Water Agencies Standards.pdf

WAS Section 5.1 Design Guidelines Page 1 of 7 Revised: 01/11/2012

WATER AGENCIES’ STANDARDS

Design Guidelines for Water, and Sewer Facilities

SECTION 5.1 PRESSURE PIPELINE DESIGN

5.1.1 PURPOSE

The purpose of this section is to provide general guidelines for open trench pressure pipeline design. These design criteria should be considered in the appropriate stage of the design submittals for a pipeline project.

5.1.2 STANDARD TERMS AND DEFINITIONS

Wherever technical terms occur in these guidelines or in related documents, the intent and meaning shall be interpreted as described in Standard Terms and Definitions.

5.1.3 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.

5.1.4 GUIDELINES

This section covers general design parameters for pipelines installed in trenches with minimum depth of cover over top of the pipelines at three to eight feet (3’ to 8’). Any variance of these depths requires special design approval by the Agency Engineer.

A. To the extent possible, distribution and transmission pipelines shall be laid out in the

public right-of-way.

B. Pipeline design plans and specifications shall reference WAS Standard Drawings and Standard Specifications where appropriate.

C. Pipeline plans shall be prepared in digital format, in accordance with Section 1.2 or

Section 1.3.

D. Pipelines shall be designed in accordance with the requirements of the California Safe Drinking Water Act and the California Water Works Standards, Title 22 of the California Code of Regulations “Blue Book”.

E. Pipeline plans shall conform to the latest standards of the State of California,

Department of Health Services, “Criteria for the Separation of Water Mains and Sanitary Sewers”.

F. Geotechnical evaluations may be required in order to determine appropriate trench

loading and pipeline material selection.


5.1.5 PIPELINE LAYOUT

A. For new development the designer must consult with the respective water agency as well as the local City and County government, utility companies (e.g., SDG&E, Cable TV, SBC) to determine the standard for location of new facilities.

B. For existing development the designer must research existing utility information by

reviewing available record drawings from local City and County government, utility companies (e.g.; SDG&E, Cable TV, PacBell, County Water Authority), and other governmental agencies with jurisdiction within the pipeline alignment. The designer shall contact all utility companies and municipal agencies to request record drawings of existing and future planned utilities and verify ownership of facilities. Research with municipalities should include future road and utility improvement and master planned land development projects.

C. Obtain and review right-of-way and road boundaries. Verify right-of-way or easement

acquisition requirements, as identified in the Design Report or Sub-Area Master Plan (SAMP).

D. With the above information, plot existing utilities and right-of-ways on base maps.

Identify potential utility conflicts and pipeline tie-in points. Complete additional field research including pothole information to verify record drawing information.

E. Dead-end distribution systems (those with a single supply pipeline) tend to reduce

water quality and system reliability; therefore, distribution systems shall be designed with two or more separate supply pipelines whenever it is feasible. Distribution systems located in urban areas that serve seventy (70) or more DU, or those located in rural areas that serve 30 or more DU must be designed with two or more separate supply pipelines unless otherwise approved by the Agency Engineer.

F. Confirm that the proposed alignment complies with the separation requirements of

the State Health Department with respect to separation between water, sewer, and recycled water pipelines (refer to WAS Standard Drawings WI-01 through WI-03 for separation requirements). There will also be a minimum horizontal separation of five feet and a vertical separation of one foot between pipelines and other utilities e.g., SDG&E utilities and storm drains. The Design Engineer shall consultation with the respective utilities should occur for larger size pipelines and utilities as they may require these separations be expanded.

G. Provide final right-of-way requirements for permanent and temporary easements to

the Agency Engineer as noted in Section 1.5.

H. Perform a final field check of the alignment to determine if any field changes have occurred since the previous check. Update plans to reflect field conditions.

I. Horizontal and vertical curves for PVC pipelines shall be in accordance with WAS

Specification Section 15064. Horizontal and vertical curves for pipeline materials other than PVC shall follow the manufacturer's recommendations.

J. Where the future main is in a major street that would be difficult and expensive to

access a pipe stub and cap per WAS shall extend out to the edge of pavement or out ten feet (10’) from the main, whichever is the greater distance.

5.1.6 PLAN AND PROFILE

A. Complete a preliminary alignment with horizontal control data, using the available information from the Design Report or SAMP and as obtained during the record drawing reviews and field investigations.


B. Confirm point of connection (POC) with the respective water agency and obtain pothole information at potential utility conflicts. If the alignment of the existing main is in question, additional potholes should be performed to determine the horizontal and vertical alignment of the existing main at the POC location. Pothole data should be obtained as necessary for utility mains, conduits, and service laterals that are six inch (6”) and larger, that cross or are parallel to the proposed pipeline. Pothole data should include depth to top of pipe, pipe diameter, pipe material, and length to nearest point.

C. Plot pothole data on the plan and profile drawings.

D. Check the proposed alignment for conflicts and make revisions as required.

E. Add stationing and horizontal control data to the pipeline plan and profile views in

accordance with Section 1.1.

F. Accurately detail and locate tie-in connections and appurtenances. Provide coordinates and vertical control data to provide precise locations of tie-ins, valves, blow-offs, air valves, vaults, fire hydrants and etcetera. Review location and layout of appurtenances to determine accessibility for operations and maintenance personnel and ensure constructability.

G. The Engineer of Work shall arrange for the preliminary alignment centerline (P-line)

to be marked-out in the field by a land surveying crew. Mark-out of the P-line shall consist of spray paint within paved or developed area or wood lath and flagging for undeveloped areas. The Engineer of Work and the Agency Engineer (when applicable) shall field check the P-line layout for constructability issues.

H. Identify conflicts between existing utilities and appurtenant facilities. Revise design to

address utility conflicts. 5.1.7 PIPELINE MATERIALS

A. General: The material for pressure pipelines shall be in accordance with the WAS Approved Materials List for Water Facilities.

