valves, flow meters, buildings and other structures, instrumentation and con-trol, and other appurtenances.

1.4. Chapter 4 – Flow Control Facilities

Describes requirements for Water Authority above-ground and below-ground flow control facilities, including flow meter types and requirements, control valve types and requirements, build-ings, underground vaults, instrumentation and control, and other appurtenances.

1.5. Chapter 5 – Seismic Design Criteria

Describes seismic design criteria applicable to Water Authority pipelines, flow control facilities, pump stations, and other facili-ties.

1.6. Chapter 6 – SCADA and Instrumentation & Control

Describes SCADA and Instrumentation & Control requirements applicable to Water Authority pipelines, flow control facilities, pump stations, and other facilities.

1.3.2 Engineering Disciplines

1. Where appropriate, Chapters 2, 3, 4, 5 and 6 include related guide-lines for the disciplines listed below. Other disciplines may be ad-dressed as well.

1.1. Civil

1.2. Structural

1.3. Architectural

1.4. Landscaping and irrigation

1.5. Electrical

1.6. Instrumentation and Control

1.7. SCADA (Supervisory Control and Data Acquisition)

1.8. Mechanical � Equipment, piping and plumbing, and HVAC

(Heating, Ventilating, and Air Conditioning)

1.9. Hydraulics

1.10. Corrosion

1.11. Miscellaneous

1.3.3 Chapter Layout 1. Each chapter of the Facility Design Guide is composed of sections as illustrated in Figure 1-1.

Figure 1-1: Chapter Layout

2. An overview is provided for each chapter, identifying the specific sections within that chapter. Each section in the chapters is a major chapter topic, and the blocks of information provided within each section are the chapter subtopics.

Chapter Section Topic 3

Section Topic 2

Section Topic 1

October 2007 1-5 REV 00

SDCWA Design Manual Chapter 2. Transmission Pipelines

September 2012 Chapter 2 REV 01

Chapter 2 Transmission Pipelines

Purpose This chapter presents the Water Authority general requirements for design of pipelines and pipeline appurtenances.

Topics This chapter is composed of the following topics:

CHAPTER 2 TRANSMISSION PIPELINES ............................................................................... 2-1

2.1 INTRODUCTION ...................................................................................................................... 2-1

2.1.1 GENERAL ........................................................................................................................... 2-1

2.1.2 STANDARDS AND GUIDELINES ............................................................................................. 2-1

2.2 PIPELINE ALIGNMENT ............................................................................................................ 2-4

2.2.1 HORIZONTAL ALIGNMENT .................................................................................................... 2-4

2.2.2 VERTICAL ALIGNMENT ........................................................................................................ 2-4

2.2.3 HORIZONTAL AND VERTICAL CURVES .................................................................................. 2-5

2.2.4 UTILITY SEPARATIONS ........................................................................................................ 2-6

2.2.5 PROPERTY REQUIREMENTS ................................................................................................ 2-6

2.3 PIPE MATERIALS, LININGS, AND COATINGS ............................................................................. 2-8

2.3.1 PIPE MATERIALS ................................................................................................................ 2-8

2.3.2 PIPE LININGS AND COATINGS .............................................................................................. 2-9

2.4 PIPE FITTINGS, JOINTING, AND SPECIAL CONNECTIONS ......................................................... 2-11

2.4.1 PIPE FITTINGS .................................................................................................................. 2-11

2.4.2 PIPE JOINTING / COUPLING ............................................................................................... 2-11

2.4.3 PIPE SPECIAL CONNECTIONS ............................................................................................ 2-14

2.5 PIPELINE APPURTENANCES ................................................................................................. 2-15

2.5.1 GENERAL ......................................................................................................................... 2-15

2.5.2 VALVES ........................................................................................................................... 2-15

2.5.3 OTHER APPURTENANCES ................................................................................................. 2-18

2.6 PIPE TRENCH ...................................................................................................................... 2-22

2.6.1 GENERAL ......................................................................................................................... 2-22

2.6.2 PIPE TRENCH WIDTH ........................................................................................................ 2-22

2.6.3 PIPE TRENCH DEPTH ........................................................................................................ 2-22

September 2012 Chapter 2 REV 01

2.6.4 CONSTRUCTION ISSUES ................................................................................................... 2-23

