Guidelines for Thrust Blocks

Design Guidelines for Water and Sewer Facilities MASTER TABLE OF CONTENTS

SECTION

SECTION NAME

APPROVAL DATE

Introduction Signatory Agencies Technical Review Standard Terms and Definitions

09/07/2004 09/07/2004 09/07/2004 09/07/2004

2 1 1 3

09/07/2004 09/07/2004 Future Release 05/02/2006 09/07/2004 09/07/2004 09/07/2004

11 10 5 6 5 3

09/07/2004 09/07/2004 09/07/2004 09/07/2004 09/07/2004

5 12 4 4 11

09/07/2004 09/07/2004 09/07/2004 05/02/2006 09/07/2004

2 6 3 13 4

09/07/2004 09/07/2004 09/07/2004 09/07/2004 09/07/2004 09/07/2004 05/02/2006

13 8 5 6 11 5 5

1.0

GENERAL

1.1 1.2 1.3 1.4 1.5 1.6 1.7

Drafting Guidelines AutoCAD Guidelines MicroStation Guidelines Land Acquisition and Disposition Easements and Encroachments Survey Standards Guideline Record Drawing Guidelines

2.0

PRIVATE DEVELOPMENT PROJECTS

2.1 2.2 2.3 2.4 2.5

Procedural Guidelines Development Plan and Permit Processing Procedures Water Facility Guidelines Sewer Facility Guidelines Recycled Water Facility Guidelines

3.0

AGENCY IMPROVEMENT PROJECTS

3.1 3.2 3.3 3.4 3.5

Agency Capital Improvement Projects Design Project Progress Submittals Submittals (Shop) Project Cost Estimates Technical Specifications

4.0

PLANNING

4.1 4.2 4.3 4.4 4.5 4.6 4.7

Water Planning Sewer Planning Recycled Water Planning Sub-Area Master Plan Development Environmental Review National Pollutant Elimination System (NPDES) Other Agency Permits

WAS Design Guidelines

Master Table of Contents Page 1 of 3

PAGES

Revised: 09/26/2007

Design Guidelines for Water and Sewer Facilities MASTER TABLE OF CONTENTS CONTINUED

APPROVAL DATE

SECTION

SECTION NAME

5.0

WATER PIPELINE DESIGN

5.1 5.2 5.3 5.4 5.5 5.6 5.7

Pressure Pipeline Design Thrust Restraint and Anchor Blocks Line Valves Selection and Placement Fire Hydrants and Fire Services Air Valves Blowoffs Water Services and Test Stations

6.0

SEWER PIPELINE DESIGN

6.1 6.2 6.3 6.4

Gravity Sewer Pipeline Design Sewer Manholes and Cleanouts Sewer Laterals Pressure Systems (Force Mains)

7.0

RESERVOIR DESIGN

7.1 7.2

Storage Facilities Seismic Sensing Devices

8.0

CONTROL VALVES

8.1 8.2 8.3

Pressure/Flow Control Stations Vaults & Equipment Agency Interconnections

9.0

WATER PUMP STATION DESIGN

9.1 9.2 9.3

Water Pump Station Design Structural Guidelines Noise Control Guidelines

10.0

SEWAGE PUMP STATION DESIGN

10.1 10.2

Sewage Pump (Lift) Station Design Surge Control/Analysis

WAS Design Guidelines

Master Table of Contents Page 2 of 3

PAGES

09/07/2004 09/26/2007 09/26/2007 09/07/2004 09/07/2004 09/07/2004 09/07/2004

6 8 5 4 4 4 6

09/07/2004 09/07/2004 09/07/2004 05/02/2006

5 5 4 5

05/02/2006 Future release

32

05/02/2006 Future Release Future Release

6

05/01/2007 05/01/2007 05/01/2007

37 12 18

Future Release Future Release

Revised: 09/26/2007

Design Guidelines for Water and Sewer Facilities MASTER TABLE OF CONTENTS CONTINUED

