Town of Middletown, DE Sanitary Sewer

Polyvinyl chloride (PVC) pipe.

PVC pipe, used for gravity sewer construction, shall equal or exceed the requirements of ASTM D-3034 and shall have a minimum standard dimension ratio (SDR) of 26 and the minimum pipe stiffness, as tested in accordance with ASTM D-2412, shall be 45 psi when measured under 5% deflection at 73° F. Pipe shall be manufactured with integral wall bell and spigot joints in standard lengths not exceeding 20 feet.

Polyvinyl chloride (PVC) pipe fittings shall utilize an elastomeric O-ring gasketed joint assembly in accordance with the manufacturer's recommendations.

Polyvinyl choride (PVC) Wye, 45° wye branches, pipe stoppers and other fittings shall be manufactured in accordance with the same specifications and shall have the same thickness, depth of socket, and annular space as the main pipe. Wye and 45° wye branches shall be complete pipe sections.

Service saddles will not be permitted for use in new construction.

Polyvinyl chloride (PVC) pipe shall be delivered and stockpiled in unit pallets. No stacking of pallets above five feet in height will be allowed. If pipe is stockpiled for more than 30 days' prior to installation, it must be suitably covered with reflective material to protect the pipe from ultraviolet rays emanating from sunlight. Do not use plastic sheets. Allow for air circulation under covering.

Bowed sections of pipe will be unacceptable. Installation of pipe which has bowed, whether or not the bow has been corrected, will not be allowed.

Ductile iron (DIP) pipe.

DIP pipe shall be manufactured in accordance with ANSI A21.51, latest edition, and shall be thickness Class 52 unless otherwise approved by the Town. Push-on joints conforming to ANSI A21.11, latest edition, shall be utilized for gravity sanitary sewer applications.

Pipe and fittings shall be double cement-lined with seal coat and shall receive an external standard bituminous foundry coating in accordance with ANSI A21.4. The pipe and fittings shall also have an internal coating system. The internal coating shall be a ceramic epoxy and shall be an amine cured novalac epoxy containing at least 20% by volume of ceramic quartz pigment. The coating shall be US Pipe and Foundry Protecto 401 or an approved equal.

Gravity sewer mains installed at depths exceeding 15 feet shall not be permitted unless approved, in writing, by the Town of Middletown based on extenuating circumstances that cannot be avoided. Before the Town will consider sewer deeper than 15 feet, the engineer must consider and present alternatives to the Town which shall include, but not be limited to:

The installation of a pump station and forcemain;

Realignment of the sewer main to avoid the excessive depth; and

[3]

Adjustment of the site grading to reduce or eliminate the excessive depth.

All fittings used to connect ductile iron sewer main pipe shall be ductile iron with a 250 psi pressure rating and marked in accordance with ANSI A21.10.

Sanitary sewer lateral cleanout frames and covers. Cleanout frames and covers shall be cast iron. Cleanout frames and covers shall be watertight with recessed lifting holes. Terminal sewer and house lateral cleanout frames and covers shall be brass caps used with PVC pipe.

Detection tape. Pipeline detectable tape shall be installed continuously along all gravity sewers. The tape shall be installed directly above the gravity sewers and 24 inches below the ground surface. The tape shall be Lineguard Type III Detectable Tape as manufactured by Lineguard, Inc., of Wheaton, Illinois, or equal. The tape shall be a minimum of two inches wide, green in color, imprinted with the words "Caution-Sewer Line Below," and be capable of being detected with inductive methods.

Concrete. All concrete for manhole base slabs and cradles, flow channels, encasements, blocking, etc., shall have a minimum compressive strength of 3,000 psi at 28 days. Type II Portland cement shall be used.

Sand.

Sand shall be composed of sharp, angular, siliceous grains, coarse, or graded from fine to coarse with the coarsest grains predominating, and sensibly free from clay, loam, dirt, mica, organic matter, or other impurities.

Sand containing more than 5% by weight of foreign material shall not be used. This limit may be changed for special classes of work if hereinafter specified.