2.7 PIPELINE DESIGN ................................................................................................................ 2-25

2.7.1 GENERAL ........................................................................................................................ 2-25

2.7.2 PIPE WALL THICKNESS .................................................................................................... 2-25

2.7.3 PIPE SIZE ........................................................................................................................ 2-29

2.7.4 TRANSIENT ANALYSIS ...................................................................................................... 2-29

2.7.5 THRUST RESTRAINT ......................................................................................................... 2-29

2.7.6 CATHODIC PROTECTION ................................................................................................... 2-31

2.7.7 PIPELINE SUPPORTS ........................................................................................................ 2-36

2.7.8 PIPELINE ENCASEMENT .................................................................................................... 2-37

2.8 SPECIAL CROSSINGS .......................................................................................................... 2-38

2.8.1 GENERAL ........................................................................................................................ 2-38

2.8.2 PERMANENT CROSSINGS ................................................................................................. 2-38

2.8.3 TEMPORARY CROSSINGS ................................................................................................. 2-39

2.9 TRENCHLESS CONSTRUCTION ............................................................................................. 2-40

2.9.1 GENERAL ........................................................................................................................ 2-40

2.9.2 TUNNELING ..................................................................................................................... 2-41

2.9.3 TUNNEL PORTAL .............................................................................................................. 2-43

2.10 INSTRUMENTATION AND CONTROL ....................................................................................... 2-44

2.10.1 GENERAL ........................................................................................................................ 2-44

2.10.2 VALVES AND OTHER EQUIPMENT ...................................................................................... 2-44

Attachment 2-1: Cover Page of the Water Authority General Conditions and Standard Specifications .............................................................................................. 2-46

Attachment 2-2: Cover Page of the Water Authority Standard Drawings & Standard Details ......................................................................................................... 2-47

Attachment 2-3: Cover Page of the Water Authority Cathodic Protection Guide Drawings ..................................................................................................... 2-48

Attachment 2-4: Cover Page of the Water Authority Electrical/Instrumentation Guide Drawings ...................................................................................................... 2-49

Attachment 2-5: Cover Page of the Water Authority Drafting Manual ................................. 2-50 Attachment 2-6: General Design Criteria for Pipeline Appurtenances ................................ 2-51 Attachment 2-7: Cover Page of San Diego Regional Standard Drawings ........................... 2-53 Attachment 2-8: Cover Page of the Water Authority Engineering Guidelines for Review of Proposed Right-of-Way Encroachments ............................................... 2-54 Attachment 2-9: Cover page of the Water Authority PLC Implementation Standards ........ 2-55

September 2012 2-1 REV 01

2.1 Introduction

2.1.1 General

This chapter outlines the standards that shall be followed in the design and construction of Water Authority pipeline projects. These standards cover the following items:

Pipe alignment (horizontal and vertical).

Pipe materials.

Linings and coatings.

Pipe fittings (wyes, tees, etc.).

Pipe jointing.

Pipe special connections (e.g., connection to other pipes and structures).

Thrust restraint.

Special crossings (e.g., freeways, highways, railroads, etc.)

Pipeline appurtenances including:

o Isolation and control valves, valve actuators, and associated structures.

o Air valve assemblies and associated structures.

o Blowoff and pump well and associated structures.

Pipe hydraulic design and transient flow analysis.

Pipe installation and layout.

Pipe trench (bedding, backfill, etc.).

Trenchless pipe construction.

Pipeline assessment.

Pipeline instrumentation and control (I&C).

2.1.2 Standards and Guidelines

In several sections of this chapter, the Design Contractor is required to use and specify Water Authority Standard Documents including standard specification sections and standard drawings. In all cases, the Design Contractor shall verify the adequacy of these standard documents to the project specifics. The Design Contractor shall review and propose changes to the Water Authority documents, per project needs and shall follow the procedure outlined in Chapters 1 and 14 of the Design Contractor Guide (Design Manual – Volume One; ESD-160) in proposing and requesting changes.

It is to be noted that the Water Authority standards are usually higher than AWWA standards, which are considered by the Water Authority as minimum requirements. Whenever using an AWWA standard, the

September 2012 2-2 REV 01

Design Contractor shall confirm that no higher standard is required by the Water Authority Standard Specifications and/or Drawings.

