PIPELINE DESIGN MANUAL

WASHINGTON

SUBURBAN

SANITARY

COMMISSION

REGULATION

APRIL 19, 2017

2017 1

SUMMARY OF MAJOR CHANGES

2017 PIPELINE DESIGN MANUAL

All revisions/changes to this 2017 Pipeline Design Manual is shown with red text.

GENERAL SECTION

• Add Variance (Waivers) Requirements.

PART ONE – WATER DESIGN GUIDELINES

Section 2 – Pipe Materials and Fittings.

• Change standard exterior coating of Ductile Iron Pipe to Zinc Coating.

• Change all Ductile Iron to be Fusion Bond Epoxy Coating.

Section 4 – Selection of Pipe Material.

• Revised maximum operating pressure for PVC AWWA C-900 to 130 psi.

• Add requirements for PVC AWWA C-900 fittings to have anode protection.

• Added continuity test stations for PVC AWWA C-900 pipe.

• Added Chart on Determining Type of Pipe Material

Section 8 – Horizontal Alignment.

• Revised location of water pipelines in streets.

• Add looping water systems requirements

Section 11 – Vertical Alignment (Profiles).

• Revised requirements for crossing ditches and streams.

Section 17 – Tunnel or Casing Pipes.

• Added requirements for installing casing pipe around existing water pipelines.

Section 22 – Specialty Valves.

• Added requirements for Flow Control Valves.

• Revised requirements when Pressure Relief Valves.

Section 24 – Fire Hydrants.

• Added High Traffic Fire Hydrants requirements.

Section 25 – Water Services Connections.

• Added operating pressures for water services connections.

• Revised new residential services to be 1-1/2 inches.

• Added Ultrasonic Meter requirements.

• Added requirements for replacing existing detector check meters

• Added requirements for connecting to existing PCCP water pipelines.

PART TWO – SEWER DESIGN GUIDELINES

Section 5 – General Horizontal Alignment.

• Revised location of water pipelines in streets.

Section 8 - Vertical Alignment (Profiles).

• Revised requirements for crossing ditches and streams.

Section 10 – Tunnel or Casing Pipes.

• Added requirements for installing casing pipe around existing sewer or force main pipelines..

Section 24 – Force Main Design.

• Added High-Density Polyethylene Pipe requirements.

Section 27 – Sewer Service Connection.

• Added requirements for 8-inch and larger service connections.

2017 2

PART THREE – COMMON DESIGN GUIDELINES

Section 2 – Easements and Construction Strips.

• Changed Right of Way to Easements.

Section 3 – Pipeline Crossings and Clearances.

• Revised MTA Light Rail Zone of Influence requirements.

Section 11 – Loading Analysis of Existing Pipelines.

• Added requirements for PVC AWWA C-900 water and sewer pipelines Section 16 – Design of Pipeline Structures.

• Added additional requirements.

Section 22 – Slope Stability.

• Added additional requirements.

Section 27 – Thrust Restraint Design for Buried Pipelines.

• Revised restrain joint requirements.

Section 28 – Corrosion Control.

• Revised requirements for Corrosion Protection.

APPENDIX A – DESIGN CHECKLIST

• Updated Checklist.

APPENDIX D – WSSC SURVEY AND EASEMENT CRITERIA

• Change Right of Way to Easements.

• Update surveys and easement requirements.

APPENDIX D – SUBSURFACE INVESTIGATION REQUIREMENTS FOR WATER AND SEWER

DESIGN AND CONSTRUCTION.

• Updated requirements for subsurface investigations.

APPENDIX E – SOIL INVESTIGATION FOR SOFT GROUND TUNNEL PROJECTS.

• Updated requirements for subsurface investigations.

PROPOSED REVISIONS

to the WSSC Pipeline Design Manual

Manual Part Section Number Page Number

Manual Users Name Phone ( )

Email Address

Company

Address

Proposed Revision: In the space below, please provide a detailed description of your suggested change or revision to the Pipeline Design Manual. All comments or recommendations for revisions are encouraged to point out discrepancies, suggested modifications or recommendations for additional information, examples, etc. to be added. Please include a descriptive reason for the change or addition, attach any necessary pages and supporting documentation and mail it to the address below.

Mail to: Washington Suburban Sanitary Commission Technical Services Group 14501 Sweitzer Lane Laurel, MD 20707

OBTAINING MANUAL REVISIONS

Attention Manual Holders:

Revisions to the Pipeline Design Manual can be conveniently downloaded and printed from the WSSC Corporate Website. As the holder of the manual, it is your responsibility to keep your manual up to date. Prior to the start of any new water and sewer pipeline design for the WSSC, please be sure to visit the website to obtain any revisions and insert them in your manual. Approval of plans may be delayed if the latest design guidelines are not used.

The revisions can be obtained by visiting the WSSC website at http://www.wsscwater.com/ and clicking on "Business & Construction" from the Navigation Bar. From the pull down menu, select "Doing BusinessCode & Standards" and then "Pipeline Design Manual".

No Internet Access ??

If you do not have access to the Internet, please contact the WSSC Technical Services Group to obtain a copy of any manual revisions.

http://www.wsscwater.com/

CONTENTS

Table of Contents PIPELINE DESIGN MANUAL

TABLE OF CONTENTS

PIPELINE DESIGN MANUAL

Introduction

General Table of Contents General

Part One - Water Design Guidelines General Table of Contents

Part Two - Sewer Design Guidelines General Table of Contents

Part Three - Common Design Guidelines General Table of Contents

Appendix Appendix A Design Checklist Appendix B WSSC Design Criteria for Water Distribution Systems Appendix C WSSC Design Criteria for Sewer Systems Appendix D WSSC Survey and Right of Way Criteria Appendix E Subsurface Investigation Requirements for Water and Sewer Design and Construction Appendix F Soil Investigation for Soft Ground Tunnel Projects

INTRODUCTION

The Washington Suburban Sanitary Commission's Pipeline Design Manual covers the minimum standard criteria to be followed by Designers and Engineers when preparing plans and/or specifications for the design of water and sewer pipelines for the Washington Suburban Sanitary Commission (WSSC) within the Washington Suburban Sanitary District (WSSD). It covers criteria such as submittal requirements, horizontal and vertical alignment, thrust restraint, tunneling, corrosion control, structural requirements, appurtenances, specifications, materials, hydraulics, etc.