APPROVAL DATE

SECTION

SECTION NAME

11.0

CORROSION CONTROL

11.1 11.2

Pipeline Corrosion Control Systems Reservoir Corrosion Control Systems

12.0

SPECIALIZED DESIGN

12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8

Bridge Crossings Trenchless Construction Pipe Bursting Railroad and Freeway Crossings Pipe Rehabilitation Temporary Above Ground Piping (Water) Temporary Bypass Requirements (Sewer) Facility Security Guidelines

13.0 A B

PAGES

Future Release Future Release

05/02/2006 05/02/2006 05/02/2006 05/02/2006 05/01/2007 05/02/2006 05/02/2006 Future Release

8 9 8 2 8 5 3

09/07/2004 09/07/2004

3 5

APPENDICES Revisions Units of Measurement

WAS Design Guidelines

Master Table of Contents Page 3 of 3

Revised: 09/26/2007

WATER AGENCIES’ STANDARDS Design Guidelines for Water and Sewer Facilities SECTION 5.2 THRUST RESTRAINT AND ANCHOR BLOCKS

5.2.1

PURPOSE The purpose of this section is to provide guidelines for the design of thrust blocks and anchor blocks for underground pressure pipelines. In general, thrust blocks and anchor blocks are required to provide thrust restraint to counteract forces created by the contents of underground pressure pipelines. For design specific to steel pipelines the reader should also refer to AWWA M-11.

5.2.2

STANDARD TERMS AND DEFINITIONS Wherever technical terms or pronouns are used in these guidelines or in related documents, the intent and meaning shall be interpreted as described in industry accepted nomenclature and reference materials.

5.2.3

GENERAL It is the responsibility of the user of these documents to refer to and utilize industry standards not directly referenced within this document as necessary. The Engineer of Work may not deviate from the criteria presented in this section without prior written approval of the Agency’s Engineer.

5.2.4

GUIDELINE Thrust blocks and anchor blocks are not required on steel pipe with welded joints where, in the opinion of the Agency’s Engineer, pipe design provides adequate thrust restraint. In addition, thrust blocks and anchor blocks are not required on steel or ductile-iron pipe with flanged joints if sufficient thrust restraint has been achieved by the restraint system. For design of collar, wrapper and crotch plates for steel pipe refer to AWWA M-11. Thrust blocks and anchor blocks may also be eliminated in locations where thrust-restraining fittings (including flanged fittings) are utilized along with thrust-restraining pipe joints, provided that thrust restraint systems are designed by the Engineer of Work in accordance with the manufacturers’ instructions, are approved by the Agency’s Engineer, and are shown on the Approved Plans. The design and sizing of thrust blocks and anchor blocks shall conform to the following guidelines: A.

Thrust blocks or anchor blocks are required on all unrestrained pressure pipelines at locations where thrust forces caused by internal pressures act upon the sides or ends of pipelines. 1.

WAS Design Guidelines

Thrust blocks are required at all unrestrained tees, wyes, reducers, horizontal bends, ascending vertical bends, and dead-ends. Since the act of closing an inline valve creates a dead-end, valves not connected to other fittings also require thrust blocks. Section 5.2 Page 1 of 8

Revised: 09/26/2007

2. B.

5.2.5

Anchor blocks are required at all unrestrained descending vertical bends.

Thrust blocks and anchor blocks shall be formed from concrete poured against wetted, undisturbed soil. Concrete materials shall be in accordance with Section 03000 of the WAS Specifications unless otherwise directed by Agency’s Engineer. Concrete shall be placed in accordance with the WAS Standard Drawing WT-01 and such that fittings and valves are accessible for repairs or replacement.

THRUST CALCULATIONS Pipeline thrust shall be calculated using the following formulae. Calculations below use standard American units. A.

Pipeline thrust at tees, wyes, in-line valves, and dead-ends:

T = 0.25πpd 2 Where:

T = resultant thrust force (lb), p = internal pressure (lb/in2), and d = outside diameter of side (branch) outlet piping (for tees or wyes) or dead-end pipe (in).

B.

Pipeline thrust at bends:

T = 0.50πpd 2 (sin Δ / 2) Where:

C.