A. Water Authority Standards and Guidelines

The main Water Authority standards and guidelines for use in pipeline design and construction include:

General Conditions and Standard Specifications (hereinafter referred to as ―GC&SS‖). Refer to Attachment 2-1 for the cover page of the GC&SS.

Standard Drawings & Standard Details (hereinafter referred to as SD&SD). Refer to Attachment 2-2 for the cover page of

SD&SD.

Cathodic Protection Guide Drawings. Refer to Attachment 2- 3 for the cover page of the Cathodic Protection Guide Drawings.

Electrical/Instrumentation Guide Drawings. Refer to Attachment 2-4 for the cover page of the Electrical/Instrumentation Guide Drawings.

B. National Standards and Guidelines

Several national standards and guidelines are available for use in pipeline design and construction including:

Cal-OSHA (California Occupation Safety and Health Administration/Act) standards, as applicable.

C200, AWWA Standard for Steel Water Pipe – 6 In. (150 mm) and Larger.

C203, AWWA Standard for Coal-Tar Protective Coatings and Linings for Steel Water Pipelines – Enamel and Tape – Hot- Applied.

C205, AWWA Standard for Cement-Mortar Protective Lining and Coating for Steel Water Pipe – 4 In. (100 mm) and Larger

– Shop Applied.

C206, AWWA Standard for Field Welding of Steel Water Pipe

C207, AWWA Standard for Steel Pipe Flanges for Waterworks Service – Sizes 4 In. Through 144 In. (100 mm through 3,600 mm).

C208, AWWA Standard for Dimensions for Fabricated Steel Water Pipe Fittings.

C209, AWWA Standard for Cold-Applied Tape Coatings for the Exterior of Special Sections, Connections, and Fittings for Steel Water Pipelines.

C214, AWWA Standard for Tape Coating Systems for the Exterior of Steel Water Pipelines.

September 2012 2-3 REV 01

C215, AWWA Standard for Extruded Polyolefin Coatings for the Exterior of Steel Water Pipelines.

C217, AWWA Standard for Cold-Applied Petrolatum Tape and Petroleum Wax Tape Coatings for the Exterior of Special Sections, Connections, and Fittings for Buried or Submerged Steel Water Pipelines.

C219, AWWA Standard for Bolted, Sleeve-Type Couplings for Plain-End Pipe.

C221, AWWA Standard for Fabricated Steel Mechanical Slip- Type Expansion Joints.

C224, AWWA Standard for Two Layer Nylon-11 Based Polyamide Coating System for Interior and Exterior of Steel Water Pipe, Connections, Fittings, and Special Sections.

C602, AWWA Standard for Cement-Mortar Lining of Water Pipelines In Place – 4 In. (100 mm) and Larger – In Place.

C606, AWWA Standard for Grooved and Shouldered Joints.

ASTM (American Society for Testing and Materials) standards, as applicable.

AWWA M11, Steel Pipe—A Guide for Design and Installation.

AWWA M27, External Corrosion—Introduction to Chemistry and Control.

AWWA M29, Cleaning and Lining Water Mains.

AWWA M44, Distribution Valves: Selection, Installation, Field Testing, and Maintenance.

American Society of Civil Engineers (ASCE) Manual No. 89, Pipeline Crossings.

ASCE Manual No. 46, Report on Pipeline Location.

American Iron and Steel Institute (AISI) Steel Plate Engineering Data, Vol. 3, Welded Steel Pipe.

September 2012 2-4 REV 01

2.2 Pipeline Alignment

2.2.1 Horizontal Alignment

Preliminary pipeline horizontal alignment is generally developed during the project planning or predesign phase and is presented in the project Planning Study or Predesign Report. If a horizontal preliminary alignment is available, the Design Contractor shall review and recommend the necessary changes to accommodate the development of design. Such changes may be triggered by utility conflicts, constructability issues, environmental issues, permitting requirements, easement/right-of-way needs, etc. Refer to Chapters 5, 7, and 10 of the Design Contractor Guide for more information.

The pipeline horizontal alignment may need to be chosen to:

Avoid vertical high points or to conform to other requirements of the hydraulic transient analysis. Refer to Section 2.7.4 for additional information.