1. In general, pipelines buried between three feet (3’) and eight feet (8’) of cover

shall be PVC. Materials for pipelines exposed to atmosphere, buried with less than three feet (3’) or more than eight feet (8’) of cover shall be determined by the Engineer of Work and shall be approved by the District Engineer.

The Engineer of Work should consider the following factors in determining the appropriate material including lining and coatings:

• Fabrication and installation costs • Flow conditions (e.g., higher velocity flows or periods of dry pipe conditions) • Potential conflicts with existing and future utilities • Safety and security of the pipeline • Geotechnical conditions • Maintenance

B. PVC Pipe: A dimension ratio (DR) is used to standardize the specification of PVC

pipe. Dimension ratios (DR=O.D./t) provide a method of specifying product dimensions to maintain mechanical properties regardless of size. For a given dimension ratio, pressure capacity and pipe stiffness remain constant for all pipe sizes.


PVC pipe for distribution mains six inches (6”) through twelve inches (12”) in diameter shall conform to AWWA C900 (Standard for Polyvinyl Chloride Pressure (PVC) Pressure Pipe, 4 In. through 12 In., for Water Distribution), Class 305 (DR14).

PVC pipe fourteen inches (14”) through thirty inches (30”) in diameter used for transmission mains shall conform to AWWA C905 (Standard for Polyvinyl Chloride (PVC) Water Transmission Pipe, Nominal Diameters 14 In. through 36 In.), Class 165 (DR 25) or Class 235 (DR18).

Solvent cement or mechanical joints are not acceptable for pipe-to-pipe connections. Use bell and spigot pipe only. Exceptions may be allowed to use restrained joints but are subject to the approval of the Agency Engineer. Pipe-to-fitting connections shall be in accordance with the latest edition of the WAS Approved Materials List for Water Facilities.

Concrete encasement with PVC pipe is not allowed. Higher strength pipe (steel or ductile iron) supported by design calculation shall be used in lieu of encasement.

C. Steel Pipe: Steel pipe shall be designed per "AWWA Manual of Water Supply

Practices, Steel Pipe - A Guide for Design and Installation, M-11." Minimum pipe wall thickness for distribution and transmission mains shall be one quarter inch (¼”) unless otherwise directed by the Agency Engineer. Minimum pipe wall thickness for pump station, pressure reducing valve station, and all above ground pipe applications shall be one quarter inch (¼”). Non-Welded (push-on joints) steel pipe shall not be allowed.

1. Lining: Steel pipe shall be designed with a cement lining. However, cement

material will not be used when the pipeline is design for intermittent use only resulting in being out of service for extended periods of time. The alternative material (e.g., polyurethane) design will be submitted to the Agency Engineer for approval.

2. Coatings: For below ground applications, the coating of steel pipe can be

cement, poly tape, or a combination of these materials. For above ground applications the steel pipe shall be paint-coated unless otherwise Directed by the District Engineer.

3. Cathodic Protection (CP): Steel pipe that is subjected to corrosion may

require the installation of either a passive or active CP system. D. Ductile Iron Pipe (DIP): Minimum thickness design shall conform to AWWA C150

(American National Standard for Thickness Design for Ductile Iron Pipe) and AWWA C151 (American National Standard for Ductile Iron Pipe, Centrifugally Cast, for Water and Other.

1. Lining: All DIP shall be designed with a cement lining. However, cement

material will not be used when the pipeline is design for intermittent use only resulting in being out of service for extended periods of time. The alternative material (e.g., polyurethane) design will be submitted to the Agency Engineer for approval.

2. All ductile pipe installed underground shall be factory-coated with a

bituminous material in accordance with AWWA C151 (American National Standard for Ductile-Iron Pipe, Centrifugally Cast, for Water or Other Liquids) and polyethylene film wrap per AWWA C105 (American National Standard for Polyethylene Encasement for Ductile-Iron Pipe Systems), Installation Method A. The polyethylene film wrap shall be a minimum eight (8) mil thick, overlapped by twelve inches (12”) at joints and secured with two inch (2”) wide black polyethylene adhesive tape.


E. Other material: For pipeline material designed for other than those listed above the designer must be submit a request to the Agency Engineer for approval.

5.1.8 BURIED PIPELINE DESIGN

A. General:

1. Depth of pipe: The minimum depth of cover for potable water pipelines up to sixteen inches (16”) is generally three feet (3’). The minimum depth of cover for recycled water pipelines up to sixteen inches (16”) is generally four feet (4’). Water mains sixteen inches (16”) and larger shall be a minimum of one foot (1’) deeper that indicated above. The Engineer of Work must perform calculations to determine the appropriate wall thickness of a pipeline where there are unusual external (i.e., depths less than three feet (3’) or greater than eight feet (8’) and bridge installations), internal conditions (e.g., surge pressure), and/or use of steel or ductile iron pipe.

2. The Engineer of Work shall recognize that in order to calculate trench loads,

both dead loads and live loads must be considered.

3. Water and sewer trench dead loads shall be calculated using the Prism Load Method.

4. Geotechnical investigations shall be completed to determine unit soil weights

for soil load calculations. B. Dead Loads:

1. The prism load is the superimposed load due to the weight of the soil column

for the full height of the backfill directly above the pipe. The prism load is considered to be the maximum load that will be imposed by the soil on a buried pipe. The prism load condition provides a conservative design approach.

2. The unit weight of the soil shall be determined during the geotechnical

investigations completed for the pipeline design.

3. The Prism Load Method: The design trench loads shall be calculated using the following equation:

Where:

Wc = Design Trench Load on Conduit (lbs/lf) H = Depth of Cover over Pipe (ft) w = Unit Weight of Soil (lb/cf) Bc = Outside Diameter of Pipe (ft)

4. The design trench load (Wc) shall be used in the pipe strength and deflection

calculations to determine the appropriate pipe strength and wall thickness for flexible pipe materials.