T p d Δ

= resultant thrust force (lb), = internal pressure (lb/in2), = outside diameter of pipe adjacent to bend (in), and = true angle of bend (degrees).

Pipeline thrust at reducers:

T = 0.25πp( D 2 − d 2 ) Where:

T = resultant thrust force (lb), p = internal pressure (lb/in2), D = outside diameter of pipe adjacent to the large end of the reducer (in), and

d = outside diameter of pipe adjacent to the small end of the reducer (in). D.

Pipeline thrust at crosses: For the most conservative approach and due to the fact that valves can be placed at crosses on any leg and the valve then closed the designer should use the approach above in Item B. for pipeline thrust at bends. The only difference is the angle at a cross will always be 90°.

WAS Design Guidelines

Section 5.2 Page 2 of 8

Revised: 09/26/2007

E.

Thrust Table for C900/C905 PVC: The following tables show the thrust, in pounds, resulting from the installation of the noted fittings per 100 lb/in2 of hydrostatic pressure applied to C900 and C905 PVC Pipe. For instance, if the required design pressure is 235 lb/in2, multiply the values in the table by 2.35. Note that the design pressure is the class of pipe. The safety factor in conjunction with using the class of pipe as the design pressure provides sufficient redundancy for hydro-test conditions and minor surges for both thrust and anchor blocks. Values in the following tables are identical to those derived from the formulae shown above and are listed for convenience. Refer to AWWA M23 Manual of Water Supply Practices for more detail. Thrust values for all other pipe materials shall be calculated by the Engineer of Work. Table 1 – Sample Table Thrust for AWWA C900 PVC Pipe (lb) Tees, Wyes, Pressure 90° 45° 22.5° Valves, (lb/in2) and Bend Bend Bend Dead Ends 100 1,810 2,559 1,385 706

Nominal Pipe Size (in)

Average Outside Diameter (in)

4

4.80

6

6.90

100

3,739

5,288

2,862

1,459

8

9.05

100

6,433

9,097

4,923

10

11.10

100

9,677

13,685

12

13.20

100

13,685

19,353

11.25° Bend

Class

355

200

733

200

2,510

1,261

200

7,406

3,776

1,897

200

10,474

5,340

2,683

200

Table 2 – Sample Table Thrust for AWWA C905 PVC Pipe (lb) Tees, Wyes, Pressure Valves, 90° 45° 22.5° (lb/in2) and Dead Ends 100 18,385 26,001 14,072 7,174

11.25°

Class

3,604

165/235

Nominal Pipe Size (in)

*Outside Diameter (in)

14

15.30

16

17.40

100

23,779

33,628

18,199

9,278

4,661

165/235

18

19.50

100

29,865

42,235

22,858

11,653

5,855

165/235

20

21.60

100

36,644

51,822

28,046

14,298

7,183

165/235

24

25.80 100 52,279 73,934 40,013 20,398 10,249 165/235 * The outside diameter is the same for both Class 165 and Class 235 PVC pipe. The thrust values are per 100 lb/in2.

5.2.6

ALLOWABLE SOIL BEARING CAPACITY Calculations to determine the size of thrust blocks or valve support blocks shall use the results of soil bearing capacity tests performed by a qualified geotechnical engineer when such test results are available. In the absence of such test results, allowable soil bearing capacity shall be determined by using the following table:

WAS Design Guidelines

Section 5.2 Page 3 of 8

Revised: 09/26/2007

Chart 1 – Estimated Bearing Strength (Undisturbed Soil) Type of Soil Allowable Soil Bearing Capacity Muck, peat, etc.* 0 lb/ft2 Soft Clay 500 lb/ft2 Fine Sand 1,000 lb/ft2 Decomposed Granite (D.G.) 1,500 lb/ft2 Sandy Gravel 2,000 lb/ft2 Cemented Sandy Gravel 4,000 lb/ft2 Hard Shale 5,000 lb/ft2 Granite 10,000 lb/ft2 *In muck, peat or other incompetent soils, resistance shall be achieved by removal and replacement with ballast of sufficient stability to resist the intended thrusts. Design of thrust restraint systems in such cases shall be prepared by a qualified geotechnical engineer and shall be approved by the Agency’s Engineer.