Avoid, if possible, running parallel to sewer or reclaimed water lines.

The Design Contractor shall submit the proposed horizontal alignment changes to the Design Manager for approval prior to their incorporation into the project design. If no horizontal alignment is available, the Design Contractor shall develop one for the project. The horizontal pipeline alignment shall be detailed and finalized during subsequent design phases of the project.

Drafting of pipeline horizontal alignment drawings shall be per the requirements stated in the Water Authority Drafting Manual (ESD-120;

refer to Attachment 2-5 for the cover page of the Manual). Elements of the horizontal alignment shall be as indicated in Section 2.2 (Pipelines Plans and Profiles) of ESD-120 and include:

Pipeline material and size.

Pipeline lining and coating.

Pipeline station on pipe centerline.

Pipeline horizontal curve data.

Pipeline appurtenances.

Easement limits.

2.2.2 Vertical Alignment

The Design Contractor shall develop the pipeline vertical alignment (profile) that minimizes construction costs while still meeting the needs and design intent of the project. Abrupt vertical grade breaks resulting in upward thrust shall be avoided. Whenever practical, use a depth of one pipe diameter for large pipes and two pipe diameters for small

September 2012 2-5 REV 01 pipes. Minimum cover for pipelines is discussed in Section 2.6 of this chapter.

Factors to be considered in vertical alignment design include:

Pipe material, fabrication, and installation costs.

Potential conflicts with existing and future utilities or other improvements.

The safety and security of the pipeline.

Geotechnical conditions.

The requirements of governing agencies and permitting requirements.

Construction requirements.

Maintenance requirements.

The Design Contractor shall submit the proposed vertical alignment to the Design Manager for approval prior to their incorporation into the project design. Vertical pipeline alignment shall be detailed and finalized during subsequent design phases of the project.

Drafting of pipeline vertical alignment drawings shall be per the requirements stated in the Water Authority Drafting Manual (ESD-120).

Elements of the vertical alignment shall be as indicated in Section 2.2 (Pipelines Plans and Profiles) of ESD-120 and include:

Stations and invert elevations at grade breaks with the pipeline stationing representing the centerline of the pipe (refer to Chapter 6 of the Design Contractor Guide for information on selecting the appropriate datum for the project).

Pipeline shell thickness.

Pipeline vertical curve data.

Pipeline joint type.

Lining and coating material and thickness.

2.2.3 Horizontal and Vertical Curves

It is usually advantageous to lay out a transmission pipeline on a curve instead of a series of straight chords. Curved alignment offers the potential advantages of better hydraulics, reduced right-of-way requirements, and a lower cost.

Curves for welded steel pipes are accomplished using the allowable pipe deflection. Refer to the ―Steel Pipe‖ section of the GC&SS (see Attachment 2-1) for more discussion and limitations on pipe deflection.

In some cases beveled pipe joint special sections are used to provide angular changes beyond the allowable deflection. Refer to the ―Steel

September 2012 2-6 REV 01

Pipe‖ section in the GC&SS (see Attachment 2-1) for more discussion and limitations on pipe beveling. Stresses resulting from beveling the end of a pipe in excess of the amount specified in the GC&SS shall be evaluated and included in the pipe shell and joint design.

In some cases fabricated bends are used to provide the desired angular change in the pipeline alignment. Refer to the ―Steel Pipe‖ specification section in the GC&SS (see Attachment 2-1) for more discussion and limitations on fabricated bends. The radius of curvature (R) for the axis of fabricated bends shall be at least equal to 2.5 times the inside pipe diameter (D). Stresses (including stress intensification factors) at miters of fabricated bends shall be evaluated and included in the pipe shell design.

2.2.4 Utility Separations

Pipeline separation from sewer mains shall, as a bare minimum, adhere to State of California Department of Health Services (CA-DHS) criteria.

The CA-DHS requires a 10-feet minimum separation (wall to wall) between parallel sewer mains and water-conveying pipelines for most installations. Refer to CA-DHS standards for details. Sewer mains crossing water pipelines shall be sleeved across the right-of-way of the pipeline. Reclaimed water mains shall be treated as sewer mains for separation purposes.