C. Live Loads:

1. Live loads shall be calculated using standard H20 highway loading for pipe

depths of up to eight feet (8’).

cc HwBW =


2. For depths greater than eight feet (8’), live loads can be assumed to be

negligible when compared to dead loads.

D. Internal Pressure:

1. Operating Pressure

2. Field Testing Pressure

3. Surge Pressure

E. Assumptions for Pipeline Installation:

The Engineer of Work shall assume that the contractor of work installing pipelines will follow the WAS for methods related to trench preparation, backfill material, and methods and relative compaction.

F. Other Construction: Refer to Section 9 for design of pipelines at pump stations and

Section 12 for design for other conditions (e.g., trenchless, highlining) of the Design Guidelines.

5.1.9 REFERENCE

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

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 the user’s 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. Section 1.1, Drafting Guidelines 2. Section 1.2, AutoCAD Guidelines 3. Section 1.3, MicroStation Guidelines 4. Section 1.5, Easements and Encroachments

b. Standard Specifications:

Section 15064, Polyvinyl Chloride (PVC) Pressure Pipe

c. Standard Drawings:

WI-01 through WI-03 WP Series WT Series

d. Approved Materials List for Water Facilities


2. American Water Works Association (AWWA):

a. AWWA Manual M11, Steel Pipe; A Guide for Design and Installation b. AWWA Manual M23, PVC Pipe; Design and Installation c. AWWA C105, Standard for Polyethylene Encasement for Ductile Iron

Pipe d. AWWA C110, Standard for Ductile Iron and Gray Iron Fittings 3”

through 48” e. AWWA C150, Standard for Thickness Design of Ductile Iron Pipe f. AWWA C151, Standard for Ductile Iron Pipe, Centrifugally Cast, for

Water g. AWWA C900, Polyvinyl Chloride (PVC) Pressure Pipe, and

Fabricated Fittings 4” through 12” for Water Distribution h. AWWA C905, Polyvinyl Chloride (PVC) Pressure Pipe, and

Fabricated Fittings 14” through 48” for Water Transmission and Distribution

3. Others:

a. California Safe Drinking Water Act b. California Water Works Standards, Title 22 of the California Code of

Regulations “Blue Book” c. State of California, Department of Health Services, Criteria for the

Separation of Water Mains and Sanitary Sewers

END OF SECTION



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.


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 or thrust-restraining pipe joints, provided that thrust restraint systems are designed by the Engineer of Work in accordance with the manufacturers’ instructions.

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. Thrust blocks are required at all unrestrained tees, wyes, reducers, horizontal

bends, ascending vertical bends, and dead-ends. Since the act of closing an in-line valve creates a dead-end, valves not connected to other fittings also require thrust blocks.

2. Anchor blocks are required at all unrestrained descending vertical bends.


B. 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.

5.2.5 THRUST CALCULATIONS

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

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

225.0 pdT π=

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:

)2/sin(50.0 2 Δ= pdT π

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

C. Pipeline thrust at reducers:

)(25.0 22 dDpT −= π

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°.

E. Resultant Thrust Force Table for C900/C905 PVC:

The following table shows the thrust, in pounds, resulting from the required hydrostatic test pressure upon various fittings and types of pipe. Values in the following table is identical to those derived from the formulae shown above and are listed for convenience. Refer to AWWA M23, PVC Pipe Design and Installation for more detail. Thrust values for all other pipe materials shall be calculated by the Engineer of Work.


Table 1 RESULTANT THRUST FORCE

Pipe Size (In)

Outside Diameter

(In)

Test Pressure

(lb/in2)

Tee, Valve & Dead End

90O Bend

45O Bend

22.5O Bend

11.25O Bend

AWWA C900, Class 305 PVC Pipe Thrust (lbs) 4 4.8 250 4524 6398 3462 1765 887 6 6.9 250 9348 13220 7155 3647 1833 8 9.05 250 16082 22743 12308 6275 3153 10 11.1 250 24192 34213 18516 9439 4743 12 13.2 250 34212 48383 26185 13349 6707

AWWA C905, Class 165 PVC Pipe Thrust (lbs)

14 15.3 215 39529 55902 30254 15423 7749 16 17.4 215 51124 72301 39129 19948 10022 18 19.5 215 64209 90806 49144 25053 12587 20 21.6 215 78784 111417 60298 30740 15444 24 25.8 215 112400 158958 86028 43856 22034

AWWA C905, Class 235 PVC Pipe Thrust (lbs)

14 15.3 250 45963 65002 35179 17934 9010 16 17.4 250 59447 84070 45499 23195 11654 18 19.5 250 74662 105588 57144 29132 14636 20 21.6 250 91609 129554 70114 35744 17958 24 25.8 250 130698 184835 100032 50996 25621

* The outside diameter is the same for both Class 165 and Class 235 PVC pipe.

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:

Table 2

ESTIMATED BEARING STRENTH (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:

)(SFSTA

b

=

Where: A = area of thrust block (ft2),

T = resultant thrust force (lb), bS = 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:

dsdt NCNHSFTA2

)(+

=γ

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,

tH = total depth to bottom of block (ft),

dN = tan2 (45°+ F/2), F = soil internal friction angle (degrees), use appropriate soil

value, sC = soil cohesion (lb/ft2), use appropriate soil value

Note: 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, PVC Pipe Design and Installation 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 THRUST BLOCK BEARING AREA

Pipe Size (In)

Outside Diameter

(In)

Test Pressure

(lb/in2)

Tee, Valve

& Dead End

90O Bend

45O Bend

22.5O Bend

11.25O Bend

AWWA C900, Class 305 PVC Pipe Bearing Area (ft2) 4 4.8 250 4.5 6.4 3.5 1.8 0.9 6 6.9 250 9.3 13.2 7.2 3.6 1.8 8 9.05 250 16.1 22.7 12.3 6.3 3.2