5.2.7

THRUST BLOCKS A.

Thrust blocks shall be installed on unrestrained pressure pipelines at all tees, wyes, reducers, horizontal bends, ascending vertical bends, and dead-ends, and shall bear directly against fittings and firm, wetted, undisturbed soil. Thrust blocks shall be located so that bearing areas on both fittings and soil are centered along the direction of thrust. For tees and wyes, the direction of thrust is along a line directly opposite the side outlet. For bends, the direction of thrust is along a line bisecting the outside angle formed by the adjacent pipe segments. For reducers, the direction of thrust is along the pipeline from the large end to the small end of the reducer. For dead-ends, including in-line valves, the direction of thrust is along the pipeline.

B.

The required minimum area, in square feet, that a concrete thrust block must bear against undisturbed soil shall be in accordance with the following formula:

A=

T (SF ) Sb

Where:

A = area of thrust block (ft2), T = resultant thrust force (lb), S b = allowable soil bearing capacity (lb/ft2), see Chart 1 for values, and

SF = safety factor (Use 1.5) A passive resistance thrust block design is required if the height of the thrust block is greater than 0.5 times the depth from finish grade to the bottom of the designed thrust block. The required thrust block area using this method can be calculated as follows:

A=

T ( SF )

γH t N d + 2C s N d

Where:

A = area of thrust block (ft2), T = resultant thrust force (lb), SF = safety factor (Use 1.5),

γ

= unit weight of soil (lb/ft3), use appropriate soil value,

H t = total depth to bottom of block (ft), WAS Design Guidelines

Section 5.2 Page 4 of 8

Revised: 09/26/2007

N d = tan2 (450+ F/2),

Cs Note:

F = soil internal friction angle (degrees), use appropriate soil value, = soil cohesion (lb/ft2), use appropriate soil value

The thrust block area using the passive resistance thrust block design is generally larger than what is shown in Table 3. The engineer shall calculate thrust block sizes for this condition based upon each specific case. Refer to AWWA M23 Manual of Water Supply Practices for more detail.

The formulas above do not consider the weight of pipe and fittings. The Engineer of Work may alternately supply thrust block calculations that include the weight of the pipe and fittings to be restrained. Such alternate calculations shall be submitted to the Agency’s Engineer for review and approval. An undisturbed section of trench wall adjacent to the fitting and centered in the direction of thrust shall be excavated to dimensions providing the minimum bearing area calculated from the formula given above. In general, the bearing area shall be as close to square as is possible given actual field conditions. The shape and location of all thrust block excavations shall be approved by the Agency’s Engineer prior to placing concrete. Thrust block excavations shall be keyed a minimum of twelve inches (12”) into undisturbed soil. Table 3 – Sample Table Thrust Block Size for PVC Pipe (ft2) Design Pressure = Class of Pipe; Sb=1,500 lb/ft2; SF=1.5 Nominal Pipe Size (in)

Average Outside Diameter (in)

Tees, Wyes Valves, and Dead Ends

90° Bend

45° Bend

22.5° Bend

11.25° Bend

Class

4

4.80

3.6

5.1

2.8

2.0

2.0

200

6

6.90

7.5

10.6

5.7

2.9

2.0

200

8

9.05

12.9

18.2

9.8

5.0

2.5

200

10

11.10

19.4

27.4

14.8

7.6

3.8

200

12

13.20

27.4

38.7

20.9

10.7

5.4

200

14

15.30

30.3

42.9

23.2

11.8

5.9

165

16

17.40

39.2

55.5

30.0

15.3

7.7

165

18

19.50

49.3

69.7

37.7

19.2

9.7

165

20

21.60

60.5

85.5

46.3

23.6

11.9

165

24

25.80

86.3

122.0

66.0

33.7

16.9

165

14

15.30

43.2

61.1

33.1

16.9

8.5

235

16

17.40

55.9

79.0

42.8

21.8

11.0

235

18

19.50

70.2

99.3

53.7

27.4

13.8

235

20

21.60

86.1

121.8

65.9

33.6

16.9

235

24

25.80 122.9 173.7 94.0 47.9 24.1 235 * The values in this table were obtained assuming an allowable soil bearing capacity of 1500 lb/ft2 for decomposed granite and per 100 lb/in2. Differing soil conditions may apply.

