5-1

ARTICLE 5

WATER DISTRIBUTION SYSTEM

TABLE OF CONTENTS

Page Number

SECTION 5-100 WATER MAIN DESIGN CRITERIA 5-5

5-110 MINIMUM WATERLINE SIZE 5-5

5-120 LOCATIONS AND SEPARATIONS 5-5

5-130 FIRE SERVICE SYSTEMS 5-6

5-140 DETECTOR CHECK VALVES 5-7

5-150 GENERAL CRITERIA 5-7

5-160 EASEMENTS 5-9

5-170 SURFACE WATER CROSSINGS 5-9

SECTION 5-200 WATERLINE CONSTRUCTION 5-10

5-210 GENERAL REQUIREMENTS 5-10

5-220 EXCAVATIONS, BEDDING AND BACKFILL 5-10

5-230 CONSTRUCTION PERMITS 5-12

5-240 UNDERGROUND LOCATES 5-12

SECTION 5-300 STANDARD SPECIFICATIONS

5-12

5-310 DESCRIPTION OF WORK 5-12

5-310.1 Related Work Specified Elsewhere 5-12

5-310.2 Applicable Specifications 5-12

5-310.3 Applicable References 5-13

5-310.4 Submittals 5-13

5-310.5 Quality Assurance 5-13

5-2

5-320 MATERIALS 5-13

5-320.1 General Criteria 5-13

5-320.2 Iron Pipe 5-14

5-320.3 Tie Rods and Accessories: Restrainer Glands 5-14

5-320.4 Gate Valves 5-14

5-320.5 Butterfly Valves and Cone Valves 5-15

5-320.6 Fire Hydrants 5-15

5-320.7 Valve Boxes 5-16

5-320.8 Copper Pipe 5-16

5-320.9 Corporation Stops 5-16

5-320.10 Water Meters and Services 5-16

5-320.11 Air Release Valves and Assemblies 5-16

5-320.12 Tapping Sleeves and Valves 5-17

5-320.13 Inserting Valves 5-17

5-320.14 Service Clamps 5-17

5-320.15 Valve Vaults 5-17

5-320.16 Manhole Frames and Covers 5-18

5-320.17 Manhole Steps 5-18

5-330 EXECUTION 5-18

5-330.1 Laying Pipe 5-19

5-330.2 Connections to Existing Mains 5-21

5-330.3 Installing Valves and Fittings 5-22

5-330.4 Setting Fire Hydrants 5-22

5-330.5 Thrust Restraint 5-23

5-330.6 Water Service Connections 5-23

5-330.7 Abandoning Existing Water Mains

5-24

5-330.8 Sterilization of Water Mains 5-24

5-330.9 Hydrostatic Testing 5-28

5-330.10 Repair Guidelines 5-30

5-3

5-330.11 Certificate to Operate 5-31

5-330.12 Final Approval 5-31

SECTION 5-400 WATER DISTRIBUTION

SYSTEM DETAILS 5-32

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ARTICLE 5

WATER DISTRIBUTION SYSTEM

SECTION 5-100 WATER MAIN DESIGN CRITERIA

Water mains and appurtenances shall be designed and installed to conform to

the latest revision or revised edition of the City of Manassas Design and Construction

Standard Manual, the Virginia Department of Health Water Works Regulations,

American Water Works Association Standards, National Fire Protection Association

Codes and Standards and the design criteria specified hereinafter. The review of all

water distribution systems will be performed by Public Works and coordinated with the

City’s Water Department with approval by the Director or his designated agent. The

authority for discretionary provisions for water main designs shall vest with the Director

of Public Works of the City of Manassas.

5-110 MINIMUM WATER LINE SIZE

The minimum size of waterline shall be as follows:

A. In residential districts, eight (8”) inch is required.

B. In other areas, eight (8”) inch and twelve (12”) inch; eight inch (8")

to be used only when it completes a good gridiron and twelve inch

(12") for long lines not interconnected.

C. Lead lines for fire hydrants shall not be less than six inches (6") in

diameter.

.

5-120 LOCATIONS AND SEPARATIONS

In general, water mains shall be installed in the street right-of-way and six

(6’) feet minimum from the centerline of the water main, to the edge of the gutter

in streets with curb and gutter, and ten (10’) feet from the centerline in streets

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without curb and gutter. Water mains shall be a minimum horizontal distance of

ten (10’) feet measured edge to edge from a sanitary sewer main or manhole.

When unusual conditions prevent a ten (10’) foot horizontal separation, a

minimum horizontal separation of six (6’) feet may be allowed, provided the

sewer main has a minimum of eighteen (18”) inches of clearance below the

water main. Also, provide a minimum of at least eighteen (18”) inches between

steel gas lines and water mains, and services.

Water mains crossing sanitary sewers shall be laid to provide a separation

of at least eighteen (18”) inches between the bottom of the water main and the

top of the sewer. If this vertical separation cannot be accomplished, the water

main shall be relocated to provide the separation directed by a City of Manassas

Utilities Engineer, or the sewer shall be constructed of ductile iron pipe, pressure

tested in place, with no joint of the sewer closer than eight (8’) feet to the water

main. Concrete piers are an option when the conflict involves RCP storm sewers

when approved by the Utilities and Public Works Engineer, in accordance with

Standard Detail SS - 4.2 of this Manual.

5-130 FIRE SERVICE SYSTEMS

Fire service systems and fire hydrants shall be located in accordance with

Article 6 of this manual.