This manual is a design guideline that shall be followed and used in conjunction with the WSSC Standard Details for Construction and the WSSC General Conditions and Standard Specifications. It is the Designer's responsibility to review and verify the applicability of all material presented in this manual as it pertains to the specific project under design and to submit, as required by WSSC and herein, all reports, design computations, worksheets, geotechnical investigations, surveys, rights of way determinations, checklists, etc. All such submittals shall be signed and sealed by the Professional Engineer or Professional Land Surveyor, as appropriate, licensed to practice in the State of Maryland, who is in responsible charge of that portion of the project.

This manual covers design guidelines for all pipeline projects under the jurisdiction of WSSC including water mains 54-inch diameter and smaller and all sizes of gravity and pressure sewers with the exception of privately owned and maintained systems referred to as "on-site" systems.

It is the WSSC's policy to avoid and protect environmentally sensitive areas wherever possible including wetlands, woodlands, one hundred (100) year flood plains, park property, steep slopes, historical/archaeological sites, Chesapeake Bay Critical Areas, Areas of Special State Concern and public tree areas.

GENERAL

Table of Contents GENERAL

1. Contract Drawings and Documents. G - 1

a. General G - 1

2. Variance (Waivers) G - 2

3. Contract Drawings and Specifications G - 7

a. General Instructions. G - 6

b. Utility Coordination. G - 6

c. Contract Specifications and Special Provisions. G - 6

d. Data and Flow Computations. G - 6

e. Estimate of Quantities. G - 6

4 Additional Requirements. G - 8

a. Location of Existing Utilities and Physical Features. G - 8

b. Proposed Construction. G - 8

c. Design Checklist. G - 8

d. Discrepancies. G - 8

2017 G - 1

1. General.

a. The Washington Suburban Sanitary Commission (WSSC) is authorized by Public Utilities Article, Division II of the Annotated Code of Maryland to adopt, administer and enforce regulations for the design, construction, installation and development of water and sewer systems and their appurtenances. This Design Manual constitutes a duly adopted WSSC regulation.

b. The purpose of this Design Manual is to provide the minimum requirements and standards which must be followed in the design, construction, installation and development of water and sewer systems within the Washington Suburban Sanitary District. This manual was developed and adopted in an effort to fulfill WSSC's mission of providing safe and reliable water and returning clean water to our environment for the protection of the public health, safety and well-being.

2. Variance.

a. WSSC’s Approving Authority shall have the authority to grant a modification, variance and/or waiver (“Variance”) of any requirements and/or standards set forth herein on a case-by-case basis when the determinations set forth in paragraph 2.b.3) below have been made. Records of action granting a Variance shall be maintained by the WSSC’s Approving Authority.

b. Request for Variance.

1) A Variance request shall be submitted on the WSSC Official Variance Request Form. The form shall be signed by the Applicant and Applicant’s Engineer (the “Engineer”).

2) Variance requests may be subject to an additional fee.

3) A Variance request may be granted in whole or in part, when WSSC’s Approving Authority has determined that:

a) Strict compliance with the Design Manual is impractical;

b) The Variance is in conformity with the intent and purpose of the Design Manual;

c) The Variance does not compromise safety, health, life or fire safety standards or requirements;

d) The Variance does not pose a threat or cause damage to WSSC’s water or sewer system or appurtenances;

e) Denial of the Variance will result in undue burden or undue hardship to the Owner;

and

f) The grant of the Variance will be in the public interest.

2017 G - 2

4) Design drawings and calculations: A Variance request shall be accompanied by design drawings, plans, calculations, product literature and other documentation as necessary to document and support the requested Variance and justification for the Variance.

5) Indemnification. To obtain a Variance, the Applicant must sign the hold-harmless agreement section of the Variance request form, and agree to indemnify WSSC and its Commissioners, officers, agents and employees as described therein.

2017 G - 3

WASHINGTON SUBURBAN SANITARY COMMISSION

OFFICIAL VARIANCE REQUEST

JOB NAME: WSSC JOB NUMBER:

DATE OF REQUEST:

DESCRIPTION OF REQUESTED VARIANCE

(INCLUDE APPLICABLE PIPELINE DESIGN MANUAL SECTION AND REFERENCES):

JUSTIFICATION FOR REQUESTED VARIANCE

Applicant’s Signature

Print Name

Phone e-mail

Engineer’s Signature

2017 G - 4

OFFICAL VARIANCE REQUEST

HOLD HARMLESS AGREEMENT

To the fullest extent permitted by law, the undersigned Applicant agrees to indemnify, defend and save harmless the Washington Suburban Sanitary Commission and its Commissioners, Officers, Agents and Employees from and against any and all claims, suits, actions, losses, damages, expenses, costs, injuries and liabilities of any nature (including but not limited to claims for bodily injury, death, business interruption and/or property damage) relating to, arising out of or resulting from the granting and/or implementation of the Variance requested herein.

Applicant’s Signature

2017 G - 5

OFFICAL VARIANCE REQUEST

FOR WSSC USE ONLY

DATE RECEIVED:

ACTION TAKEN: Approved Denied

EXPLAINATION OF ACTION / SPECIAL CONDITIONS OF VARIANCE:

SIGNATURE: DATE:

WSSC’s Approving Authority

2017 G - 6

INSTRUCTIONS FOR COMPLETING FORM

1. A single waiver is acceptable for projects with the same job number and different alpha suffixes (e.g. DA1234Z05, DA1234A05, DA1234B05, and DA1234C05).

2. In the same box with Job Number, list the Permit No. or On-Site Plan No. if applicable.

3. The Description of and Justification for the Variance must be detailed and complete.

4. Give details such as elevations, lengths, existing conditions, job related limitations, etcetera. Attach supporting documentation, (e.g. letters from County, MNCP+PC) if this supports your request.

5. Attach any applicable documents (e.g. plans, drawings, calculations, product literature etc.).

6. The Applicant must sign the form. The Engineer shall not sign as the Applicant.

7. The Engineer’s signature is required.

8. The Variance form and supporting information must be uploaded into ePlan Review or e-builder as a single PDF into the Documents Folder.