WAS Design Guidelines

Section 5.2 Page 5 of 8

Revised: 09/26/2007

C.

Thrust blocks are required for in-line valves not located adjacent to pipe fittings. Deadend thrust is created when such valves are closed for repair or maintenance. Thrust blocks for in-line valves not located adjacent to pipe fittings shall be designed by the Engineer of Work for the approval of the Agency’s Engineer and shall be detailed on the Approved Plans. Concrete valve support blocks as described in Section 5.3 are not intended to provide thrust restraint, and cannot be substituted for concrete thrust blocks.

D.

Concrete support blocks are required for all valves and fittings.

E.

Thrust blocks are to be placed in accordance with WAS Standard Drawing WT-01.

5.2.8

ANCHOR BLOCKS A.

Anchor blocks shall be located at all unrestrained descending vertical bends. Thrust blocks are not suited for such applications because excavation necessarily disturbs soil in the direction of thrust. Anchor blocks rely on the weight of the concrete used to restrain thrust. Anchor blocks must include as a minimum two (2) number four (#4) steel reinforcing bars with 2-inch minimum concrete embedment as directed by the Agency’s Engineer to assure secure attachment to the vertical bend.

B.

The required minimum volume, in cubic feet, of concrete anchor blocks shall be in accordance with the following formula:

Volume =

T ( SF ) = B

Where:

⎛ Δ⎞ Δ 0.5πpd 2 ⎜ sin ⎟ 2⎠ ⎝ 2 ( SF ) = ( SF ) B B

2 pA sin

T = total thrust (lb), p = internal pressure (lb/in2), A = area of pipe using outside diameter (in2) B = density of block material, lb/ft3 (approximately 140 lb/ft3), SF = Safety Factor (suggest 1.5) Δ = true angle of bend (degrees).

The formula above does not consider the weight of pipe and fittings. The Engineer of Work may alternately supply anchor block calculations that include the weight of the pipe and fittings to be restrained. Such alternate calculations shall be submitted to the Agency’s Engineer for review and approval. In addition, the buoyant density of the thrust block material must be used if it is anticipated that the soil could become saturated or if the water table is above the thrust block elevation. The shape and location of all anchor blocks shall be approved by the Agency’s Engineer prior to placing concrete.

5.2.9

NOTATIONS ON PLANS A.

WAS Design Guidelines

The Engineer of Work shall show the results of calculations for all thrust blocks and anchor blocks on the Approved Plans.

Section 5.2 Page 6 of 8

Revised: 09/26/2007

B.

Results of calculations for all thrust blocks and anchor blocks may be individually noted in plan drawings at the location(s) required, or may be presented in the form of a clear and complete “Thrust/Anchor Block Table.” Thrust block and anchor block information shall include pipe station, type of block (Thrust or Anchor), test pressure, total thrust, assumed or tested soil capacity, and area or volume of block(s) required. If Thrust/Anchor Block Table(s) are used, they shall be shown on the same plan sheet as the fittings for which the thrust block(s) or anchor block(s) are required. An example of a typical Thrust/Anchor Block Table is shown in Figure A below: FIGURE A Sample Table THRUST/ANCHOR BLOCK TABLE

Pipe Sta.