Fire hydrants shall be painted in accordance with the City of Manassas

Fire Marshal Specification. See Standard Detail FS - 1.0 of this Manual.

Fire hydrants shall be controlled by an independent six(6”) inch gate

valve, located as near to the service main as practical. Where the six (6”) inch

hydrant service line is longer than fifty-feet (50') a second six (6”) inch gate valve

shall be located not less than one (1’) foot or more than six (6’) feet from the

hydrant.

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5-140 DETECTOR CHECK VALVES

Approved detector check valves shall be required on all building fire

service mains that serve a "wet pipe" sprinkler system. The detector check valve

shall be equipped with an appropriately sized gate valve on either side of the

check valve. The O.S. and Y and the post indicator valve are required to have

tamper switches in use groups A, E, I, and R.

5-150 GENERAL CRITERIA

Water systems shall be so designed as to adequately supply the normal

and peak demands of all customers, both domestic and commercial, maintaining

a pressure of not less than thirty (30) pounds per square inch at all points of

delivery, without reducing the service to existing customers. Where the

supplying system can provide sufficient water, the designed extension shall have

adequate capacity to be capable of delivering not less than the required fire flows

as specified by the Fire Marshal, with a residual pressure of not less than twenty

(20) pounds per square inch to at least one (1) point within five hundred (500’)

feet of each building proposed to be served by such extension. In those cases

where the source of supply cannot deliver fire flows at adequate pressures, the

developer shall design his water system based on achieving the required fire

flows with an assumed pressure of 30 p.s.i. at point of connection. A pressure

regulating valve will be installed by the developer or property owner in the

building plumbing system where the pressure exceeds eighty (80) psi.

Valve boxes shall be set and adjusted so that the covers shall be exposed

and flush with the street surface. If street surfaces are renewed or replaced by

the developer or owner after the water system has been approved and accepted

by the City, but while such streets are still the obligation of the developer or

owner, the valve boxes therein shall be readjusted to proper location relative to

the new street surfacing. Valve boxes located in sodded or other off-street areas

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shall be set and adjusted so that the covers shall be exposed and flush with the

immediate surface.

Where a water main is terminated beyond a gate valve in that main, the

minimum length of pipeline between valve and end of the line shall be two (2)

pipe lengths or as directed otherwise.

No water main shall terminate under a concrete valley gutter. Whenever

possible to avoid, no gate valve shall be located under a concrete valley gutter.

All pipe shall be laid to a minimum depth of forty-two (42”) inches from

established grade to the top of the pipe. Water lines will not be laid at depths

greater than eight (8') feet without the permission of the Director of Public Works.

Valves shall be installed at the intersection of waterlines. Generally, a

minimum of four (4) valves will be used at crosses and three (3) valves at tees.

A valve shall be also be installed every one thousand (1000’) feet on distribution

mains.

Provide a means to blow off dead-end lines in residential developments

by installing a fire hydrant at the lines terminous.

A standard blow-off assembly shall only be provided at the end of a dead-

end line in a commercial development where fire hydrants cannot be installed

and located within the pavement. Or where it is not possible to complete a loop

within the system. Refer to Standard Detail W-5.0 of this Article.

Air release valves or hydrants shall be placed at strategic high points in

the system to provide for the release of trapped air.

All transmission mains shall be provided with blow- off valves at strategic

low points in the line.

No water pipes shall pass through or come in contact with any part of a

sanitary or storm sewer manhole.

Cross connections and backflow prevention connections shall be

inspected to insure compliance with the adopted cross-connection and backflow

ordinance. Refer to Article 13 of this Manual.

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5-160 EASEMENTS

Water mains may be installed on private property if an easement of a

minimum of fifteen (15’) feet in width is duly recorded. Increased easement

widths may be required by the Engineer when determined necessary due to

large mains or excessive depths. Easement instruments denoting waterline

easements shall include a note giving the water purveyor the right- of- access to

the water service connection and the water meter for the purpose of

maintenance and operation. No permanent structure shall be constructed within

an easement.

Where deemed necessary by the Director of Public Utilities and in order to

assure maximum utilization of the public water system, it will be required that

appropriate easements be provided to adjacent properties for access to future

extensions.

5-170 SURFACE WATER CROSSINGS

Surface water crossing, both over and under water, present special

problems and should be discussed with the Engineer before final plans are

prepared.

A. Above Water Crossings - The pipe above water crossings shall be:

1) Adequately supported.

2) Insulated to protect from damage due to freezing.

3) Accessible for repair or replacement.

4) Installed so that the bottom of the pipe is a minimum of one (1’)

foot above the 100 - year flood level.

B. Under Water Crossing:

1) The pipe shall be of special construction, having flexible watertight

joints.

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2) Valves shall be provided at both ends of the water crossing so that

the section can be isolated for tests or repair; the valves shall be

easily accessible and not subject to flooding.

3) Sample taps shall be available at each end of the crossing and at a

reasonable distance from each side of the crossing.

SECTION 5-200 WATERLINE CONSTRUCTION

5-210 GENERAL REQUIREMENTS

Pipe, fittings, valves, hydrants and accessories shall be loaded and

unloaded by lifting with hoists of skidding so as to avoid shock or damage.

Under no circumstances shall such material be dropped. Pipe shall be so

handled that the coating and lining shall not be damaged.

The water main shall be laid and maintained to the required lines and

grades with fittings, valves, hydrants and accessories set at the required

locations as indicated on the approved plans for the project. All valves and

hydrant stems shall be set plumb. Whenever obstructions not shown on the

plans are encountered during progress of the work and interfere to such an

extent that alteration in plans is required, the Director of Public Works and

Assistant Water and Sewer Director shall be advised and approval given by the

Director of Public Works before such alternatives are put into effect. All

development plans shall be properly noted to specify this requirement.