Sand exhibiting more than an acceptable amount of fine matter or impurities may be required to be washed after delivery or shall be rejected altogether. The contractor shall submit samples of the sand he proposes using. These shall be retained in the office of the Inspection Agency as a standard for comparison during the progress of the work, and all sand used shall be equal in quality to the acceptable samples. Sand for mortar shall be screened to reject all particles of a greater diameter than 1/4 inch and shall not contain more than 5% by weight of a very fine material.

(7)

Mortar.

Cements shall be Class B sulfur-resistant in accordance with the "Standard Specifications for Portland Cement," ASTM Designation C 150 for Type II.

Unless hereinafter specified otherwise, all mortar shall be composed of cement and sand of the character specified above. The proportion by volume shall be one part of cement to two parts of sand. One volume of cement shall be 94 pounds net. One volume of sand shall be 0.9 cubic feet, the sand not being packed more closely than by throwing it into a box in the usual way. Mortar shall be fresh mixed in small batches for the work in hand. Tight boxes or platforms made for the purposes shall be used. The sand and cement shall be thoroughly mixed dry, in the proper proportions, until a uniform color has been produced, whereupon a moderate dose of water shall be added, so as to produce a stiff paste of the proper consistency.

Sand obtained from the excavation shall not be used.

Construction methods.

Topsoil, vegetative matter, and other organic material shall be stripped from areas that are to be disturbed by construction, and stockpiled. Topsoil shall be segregated from nonorganic trench excavation material and debris.

Trench backfill material shall be satisfactory soil excavated from the trench, or imported soil meeting DelDOT specifications for trench backfill. Satisfactory trench backfill shall be free from frozen matter, stumps, roots, brush, other organic matter, cinders or other corrosive material, debris, and any rocks or stone larger than six inches, in any dimension. Material that is excessively wet and or unable to compact in a satisfactory manner will not be placed for backfill. The Town of Middletown Inspection Department will direct the contractor to stop installation and backfilling operations if proper compaction is not achieved.

Laying pipe.

Pipe shall be carefully handled and lowered into the trench. In laying pipe, special care shall be taken to ensure that each length shall abut against the next in such a manner that there shall be no shoulder or unevenness of any kind along the inside of the bottom half of the pipeline. No wedging or blocking will be permitted in laying any pipe unless by written order or permission from the Town.

Before joints are made, each pipe shall be well-bedded on a solid foundation, and no pipe shall be brought into position until the preceding length has been thoroughly embedded and secured in place with a minimum of six inches of crushed angular stone, 3/4 inch maximum size, or No. 57 stone. The contractor shall make any defects due to settlement good. Bell holes shall be dug sufficiently large enough to ensure that the pipe is firmly bedded on the full length of the barrel.

Proper and suitable tools and appliances for the safe and convenient handling and laying of pipes shall be used.

The pipes shall be thoroughly cleaned before they are laid and shall be kept clean until the acceptance of the completed work. The open ends of all pipelines shall be provided with a stopper carefully fitted, so as to keep dirt and other substances from entering. This stopper shall be kept in the end of the pipeline at all times when not in the process on laying pipe.

Whenever a pipe requires cutting to fit into the line or to bring it to the required location, the work shall be done in a satisfactory manner so as to leave a smooth end, without extra compensation.

All concrete required to support and reinforce wye branches and bends shall be placed as shown in the standard details or as directed by the Town.

(g)

All sewer house connections shall be laid on a 2% grade unless otherwise directed. All house connections shall meet the requirements of the Town of Middletown's adopted Plumbing Code unless otherwise directed by the Town.

(h)

All sewer house connections shall be surrounded by No. 57 stone (to a minimum depth of six inches on all sides) from the connection at the sewer main all the way to the cleanout at the property line/right-of-way.

(i)

All sewer house connections shall be constructed to terminate at an angle perpendicular to the property lines unless otherwise noted on the plans.

(j)

The excavation in which pipe is being laid shall be kept free from water and no joint shall be made under water. Water shall not be allowed to rise in the excavation until pipe bedding and backfill has been completed. The greatest care shall be used to secure water tightness and to prevent damage to, or disturbing of, the joints during the backfilling process, or at any time. After pipes have been laid and the joints have been made, there shall be no walking on or working over them except such as may be necessary in tamping, until there is a covering at least two feet in depth, over their top.