A minimum 4-foot separation from the edge of the proposed trench section is recommended between water-conveying pipelines and other utilities (e.g., storm drains, gas mains, etc.). Verify that the separation distance is sufficient to ensure the lateral soil support of the Water Authority Pipeline.

Special construction methods and materials are necessary whenever the minimum horizontal and vertical separations cannot be maintained.

In selecting the special construction method and design, the Design Contractor shall consider design factors such as external forces, impacts of groundwater, soil strength characteristics, and electrolytic interaction between pipelines’ cathodic protection systems. Approval by CA-DHS is mandatory in cases where special construction methods and materials are required.

It is to be noted that no utilities are allowed to be located within the pipeline trench section. In most cases, this will result in clearance requirements considerably larger than the CA-DHS minimums.

2.2.5 Property Requirements

Land space requirements are usually determined during the project planning phase. During the project design phase, the Design Contractor shall precisely determine additional land space requirements, if needed, to safely install and maintain the pipeline.

September 2012 2-7 REV 01

Additional property requirements may be needed for deeper than usual pipelines, or pipelines located in canyons, ―open space‖ areas, and other areas with difficult accessibility. All property requirements shall be coordinated with the Water Authority Right of Way Section , as outlined in Chapter 7 of the Design Contractor Guide (Design Manual - Volume One; ESD-160).

Additional land space requirements may be needed to maintain the pipe appurtenances. The Design Contractor shall include provisions for access roads to all pipeline appurtenances (e.g. blowoffs, air valves, isolation valves, access manways, etc.). Access roads shall have a minium width of 14 feet with a two foot shoulder on each edge (overall 18 feet minimum). The materials used for access roads depend on the maximum slope and anticipated service conditions. The following table is provided as a guide.

Slope Material Notes

<15% Aggregate base or native material

GC&SS, Section 02510

15-25% Asphalt-concrete 3-inch minimum with base

>25% Roughened Concrete As approved by the Water Authority

The minimum inside radius of curvature for access roads shall be 50 feet. Include in the design of access roads appropriate drainage features to control stormwater and prevent the depositing of road base onto adjacent properties. For additional requirements, refer to Section 02510, Access Roads in the GC&SS (see Attachment 2-1).

September 2012 2-8 REV 01

2.3 Pipe Materials, Linings, and Coatings

2.3.1 Pipe Materials

An array of pipe materials is currently available in the market. The choice of a particular pipeline material is usually a function of project type and nature, cost (initial and maintenance), pressure requirements, owner requirements, operation and maintenance requirements, etc.

The Design Contractor shall use and specify the materials outlined in the specification sections in the GC&SS (see Attachment 2-1) in the design of pipelines. The Design Contractor shall follow the procedures outlined in Chapters 1 and 14 of the Design Contractor Guide in using and proposing changes to the GC&SS.

Pipeline material in use by the Water Authority varies according to the purpose of the pipe. The following are the materials used by the Water Authority.

A. Steel Pipe

Steel pipes and fittings are used by the Water Authority in all new transmission pipelines and sometimes used in blowoff discharge piping and other appurtenances. The Design Contractor shall use and reference in the Contract Documents the steel pipe specifications outlined in the GC&SS (see Attachment 2-1). Applicable specification sections to steel pipeline design in the GC&SS include:

Steel Pipe.

Installation of Pipe.

Disinfection of Piping.

Pressure Testing of Piping.

Piping Schedule and General Piping Requirements.

Pipe Hangers and Supports.

B. Ductile Iron (DI) Pipe

DI pipes and fittings may be used by the Water Authority in blowoff discharge piping. The Design Contractor shall use and reference in the Contract Documents the ―Ductile Iron‖ specifications outlined in the GC&SS (see Attachment 2-1).

C. PVC Pipe PVC pipes and fittings may be used by the Water Authority in blowoff discharge piping. The Design Contractor shall reference appropriate standards such as the Standard Specifications for Public Works Construction (Green Book) or regional standards such as the Water Agencies Standards (www.sdwas.com).

http://www.sdwas.com/

September 2012 2-9 REV 01

2.3.2 Pipe Linings and Coatings

A. Linings

Linings are materials applied to the pipe interior for corrosion protection. Lining materials and requirements for pipe lining are outlined in the GC&SS (see Attachment 2-1). Applicable specification sections to pipe lining in the GC&SS include:

Steel Pipe.