9. Determination of the Variance request will be posted in the approved folder in ePlan review or e-builder.

10. Contact the WSSC’s Project Manager assigned to the project, if you have questions regarding this form.

2017 G - 7

3. Contract Drawings and Specifications.

a. General Instructions.

1) Prepare plans on WSSC standard size drawings, contact WSSC’ s Project Manager for standards.

2) Each drawing shall have the professional seal, signature and registration number of the licensed engineer responsible for the design.

3) Include notes common to all contract drawings on the first sheet of the set and labeled as General Notes, Blocking Notes, Miss Utility Note, Dependency Note, etc., as required.

4) All plans, profiles and details shall be drawn to scale unless otherwise approved or directed by

WSSC. Plan view scales shall be 1" = 50' except for townhouses/cluster type developments or congested areas where 1" = 30' scale shall be used. Draw profiles to horizontal scale 1" = 100' and vertical scale 1" = 10' except for large diameter mains 24-inches and larger, where the profile shall use the same horizontal scale as the plan.

b. Utility Coordination.

1) Closely coordinate all water and sewer pipeline design and construction with storm drains and all other utility design and construction so that there are no conflicts. Accurately show on the plans and profiles the location of both future and/or existing storm drains and all other utilities.

c. Contract Specifications and Special Provisions.

1) Prepare the contract specifications and/or special provisions according to WSSC standards, as required. For additional information regarding special provisions, see Part Three, Section 6 (Modifications to Specifications and Standard Details).

d. Design Data and Flow Computations.

1) Furnish design data and computations as indicated in this manual. The design data and computations must be clear and legible, and sealed and signed by a Professional Engineer.

Submit this data along with the design, unless otherwise indicated by WSSC’ s Project Manager.

e. Estimate of Quantities.

1) Furnish a tabulated estimate of quantities and costs, including contingency items, if required by

WSSC. The tabulated estimate must be clear and legible, and sealed and signed by a Professional Engineer. Submit this data along with the design, when required by WSSC’ s Project Manager.

2017 G - 8

4. Additional Requirements.

a. Location of Existing Utilities and Physical Features.

1) The Designer is responsible for obtaining locations of all existing utilities and physical features through field surveys and as-built record information. When directed by the WSSC’ s Project Manager, obtain test pits wherever exact locations of underground utilities are uncertain, and/or where locations are critical to design. The WSSC will assist in the coordination of test pits as deemed necessary. The number, location and type of test pits will be dictated by specific design requirements.

b. Proposed Construction.

1) Research all pertinent data on all proposed construction projects which may impact the design and coordinate the same with the development of the contract drawings and specifications.

c. Design Checklist.

1) The Design Checklist, Appendix A, can be used as a design guide for preparing water and sewer pipeline designs according to this design manual. Items listed in the design checklist are general and may not cover all items that may be required to complete the specific project under design.

The Designer is fully respons1ible for preparing complete contract documents. The WSSC is not responsible for design items which may be required but are not included on the Design Checklist.

d. Discrepancies.

1) Whenever any conflict, discrepancy or ambiguity exists within this manual or between any code, regulation or policy promulgated by any other jurisdictional agency within the WSSD, advice WSSC immediately in writing and WSSC’s Project Manager will render expeditious interpretations and guidelines to be followed.

PART ONE

Water Design

Guidelines

WATER DESIGN GUIDELINES

PART ONE

WATER DESIGN GUIDELINES

General.

Part One of the Pipeline Design Manual covers the minimum standard design criteria to be followed when preparing the design of water pipelines and appurtenances within the Washington Suburban Sanitary District (WSSD). Use this part in conjunction with Part Two, Sewer Design Guidelines and Part Three, Common Design Guidelines. Although this manual is intended as a guideline, it is the Designer's responsibility to review and verify the applicability of all material presented herein as it pertains to the specific project under design.

The portions of the water supply system which are considered as the property and responsibility of the

WSSC are the water pipelines, appurtenances and those portions of the water service connections which lie in the public right of way and in rights of way granted to the WSSC. All other systems are in most cases the responsibility of the respective property owner(s).

For projects that are constructed and maintained by WSSC, WSSC will indicate the size and limits of the water pipeline(s) and appurtenances to be designed and constructed. The WSSC Design Criteria for Water Distribution Systems are found in Appendix B.

In the preparation of the contract documents, the Designer will take into full account such matters as environmental impact, public impact including maintenance of pedestrian and vehicular traffic, maintenance of existing and proposed utility services, constructability, and system maintenance to produce the most cost-effective design.

Table of Contents WATER DESIGN GUIDELINES

2017 1

PART ONE - WATER DESIGN GUIDELINES

1. Terminology and Abbreviations. W - 1.1

a. General. W - 1.1

b. Types of Pipelines. W - 1.1

c. WSSC Documents. W - 1.1

d. Pipe Material. W - 1.1

e. Miscellaneous. W - 1.2

2. Pipe Materials and Fittings. W - 2.1

a. General. W - 2.1

b. Pipe Material. W - 2.1

c. Fittings. W - 2.2

3. Pipe and Fitting Joints. W - 3.1

a. Specifications Requirements. W - 3.1

b. Type of Allowable Joints. W - 3.1

c. Joint Requirements for Pipe and Fittings. W - 3.2

d. Insulation Joint Requirements. W - 3.2

4. Selection of Pipe Material. W - 4.1

a. General. W - 4.1

b. Determining Pipeline Cover. W - 4.1

c. Selection of Pipe Material, Pipe Class and Wall Thickness. W - 4.1

d. Determining Type of Pipe Material. W - 4.4

e. Depth of Cover for DIP Greater Than WSSC Requirements. W - 4.5 f Wall Thickness of DIP for Special Applications. W - 4.5