Type/ Dia, of Pipe

Type of Block

Type of Appurtenance

Design Pressure

Total Thrust

3+52.50

PVC/8”

Thrust

22.5° Hor Bend

200 lb/in2

6+10.00

PVC/8”

Thrust

45° Hor Bend

200 lb/in2

6+20.00

PVC/8”

Anchor

22.5° Vert Bend

200 lb/in2

6+30.00

PVC/8”

Anchor

45° Vert Bend

200 lb/in2

5,020 lb 9,847 lb 5,020 lb 9,847 lb

Assumed Soil Capacity

Area or Volume of Block

1,500 lb/ft2

5.0 ft2

1,500 lb/ft2

10.0 ft2

*N/A

54.0 ft3

*N/A

105.5 ft3

* The specific weight of concrete is 140lb/ft3. The example table shown above is intended to be representative only. Any similar format that conveys all information required to size thrust blocks and anchor blocks is acceptable. Calculated areas or volumes shown in Thrust/Anchor Block tables shall be rounded up to the next ½ ft2 or ½ ft3. In the example above, an assumed soil capacity of 1,500 lb/ft2 is used. If soil bearing capacities are assumed, and, in the opinion of the Agency’s Engineer, soils actually encountered on-site are not equal to or better than those assumed, the Engineer of Work shall promptly recalculate thrust block sizes based on observed soil conditions or on soil capacity tests and transmit such recalculations to the Agency’s Engineer. If thrust block calculations rely upon the results of soils capacity tests, the appropriate column shall be labeled “Tested Soil Capacity” and the soils tests shall be submitted to the Agency’s Engineer for review. C.

5.2.10

In locations where thrust-restraining fittings (including flanged fittings) and thrustrestraining pipe joints are used in lieu of concrete thrust blocks, the length of the required thrust-restraining pipe system shall be clearly delineated and noted on the pipeline profile drawing(s). Thrust restraining systems shall not be used in conjunction with thrust blocks. The Engineer of Work shall submit calculations confirming the adequacy of the thrust restraint design detailed in the drawing(s) for the review and approval of the Agency’s Engineer.

REFERENCES A.

Should the reader have any suggestions or questions concerning the material in this section, contact one of the member agencies listed.

WAS Design Guidelines

Section 5.2 Page 7 of 8

Revised: 09/26/2007

B.

The publications listed below form a part of this section to the extent referenced and are referred to in the text by the basic designation only. Reference shall be made to the latest edition of said publications unless otherwise called for. The following list of publications, as directly referenced within the body of this document, has been provided for convenience. It is the responsibility of the user of these documents to make reference to and/or utilize industry standards not otherwise directly referenced within this document.

1.

Water Agencies’ Standards (WAS) a.

Design Guidelines: 1.

b.

Standard Specifications: 1.

c.

Section 5.3, Line Valves

Section 03000 Cast in Place Concrete

Standard Drawings: 1.

WT-01

2.

AWWA M23 PVC – Design and Installation

3.

AWWA M11 Steel Pipe – A Guide for Design and Installation

END OF SECTION

WAS Design Guidelines

Section 5.2 Page 8 of 8

Revised: 09/26/2007

WATER AGENCIES’ STANDARDS Design Guidelines for Water and Sewer Facilities SECTION 5.3 LINE VALVES

5.3.1

PURPOSE The purpose of this section is to provide guidelines for the type, spacing and location of line valves on water pipeline projects.

5.3.2

STANDARD TERMS AND DEFINITIONS Wherever technical terms or pronouns occur in these guidelines or in related documents, the intent and meaning shall be interpreted as described in Standard Terms and Definitions. The following terms and definitions as found in this section shall have the following meaning: DU:

5.3.3

Dwelling Unit

GENERAL It is the responsibility of the user of these documents to make reference to and/or utilize industry standards not otherwise directly referenced within this document. The Engineer of Work may not deviate from the criteria presented in this section without prior written approval of the Agency’s Engineer.

5.3.4

GUIDELINES A.

In general, line valves are installed in distribution and transmission pipelines to isolate and depressurize pipeline segments for repairs, modifications, inspections or maintenance.

B.

Isolation of water lines during repairs, modifications, inspection or maintenance causes a temporary loss of water service within the affected area. Locations of line valves shall be based on the following considerations: 1. 2. 3. 4. 5. 6. 7.

C.