Ductile Iron Pipe.

Plant-Applied Cement Mortar Lining.

Fusion-Bonded Epoxy Lining and Coating.

Field-Applied Cement Mortar Lining.

Polyurethane Lining and Coating.

The Design Contractor may propose changes to the GC&SS (see Section 2.1 for more information on change procedure).

Large steel pipelines are normally cement-mortar lined. Large pipelines may be polyurethane or epoxy lined, if they are subjected to frequent wet/dry cycles, to avoid cracking of cement mortar lining.

Small pipelines may be polyurethane or epoxy lined, if needed, to preserve hydraulic characteristics. Polyurethane and epoxy linings may also be used if velocity of water in the pipeline is greater than the maximum limit for cement-mortar lining.

Where pipes are cement mortar lined, hoop circumferential stresses in the pipe shell due to internal and external pressure and resultant strains in the cement mortar lining shall be limited to thresholds that will minimize the potential for cracking and/or delamination of the lining and ensure its design life under all operating scenarios

B. Coatings

Coatings are materials applied to the exterior of the pipe for corrosion protection. When selecting coating materials, the Design Contractor shall consider:

Capability of the material to perform the desired function in a safe and economical manner.

Material deterioration and its satisfactory operation over the design life of the pipeline.

Capability of the selected material to withstand the aggressive environment to which it will be exposed.

Coating materials and requirements for pipe coating are outlined in the GC&SS (see Attachment 2-1). Applicable specification sections to pipe coating in the GC&SS include:

Cement Mortar Coating.

September 2012 2-10 REV 01

Coal-Tar Coating.

Cold-Applied Plastic Tape Coating.

Fusion-Bonded Epoxy Lining and Coating.

Polyurethane Lining and Coating.

Painting and Coating.

The Design Contractor may propose changes to the GC&SS (see Section 2.1 for information on change procedure).

Reinforced cement mortar coating for buried steel pipes shall be a minimum of one-inch thick on top of a cold-applied tape wrap.

Coatings for steel surfaces exposed to the atmosphere shall be epoxy or polyurethane.

DI pipe and fittings shall be coated per requirements outlined in ―Ductile Iron‖ specification section in the GC&SS (See Attachment 2-1).

September 2012 2-11 REV 01

2.4 Pipe Fittings, Jointing, and Special Connections

2.4.1 Pipe Fittings

Pipe fittings include all special pieces, such as wyes, elbows (5 up to

), tees, and reducers.

A. Steel Pipe Fittings

Refer to the ―Steel Pipe‖ specification section in the GC&SS (see Attachment 2-1) for requirements of steel pipe fittings. Steel fittings shall comply with ANSI/AWWA C-208.

Fittings for welded steel pipe shall be designed in accordance with standard practices as stated in AWWA M11 (Steel Pipe – A Guide for Design and Installation) and other AWWA standards.

Welded steel pipe elbows shall have a maximum deflection of 15 degrees on miter ends. As such, elbows of 0 to 22.5 degrees shall be fabricated in two welded pieces; 22.5 to 45 degrees shall be fabricated in three welded pieces; 45 to 60 degrees shall be fabricated in four welded pieces; and 60 to 90 degrees shall be fabricated in five welded pieces. The evaluation of pipe stresses within the elbow shall include the hoop stress intensification factor resulting from the geometry of the elbow.

Some welded steel pipe fittings such as tees and wyes may require reinforcement using wrapper plates or crotch plates. The Design Contractor shall provide calculations, per AWWA M11 procedure, to determine the required increase in wall thickness or crotch plates in steel pipe fittings.

Wall thickness of steel pipe fittings shall conform to requirements outlined in AWWA M11 and other AWWA standards. Coating and lining shall be per Section 2.3.

B. Ductile Iron Fittings

Refer to the ―Ductile Iron Pipe‖ specification section in the GC&SS (see Attachment 2-1) for requirements of DI pipe fittings.

2.4.2 Pipe Jointing / Coupling

Several methods are available for connecting pieces of pipe together.