(k)

All pipe shall be placed in accordance with the installation recommendations of the pipe manufacturer and applicable portions of this specification.

(l)

No pipe shall be laid upon a foundation into which frost has penetrated at any time such that there is danger of the formation of ice or the penetration of frost at the bottom of the excavation, unless the minimum length of open trench and promptness of refilling are observed.

(m)

Branches shall be located in a position designated by the developer's engineer or his representative. Short pieces of lateral sewer shall be field-cut to meet this condition. The contractor shall have on the work site, at all times, factory-approved equipment to machine and adapt the field-cut end of short pieces to standard couplings and jointing materials.

(n)

Minimum depth of cover for any sewer main shall be 42 inches measured from the top of the pipe to the final grade above the pipe.

Backfill and compaction. All trench backfill shall be compacted. Backfill of pipe and manholes shall be compacted with equipment in a manner which is capable of producing the required results. Backfill material shall be placed and graded in uniform horizontal lifts, which may not exceed eight inches. Compaction will not be performed by jetting or water settling. If during the compaction of the trench any soft, yielding, or spongy areas are observed, backfilling operations will cease until stability of these areas is achieved. The Town of Middletown has the authority to request field moisture/density control tests to document compliance of work as per DelDOT's specifications. Failed areas shall be compacted again and retested. A geotechnical consultant approved by the Town of Middletown shall perform moisture/density tests at the developer's expense.

Connection to existing manholes.

Connection to existing manholes shall be made at such points and of such form, dimensions and elevations as indicated on the plans or as the Town of Middletown shall require.

The size of the opening through the wall of the existing manhole for the pipeline connections shall not exceed the outside diameter of the pipe plus six inches. All connections shall be fully grouted by using hydraulic cement with a sand collar or a link-seal/boot-type system. Sand collars will not be permitted in deep (greater than 10 feet below ground surface) or high groundwater conditions. Manhole adapters shall be used on all connections to existing manholes.

Care shall be taken by the contractor to prevent broken brick and mortar from entering the existing or proposed pipes. A screen shall be provided below the area of work to catch any falling debris.

Core drilling is the only acceptable method of making a new opening in an existing reinforced concrete manhole.

Alignment. Sanitary sewers shall be installed with straight horizontal and vertical alignments between manholes. When a smaller sewer joins a larger one, the invert of the larger sewer should be lower to allow the crowns of both pipes to be at the same elevation. The invert of a pipe exiting a manhole shall be lowered the appropriate distance compared to the invert of the pipe(s) entering the manhole to account for the head loss within the manhole.

Storm drain separation. Sanitary sewers shall be laid at least three feet horizontally from any storm drain pipe measured edge to edge. Sanitary sewer mains that cross a drainage pipe shall be encased in concrete, a minimum of five feet on either side of the center line of the crossing, if there is less than two feet of clearance between the outside diameter of the sanitary sewer and the outside diameter of the drainage pipe. A full length of sanitary sewer pipe shall be installed centered on the storm drain to maximize the distance to a sanitary sewer pipe joint.

Horizontal and vertical separation.

In general, horizontal and vertical separation shall be per 10 State Standards. Sewer mains shall be laid at least 10 feet horizontally from any existing or proposed water main. The distance shall be measured edge to edge. Separation between sewer and water laterals shall be a minimum of three feet measured inside edge to inside edge, or as required in the adopted plumbing code, whichever is stricter.

Sewers crossing water mains shall be laid to provide a minimum vertical distance of 18 inches between the outside of the water main and the outside of the sewer.

Sewer lines shall be located below water mains unless otherwise authorized by the Town.

When a sewer main crosses an existing water main, the crossing shall be arranged so that the sewer joints will be equidistant and as far as possible from the water main joints.

Where a water main crosses under a sewer, adequate structural support shall be provided for the sewer to maintain line and grade and prevent damage to the water main.

When it is impossible to obtain proper horizontal and vertical separations stipulated above, the Town may allow deviations on a case-by-case basis, if supported by data from the design engineer. Alternate design shall meet 10 State Standards.