5-220 EXCAVATION, BEDDING AND BACKFILL

The trench shall be dug so that the pipe can be laid to the alignment and

depth required and it shall be excavated not more than five hundred (500) feet in

advance of the completed pipe laying operation. The width of the trench shall be

ample to permit the pipe to be placed, backfilled, and thoroughly compacted in

accordance with the requirements of these specifications. Trenches shall be of

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such extra widths when required as will permit the convenient placing of timber

supports, sheeting and bracing and handling of special fittings or appurtenances.

The trench shall be excavated to the depth required so as to provide a

uniform and continuous bearing and support for the pipe on solid and

undisturbed ground at every point between bell holes, except that it will be

permissible to disturb and otherwise damage the finished surface over a

maximum length of eighteen (l8) inches near the middle of each length of pipe by

the withdrawal of pipe slings or other lifting tackle. Any part of the bottom of the

trench excavated below the specified grade shall be backfilled with approved

materials, thoroughly compacted. The finished subgrade shall be prepared

accurately by means of hand tools.

Where excavation is made in rock, boulders, or other unsuitable material,

the subgrade shall be made by backfilling with a minimum four (4) inches of

gravel or clean selected soil which shall be thoroughly compacted.

Bell holes shall be provided at each joint to permit the jointing to be made

properly.

Ledge rocks, boulders, and large stones shall be removed to provide a

clearance of at least six (6) inches below and on each side of all pipes, valves

and fittings. The specified minimum clearances are the minimum clear distances

which will be permitted between any part of the pipe and appurtenances being

laid and any part, projection, or joint of such rock or stone.

No pipe shall be laid in water or when, in the opinion of the Director of

Public Works and/or the Assistant Water and Sewer Director, the trench

conditions are unsuitable.

Backfill shall be placed in two (2), one (l) foot layers over the pipe and

shall be thoroughly compacted to 95% density, the remainder of the backfill shall

be placed in no greater than one layer eight (8) inches thick uncompacted, then

thoroughly tamped to 95% of the maximum dry density. Backfill material shall be

free of perishable material, frozen clods, sticky masses of clay and other

unsuitable matter. Rock pieces larger than two (2) inches shall not be used in

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the backfill which is within two (2) feet of the pipe. Refer to Section 9-5100, 10-

700, and Standard Detail TS-15.0 of this Manual for backfill required within

existing/proposed roads or rights- of- way.

5-230 CONSTRUCTION PERMITS

No water main shall be constructed, added to, or altered without the

issuance of a construction permit by the Inspections Department. The

requirements and procedures outlined in Chapter 34 of the City Ordinances and

Section 2-830 of this Manual shall be followed in applying for a construction

permit.

5-240 UNDERGROUND LOCATES

The contractor/excavator who is performing the actual work must contact

"Miss Utility" prior to the commencement of work.

SECTION 5-300 STANDARD SPECIFICATIONS

5-310 DESCRIPTION OF WORK

Provide all parts, labor, materials and equipment to install all water pipe

and appurtenances to the lines and depths as called for on the approved plans

and as described herein for a complete and operable water distribution system.

5-310.1 RELATED WORK SPECIFIED ELSEWHERE

Section 10-600 Geotechnical Guidelines

Section 11-500 Tunneling

Section 11-600 Boring and Jacking

5-310.2 APPLICABLE SPECIFICATIONS

American National Standards Institute (ANSI).

American Society for Testing and Materials (ASTM and current standard).

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American Water Works Association (AWWA).

National Fire Protection Association (NFPA).

5-310.3 APPLICABLE REFERENCES

Virginia Soil and Water Conservation Commission Erosion and Sediment

Control Handbook.

Erosion and Sediment Control Ordinance (Chapter 9 of the City of

Manassas Code).

For definition of terms used within this Article, Refer to Section 1-500 of

this Manual.

5-310.4 SUBMITTALS

Submit full descriptions and details of all pipe, valves, hydrants,

and other appurtenances proposed for the project to include an affidavit of

compliance that all products meet the specifications herein. Submit sworn

statements from the manufacturers that the inspections and tests

specified in the referenced standards have been made and that the

results of such inspections and tests comply with the requirements of the

applicable standard. Certificates of compliance and approval shall apply.

5-310.5 QUALITY ASSURANCE

The manufacturer shall provide facilities or a certified laboratory for

conducting load bearing and other tests required by the referenced

specifications such as the current ASTM.

The Engineer will inspect pipe, fittings and joint material upon

delivery to the site. The Contractor shall provide ample space between

rows of stockpiled pipe to facilitate adequate inspections.

5-320 MATERIALS

5-320.1 GENERAL CRITERIA

5-14

A. All water mains shall be constructed using ductile iron pipe as

specified herein.

B. All materials shall be suitable for 150 psi working pressure unless

otherwise indicated.

C. Pipe of the same size and material shall be furnished by the same

manufacturer. Each pipe length and fitting shall be clearly marked

with the manufacturer's name, trademark and class of pipe.

D. Materials shall be recently manufactured and unused. Only

previously approved manufacturers items may be furnished.