The choice of a particular jointing method is generally a function of pipe material size, pressure requirements, and thrust forces, among other factors.

The following are some of the most commonly used pipe jointing types with their restraining and misalignment characteristics:

1. Flanged Joints:

September 2012 2-12 REV 01

Complete restraint against all movement.

Limited tolerance for misalignment.

2. Welded Joints:

Complete restraint against all movement.

Tolerance for misalignment varies with welding as follows:

o Butt weld - None except by trimming pipe ends.

o Lap weld – Limited.

o Butt strap – Limited.

3. Restrained Flexible Sleeve Coupling Joints:

Restraint against axial movement with allowance for limited angular and translational movement.

Good allowance for misalignment.

The following are specific requirements for different pipe materials used by the Water Authority. The Design Contractor shall refer to Water Authority Standard Specification Section 15122 (Pipe Couplings and Expansion Joints) for more information.

A. Steel Joints

Steel pipe jointing can be done with flanges, welds, or restrained flexible sleeve coupling depending on the longitudinal force, the type of adjoining end (another piece of pipe, fitting, valve, flowmeter, etc.), and the need to easily disassemble the joint. The Design Contractor shall refer to the ―Steel Pipe‖ and ―Installation of Pipe‖ specification sections in the GC&SS (see Attachment 2-1) for requirements of steel pipe joints.

Depending on the longitudinal stresses caused by forces due to thrust or due to Poisson’s effect and temperature, pipeline joints may be welded or flanged. The procedure for design of pipe joints to resist longitudinal forces is discussed in Section 2.7. The Design Contractor shall refer to Chapter 5, Seismic Design, for design guidelines of steel pipes and joints subjected to traveling waves and ground deformations as well as where the pipes cross active faults, liquefaction zones, or landslide hazards.

Flanged joints shall comply with the GC&SS (see Attachment 2-1).

Flanges shall be selected in accordance with design pressure, test pressure, surge pressure, and the drilling pattern of the adjoining equipment (i.e., valves).

Welded joints may be lap welded, butt welded, or butt-strap welded.

Field welding shall conform to the ―Installation of Pipe‖ section in the GC&SS (see Attachment 2-1). The Design Contractor shall refer to the SD&SD for welding details of steel pipe joints (refer to Attachment 2-2).

September 2012 2-13 REV 01

Single and double welded lap, butt, and butt-strap joints are shown in the ―Welded Steel Pipe Details I, II, and III‖ drawings in the SD&SD.

The following are general requirements and allowable forces for each type of weld:

1. Lap Welds

Preparation of lap-welded joints (commonly referred to as bell and spigot joints) shall be in accordance with the GC&SS (see Attachment 2-1). Shaping the pipe bell with an expanding press or by moving the pipe axially over a die is acceptable. However, shaping the pipe bell using offset rollers which move around the pipe end shall not be permitted.

The stresses within the lapwelded joint shall be computed by the Design Contractor.

If the stresses are greater than the allowable stresses, three options or a combination of these options shall be considered.Increase the wall thickness.

Use a double lap weld (one weld inside and one weld outside the pipe) instead of a single lap weld with a seal weld.

Use a butt weld instead of a lap weld.

2. Butt Welds

Full penetration butt joint welds with appropriate inspection and nondestructive testing can resist stresses equal to stressesresisted by the pipe wall.

3. Butt Strap Welds

Butt strap joints may be necessary on closure sections or for connecting new to existing pipelines. Refer to ―Installation of Pipe‖ specification section in the GC&SS (see Attachment 2-1) for additional information. Closure joints, as recommended by AWWA M11 Chapter 8 (Pipe Joints), shall be included in the design of steel pipelines to minimize the effect of contraction due to temperature variation.

. The stresses within the butt-strap joint shall be computed by the Design Contractor. If the stresses are greater than the allowable stresses, consider increasing the wall thickness and/or using a wider butt-strap.

B. Ductile Iron Joints

DI pipe jointing can be done with flanges, mechanical joints, grooved or shouldered joints. The Design Contractor shall refer to the ―Ductile Iron Pipe‖ specification section in the GC&SS (see Attachment 2-1) for requirements of DI pipe joints.