g. When pipelines are to be designed near or within Marlboro Clay. W - 4.6

5. Total Internal and Transient Pressures. W - 5.1

a. Total Internal Pressure. W - 5.1

b. Operating Pressure. W - 5.1

c. Surge (Transient) Pressures. W - 5.2

6. Buckling Designs. W - 6.1

a. Criteria. W - 6.1

b. References. W - 6.1

7. Allowable Fittings. W - 7.1

a. General Requirements. W - 7.1

b. Design Considerations. W - 7.1

c. Type of Fittings. W - 7.2

2017 2

8. Horizontal Alignment. W - 8.1

a. General. W - 8.1

b. Considerations. W - 8.1

c. Location. W - 8.1

d. Looping Water Systems W - 8.2

e. Labeling Pipeline in Plan. W - 8.2

9. Connections to Existing or Proposed Water Pipelines. W - 9.1

a. Design of Connections to Existing Pipelines. W - 9.1

b. Revising Designed Connections During Construction. W - 9.2

c. Connection to Proposed or Future Pipelines. W - 9.3

d. Labeling Existing Pipelines on the Drawings. W - 9.3

e. Special Items. W - 9.3

10. Relocating Water Pipelines. W - 10.1

a. General. W - 10.1

b. Alignment - Horizontal and Vertical. W - 10.1

c. Thrust Restraint. W - 10.2

d. Abandonment. W - 10.2

11. Vertical Alignment (Profiles). W - 11.1

a. Cover Over Pipeline. W - 11.2

b. Labeling Pipeline in Profile. W - 11.2

c. Change in Vertical Alignment. W - 11.2

d. Stations and Elevations. W - 11.2

e. Design of Structures on Profile. W - 11.2

f. Profile Grade Lines. W - 11.3

g. Length of Profile. W - 11.4

h. Pipeline Stationing. W - 11.4

12. Allowable Joint Deflections. W - 12.1

a. General. W - 12.1

b. DIP and PVC with Push-on Type Joints W - 12.1

c. DIP Mechanical Joints. W - 12.2

d. Restrained Joint Pipe. W - 12.2

e. Determining Joint Deflections and Offset Distances. W - 12.5

13. Rotation of Fittings. W - 13.1

a. Rotation of Bends. W - 13.1

b. Rotation of Tees. W - 13.6

c. Rotation of Other Fittings. W - 13.6

14. Joint Deflections at Fittings. W - 14.1

a. Requirements. W - 14.1

15. Deflection of Pipe Joints. W - 15.1

a. General. W - 15.1

b. Alignment Design. W - 15.1

2017 3

16. Design of Structures. W - 16.1

a. Standard Details. W - 16.1

b. Special Design Structures. W - 16.1

c. Design of Structures on Profiles. W - 16.1

d. Access Openings. W - 16.1

e. Setting of Frames and Covers or Hatches. W - 16.1

f. Labeling Structures on the Drawings. W - 16.2

17. Tunnels or Casing Pipes. W - 17.1

a. Requirements. W - 17.1

b. Installing Casing Pipes for Existing Water Pipelines. W - 17.1

18. Pipeline Valves. W - 18.1

a. General. W - 18.1

b. Valve Types W - 18.1

c. Valve Locations W - 18.1 d.. Special Requirements. W - 18.2 e.. Valve Size. W - 18.2

f. Valve Spacing. W - 18.2

g. Restraining of Valves. W - 18.3

h. Plan Design Information. W - 18.3

i. Profile Design Information. W - 18.3

j. Type of Valves (Double Disc Gate Valves and Resilient Seated (Wedge) Gate Valve). W - 18.4

k. Horizontal Gate Valve Vault Design for Pipelines Larger Than 16-inch Diameter. W - 18.5

19. Air Valves. W - 19.1

a. General. W - 19.1

b. Specification Requirements. W - 19.1

c. Design Requirements for 16-inch and Larger Pipelines. W - 19.1

d. Sizing of Air/Vacuum Valves. W - 19.2

e. Sizing of Air Release Valves. W - 19.2

f. Location of the Air Valve or Combination Air and Vacuum Valve. W - 19.3

g. Connecting the Air Valve or Combination Air and Vacuum Valve to the Mainline Pipe. W - 19.4

h. Piping and Vault Configuration. W - 19.4

20. Entry Ports. W - 20.1

a. General Requirements. W - 20.1

b. Piping and Vault Configuration. W - 20.1

21. Air Valves with Entry Port. W - 21.1

a. General Requirements. W - 21.1

b. Piping and Vault Configuration. W - 21.1

2017 4

22. Specialty Valves. W - 22.1

a. Type of Specialty Valves. W - 22.1

b. General Requirements for Valve and Piping Arrangement in Vaults. W - 22.1

c. Altitude Valves. W - 22.3

d. Pressure Reducing Valves (PRV). W - 22.4

e. Flow Control Valves (FCV) W – 22.7

h. Pressure Relief Valves (Relief Valve). W - 22.7

i. Swing Check Valves. W - 22.10

j. Backflow Preventers. W - 22.11

k. Butterfly Valves. W - 22.11

l. Eccentric Plug Valves. W - 22.12

m. Line Stop W - 22.13

23. Blowoff Connections. W - 23.1

a. Design Requirements for Blowoff Connections. W - 23.1

b. Types of Blowoff Connections. W - 23.1

c. Blowoff Connection to the Mainline Pipeline. W - 23.2

d. Drawing Requirements for Blowoffs. W - 23.3

24. Fire Hydrants. W - 24.1

a. General Requirements. W - 24.1

b. Type of Fire Hydrants W - 24.1

c. Fire Hydrant Settings (Horizontal). W - 24.2

d. Fire Hydrant Leads. W - 24.2

e. Fire Hydrant Spacing. W - 24.3

25. Water Service Connections (WHC). W - 25.1

a. General Requirements. W - 25.1

b. Operating Pressure for WHC’s W – 25.1

c. Types of WHCs. W - 25.1

d. Size of WHCs. W - 25.2

e. Allowable Pipe Material for WHCs. W - 25.2

f. Horizontal WHC Alignment. W - 25.3

g. Vertical WHC Alignment. W - 25.5

h. Location of Outside Meters. W - 25.6

i. Connection of the WHC to the Mainline Pipeline. W - 25.8

j. Insulated Joints on WHCs. W - 25.9

CHARTS

Chart "E" Selection of Pipe Material. W - 4.4 Chart "A" Rotation of Bends. W - 13.5