E. Materials shall be listed by an approved testing laboratory.

5-320.2 IRON PIPE

Iron pipe shall be ductile iron conforming to AWWA C151 (ANSI

A21.51), class 52 unless otherwise indicated. Pipe shall be single cement

lined conforming to AWWA C104 (ANSI A21.4) and shall have

mechanical or push-on joints utilizing rubber gasket rings, conforming to

AWWA C111 (ANSI A21.11). Polyethylene encasements shall be used in

accordance with ANSI/AWWA C105 / A21.5 American National Standard

for Polyethylene Encasement for Ductile Iron Pipe Systems.

Fittings shall be mechanical joint ductile or gray iron conforming to

AWWA C110 (ANSI A21.10), with a minimum pressure rating of 250 psi.

Fittings shall be cement lined conforming to ANSI A21.4.

5-320.3 TIE RODS AND ACCESSORIES: RESTRAINER BANDS

Tie Rods, tie bolts and accessories shall be manufactured of

corrosion resistant steel conforming to ASTM-A242. Restraining bands

shall be Megalug manufactured by Ebaa Iron or approved equal.

5-320.4 GATE VALVES

A. Gate valves four (4") inches through twelve (12") inches for buried

installation shall be iron-body, bronze mounted, resilient seat, 0-

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ring sealed, inside screw, non-rising stem, fitted with a two(2")

inches operating nut opening left, with mechanical joint ends,

unless indicated otherwise on the drawings. Valves shall conform

to AWWA C509. Provide buried valves with valve boxes. Provide

extension stems extended to within two (2’) feet of finished grade if

valve depth exceeds five ( 5') feet. Valves shall be as

manufactured by Mueller - American-Darling, Kennedy or approved

equal.

B. Gates valves three ( 3") inches and larger for vault or interior

installation shall be iron-body, bronze mounted, solid wedge disc,

bolted bonnet, class 125 psi, outside screw and yoke, rising stem

with hand wheel, opening left, with flanged ends.

C. Gate valves two ( 2") and smaller shall be bronze-body, solid disc,

union bonnet, class 125 psi, non-rising stem with hand wheel,

opening left, with inside threaded ends.

5-320.5 BUTTERFLY VALVES AND CONE VALVES

Butterfly and cone valves shall be as directed by the Engineer as a

special project basis.

5-320.6 FIRE HYDRANTS

Fire hydrants shall be dry top, dry barrel compression type, with a

valve opening of 5¼ inches, double O-ring seals and safety flange, and

shall conform to AWWA C502 requirements. Hydrants shall be provided

with two--2½ inch hose nozzles and one- 4½ inch pumper nozzle with

threading conforming to NFPA No. 194 for National Standard Fire Hose

Company Screw Threads, six ( 6”)’ inch mechanical joint inlet connection,

National Standard one and one-half (1-1/2) inch pentagon operating nut

and outlet nozzle cap nuts, chains on outlet nozzle caps, and harnessed

lugs. Hydrants shall open left and counterclockwise. Protective coating

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color shall be as directed by the Fire Marshal. Hydrants shall be Mueller

Centurion (Model A-423), American Darling (Model B-84-B), Kennedy

Guardian (Model K-81-A) or approved equal.

5-320.7 VALVE BOXES

Valve boxes shall be of the two-piece, sliding type five and one

fourth (5¼ inch shaft, cast iron kind. Valve box shall read "Water". Valve

boxes shall be as manufactured by Bingham and Taylor Company or

Tyler Company and conform to their standard dimensions.

5-320.8 COPPER PIPE

Copper pipe shall be seamless water tube, type K conforming to

ASTM designation B88. Fittings shall be undergound copper service,

flare type, or lead-free solder.

5-320.9 CORPORATION STOPS

Corporation stops shall be Mueller H-15008 series, Ford-F1000 or

approved equal.

5-320.10 WATER METERS AND SERVICE

Water meters including taps, pipe fittings, meter box and

accessories from the water main through the meter, will be furnished and

installed by the City after payment of the appropriate fees. Newly installed

meters shall be of the touch read type.

5-320.11 AIR RELEASE VALVES AND ASSEMBLIES

Air release valves shall be constructed of cast iron body and cover

conforming to ASTM A48, class 30. The float shall be stainless steel

conforming to ASTM A240 and the seat shall be Buna-N. Air release

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valves shall be Apco or approved equal. All piping and miscellaneous

fittings shall be brass as shown on standard detail W-4.0 of this article

5-320.12 TAPPING SLEEVES AND VALVES

Tapping sleeves and valves shall conform to the applicable

requirements specified herein for fittings and gate valves. The tapping

sleeves shall be of iron body, corrosion resistant construction and shall be

the mechanical joint type. All bolts used in valve assembly shall be

stainless steel. A bituminous coating shall be applied to all exposed

surfaces of the sleeve and valve assembly prior to backfill. The tapping

sleeve and valve shall be as manufactured by Mueller Co., Clow

Company, or approved equal.

5-320.13 INSERTING VALVES

Inserting valves shall conform to the specifications for gate valves.

Inserting valves twelve (12”) inches and smaller shall be No. H-800 as

manufactured by Mueller Company. Inserting valves twelve (12”) inches

and larger shall be as manufactured by A.P. Smith, or approved equal.

Valve shall be suitable for installation on the existing pipe.

5-320.14 SERVICE CLAMPS

Generally, service clamps are required for 1 ½” and 2” service

lines and shall be double strap ductile iron with corporation stop,

neoprene gasket cemented in place, cadmium plated nuts and removable

straps (for cast iron pipe) and shall be the diameter required. Clamps

shall be manufactured by Mueller, or approved equal.