10 11.1 250 24.2 34.2 18.5 9.4 4.7 12 13.2 250 34.2 48.4 26.2 13.3 6.7

AWWA C905, Class 165 PVC Pipe Bearing Area (ft2)

14 15.3 215 39.5 55.9 30.3 15.4 7.7 16 17.4 215 51.1 72.3 39.1 19.9 10.0 18 19.5 215 64.2 90.8 49.1 25.1 12.6 20 21.6 215 78.8 111.4 60.3 30.7 15.4 24 25.8 215 112.4 159.0 86.0 43.9 22.0

AWWA C905, Class 235 PVC Pipe Bearing Area (ft2)

14 15.3 250 46.0 65.0 35.2 17.9 9.0 16 17.4 250 59.4 84.1 45.5 23.2 11.7 18 19.5 250 74.7 105.6 57.1 29.1 14.6 20 21.6 250 91.6 129.6 70.1 35.7 18.0 24 25.8 250 130.7 184.8 100.0 51.0 25.6

* The values in this table were obtained assuming an allowable soil bearing capacity of 1500 lb/ft2 for decomposed granite, differing soil conditions may apply.

C. Thrust blocks are required for in-line valves not located adjacent to pipe fittings. Dead-

end 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:

)(2sin2

)( SFB

pASF

BTVolume

Δ

== )(2sin5.0 2

SFB

pd ⎟⎠⎞

⎜⎝⎛ Δ

=π

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

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 for Plans

THRUST/ANCHOR BLOCK TABLE

Pipe Station

Type/ Diameter of Pipe

Type of

Block Type of

Appurtenance Test

PressureTotal

Thrust Assumed

Soil Capacity

Area or Volume of Block

3+52.50 PVC/8” Thrust 22.5° Hor Bend 250 lb/in2 12,308 lb 1,500 lb/ft2 12.3 ft2

6+10.00 PVC/8” Thrust 45° Hor Bend 250 lb/in2 22,743 lb 1,500 lb/ft2 22.7 ft2

6+20.00 PVC/8” Anchor 22.5° Vert Bend 250 lb/in2 12,308 lb *N/A 54.0 ft3

6+30.00 PVC/8” Anchor 45° Vert Bend 250 lb/in2 22,743 lb *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. In locations where thrust-restraining fittings (including flanged fittings) and thrust-

restraining 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.

5.2.10 REFERENCES


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)


1. Section 5.3, Line Valves


1. Section 03000 Cast in Place Concrete


1. WT-01 2. AWWA M23 - PVC Pipe Design and Installation 3. AWWA M11 Steel Pipe – A Guide for Design and Installation

END OF SECTION




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.


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: Dwelling Unit

5.3.3 GENERAL


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. Limiting the number of customers that will be out of service, 2. Limiting the number of fire hydrants out of service, 3. Limiting the time it takes to drain a pipe segment, 4. Limiting the number of customers impacted by future system modifications, 5. Limiting future construction within major streets or intersections, 6. Conformance to State of California Codes and Regulations 7. Avoiding excessive number of valves thus reducing initial capital cost,

exercising and maintenance of valves, and replacement costs.

C. 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.


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.

5.3.5 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.


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.


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.


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. Section 1.1, Drafting Guidelines 2. Section 5.5, Air Valves 3. Section 5.6, Blowoffs

b. Standard Specifications

1. Section 15000, General Piping System and Appurtenances 2. Section 15100, Resilient Wedge Gate Valves 3. Section 15102, Butterfly Valves

c. Standard Drawings

1. WV-01, Gate Well Installation


2. American Water Works Association (AWWA): a. C504, Rubber Seated Butterfly Valves b. C509, Resilient Seated Gate Valves

3. California Code of Regulations (CCR):

a. Title 21,


LINE VALVE SPACING AND LOCATION FLOWCHART

Place Valves So No More Than2 FH out of Service

High DensityResidential > 10 DU /

Acre

Commerical Area

Medium DensityResidential > 5 DU /

Acre

Place Valves at One City Block but not>1000 feet

Place Valves at All Tees and Xs onBranch and Main

System LoopingAllows Elimination of

a Valve on Main

Place Valves at All Tees andXs on Branch and one onMain Prior to Each Branch

Place Valves So No More Than 1 FH out ofService as Directed by Agency EngineerYES

NO

YES

Place Valves so no More Than 70 DU sOut of Service but not > ¼ mile

Low Density Residential < 2 DU / AcrePlace Valves so no More Than 30 DU s

Out of Service but not > ¼ mile

YES

NO

NO

Place Valves at noMore Than ½ mile

Place Valves at noGreater Than 1/4 mile

16-in or GreaterPL- No Braches, DU s, or

FH s for over ½ Mile

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

Pipeline > 30-in

Calculate ValveSpacing Per 5.6 YESYES

NO

YESNO

NO

YES

NO

Adjust Spacing of Line Valves forLocation of Blowoffs and Air/Vacum

Valves per 5.5 and 5.6

END OF SECTION




SECTION 5.4 FIRE HYDRANTS AND FIRE SERVICES

5.4.1 PURPOSE

The purpose of this section is to provide an overview and general information regarding the use, sizing, location and design of fire hydrants and fire services.


Wherever technical terms 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:

FH: Fire Hydrant Assemblies

FS: Fire Service Assemblies

5.4.3 GENERAL


5.4.4 GUIDELINES

A. To the extent possible, fire hydrants and fire services shall be laid out in the public right-of-way. Easements may be required in accordance with Section 1.5.

B. Requirements of need and location of fire hydrants and fire services are established

by the Fire Department having jurisdiction in the project area.