Acceptance testing. Prior to the request for final acceptance by the Town, it shall be the contractor's responsibility to examine all completed pipe lines to insure that they are laid to the proper alignment and grade and free from foreign material. After this has been done to the satisfaction of the Town, the Town will order tests to be made on all portions of the sewers built under the contract. The contractor shall cooperate and furnish all assistance necessary to perform the tests as specified herein and as directed by, and under the direction of the Town's inspector.

Deflection testing of sanitary sewers. Sanitary sewers shall be tested in the presence of the Town's inspector and the contractor's representatives to determine the amount of vertical deflection in the completed pipe line as follows:

Deflection testing as specified hereinafter shall be accomplished by the contractor on all sanitary sewers installed. Should significant failures be detected, additional deflection testing shall be performed by the contractor.

Installation of sanitary sewers shall be complete prior to the start of deflection testing. All sheeting shall be removed except where written approval from the Town to keep the sheeting has been obtained. All backfill shall be placed to finished grade and dewatering operations ceased.

A mandrel with a diameter equivalent to 95% of the inside diameter of the pipe to be tested shall be pulled through the pipeline, from manhole to manhole, by hand. If the mandrel is unable to pass through the pipe without applying excessive force (as judged by the Town), it will be constructed as evidence that the pipe has deflected more than 5% of the inside pipe diameter. A permanent record of all testing with locations where excessive pipeline deflections occur shall be kept by the contractor and forwarded to the inspection agency after completion of testing on each line. The mandrel shall be approved by the inspection agency prior to use. Mandrels shall have an odd number of gauging plates. The minimum number of plates shall be nine with a contact surface length equal to the inside pipe diameter plus two inches for pipelines 10 inches in diameter and smaller. On larger diameters, the contact surface length shall equal the inside pipe diameter.

The contractor shall immediately replace all sections of pipe which deflect more than 5%.

Air acceptance test.

The Town of Middletown reserves the right to utilize a low pressure air acceptance test for pipe with a diameter of 39 inches or less. The contractor shall furnish all equipment and personnel to conduct this test in accordance with ASTM F1417 - 92 and the following procedure:

All branch fittings and ends of lateral stubs shall be securely plugged to withstand the internal test pressures. The section of line being tested shall also be securely plugged at each manhole. All stoppers shall be adequately braced when required.

Air shall be slowly supplied to the plugged pipe line until the internal air pressure reaches 4.0 pounds per square inch (psi) and the test pipe section is stabilized.

[3]

Disconnect the air supply and decrease the pressure to 3.5 psi before starting the test.

[4]

The pressure within the test pipe section must remain at or above 3.0 psi for the minimum holding time based on Table 2 below:

TABLE 2 Minimum Specified Time Required for a 0.5 psig Pressure Drop for Size and Length of Pipe Indicated for Q = 0.0015
Note - Consult with pipe and appurtenance manufacturer for maximum test pressure for pipe size greater than 30 inches in diameter.
Pipe Diameter (in)	Minimum Time (min:sec)	Length for Minimum Time (ft)	Time for Longer Length (sec)	Specification Time for Length (L) Shown (min:sec)
Pipe Diameter (in)	Minimum Time (min:sec)	Length for Minimum Time (ft)	Time for Longer Length (sec)	100 ft	150 ft	200 ft	250 ft	300 ft	350 ft	400 ft	450 ft
4	1:53	597	0.190 L	1:53	1:53	1:53	1:53	1:53	1:53	1:53	1:53
6	2:50	398	0.427 L	2:50	2:50	2:50	2:50	2:50	2:50	2:51	3:12
8	3:47	298	0.760 L	3:47	3:47	3:47	3:47	3:48	4:26	5:04	5:42
10	4:43	239	1.187 L	4:43	4:43	4:43	4:57	5:56	6:55	7:54	8:54
12	5:40	199	1.709 L	5:40	5:40	5:42	7:08	8:33	9:58	11:24	12:50
15	7:05	159	2.671 L	7:05	7:05	8:54	11:08	13:21	15:35	17:48	20:02
18	8:30	133	3.846 L	8:30	9:37	12:49	16:01	19:14	22:26	25:38	28:51
21	9:55	114	5.235 L	9:55	13:05	17:27	21:49	26:11	30:32	34:54	39:16
24	11:20	99	6.837 L	11:24	17:57	22:48	28:30	34:11	39:53	45:35	51:17
27	12:45	88	8.653 L	14:25	21:38	28:51	36:04	43:16	50:30	57:42	64:54
30	14:10	80	10.683 L	17:48	26:43	35:37	44:31	53:25	62:19	71:13	80:07
33	15:35	72	12.926 L	21:33	32:19	43:56	53:52	64:38	75:24	86:10	96:57
36	17:00	66	15.384 L	25:39	38:28	51:17	64:06	76:55	89:44	102:34	115:23