5-320.15 VALVE VAULTS

Valve vaults shall be cast-in-place concrete, as specified in Section

11-700, Cast-in-Place Concrete, or precast concrete as specified in

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Section 11-800, precast Concrete. The vaults shall be constructed to the

dimensions shown on the contract drawings. All vaults shall be

waterproofed according to Section 11-1400, Waterproofing, and shall be

provided with a double-leaf door as manufactured by Bilco Co. or

approved equal.

5-320.16 MANHOLE FRAMES AND COVERS

Manhole frames and covers shall be constructed of gray or ductile

iron conforming to ASTM A-48 and A-536. Frames and covers shall have

machined bearing surfaces to prevent rocking and rattling under traffic.

Frames and covers shall be manufactured by Dewey Brothers or

approved equal.

5-320.17 MANHOLE STEPS

Manhole steps shall be a composite of a No. 3 grade 60 deformed

steel bar encased in copolymer polypropylene plastic of the "press-fit"

design or rubber. Steps shall be PSI-PF as manufactured by M. A.

Industries, Inc. or Wedge-Lok as manufactured by Delta Pipe Products,

Inc. or approved equal.

5-330 EXECUTION

Maintain a minimum ten (10’) feet horizontal distance (edge to edge)

between sanitary sewers and water mains. If this cannot be done, a minimum

horizontal distance of six (6’) feet may be allowed, provided the bottom of water

main is at least eighteen (18”) inches above the crown of sewer main. Ductile

iron pipe may be required by the City for sewer mains at this separation.

Maintain at least eighteen (18”) inches between the top of the sewer and

the bottom of the water main whenever water main must cross over sewers. If

this cannot be done, the water main shall be relocated to provide the separation

directed by the Engineer, or the sewer shall be constructed of ductile iron pipe

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pressure tested in place with no joint of the sewer closer than eight (8’) feet to

the water main.

Use proper and suitable tools for the safe handling and laying of pipes

and fittings. Prevent fitting linings and coatings from being damaged. Damaged

pipe shall be replaced or repaired to the satisfaction of the Engineer.

5-330.1 LAYING PIPE

A. Unless indicated otherwise, the depth of trench shall be sufficient to

provide a minimum cover over the top of the pipe of three and one-

half (3.5’) feet from the finished grade elevation and to avoid

interfere of the pipe-line with other utilities. Install pipe on

continuous grades, as indicated on plans, to avoid sags or crests in

the line. Whenever obstructions are encountered during progress

of the work and interfere to such an extent that alteration in plans is

required, the Public Works and Water and Sewer Engineers shall

be advised and approval given before such alternatives are put into

effect.

B. The cutting of pipe for inserting valves, fittings, or closure pieces

shall be done in a neat and workmanlike manner in accordance

with the manufacturer's specifications without damage to the pipe,

so as to leave a smooth end at right angles to the axis of the pipe.

The outside edge of cut pipe shall be beveled and smoothed to

avoid damage to the gasket and avoid damage to the lining. Do

not flame cut cast iron pipe with an oxyacetylene torch.

C. Thoroughly clean pipes and fittings before they are laid.

D. Carefully lower pipe fittings into trench. Every precaution shall be

taken to prevent foreign material including nonpotable water from

entering the pipe while it is being placed in the line. If the pipe-

laying crew cannot put the pipe into the trench and in place without

getting earth into it, a heavy, tightly woven canvas bag of suitable

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size shall be placed over each end and left there until the

connection is to be made to the adjacent pipe. During laying

operations, no debris, tools, clothing, or other materials shall be

placed in the pipe. Butt ends of pipe against each other in such

manner that there shall be no shoulder or unevenness on the

inside of main.

E. Pipe shall not be laid in water or when, in the opinion of the Public

Works Engineer, trench conditions are unsuitable.

F. Insure that pipe is well bedded on a solid foundation as shown in

the standard details. Correct any defects due to settlement.

Excavation bell holes sufficiently large to insure making proper

joints. Exercise precautions to include the furnishing and placing of

aggregate to prevent any pipe from resting directly on rock.

G. After placing a length of pipe in the trench, the spigot end shall be

centered in the open bell of the pipeline and the pipe pushed until

seated so that the face of the spigot is in close contact with the

shoulder of the bell. Ductile cast iron pipe shall be laid with the

bells facing the direction of the laying.

H. No stub of any water main shall terminate with a capped or plugged

valve. Where a valve is required to be installed near a stub end,

not less than two (2) standard lengths of pipe shall be installed

between the valve and the plugged stub end of the pipe for

adequate anchoring. All tees, bends, plugs, caps and fire hydrants

shall be substantially braced, blocked and/or strapped to prevent

any movements by providing adequate reaction blocking and/or

other approved restraining method. Blocking is not required if

Megalug is used at these locations.

I. Whenever it is necessary to deflect pipe from a straight line, either

in the vertical or horizontal plane, to avoid obstructions or plumb

stems, or where long-radius curves are permitted, the amount of

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deflection allowed shall not exceed that required, for satisfactory

joining of the pipes, as specified by the manufacturer.

J. Iron pipe shall be jointed in full accordance with AWWA Standard

C600, the manufacturer's recommendations and the following

requirements:

1) Push-on joints shall be thoroughly cleaned. Insert the

rubber gasket in the bell socket. Supply a thin film of

approved gasket lubricant; center the spigot end of the pipe

into the socket; complete the joint by forcing the spigot end

to the bottom of the socket.