Limiting the number of customers that will be out of service, Limiting the number of fire hydrants out of service, Limiting the time it takes to drain a pipe segment, Limiting the number of customers impacted by future system modifications, Limiting future construction within major streets or intersections, Conformance to State of California Codes and Regulations Avoiding excessive number of valves thus reducing initial capital cost, exercising and maintenance of valves, and replacement costs.

Valves shall be placed on all branches of crosses and tees unless otherwise directed by the Agency’s Engineer. Valves may be placed at each street intersection on the main prior to the branch and on each branch if the system is looped in a fashion that allows isolation of each reach of pipe segment.

WAS Design Guidelines

Section 5.3 Page 1 of 5

Revised: 09/26/2007

5.3.5

D.

In high-density residential (ten (10) + DU’s per acre) areas and commercial areas, the valve placement is not to exceed one city block up to a maximum of one thousand feet (1,000’).

E.

In medium density residential (five (5) + DU’s per acre) areas, the valve placement is not to exceed one quarter (¼) mile or seventy (70) DU’s out of service.

F.

In low-density residential (two (2) + DU’s per acre) or rural areas (one (1) DU per acre), the valve placement is not to exceed one quarter (¼) mile or thirty (30) DU’s out of service,

G.

Line valves shall be incorporated into the design to ensure that no more than two (2) fire hydrants are out of service when a line valve is closed. Fire hydrants shall be spaced in accordance with Section 5.4.

H.

Valves are placed on fire hydrants and private fire service laterals, air/vacuum valves, three inch (3) and larger service connections and blow-offs in accordance with the WAS Standard Drawings.

I.

Line valves may be located between each fire hydrant and/or side connection in commercial areas as required by the Agency’s Engineer.

J.

The maximum spacing between valves on distribution lines twelve inch (12”) or less shall be one-quarter (¼) mile. The maximum spacing between valves on transmission lines sixteen inch (16”) or larger shall be one half (½) mile.

K.

For maintenance purposes the line valve spacing may be reduced to accommodate the location of blowoff, air release, and air/vacuum valves. Typically blowoff, air re release, and air/vacuum valves should be placed at no greater spacing than that which allows the pipe to be drained in the time specified in Section 5.6.

L.

Where future water main extensions are anticipated, valves shall be located on the branch line at the tee or cross and blind flanged only as directed by the Agency’s Engineer.

M.

The maximum spacing for line valves on distribution lines is governed by the one thousand three hundred twenty foot (1,320’) maximum distance recommended by the California Code of Regulations (CCR), Title 21, Public Works.

N.

Selection of valves and appurtenances to be used with the installation of valves shall be in accordance with WAS Standard Specification 15100 and 15102 and the Approved Materials List.

O.

Concrete support blocks are required for all valves, and shall be installed in accordance with the requirements shown in the WAS Standard Drawings. Concrete support blocks are not intended to provide thrust restraint when valves are operated. In locations where valves are not adjacent to pipe fittings or are otherwise not provided with thrust restraint when valves are operated, thrust blocks are required instead of support blocks. The Engineer of work shall design thrust blocks in accordance with Section 5.2.

MISCELLANEOUS VALVE INFORMATION

A.

Motor operated valves will be used in locations where valves are operated and installed in a vault or on inlet/outlets of reservoirs as required by the Agency’s Engineer. Locations shall be approved by the Agency’s Engineer during the sixty percent (60%) submittal plan review.

WAS Design Guidelines

Section 5.3 Page 2 of 5

Revised: 09/26/2007

5.3.6

B.

Installation: Valves and gate wells shall be installed at locations shown on the approved plans in accordance with the applicable sections of the WAS Standard Specification and Standard Drawings.

C.

Only resilient-seated gate valves (twelve inch (12”) or less) and butterfly valves (sixteen inch (16”) or larger) are allowed in accordance with the Approved Materials List. The Agency’s Engineer may require the use of plug valves or ball valves in high-pressure locations and other locations.

D.

Valves rated for higher pressures are available (i.e. two hundred fifty (250) psi class), but are not covered by the AWWA Standards. In these situations, valve specifications must be individually prepared to meet the requirements of each project.

E.