FIGURES

Figure "A" Pipeline Joint Deflections. W - 12.5

2017 5

SKETCHES

Sketch "B" Location of Welded-on Connection, Flanged Pipe. W - 7.5 Sketch "C" Location of Welded-on Connection, Pipe Other Than Flanged Pipe. W - 7.6 Sketch "D" Rotation of Bends (Horizontal and Vertical). W - 13.2 Sketch "E" Profile - Rotation of Bends. W - 13.3 Sketch "F" Profile - Deflections at Pipe Joints. W - 15.2 Sketch "G" Labeling Manholes or Vaults on Proposed or Finished Grades. W - 16.2 Sketch "H" Labeling Manholes or Vaults on Existing Grades. W - 16.2 Sketch "I" Maximum Pipe Slope for Valves. W - 18.3 Sketch "J" WHC Lowering at Storm Drains and Other Utility Crossings. W - 25.5

TABLES

Table "1" Surge Pressures. W - 5.2 Table "3" Deflection Table - DIP Push-on Joint Pipe. W - 12.1 Table "3.1" Deflection Table - PVC Pipe with Push-on Joints. W - 12.1 Table "4" Deflection Table - DIP Mechanical Joint Pipe. W - 12.2 Table "5.0" Deflection Table - Wedge Action Restraining Glands – Mechanical Joint DIP. W - 12.3 Table "5.0a" Maximum Total Pressure for Wedge Action Restraining Glands for DIP. W - 12.3 Table "5.1" Deflection Table - Manufacturer's Proprietary Restrained Joint DIP - Push-on Restrained Joint Gaskets. W - 12.3 Table "5.2" Deflection Table - Manufacturer's Proprietary Restrained Joint DIP. W - 12.4 Table "5.3" Deflection Table - Wedge Action Restraining Glands - DIP Push-on Joints. W - 12.4 Table "5.3a" Maximum Total Pressure for Wedge Action Restraining Glands – DIP Push-on Joints. W - 12.4 Table "5.4" Deflection Table - Wedge Action Restraining Glands – Push-on PVC Pipe. W - 12.5 Table "6" Valve Sizes. W - 18.2 Table "7" Spacing of Valves. W - 18.2

Part One, Section 1. Terminology and Abbreviations WATER DESIGN

2017 W-1.1

1. Terminology and Abbreviations:

The following terms and abbreviations are used in Part One of the Design Manual.

a. General.

WSSC Washington Suburban Sanitary Commission.

WSSD Washington Suburban Sanitary District.

AWWA American Water Works Association.

ANSI American National Standards Institute.

AISI American Iron and Steel Institute.

AASHTO American Association of State Highway and Transportation Officials.

DIPRA Ductile Iron Pipe Research Association.

MDE Maryland Department of the Environment.

MSHA Maryland State Highway Administration.

b. Types of Pipelines.

Distribution Mains Water pipelines (4-inch to 12-inch) designed and constructed to provide localized services.

Transmission Mains Water pipelines (16-inch and larger) designed and constructed to provide a major water supply from the water treatment plant to the Distribution Mains.

c. WSSC Documents.

SEP System Extension Process.

DRP Developer Relocation Projects Specifications WSSC General Conditions and Standard Specifications.

Standard Details WSSC Standard Details for Construction.

Drawings Contract Design Drawings.

Plumbing Code WSSC Plumbing and Fuel Gas Code.

d. Pipe Material.

DIP Ductile Iron Pipe.

CIP Cast Iron Pipe.

PCCP Prestressed Concrete Cylinder Pipe.

PVC (AWWA C900) Polyvinyl Chloride (Water Pipe)

ACP Asbestos Cement Pipe.

Part One, Section 1. Terminology and Abbreviations WATER DESIGN

2017 W-1.2

e. Miscellaneous.

psi pounds per square inch. ID Pipe inside diameter.

HHG High Hydraulic Grade. OD Pipe outside diameter.

LHG Low Hydraulic Grade. R/W Public Road Right of Way.

SHC Sewer Service (House) Connection. PIE Public Improvement Easement.

WHC Water Service (House) Connection. PUE Public Utility Easement.

PE Plain End Joint. MJ Mechanical Joint.

FLG Flange Joint. TS&V Tapping Sleeve and Valve.

DR Dimension Ratio. SDR Standard Dimension Ratio.

Part One, Section 2. Pipe Materials and Fittings WATER DESIGN

2017 W-2.1

2. Pipe Materials and Fittings.

1) Standard pipe materials and fittings. Ensure that all designs allow for the use of materials that conform to all applicable sections of the Specifications and the Standard Details.

2) Special pipe materials and fittings. Submit any special design features and/or materials required due to the specific nature of the contract for approval, prior to being incorporated into the contract documents. If approved, it will be for the specific case in question and is not to be considered a general approval for use elsewhere (other contract documents). Provide Special Provisions to the Specifications and Modifications to the Standard Details; see Part Three, Section 6 (Modifications to Specifications and Standard Details).

b. Pipe Material.

1) Standard Pipe Material.

a) DIP in accordance with the Specifications, with the class of pipe noted on the drawings.

(1) Minimum pipe of class of pipe is Class 54.

(2) Design the class of pipe (wall thickness) for the allowable cover; see Part One, Section 4 (Selection of Pipe Material).

(3) Exterior Coating Systems for DIP.

(a) Standard coating shall be zinc basecoat applied to pipe surface and asphaltic topcoat, and must have V-Bio encasement in accordance with the Specifications.

(b) Special exterior coating systems with cathodic protection system in accordance with the Specifications may be required. For additional information on cathodic protection system; see Part Three, Section 28 (Corrosion Control).

(4) DIP larger than 48-inch diameter:

(a) Verify with the pipe manufacturer that the material specified can be produced. For example: Larger sized DIP may be available in Pressure Class instead of Class of Pipe.

(b) The design pipeline must be reviewed for acceptable working pressure and cover over the pipe and Special Provisions to the Specifications will be required to be submitted for review.

(5) Allowable pipe joints see Part One, Section 3 (Pipe and Fitting Joints).

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b) PVC - AWWA C900 in accordance with the Specifications with the pipe dimension ratio (DR) noted on the drawings.

(1) For pipe sizes 12-inch and smaller

(2) Pipe dimension Ratio is DR14

(3) Operating pressure, allowable cover and pipe dimension ratio (DR); see Part One, Section 4

(Selection of Pipe Material) for design information.

(4) Allowable pipe joints see Part One, Section 3 (Pipe and Fitting Joints).