C. Backflow prevention devices are required in accordance with Section 2.2.

D. Size-on-size wet taps (6-inch to 6-inch, 8-inch to 8-inch, etc.) are not allowed. Size-on-size connections must be made with in-line “Tee” fitting in accordance with WAS Standard Specification 15000 unless otherwise directed by the Agency.

E. Service taps are not allowed off the fire hydrant or fire service lateral in accordance

with Section 5.7. 5.4.5 FIRE HYDRANTS

Fire hydrants shall be installed on potable water mains only. Fire hydrants shall not be installed on recycled water mains. Fire hydrants must conform to AWWA C-503 and to the requirements of the Fire Department having jurisdiction in the project area.


A. Wet-barrel hydrants shall generally be used for pressures up to two hundred (200) psi. System pressures up to and including one hundred fifty (150) psi require standard wet-barrel hydrants, and pressures up to two hundred (200) psi require high-pressure wet-barrel hydrants in accordance with the WAS Approved Materials List.

B. The Fire Department having jurisdiction in the area of the proposed fire hydrant shall

provide the location(s) of fire hydrant(s) within a development with the specific location in accordance with WAS Standard Drawings WF-01 through WF-05. If there are conflicts with the proposed location or if a different location would be more beneficial then the Engineer of Work shall consult with the Fire Department for approval.

C. In general, fire hydrants are located at street intersections, but not more than six

hundred feet (600’) apart in single-family residential areas nor more than three hundred feet (300’) apart in multi-family residential, commercial, and industrial areas. Fire hydrants in the middle of blocks are located on lot lines.

D. Fire hydrants shall be installed in accordance with WAS Standard Specification

15300 and Standard Drawings WF-01 through WF-04 and the following criteria: For eight inch (8”) or larger diameter dead-end mains, a maximum of two fire

connections with either fire hydrants and/or fire services are allowed.

For eight inch (8”) or larger diameter mains when looped, two or more fire hydrants can be installed.

No more than two fire hydrants (fire services), or one fire hydrant and one fire

service, are allowed on dead-end mains or to be out of service at any time.

E. Fire hydrant outlet sizes and configuration shall be as shown on the Approved Plans or as directed by the Fire Department of jurisdiction. Hydrants shall generally have the following number and size of outlets as directed by the fire department of jurisdiction: 1. Residential: One (1) two and one half inch (2½") outlet and one (1) four inch

(4") outlet. 2. Commercial and light industrial: Two (2) two and one half inch (2½") outlets

and (1) four inch (4") outlet.

3. Industrial: One (1) two and one half inch (2½") outlet and two (2) four inch (4") outlets.

F. Fire hydrants must be installed perpendicular to the water main, and may not be

installed in cul-de-sacs unless otherwise approved by the Agency Engineer. The Engineer of Work should check (on a case-by-case basis) if an eight inch (8”) diameter fire hydrant lateral is necessary to supply such fire hydrants. Alignment of fire hydrant ports shall be in accordance with WAS Standard Drawing WF-04.

G. Depending on location, fire hydrant assemblies may require protection posts or

concrete retaining walls. When required by the Agency Engineer, or when shown on the Approved Plans, protection posts or retaining walls shall be installed in accordance with WAS Standard Drawings WF-04, WM-03 and WM-04.


H. Relocation: When a water main is replaced by a parallel main, the fire hydrant is moved three feet (3’) in either direction from its original location; when the main is replaced in place, the fire hydrant can be replaced in its original location. Reconnection to existing fire hydrants from new water mains is acceptable provided no horizontal offset of the stub line is required. Age and condition of an existing fire hydrant will also dictate the need for replacement that is established by the Agency Engineer.

5.4.6 FIRE SERVICES

Fire service shall be installed on potable water mains only. Fire services shall not be installed on recycled water mains.

A. Fire service requirements are determined by the Fire Department having jurisdiction

in the area of the proposed fire service. The Fire Department of jurisdiction shall provide the location(s) of fire service(s) within a development with the specific location in accordance with WAS Standard Drawings WF-01 through WF-05. If there are conflicts with the proposed location or if a different location would be more beneficial then the Engineer of Work shall consult with the Fire Department for approval.

B. Fire service plans must show all existing onsite fire hydrants.

C. Fire services must be installed perpendicular to the water main and in accordance

with WAS Standard Specification 15112 and Standard Drawing WF-05.

D. Relocation: When a water main is being replaced or relocated, existing, unused fire services to fully developed lots may not be replaced or reconnected. Conversely, existing active fire services to vacant lots may be replaced or reconnected, unless a permitted building plan for the lot shows otherwise.


Fire hydrants and fire services shall be shown in the plan view portion of the sheet(s) only and shall include, but not be limited to, the following minimum information: A. Standard symbols, stationing and plan callout notes shall be in accordance with

Section 1.1. B. Fire hydrants and fire services shall be shown with the following information:

• Stationing of the Fire hydrant and/or fire service at the connection to the pipeline.

• Size of Fire hydrants and/or fire services. • Refer to Figure 1 below.

Figure 1 Fire Hydrants and Fire Service Assembly Plan Callouts


5.4.8 MATERIAL SELECTION

Fire hydrants, fire services and appurtenant components to be used with the installation of water systems shall be in accordance with WAS Standard Specification Section 15112 and 15300 and the Approved Materials List.

5.4.9 REFERENCE



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 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. Section 1.1, Drafting Guidelines 2. Section 1.5, Easements and Encroachments 3. Section 2.2, Development Plan and Permit Processing

Procedures 4. Section 5.7, Water Services and Test Stations


1. Section 15000, General Piping System and Appurtenances 2. Section 15112, Backflow Preventers 3. Section 15300, Fire Hydrants


1. WF-01 through WF-05 for fire hydrants and fire services. 2. WM-03 3. WM-04

d. Approved Materials List for Water Facilities 2. American Water Works Association (AWWA):

a. AWWA C503, Wet-Barrel Fire Hydrants

END OF SECTION



Design Guidelines for Water, and Sewer Facilities

SECTION 5.5 AIR VALVES

5.5.1 PURPOSE

The purpose of this section is to provide information regarding the use, sizing, location, alignment and design of air valves for use with potable and recycled water pipelines. This section focuses on the use of Combination Air and Vacuum Valves.