Vaults should have a hole cored in the lid above the valve actuator nut to allow for an extension and portable motor operator to be used to operate the valve above ground without entering a confined space.

NOTATIONS ON PLANS Valves shall be shown in the plan view portion of the sheet(s) only and include, but not limited to, the following information. A.

Standard symbols, stationing and plan callout notes shall be in accordance with Section 1.1. Note: butterfly valves shall be shown with the valve operator located to the curb line side of the water main.

B.

Valves shall be shown with the following information: • • •

Stationing of the valve. Size of valve. Refer to Figure 1 below.

Figure 1 Plan Callouts for Line Valves

5.3.7

DESIGN NOTES A.

Gate Valves: The decision to limit gate valves to a maximum size of twelve inch (12”) is based on the standard depth of cover criteria of forty-two inches (42”). Gate valves over twelve inches (12”) in size have such a tall bonnet that the operating nut is too close to finish grade. An auxiliary reason is the number of turns required to close a gate valve larger than twelve inch (12”).

B.

Butterfly Valves: Pipeline design criteria limits flow velocity to ten (10) feet per second (fps). Class 150A valves are designed for eight (8) fps, Class 150B valves are designed for sixteen (16) fps, therefore only Class 150B butterfly valves are allowed.

C.

Holes cored in the valve vault lids will allow the use of portable motor operators and reduce the need for entry into a confined space. Confined space rules significantly increase the cost of accessing vaults and therefore are avoided by designing for operation without entry by operations personnel.

WAS Design Guidelines

Section 5.3 Page 3 of 5

Revised: 09/26/2007

5.3.8

REFERENCE Reference shall be made to the latest edition of the following publications unless otherwise called for. The following list of publications, as directly referenced within the body of this document, has been provided for the users convenience. It is the responsibility of the user of these documents to make reference to and/or utilize industry standards not otherwise directly referenced within this document. 1.

Water Agencies’ Standards (WAS): a.

Design Guidelines: 1. 2. 3.

b.

Standard Specifications 1. 2. 3.

c.

2.

Approved Materials List for Water Facilities

C504, Rubber Seated Butterfly Valves C509, Resilient Seated Gate Valves

California Code of Regulations (CCR): a.

WAS Design Guidelines

WV-01, Gate Well Installation

American Water Works Association (AWWA): a. b.

3.

Section 15000, General Piping System and Appurtenances Section 15100, Resilient Wedge Gate Valves Section 15102, Butterfly Valves

Standard Drawings 1.

d.

Section 1.1, Drafting Guidelines Section 5.5, Air Valves Section 5.6, Blowoffs

Title 21,

Section 5.3 Page 4 of 5

Revised: 09/26/2007

LINE VALVE SPACING AND LOCATION FLOWCHART

Calculate Valve Spacing Per 5.6

Pipeline > 30-in

YES

Place Valves at no M ore Than ½ m ile

Place Valves at no Greater Than 1/4 m ile

YES

16-in or Greater PL- No Braches, DU s, or FH s for over ½ M ile

NO

NO

12-in or Less PL , No Branches, DU s, or FH s for over 1/4 Mile

YES

NO Place Valves at All Tees and Xs on Branch and one on M ain Prior to Each Branch

YES

System Looping Allows Elim ination of a Valve on Main NO Place Valves at All Tees and Xs on Branch and M ain

Com m erical Area

Place Valves So No M ore Than 1 FH out of Service as Directed by Agency Engineer

YES

NO Place Valves So No M ore Than 2 FH out of Service

High Density Residential > 10 DU / Acre

YES

Place Valves at O ne City Block but not >1000 feet

NO M edium Density Residential > 5 DU / Acre

YES

Place Valves so no M ore Than 70 DU s Out of Service but not > ¼ m ile

NO Low Density Residential < 2 DU / Acre Place Valves so no More Than 30 DU s Out of Service but not > ¼ mile

Adjust Spacing of Line Valves for Location of Blowoffs and Air/Vacum Valves per 5.5 and 5.6

END OF SECTION

WAS Design Guidelines

Section 5.3 Page 5 of 5

Revised: 09/26/2007