2) Mechanical joints shall be thoroughly cleaned. Lubricate the

gasket and spigot. Place the band on the spigot end,

followed by the gasket, with the pipe end seated and

centered in the socket. The gasket shall then be seated in

the sockets, gland moved into position and bolts and nuts

loosely assembled by hand. Tighten with a wrench.

K. At the close of work each day, close the end of the pipeline with an

expansion stopper so that no dirt or other foreign substance may

enter the line. Keep this stopper in place until pipe laying is

resumed.

L. Remove and replace all defective materials at no additional cost to

the City.

5-330.2 CONNECTIONS TO EXISTING MAINS

The Contractor shall notify the City two (2) working days in advance

of when the connection is to be made. The Contractor shall excavate the

trench and backfill after the connection is made. The Contractor shall

provide the tapping sleeve and valve and install it on the main for a wet

tap. For connections less than or equal to 2”, materials must be

purchased from the City. Installation of connections 2” or less may be

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performed by City or contractor labor. For connections greater than 2”,

contractor will provide labor and materials for installations.

Reaction blocking at connections to existing mains shall be made

with high early strength concrete. In the event that line pressure must be

restored less than 48 hours after the placement of reaction backing at

these connections, provide temporary deadmen and/or similar devices as

required to maintain stability of the water mains.

5-330.3 INSTALLING VALVES AND FITTINGS

Install valves, fitting, and caps to pipe in the manner herein before

specified for laying pipe. Provide valve boxes for each buried gate valve.

Boxes shall not transmit shock or stress to the valve, with the box cover

flush. Valves shall be strapped to adjacent fittings unless directed

otherwise.

Inserting valves, tapping sleeves, and valves shall be installed in

accordance with the valve manufacturer's recommendations. Test pits

shall be dug by the contractor to determine type and size of existing pipe

and suitability of tapping locations on the pipe.

5-330.4 SETTING FIRE HYDRANTS

Connect hydrants to the main with a six (6”) inch ductile iron branch

controlled by an independent six (6”) inch gate valve. Hydrants shall be

set plumb and to established finished grade as follows:

The bottom of the four and one-half inch (4½") nozzle shall be

eighteen (18”) inches above the elevation of the edge of the shoulder on

streets without curb and gutter and eighteen (18”) inches above the

elevation of the curb on streets with curb and gutter.

The two and one-half (2 1/2”) inch hose connections shall have a

minimum of four feet, zero (4.0”) inches clearance on all sides.

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Provide the drainage fill at the base of the hydrants as indicated in

the Standard Details.

5-330.5 THRUST RESTRAINT

Valves for connections to future lines, fire hydrants and related

valves, and other fittings or valves so indicated shall be anchored by steel

rods and concrete reaction blocking, as shown on the drawings or

Standard Details W-2.0 to W-4.0 and FS-1.1 of this Manual. Protect tie

rods, sleeves and clamps by two (2) coats of acid-resisting asphalt paint.

The use of mechanical joint restraint (such as megalug or an approved

equal) will be considered an option to steel rodding and thrust blocking.

(Refer to Standard Detail W-3.0 of this Article.)

5-330.6 WATER SERVICE CONNECTIONS

Water service connections from the water mains through the water

meters will be furnished and installed by the City at the owner’s expense.

New meters shall be of the touch read type. The Contractor shall provide

excavation, backfill and all other associated work. Connections from the

meter installation to the building shall be installed by the building owner's

plumber. Containment backflow prevention devices are required for all

commercial facilities and required for all 4 story or higher structures.

Provide backflow prevention devices on service lines after the meter and

prior to take offs (see section 6 and 13 DCSM). Meters shall be installed

behind the curbing in the utility strip. This is the area between the curbing

and sidewalk. The meter box shall be set at finished grade and any re-

adjustment after its initial placement will be performed by the contractor.

The water meter shall only be located within a sidewalk when there is no

utility strip and there is not sufficient room to place the meter behind the

sidewalk.

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5-330.7 ABANDONING EXISTING WATER MAINS

A. Drain and abandon existing water mains not required in the

completed system. Abandoned mains and appurtenances that

conflict with proposed construction shall be removed as required.

Abandoned mains not removed shall be capped at all open ends.

Boxes on abandoned valves shall be removed.

B. At the locations indicated on the drawings, cut the existing water

mains, cap and provide reaction blocking. Keep the length of pipe

removed to the minimum necessary for installing the cap and

concrete blocking. A cap shall be placed over the end of the pipe

to be abandoned. The concrete thrust block shall be placed to

bear against undisturbed ground. After this work has been

completed, the capped line shall not be recharged unless so

directed by the Engineer.

C. Existing fire hydrants not required in the completed system shall be

carefully removed, cleaned and transported to the City storage

yard. The hydrant lead shall be removed from the gate valve and

provided with a mechanical plug.

D. Existing water services will be discontinued at the main.

Excavation, backfill and pavement restoration between the water

meter and the main shall be the responsibility of the Contractor.

Water meters shall be removed by the City upon notification of

abandonment. Removal of meter box castings shall be the

responsibility of the Contractor.

5-330.8 STERILIZATION OF WATER MAINS

A. When each pipe length has been placed and shut off, sterilize each

section of the water main. Provide all labor, materials and

equipment to perform the sterilization operations in compliance with

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all state and local regulations. Disinfection shall conform to AWWA

C601.

B. Water for sterilization, flushing and testing will be furnished to the

Contractor from the existing water system at no charge to the

Contractor. Schedule water usage with the Engineer to result in a

minimum interference to water service throughout the existing

system. Temporary connections to the existing water system shall

be provided and removed by the Contractor and shall include

approved means to prevent backflow and possible contamination of

the existing water system. Temporary taps for removing air and

flushing the main shall be provided by the contractor as necessary.