September 2012 2-14 REV 01

2.4.3 Pipe Special Connections

A. Structure Penetrations

Design considerations taken because of pipe penetrations into structures (e.g., vaults, buildings, etc.) include:

Structure special reinforcement.

Pipe support.

Sealing to prevent water from moving into or out of the structure.

Eliminating steel reinforcement in structure walls coming in contact with the pipe which may result in a short to the cathodic protection system.

The Design contractor shall use and specify the following Water Authority documents in structure penetrations:

―Wall Pipes, Seep Rings, and Penetrations‖ specification section in the GC&SS (see Attachment 2-1).

―Structural Details I‖ drawing in the SD&SD (see Attachment 2-2).

In case of using structural walls to restrain the pipe, the Design Contractor shall size and use anchor rings per AWWA M11 requirements.

B. Connection to other Pipes

The Design Contractor shall provide the appropriate design suitable for connecting new pipelines to existing pipelines. Pipe condition , pipe size, pipe materials, cathodic protection isolation, and the maximum time allowable for making the pipe connection, are all factors that shall be considered when designing connections to existing pipelines.

A shutdown to Water Authority operations may be required for connections to existing pipes. Therefore, all connections to existing pipes shall be coordinated with the Water Authority Operations and Maintenance Department.

C. Dismantling Joints

These types of Joints are used for easy dismantle of the equipment fitted in the pipe. They are used before valves and other pieces of equipment. The Design Contractor shall refer to the ―Pipe Couplings and Expansion Joints‖ specification section in the GC&SS (see Attachment 2-1) for additional requirements on dismantling joints.

September 2012 2-15 REV 01

2.5 Pipeline Appurtenances

2.5.1

Pipeline appurtenances may include isolation valves, control valves, air valve assemblies, flowmeters, blowoff stations, outlets, and access structures. Attachment 2-6 provides a summary of general design criteria for pipeline appurtenances. The following sections outline additional requirements.

2.5.2 Valves

The location, size and type of valve shall be as outlined in the below requirements and as recommended by the Design Contractor. Valve specifications shall follow the ―Valves‖ specification section in the GC&SS (see Attachment 2-1). The Design Contractor shall follow the procedures outlined in Chapters 1 and 14 of the Design Contractor Guide in using and proposing changes to the GC&SS. Unless otherwise specified, all valves shall be minimum ANSI Class 150.

A. Isolation and Control Valves

Isolation valves constitute the majority of inline valves in the Water Authority pipeline system. However, control (throttling) valves are sometimes used depending on the project requirements. Valves commonly used in Water Authority pipeline projects include:

For isolation – Mainly metal or rubber seated, as applicable, butterfly valves, or ball valves. Plug valves may also be used.

For flow modulation (throttling) – Mainly plug valves. The Design Contractor may recommend other types of valves (e.g., sleeve, cone, and plunger) depending on the application.

Plug valves have generally four patterns (short, venturi, full bore, and regular). The Design Contractor shall specify the pattern that is most appropriate for the project. Venturi patterns are preferred unless another pattern is deemed appropriate for the project.

If mainline valves are considered for the project, they shall be supported by a complete hydraulic-transient analysis documenting no negative impact (refer to Section 2.7.4 for more information). For safety during maintenance operations, the Design Contractor shall coordinate with the Water Authority Operations and Maintenance Department in determining means for isolating pipe sections to achieve double valving requirement. This may entail adding two valves at the same general location.

Valves shall be properly sized. The Design Contractor shall provide calculations demonstrating that the valve will not experience flashing or

September 2012 2-16 REV 01 cavitation problems under all operating conditions. Refer to Attachment 2-6 for additional design requirements

The Design Contractor shall select the valve flow characteristics (quick opening, linear, equal percentage) that best match the control and the hydraulic-transient requirements (refer to Section 2.7.4 for more information). The selection shall be based on installed (i.e., actual operating conditions), and not inherent (i.e., lab controlled conditions), pressure conditions.

The majority of isolation valves are manually operated. A few isolation valves and control valves are operated with electric actuators coupled with hand-operated backup system. The Design Contractor shall refer to the ―Electric Motor Actuators‖ specification section in the GC&SS (see Attachment 2-1) for requirements of electric actuators. Refer to Section 2.10 in this chapter for information on valve closing time requirements to avoid surge problems.