ARV: Air Release Valves AVV: Air and Vacuum Valves CAV: Combination Air and Vacuum

5.5.3 GENERAL


5.5.4 GUIDELINE

A. Description of use:

1. Air Release Valves (ARV) are designed and used to vent small amounts of entrained air from the pipeline when the system is normally operating under pressure. Air release valves are installed at highpoints in the system where air will accumulate. ARV’s may also be installed on discharge piping of pump stations only as directed by the Agency’s Engineer.

2. Air and Vacuum Valves (AVV) are designed and used to allow large amounts

of air to be exhausted from a pipeline as it is being filled and allow air to enter the pipeline when the pipeline is being drained. An AVV will not allow entrained air to be released when the pipeline is operating under pressure. ARV’s shall be used at locations only as directed by the Agency’s Engineer.


3. Combination Air and Vacuum Valves (CAV) are used to vent large amounts of air to the atmosphere during the filling of the pipeline, release small amounts of air while the pipeline is operating, and to allow air to enter the pipeline when subject to vacuum. CAV’s perform the functions of both ARV and AVV as described above. CAV’s shall be used on distribution and transmission mains.

B. Requirements: CAV’s are to be specified at locations where air valves are required

unless otherwise directed by the Agency’s Engineer.

1. Air valves are to be installed with an isolation valve to allow for removal or maintenance of the valve with the pipeline under pressure.

2. Air valves are to be installed above ground within an enclosure outside the

traveled way, within the road right of way or Agency Easement.

C. Sizing: Air valves are sized as needed to release air during filling of the pipeline, to release small quantities of air during operations, and to admit air as the pipeline is being drained. Note that the valves are sized for normal operations of the pipeline and not designed for catastrophic failure. During catastrophic failure, valves can vent very large quantities of air, although damage to the valve is possible due to the resulting high airflow velocities.

Air valves shall be sized in accordance with the manufactures recommendations to admit air into pipelines at a rate equivalent to the maximum water discharge rates of blowoffs installed down-slope in accordance with Section 5.6.

The drawings or specifications must state the design pressure range for each valve. The valve pressure class shall generally match the pressure class of the pipeline to be installed with. Each pipeline is to be evaluated individually for the need of CAV’s. Minimum sizes shall be as follows: 1. Two inch (2”) CAV assemblies shall be installed on pipeline six inches (6”)

through fourteen inches (14”) in diameter. 2. Four inch (4”) CAV assemblies shall be installed on pipeline sixteen inches

(16”) and twenty inches (20”) in diameter.

3. CAV assemblies to be installed on pipeline twenty four inches (24”) and larger and pipelines on steep slopes greater than fifteen percent (15%) shall be calculated and sized appropriately and approved by the Agency’s Engineer.

D. Appurtenances: CAV appurtenances are required in accordance with Standard

Specifications Section 15108, Standard Drawings WA-02 thru WA-06 and the Approved Materials List.

E. Locations:

1. For water mains sixteen inches (16”) and smaller: The location of air valves

are generally determined by the topography of the pipeline system and, accordingly, should be installed at high points and at long sloping gradients.

Fire hydrants could also be used as a manual air valve only as approved by the Agency’s Engineer.

2. For water mains larger than sixteen inches (16”): Along with being installed at

high points, air valves are also installed on the down slope or low side of closed valves when closure of the valve creates a localized high point.


F. Installation: Air valves shall be installed above ground within an enclosure outside the traveled way, yet within the road right of way or Agency Easement in accordance with Standard Specification 15108 and Standard Drawings WA-02 through WA-06 accordingly.


Air valves shall be shown in the plan view portion of the sheet(s) only and shall include, but not be limited to, the following minimum information: A. Standard symbols, stationing and plan callout notes shall be in accordance with

Section 1.1. B. Air valves shall be shown with the following information:

• Stationing of the air valve at the connection to the pipeline. • Size of Air valve. • Refer to Figure 1 below.

Figure 1 CAV Plan Callouts


CAV and appurtenant components to be used with the installation of water systems shall be in accordance with Specification Section 15108 and the Approved Materials List.

5.5.7 REFERENCE






1. Section 5.6, Blowoff Assemblies.



1. Section 15108, Air Release Valve, Air and Vacuum Valve, and Combination Air Valve Assemblies.


1. WA-02 through WA-06.


2. American Water Works Association (AWWA):

a. AWWA C512, Air Release, Air/Vacum, and Combination Air Valves for Waterworks Service.

END OF SECTION




SECTION 5.6 BLOWOFFS

5.6.1 PURPOSE

The purpose of this section is to provide information regarding the use, sizing, location, alignment and design of blowoff assemblies for use with potable and recycled water pipelines.



BO: Blowoff Assemblies

5.6.3 GENERAL


5.6.4 GUIDELINE

A. Requirements: A Blowoff (BO) assembly is used to flush out accumulated sediments at low spots and dead-ends of pipelines and for draining pipelines for repairs, maintenance, and inspection.

B. Drainage: BO discharge shall be directed away from the pipeline into a nearby storm

drain or other non-erodible surface drainage channel. Discharge of water across the road surface is not permitted. When the discharge of a blowoff discharges to an erodible surface, consideration should then be given for the installation of an energy dissipater or an additional erosion control measure in accordance with Section 4.6. The downstream receiving system (including erosion potential) should be evaluated as to its suitability to accept the maximum flow from all affecting BO’s. However, the Design Engineer should be aware that certain mitigating conditions mandated by the Regional Water Quality Control Board and the City of jurisdiction apply to the discharge of treated potable water into storm drains and natural drainage courses, and should consider those conditions when evaluating the downstream receiving system in accordance with Section 4.6.