(5) Alternatives to the insulating flanges for 12-inch and smaller ductile iron water mains, as shown in Standard Details C/3.1, C/3.2, and C/3.3, see Standard Detail C/3.2a for PVC insulating spool. For operating pressure, allowable cover and pipe dimension ratio (DR), see Part One, Section 4 (Selection of Pipe Material) for design information.

c) Steel Pipe. The use of steel pipe for water pipelines is for special cases only, where it proves to be the most suitable material for the particular design.

(1) Pipe in accordance with AWWA M-11 (Steel Pipe - A Guide for Design and Installation) and AISI Welded Steel Pipe, Steel Plate Engineering Data, Volume 3.

(2) Use E' [Modulus of soil reaction] for soil shall be four hundred (400) psi.

(3) Specify continuous interior lining and exterior coatings and cathodic protection system.

(4) Joints:

(a) For 42-inch and smaller steel pipe shall be continuous butt-welded joints.

(b) For 48-inch and larger steel pipe double lap weld joints

(5) Design for steel pipeline generally the same as for DIP.

d) Copper Pipe. See Part One, Section 25 (Water Service Connections).

c. Fittings.

1) Standard Fitting Material.

a) Fittings for DIP and PVC in accordance with the Specifications and the following:

(1) Ductile iron in accordance with AWWA C110 or AWWA C153.

(2) All Ductile Iron Fitting shall have fusion bond epoxy coating in accordance with AWWA

C116

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(3) Polyethylene encasement; see requirements for DIP material.

(4) Standard exterior coating in accordance with the Specifications. The design may require special coatings or protection; see Part Three, Section 28 (Corrosion Control).

(5) Fittings larger than 48-inch diameter are to be designed for a working pressure rating of 150 psi. 48-inch and smaller diameter fittings are to be designed for a working pressure rating of 250 psi.

(a) Each fitting’s working pressure must be reviewed and if the working pressure is over the pressure rating of the fitting, then approval and Special Provisions to the Specifications will be required.

(6) For allowable joints on fittings see Part One, Section 3 (Pipe and Fitting Joints).

(7) For allowable fittings and special design requirements see Part One, Section 7 (Allowable

Fittings).

b) Fittings for Steel Pipe. The use of fittings for steel pipelines is for special cases only see requirements for steel pipe in this section.

(1) Fittings in accordance with AWWA M-11 (Steel Pipe - A Guide for Design and Installation) and AISI Welded Steel Pipe, Steel Plate Engineering Data, Volume 3.

(2) Specify continuous interior lining and exterior coatings and cathodic protection system.

(5) Joints:

(c) For 42-inch and smaller steel pipe shall be continuous butt-welded joints.

(d) For 48-inch and larger steel pipe double lap weld joints.

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3. Pipe and Fitting Joints.

a. Specifications Requirements.

1) DIP in accordance with the Specifications, and AWWA C110, C111 and C115.

2) PVC pipe in accordance with the Specifications and AWWA C900 and C907.

3) For joints on Steel Pipe, see requirements in Part One, Section 2 (Pipe Materials and Fittings).

b. Types of Allowable Joints.

1) For DIP 54-inch and smaller allowable joints include:

a) Mechanical joint bell.

b) Plain end (for mechanical joint or push-on).

c) Push-on bell joints. Restrain joints, if required, by means of a restrained joint gasket for pipe sizes 4-inch through 24-inch and proprietary restrained joints for pipe sizes 16-inch and larger.

d) Flanged joints.

(1) Two class of flanges:

(a) Class 125 flanges in accordance with AWWA C110.

(b) Class 250 flanges in accordance with ANSI B/16.1, full-face gaskets.

(2) Buried flanged joints are generally not desirable because of the rigidity of the joint, however, the use of buried insulated flanged joint is allowed; see Insulating Joints, this section.

(3) Design all vault and interior building piping and fittings with flanged pipe, except as follows:

(a) Tapping sleeve and valve in vaults.

(b) Mechanical joint solid sleeves in vaults, if used in lieu of mechanical couplings. See requirements for Solid Sleeves and Mechanical Couplings under Part One, Section 7 (Allowable Fittings).

(4) When connecting to Class 250 flanged gate valve, the flanged connecting pipe must have

ANSI B16.1, Class 250 flanges. For design limitations see Design Requirements for Gate Valves, Part One, Section 18 (Pipeline Valves).

(5) 54-inch diameter, ANSI B16.1, Class 250 flanges may not be available. Verify availability during the design.

(6) Flanged joints are considered as a restrained joint.

2) For PVC 12-inch and smaller: Push-on bell joints.

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3) For Steel Pipe: Continuous butt-welded pipe joints, unless otherwise approved.

c. Joint Requirements for Pipe and Fittings.

1) Pipe Joints.

a) DIP and PVC pipes must use push-on bell joints unless otherwise noted on the drawings or Standard Details.

b) Mechanical joint bell for DIP may be used in the design for pipe sizes 24-inch and smaller diameter. Verify the availability of pipe sizes before specifying in the design.

c) Flanged joints for DIP require a minimum class 54 DIP and that the flanges are threaded and screwed on the pipe by the manufacturer in accordance with AWWA C115.

d) For requirements for polyethylene encasement or special coatings, see Part One, Section 4

2) Fitting Joints.

a) For DIP, the allowable fitting joints includes:

(1) Mechanical joint or push-on bell joints for 48-inch and smaller pipe sizes in accordance with AWWA C110. Push-on bell joints for compact fittings in accordance with AWWA C153, unless otherwise noted on the drawings or Standard Details.

(2) For 54-inch fittings, push-on bell joints in accordance with AWWA C153 and the manufacturer's standards. Special considerations for operating pressure over 150 psi; see Part One, Section 2 (Pipe Material and Fittings) and Part One, Section 4 (Selection of Pipe Material).

(3) Flanged joints see Type of Joints under this section.

3) For joint deflection design criteria, see Part One, Section 12 (Allowable Joint Deflections) and

Section 14 (Joint Deflections at Fittings).

d. Insulated Joint Requirements.

1) Flanged DIP short piece (flanged by plain end) is allowed, however this is the only case in which flanged joints are approved for use in direct buried pipelines, see Standard Details C/3.1, C/3.2 and C/3.3.