C. Disinfection of the water main shall be accomplished in the

following manner:

1. Preliminary Flushing of Mains: All mains shall be flushed

prior to disinfection except when the tablet method of

disinfection is used. The mains shall be flushed at a

minimum velocity of 2.5 feet/second and all points in the

main shall receive a minimum of five (5) consecutive

minutes of flushing at this velocity, or until the water runs

clear.

2. Form of Chlorine to be used: Liquid chlorine, calcium

hypochlorite or sodium hypochlorite may be used for

disinfection. Liquid chlorine shall be used only when

approved by the Engineer. Calcium hypochlorite and

sodium hypochlorite shall be added to water to form a

chlorine water solution before being used.

3. Methods of Application: The chlorine shall be applied by

continuous feed method or the tablet method and performed

as follows:

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a. Continuous Feed Method: The rate of water and

chlorine shall be proportioned so that the chlorine

concentration of water in the pipe is maintained at a

minimum of 50 mg/l available chlorine. To assure

that this concentration is maintained, the chlorine

residual shall be measured at regular intervals.

During the application of the chlorine, valves shall be

manipulated to prevent the treatment dosage from

flowing back into the line supplying the water.

Chlorine application shall not cease until the entire

main is filled with the chlorine solution.

b. Tablet Method: Because the preliminary flushing step

must be eliminated, this method shall be used only

when scrupulous cleanliness has been exercised.

Tablet method shall not be used if trench water or

foreign material has entered the main or if the water

is below five (5) degrees C. Forty-one (41 degrees

F). Tablets are placed in each section of pipe and

also in hydrant branches and other appurtenances.

They shall be attached by an adhesive, except for the

tablets placed in hydrants and in the joints between

the pipe sections. All the tablets are fastened before

the pipe section is placed in the trench, their positions

shall be marked on the section to assure that there

will be no rotation. In placing tablets in joints, they

are crushed and placed on the inside annular space

or if the type of assembly does not permit, they are

rubbed like chalk on the butt ends of the sections to

coat them with calcium hypochlorite. The adhesive

may be Permatex No. 1 or any alternative approved

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by the Engineer. There shall be no adhesive on the

tablet except on the broad side next to the surface to

which the tablet is attached. When installation has

been completed, the main shall be filled with water at

a velocity of less than one (1) foot per second.

4. Contact Period: The chlorinated water shall be retained in

the main for at least twenty-four (24) hours during which time

all valves and hydrants, in the section treated shall be

operated in order to disinfect the appurtenances. At the end

of this twenty-four (24) hour period, the treated water shall

contain no less than twenty-five (25) mg/l chlorine

throughout the length of the main. The tests for chlorine

residual shall be made by the Engineer. The Contractor

shall install corporation cocks and copper tubing for the tests

at the locations indicated by the Engineer.

5. Final Flushing: After the applicable retention period, the

heavily chlorinated water shall be flushed from the main until

the chlorine concentration in the water leaving the main is no

higher than that generally prevailing in the system or less

than one (1) mg/l. Chlorine residual determination shall be

made by the Engineer. The heavily chlorinated water and

flushing water shall be lawfully disposed of by the

Contractor.

6. Bacteriologic Test: After chlorination and final flushing, and

before the water main is placed in service, samples shall be

collected from the main and tested for enteric bacterial

contamination and shall show the absence of coliform

organism. At least two (2) consecutive satisfactory

bacteriological samples shall be obtained from the

distribution system before the system can be placed into

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services. Samples shall be collected in duplicate at the

opposite end of the line from where the pipe was filled with

water and at approximately one (1,000) thousand foot

intervals. Samples shall be taken through the use of sample

tap consisting of a corporation cock and copper tube.

Testing shall conform to AWWA Standard C651 or C652.

All bacteriological sampling and testing shall be conducted by a

state certified laboratory. If the initial disinfection fails to produce

satisfactory samples, disinfection shall be repeated until satisfactory

samples have been obtained. After each group of samples is taken, the

Contractor shall submit in writing to the Engineer a report stating the

results of the tests. The testing of the service shall be done according to

the BOCA Plumbing Code.

5-330.9 HYDROSTATIC TESTING

Pressure tests shall conform with Section 4 of AWWA Standard

C600.

A. The water mains shall be tested for leakage by the Contractor at

his own expense in the presence of the Engineer. All tests will be

conducted in a manner to minimize as much as possible any

interference with the Contractor's work or progress. A maximum of

five thousand (5,000) linear feet of water main may be tested at

one time.

B. The Contractor shall notify the Engineer when the work is ready for

hydrostatic testing and tests shall be made as soon thereafter as

practicable under the direction of the Engineer. Personnel for

reading meters, gauges or other measuring devices will be

furnished by the Engineer, but all other labor, equipment, water and

5-29

materials, including meters and gauges, shall be furnished by the

Contractor.

C. The water mains shall be tested as a whole or in sections valved or

bulkheaded at the ends. Test piping under a hydrostatic pressure

of 200 psi unless shown otherwise on the approved plans. Apply

pressure to the piping after it has been purged of air. Maintain

water pressure for a minimum of two hours. Testing procedures

shall be in accordance with AWWA C600 and the measured

amount of leakage shall not exceed the amount found in Table 6 of

AWWA Specification C600.82.