C. Sizing: Each pipeline is to be evaluated individually for the need of BO assemblies depending on the size of pipeline, the distance between the blowoffs, the distance between line valves and locations of air valves to ensure the time required to drain each pipeline section is between two (2) to four (4) hours. If minimum time requirements cannot be met than additional BO’s may be required. Faster drain times than those mentioned above may be required by the Agency Engineer. 1. Minimum sizes shall be as follows (Note, the Engineer of Work shall consider

the minimum velocity requirements of twenty-five feet per second (25fps) at dead-end of mains per California Department of Health Services Article 5, Section 64642):

a. Two inch (2”) BO assemblies shall be installed on pipelines for

temporary use or as otherwise directed by the District Engineer. b. Four inch (4”) BO assemblies shall be installed on pipeline sizes

sixteen inches (16”) and smaller.

c. Six inch (6”) BO assemblies shall be installed on pipeline sizes twenty inches (20”) and larger.

2. Use the following formula to determine the proper blowoff size based on the

drainage time specified above.

Q = Blowoff discharge rate (cfs) Cd = Discharge coefficient (0.60) A = Area of blowoff orifice (ft2) g = Acceleration of gravity (32ft/sec2) H = Pressure head at outlet (ft). Assume one half (1/2) of

elevation difference between end of pipe and blowoff.

The time required to drain the pipe is calculated by dividing the volume of water in the pipeline segment to be drained by the calculated flow (“Q”) through the blowoff. Set the value of “Q” such that pipeline will drain within specified above and solve for “A”. Note that the value of “Q” may be limited by the volume of water that can be dechlorinated and/or conveyed to an adequate drainage system. The Agency Engineer shall determine the upper limit of “Q” if any.

D. Locations:

1. For mains sixteen inches (16”) and smaller: The locations of BO’s are generally determined by the topography of the pipeline system and, accordingly, should be installed at low points of the pipeline. BO’s shall also be placed at end of mains such as cul-de-sacs. The outlets of fire hydrants can also perform the functions of a BO. Because a fire hydrant also provides local fire protection, the use of a fire hydrant in lieu of a BO is recommended. When a fire hydrant is used in lieu of a BO, it shall be noted on the plans as “BO”.

2. For mains larger than sixteen inches (16”): Along with being installed at low

points, BO’s are also installed on the high side of closed valves if the closure of the valve creates a localized low point.


3. BO’s should also be placed up-slope of a permanently/normally closed valve separating two different pressure zones or interconnections.

E. Appurtenances: The pressure class for all piping, valves, and fittings shall be equal to

or greater than the pressure class of the water main. BO appurtenances will be required in accordance with WAS Standard Specification 15074, Standard Drawings WB-01 through WB-05 and the Approved Materials List.

F. Installation: BO’s are to be installed below finish grade within a meter box outside the

traveled way, yet within the road right of way or District easement in accordance with WAS Standard Specification Section 15074 and Standard Drawings WB-01 through WB-05 accordingly.


BO’s shall be shown in the plan view portion of the sheet(s) only and shall include, but not be limited to, the following minimum information: A. Standard symbols, stationing and plan callout notes shall be in accordance with

Section 1.1. B. BO’s shall be shown with the following information:

• Stationing of the BO at the connection to the pipeline. • Size of BO. • Refer to Figure 1 below.

Figure 1 Blowoff Assembly Plan Callouts


BO and appurtenant components to be used with the installation of water systems shall be in accordance with WAS Standard Specification Section 15074 and the Approved Materials List.

5.6.7 REFERENCE







1. Section 1.1, Drafting Guidelines


1. Section 15074, Blowoff Assemblies.

c. Standard Drawings: 1. WB-01 through WB-05.


2. California Department of Health Services Article 5, Section 64642

END OF SECTION




SECTION 5.7 WATER SERVICES AND TEST STATIONS

5.7.1 PURPOSE The purpose of this section is to provide guidelines for the design of water services and test stations installed on potable and recycled water mains.

5.7.2 STANDARD TERMS AND DEFINITIONS Wherever technical terms 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: WS: Water Service Assembly TS: Test Station Assembly

5.7.3 GENERAL


5.7.4 GUIDELINES FOR WATER SERVICES Water services supply potable and recycled water to customers for domestic, commercial and irrigation purposes.

A. Water services shall be connected to water mains within projects where new water

mains are required. Within projects where water main extensions are not required, water services are typically connected to existing water mains located in improved public streets or existing easements. Water services shall not be connected to new “stub” water mains specifically designed to provide service connection locations unless specifically required by the Agency Engineer. Water services shall not be connected to new or existing fire hydrant laterals or fire service laterals. Water services shall not be connected to new or existing water services. Refer to Figure 1 below.


Water Service Limitations

Figure 1

B. Water services connected to new pipelines shall be installed by Contractor. Water services connected to existing pipelines shall be installed by Agency unless otherwise directed by the Agency Engineer. All meter installations shall be performed by Agency. Costs for Agency work and for other applicable fees shall be determined by consultation with Agency. All applicable fees or deposits shall be paid prior to commencement of any Agency work.


C. Water services shall be installed perpendicular to new or existing pipelines, and shall be located to minimize the distance between the service saddle and the meter box. Horizontal bends or curves in water services are not allowed. Service saddles shall be located a minimum of twenty four inches (24”) clear from the ends of all pipe joints or fittings. Service saddles connected to all pipeline types excepting cement-mortar lined and coated (CML&C) steel shall be located a minimum of twenty four inches (24”) from other service saddles. Service saddles or welded couplings connected to CML&C steel pipelines may be located closer than twenty four inches (24”) apart with the permission of the Agency Engineer.