2) PVC insulating spool is allowed as an alternative to an insulating flange for 12-inch and smaller ductile iron water mains, see Part One, Section 4 (Selection of Pipe Material), and Standard Detail C/3.2a.

3) For the design criteria for insulating joints, see Standard Details and Part Three, Section 28

(Corrosion Control).

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2017 W-4.1

4. Selection of Pipe Material.

1) Allowable water pipe material for routine projects in accordance with the Specifications are as follows:

a) Water Pipelines:

(1) DIP or PVC for pipelines 12-inch diameter and smaller.

(2) DIP for pipelines larger than 12-inch diameter.

b) Water services:

(1) Copper tubing for water house services 2-inch diameter and smaller.

(2) DIP for 4-inches to 12-inch diameter.

2) In the General Notes indicate the minimum pipe class designation.

a) On the profiles when required, indicate the change in pipe class designation and give stations to show the limits of pipe class designation.

3) For special projects, when pipe diameters exceed 54-inch or for special applications, the WSSC may require a special pipe material, such as steel.

b. Determining Pipeline Cover.

1) Determine the maximum pipeline cover using the largest differential between the profile grade or ground line shown on profile and the pipe crown.

c. Selection of Pipe Material, Pipe Class and Pipe Wall Thickness.

1) Copper tubing. See Specifications.

2) DIP in accordance with AWWA C151. The design for DIP shall be based on the allowable cover over the pipeline and the following:

a) Class of DIP, in accordance with AWWA C151 as specified as Special Pipe Classes.

(1) In the General Notes on the drawings, indicate the minimum class of pipe for DIP required for the project.

(2) On the profile indicate by pipeline stations any changes to the class of pipe.

(3) Minimum class 54 for all pipe sizes. For determining actual class of pipe higher than the minimum class 54, see the following:

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(a) Class of pipe (i.e. wall thickness) is indicated in Standard Detail W/6.0 and differs for various depths of cover. Use Standard Detail W/6.0 for determining allowable earth cover over DIP. Standard Detail W/6.0 assumes that bedding and backfill are in accordance with the Specifications and the classes of pipe are adequate for all operating pressures in the WSSC’s water distribution system. For depth of cover greater than Standard Detail W/6.0, see “Depth of Cover for DIP Greater Than WSSC Requirements” in this section.

(b) Larger than 48-inch diameter may not be manufactured in accordance with the

Specifications. Verify with the pipe manufacturers that the material specified can be produced. Example: Larger size DIP may be available in Pressure Class instead of Class of Pipe. The pipeline design must be reviewed for allowable working pressure and cover over the pipe, and Special Provisions for Pressure Class must be added to the Specifications, see requirements under Part Three, Section 6, (Modifications to Specifications and Standard Details).

(c) Pipelines with welded-on connections see Part One, Section 7 (Allowable Fittings).

(d) Flanged pipe, minimum class 54, in accordance with AWWA C115.

(e) Pipelines designed within MSHA right of way, see Wall Thickness of DIP for Special

Applications, in this section.

(4) Pipeline crossing under a railroad; verify with the railroad authority the requirements for crossing its property or right of way.

(a) When crossing under Maryland Transit Administration (MTA) Rail Lines, see Part Three, Section 3 (Pipeline Crossings and Clearances).

(5) Pipelines within tunnels and casing pipes see Part One, Section 17 (Tunnels or Casing

Pipes) and Part Three, Section 26 (Tunnel Design Criteria)

3) PVC pipe in accordance with AWWA C900 for 12-inch and smaller diameters. The design for PVC pipe shall be based on the operating pressure and cover over the pipeline.

a) Pipe dimension ratio for PVC AWWA C900.

(1) For 4-inch through 12-inch diameter:

(a) Use only AWWA C900 DR14 Pipe Dimension Ratio (DR).

(b) Maximum operating pressure is one hundred thirty (130) psi.

b) Allowable cover for PVC Pipe AWWA C900.

(1) For allowable cover over PVC pipe use Standard Detail W/6.1. Allowable cover differs for varying DRs and trench backfill. Standard Detail W/6.1 assumes bedding and backfill are in accordance with the Specifications.

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c) Design limitations.

(1) PVC pipe has a strict limitation on joint deflections; see Part One, Section 12 (Allowable Joint Deflections).

(2) Do not use PVC pipe for fire hydrant lead piping and for water house connections.

d) Information required on the Drawings.

(1) In the General Notes on the drawings, indicate the pipe dimension ratio (DR 14) for PVC Pipe.

(2) All fitting on PVC AWWA C900 pipe shall be fusion bonded ductile iron fittings, all fittings, valves and tapping sleeve and valves, hydrants, saddles and retrain joints shall have anode protection; See Standard Details C/7.0, C/7.1, C/7.2, C/7.3, C/7.4, C/7.5, C/7.6, C/7.7, C/7.8, C7.9, C7.10 and C/7.11

(3) If granular material bedding is required due to the depth of cover, see "Allowable cover for

PVC (AWWA C900)" in this section. Show on the profile by pipeline stations the required limits of granular material bedding and provide a note for borrow aggregate within the pipe embedment zone for Standard Detail M/8.1a.

(4) PVC AWWA C900 water mains require a tracer wire on top of the PVC pipe, in accordance with the Specifications.

(a) The tracer wire shall be placed on top of the PVC AWWA C900 pipe and to be connected to a Continuity Test Stations; see Standard Details W/9.0 and W/9.1.

[1] Locate Continuity Test Stations next to all fire hydrants; see Standard Details W/9.1.

[2] If spacing between Continuity Test Stations is over eight hundred (800) feet, provide

Continuity Test Stations every five hundred (500) feet; see Standard Details W/9.0.

[3] Locate Continuity Test Stations at every connection to existing water mains and every plug or cap fitting; see Standard Details W/9.0.

(4) PVC Insulating Spool is allowed for 12-inch and smaller mains, if the operating pressure, pipe dimension ratio and allowable cover are within the limits allowed; see Standard Detail C/3.2a.

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d. Determining Type of Pipe Material

1) For determining pipe material to be used in design, see Chart “E”.