The table has been established by the following formula:

L = SD P 133200 L = Allowable leakage in gallons/hour S = Total length of pipe being tested D = Nominal diameter of the pipe P = Average test pressure during testing

ALLOWABLE LEAKAGE PER 1,000 FT OF PIPE LINE * - GPH

Normal Pipe Diameter - in. Avg. Test

Pressure psi

(Bar)

3

4

6

8

10

12

14

16

18

20

24

30

36

250 (17) 0.36 0.47 0.71 0.95 1.19 1.42 1.66 1.90 2.14 2.37 2.85 3.56 4.27

225 (16) 0.34 0.45 0.68 0.90 1.13 1.35 1.58 1.80 2.03 2.25 2.70 3.38 4.05

200 (14) 0.32 0.43 0.64 0.85 1.06 1.28 1.48 1.70 1.91 2.12 2.55 3.19 3.82

175 (12) 0.30 0.40 0.59 0.80 0.99 1.19 1.39 1.59 1.79 1.98 2.38 2.98 3.58

150 (10) 0.28 0.37 0.55 0.74 0.92 1.10 1.29 1.47 1.66 1.84 2.21 2.76 3.31

125 ( 9) 0.25 0.34 0.50 0.67 0.84 1.01 1.18 1.34 1.51 1.68 2.01 2.52 3.02

100 ( 7) 0.23 0.30 0.45 0.60 0.75 0.90 1.05 1.20 1.35 1.50 1.80 2.25 2.70

• For pipe with eighteen (18’) ft. nominal lengths. To obtain the

recommended allowable leakage for pipe with twenty (20) ft. nominal

lengths, multiply the leakage calculated from the table by 0.9. If the

pipeline under test contains sections of various diameters, the allowable

leakage will be the sum of the computed leakage for each size.

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D. All joints or fittings at which leakage occurs shall be reworked to

insure tightness. Following repair, the pipeline shall be retested

until leakage is within the limit set. Methods of repair prior to

retesting shall be done with City inspection and approval. All

materials must be rated by an approved testing agency.

5-330.10 REPAIR GUIDELINES

Structural repairs to pipe (i.e., holes, crushed or slipped joints)

required as a result of a pressure test, shall be made in accordance with

the guidelines of this Manual.

Prior approval of the Director is required for repairing damaged

water mains.

A. Slipped or leaking joints may be repaired by jacking to properly

realign the pipe.

B. All other damage (i.e., displaced gasket or crushed pipe) shall be

repaired by replacement of the damaged section. To repair this

type of damage, vertical plane cuts shall be made a minimum of

one foot beyond the extremity of the damaged section. A

replacement section shall then be installed such that the joint gap

at either end shall be no more than ¾ of an inch. The replacement

section will then be installed with couplings of the same pipe

material.

C. All excavation shall be done to afford proper protection to the line

while the repair is made.

D. Location of the water main repairs will be reported to the Water and

Sewer Director to be made part of the as-built records.

E. Location of each repair will be measured from the closest valve to

the side of the repair.

F. The type of repair situation will be noted.

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G. When pipe is required to be removed and replaced, the length and

number of couplings used will be noted.

H. The design engineer of record shall be responsible for obtaining

the approved repair method from the City of Manassas.

5-330.11 CERTIFICATE TO OPERATE

No occupancy permit shall be issued where a building is connected

to a new water main until an acceptable pressure test and bacteriological

sampling indicates that construction conforms to the specifications and

criteria.

5-330.12 FINAL APPROVAL

Final approval for the satisfactory completion of the water main

system shall not be given until all site work is complete, the as-built plan (if

required) is submitted to and approved by the Director of Public Works

and the performance bond is released.

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SECTION 5-500 WATER DISTRIBUTION SYSTEM DETAILS

TABLE OF CONTENTS

DRAWING NO.

TRENCH DETAIL FOR DUCTILE IRON PIPE ........................................................ W-1.0

CONCRETE THRUST BLOCKS HORIZONTAL BENDS ........................................ W-2.0

CONCRETE THRUST BLOCKS TEES AND CAPS ................................................ W-2.1

CONCRETE THRUST BLOCKS LOWER VERTICAL BENDS ............................... W-2.2

CONCRETE THRUST BLOCKS UPPER VERTICAL BENDS ................................ W-2.3

CONCRETE THRUST BLOCKS INSERTING VALVES .......................................... W-2.4

MECHANICAL RESTRAINER GLAND .................................................................... W-3.0

AIR RELEASE VALVE SETTING ............................................................................ W-4.0

BLOWOFF DETAIL ................................................................................................. W-5.0

GATE VALVE SETTING.......................................................................................... W-6.0

WATER SERVICE CONNECTIONS 2" AND SMALLER ......................................... W-7.0

WATER METER INSTALLATION 3/4" AND 1" SERVICES .................................... W-7.1

WATER METER INSTALLATION 1½" SERVICES ................................................. W-7.2

WATER METER INSTALLATION 1" METER IN 2" SERVICE ................................ W-7.3

WATER METER INSTALLATION 2" SERVICE ...................................................... W-7.4

WATER SERVICE CONNECTIONS 3" AND 4" SERVICES ................................... W-8.0

WATER METER INSTALLATION 3" SERVICE ...................................................... W-8.1

WATER METER INSTALLATION 4" SERVICE ...................................................... W-8.2

WATER SERVICE CONNECTIONS 6" AND 8" SERVICES ................................... W-9.0

WATER METER INSTALLATION 6" SERVICE ...................................................... W-9.1

WATER METER INSTALLATION 8" SERVICE ...................................................... W-9.2