D. Water services and meter boxes shall be installed within public rights-of-way or within easements specifically granted to Agency. All piping located on the customer side of the meter box is considered private plumbing and shall be installed and maintained by the property owner. In locations where private plumbing must be installed within adjacent parcel(s) of property, easement(s) shall be dedicated to the parcel benefiting from the service, and a copy of the recorded easement document(s) must be submitted to Agency for review prior to the installation of the water service. Such easement(s) are required even if all parcels involved share common ownership. Refer to Section 1.5 for additional information regarding easements.

E. Installation of a single water service to supply two (2) or more parcels of property is not allowed. If a parcel of property is subdivided or otherwise split, new water service(s) are required for each new parcel created. Individual parcels of property that contain more than one (1) business or dwelling unit such as business parks and apartments may be served by multiple water services.

F. The Uniform Plumbing Code specifies that pressure regulators be installed in areas where the maximum line pressure is eighty (80) pounds per square inch (psi) or greater at the meter. Pressure regulators shall be located within the private plumbing system, and shall be installed by Contractor and maintained by the property owner. Designers or contractors shall consult with Agency to determine the maximum line pressure supplied at individual services.

G. Where existing water mains are to be replaced, no new water services shall be installed to provide potential future service(s) to vacant property unless specific development plans have been submitted to the Agency and all required fees have been paid. Where existing water mains are to be replaced, existing unused services shall not be connected to new water mains without the specific direction of the Agency Engineer. When existing unused service connections are so eliminated, Agency policy shall determine whether credit for capacity fees or construction costs shall be granted when and if future service is requested.

H. Backflow prevention devices may additionally be required in accordance with the

requirements of Section 2.2. I. Recycled water services are subject to additional requirements in accordance with

Section 2.5. J. Reconnections: When a water main is replaced by a parallel main or when the main

is replaced in place, the water service can be replaced in its original location. Reconnection to existing water service lateral from new water main shall be in accordance with WAS Standard Drawing WS-07. Age, condition and type of materials of existing water service lateral will also dictate the need for replacement that is established by the Agency Engineer.


5.7.5 ONE INCH & TWO INCH (1” & 2”) WATER SERVICES

A. One inch or two inch (1” or 2”) water services shall be used in typical residential and commercial situations. In certain situations involving large multi-unit dwellings, high-rise buildings, shopping centers or business parks, or where units are sub-metered or where private fire hydrants are installed, water services four inch (4”) and larger may be installed with the specific permission of the Agency Engineer.

B. One inch (1”) water services shall be copper tubing designed and installed in accordance with WAS Standard Drawing WS-01. Two inch (2”) water services shall be copper tubing designed and installed in accordance with WAS Standard Drawing WS-02.

C. Sacrificial anodes shall be installed and connected to one inch or two inch (1” or 2”) copper tubing in accordance with WAS Standard Drawings WC-17 or WC-18 when required by the Agency Engineer, and shall be indicated on construction plans.

D. Meter boxes for one inch and two inch (1” & 2”) water services shall be located in accordance with WAS Standard Drawing WS-03.

5.7.6 WATER SERVICES FOUR INCH (4”) AND LARGER A. Water services four inch (4”) and larger may be utilized in certain situations involving

multi-unit dwellings, high-rise buildings, shopping centers or business parks, or where units are sub-metered or where private fire hydrants are installed, with the specific permission of the Agency Engineer. The Engineer of Work shall submit detailed calculations to the Agency Engineer showing the water demand(s) required and justifying the water service requested. For developments that include the installation of private fire hydrants, four inch (4”) and larger water services shall be designed in accordance with WAS Standard Drawing WS-04. For developments that do not include the installation of private fire hydrants, four inch (4”) and larger water services shall be designed in accordance with WAS Standard Drawing WS-05.

B. Designs for the installation of water services eight inch (8”) and larger shall be prepared by the Engineer of Work and submitted to the Agency Engineer for approval. Such designs shall be complete and specific to the proposed location, and shall include detailed calculations showing the water demand(s) required and justifying the water service requested.

C. Requirements for fire hydrants and fire services are specified in Section 5.4.

5.7.7 GUIDELINES FOR WATER TEST STATIONS Water Agencies are required to sample potable water and perform analytical tests for conformance to water quality standards. Test stations provide locations for Agency personnel to collect water for testing purposes. The installation of one or more water test stations may be required in conjunction with private developments. The number and location(s) of test stations required shall be as directed by the Agency Engineer. When so required, test stations shall be designed in accordance with WAS Standard Drawings WM-01 and WM-02.


5.7.8 NOTATIONS ON PLANS Laterals shall be shown in the plan view portion of the sheet(s) only and shall include, but not be limited to, the following information: A. Standard symbols, stationing and plan callout notes in accordance with Section 1.1. B. Stationing of the water lateral and test stations, at the connection to the water main. C. Size of water lateral. D. Account number (if applicable). E. Refer to Figure 2 & 3 below.

Figure 2

Water Lateral

Figure 3

Water Test Station


Water laterals, test stations and appurtenant components to be used with the installation of water systems shall be in accordance with WAS Standard Specification Section 15057 and the Approved Materials List.

5.7.10 REFERENCES





a. Design Guidelines

1. Section 1.1, Drafting Guidelines 2. Section 1.5, Easements and Encroachments 3. Section 2.2, Development Plan and Permit Processing

Procedures 4. Section 2.5, Recycled Water Facility Guidelines 5. Section 5.4, Fire Hydrants and Fire Services


b. Standard Specifications: 1. Section 15057, Copper Tubing, Brass and Bronze Pipe

Fittings.

c. Standard Drawings: 1. WC-17 and WC-18 2. WM-01 and WM-02 3. WS-01 through WS-07


2. Uniform Plumbing Code (UBC)

END OF SECTION

Documents

Water Agencies Standards.pdf