Design using AWWA C900 PVC or

Zinc Coated DIP with V-BIO

See requirements under Chart "D"

Design using Coated DIP with

Cathodic Protection

Operating Pressure 130 psi or less

Yes

Design using Zinc Coated DIP with V-BIO No

Pipe Size 12-inch and smaller

Pipe Size 12-inch and smaller

Severe Exposure or Moderate Exposure with Ground Water

N o

Ye s

Design using AWWA C900 PVC or

Coated DIP with Cathodic Protection

Operating Pressure 130 psi or less

Yes

N o

Design using Coated DIP with

Cathodic Protection

Design using Zinc Coated DIP with V-BIO No

Pipe Size 16 to 20-inch Severe Exposure

Yes

Pipe Size 24-inch and

Larger

See requirements under Chart "D"

See requirements under Chart "D"

CHART "E"

Selection of Pipe Material

NOTE:

For Chart "D", see Part Three, Section 28, Corrosion Control

e. Depth of Cover for DIP Greater Than WSSC Requirements.

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1) For depths of cover greater than shown in Standard Detail W/6.0, or for other special conditions, the wall thickness for DIP must be calculated in accordance with the method in AWWA Standard C150/ANSI A.21.50. Use the assumption of Laying Condition Type 1 for pipe sizes 24-inch and smaller and Laying Condition Type 3 for pipe sizes larger than 24-inch.

2) Based on the calculated thickness, select a class of pipe greater than class 54. The thickness of the selected class must be equal to, or greater than, the calculated thickness.

f. Wall Thickness of DIP for Special Applications.

1) Wall thickness criteria for DIP for the following special applications are not covered in the Standard Details and additional consideration/calculations are required in the following situations:

a) Pipe on supports or hangers, e.g. bridge crossings.

b) Shallow cover, less than two and one half (2-1/2) feet.

c) Vehicular or equipment loading greater than AASHTO H-20 or HS-20 loads configuration.

d) Operating pressures greater than those found in the WSSC’s water distribution system.

e) Surges exceeding allowances given in the Specifications and under Part One, Section 5 (Total Internal and Transient Pressures).

f) Certain vacuum conditions; see Part One, Section 6 (Buckling Design).

g) When the pipeline crosses under a railroad, verify with the Railroad Authority, the requirements for crossing its property or right of way.

h) When required under Part Three, Section 28 Corrosion Control.

i) When pipelines are to be designed within MSHA right of way for highways, design the pipeline as follows:

(1) MSHA definition for types of highways (from MSHA Utility Policy, dated March 1998).

Contact the MSHA for current guidelines.

(a) Expressways are divided highways, with full control of access, on which all crossroads are grade separations and all entrance and exit maneuvers are via interchange ramps.

Expressways are primarily designed for high speed, long distance travel with unrestricted movement of traffic and no direct access to abutting properties.

(b) Controlled Access Highways are a higher class of highway and usually incorporate access control. Controlled access designations severely restrict the use of highway right of way for any purpose other than its primary function. Controlled access limits are denoted on MSHA drawings and plats by the words "Right of Way of Through Highway".

(2) Requirements stated below are only for pipelines within MSHA's right of ways and are only

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2017 W-4.6 general guidelines. Verify additional requirements with MSHA.

(a) Pipelines passing through MSHA's highways.

[1] All pipelines crossings must be in a sleeve, tunnel or have the class of DIP increased to the next higher class of pipe.

(b) Longitudinal occupancy by pipelines within MSHA's right of way for highways.

[1] Expressways. No longitudinal occupancy by new pipelines is permitted.

[2] Controlled Access Highways. Longitudinal occupancy is permitted by special exemption.

During the design, obtain written exemption from MSHA.

[3] Roadways other than Expressways and Controlled Access Highways. Longitudinal occupancy is permitted; see MSHA Utility Policy, dated March 1998.

j) When pipelines are to be designed near or within Maryland Transit Administration (MTA) Rail

Lines, see Part Three, Section 3 (Pipeline Crossings and Clearances) and Part Three, Section 26 (Tunnels Design Criteria).

g. When pipelines are to be designed near or within Marlboro Clay

1) See requirements under Part 3, Section 19, Geotechnical Considerations for Crossing Pipeline Alignments.

2) Design using DIP and restrain all joints at a minimum, see recommendations from Geotechnical Report.

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5. Total Internal and Transient Pressures.

a. Total Internal Pressure.

1) Determine total internal pressure for water mains from the following equation:

Total Pressure Operating Pressure Surge Pressure

a) Operating Pressure is based on ductile iron pipe

b) Surge pressure used by WSSC for ductile iron pipe.

(1) PVC AWWA C900.

(a) The pipe can sustain a total working pressure based on an operating pressure of one-hundred and thirty (130) psi and a surge allowance based on normal surge pressure allowances used by WSSC for DIP, see Table “1”. PVC may not be used if the operating pressure exceeds 130 psi.

b. Operating Pressure.

1) The operating pressure (also referred to as the working pressure) of buried water pipelines is a function of the pipe elevation. Therefore, the operating pressure (and total pressure) varies at different elevations along the pipeline.

a) Calculate the operating pressure using the following equation:

(HHG in feet pipe invert elevation in feet) 0.433 Operating Pressure in lbs/in2

2) To determine the applicable HHG, the following is required:

a) New Pipeline Designs, obtain the HHG and LHG from WSSC Planning Group.

b) Existing Water Pipelines, the HHG used for the original design of the existing pipeline can be obtained typically from the lower left-hand corner or in the General Notes on the record (as-built) drawings. If the HHG is not indicated on the record drawings, then it may be obtained from WSSC. Prior to performing any new investigations or evaluations of existing water mains, verify with the WSSC if the HHG shown on the record drawings is applicable.

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c. Surge (Transient) Pressures.

1) Use Table "1" for standard surge pressures for the design of water pipelines:

TABLE "1"

Surge Pressures

Pipeline Diameter in inches

Surge Pressure in lb/in2

Pipeline Diameter in inches

Surge Pressure in lb/in2

4 to 10 120 30 80

12 to 14 110 36 75

16 to 18 100 42 to 60 70

20 90 Greater than 60 65

24 85 -- --

2) Assure that the design does not create conditions which will result in surge pressures greater than the values shown in Table "1", and no greater than the surge pressure allowances used for the design of adjacent pipelines.

3) Exercise sound…