[5]

Upon completion of the test, open the bleeder valve and allow all air to escape. Plugs should not be removed until the air pressure in the test section has been reduced to atmospheric pressure.

The contractor shall be responsible to repair all defects in the event the pipe is unable to maintain pressure.

The contractor shall not make any active connections to the existing sanitary sewers until after the acceptance tests have been performed and approved by the Town.

Camera inspection.

The Town of Middletown reserves the right to require a TV inspection of sewer mains and laterals. This inspection will take place as a final punch list item and before top lift of hot-mix is placed.

Inspection shall be performed by a NASSCO Pipeline Assessment Certification Program (PACP) certified operator and shall meet the coding and reporting standards and guidelines as set by PACP. These same standards shall also be used for lateral inspections regardless of whether conducted using cleanout launched or mainline launched lateral camera. All report annotations, pipe conditions and pipe defects shall be identified properly using PACP codes as defined by PACP, and severity ratings shall be calculated according to PACP.

Quality of inspection recording shall be acceptable to the Town when viewed on a standard computer monitor.

Submittal of PACP certificate to Town of Middletown inspectors completing the work shall be required.

Closed circuit TV equipment: Select and use closed-circuit television equipment that will produce a color recording.

Pipe inspection camera: Produce video recording using a pan-and-tilt, radial viewing, pipe inspection camera that pans ± 275 degrees and rotates 360 degrees. Use a camera with an accurate footage counter that displays on the TV monitor the exact distance of the camera from the center line of the starting manhole. Use a camera with camera height adjustment so that the camera lens is always centered at 1/2 the inside diameter, or higher, in the pipe being televised. Provide a lighting system that allows the features and condition of the pipe to be clearly seen. A reflector in front of the camera may be required to enhance lighting in large diameter pipe. Lighting shall not cause shadows within the field of view of the camera, either when forward viewing or when using pan/tilt. The camera, television monitor and other components of the video system shall be capable of producing a minimum 500-line resolution colored video picture. Picture quality and definition shall be to the satisfaction of the Town.

(g)

Mainline launched lateral inspection camera: Produce a video recording using a fixed orientation color camera capable of extending into open laterals for a minimum distance of 80 feet from the lateral connection. Minimum performance standards are as noted above in pipe inspection camera.

(h)

Lateral cleanout launched lateral inspection camera: Alternatively, contractor may produce a video recording of the sewer lateral between the sewer lateral cleanout and the mainline using a minicam launched from the sewer lateral cleanout. Minimum performance standards are as noted above in pipe inspection camera.

(i)

TV studio: TV studio is to be contained in an enclosed truck, trailer or van. It shall have room and seating for the operator and the Town and also room for at least one standing visitor with the doors closed. The studio shall have air conditioning and heating. Normal operation of all equipment, including the TV camera, monitor, and winches is to be from a control panel in the studio. When joint testing and sealing is to be performed, the equipment shall be contained in the same unit as its TV equipment and shall be operated from the same control panel.

(j)

Recording: All recordings are to be in digital format.

Image capture. Digitized picture images shall be stored and be exportable as JPEG formats. Minimum resolution shall be 1024 x 768.

Video capture. Full time live video and audio files shall be captured for each pipe segment and lateral inspected. The files shall be stored in industry standard MPEG format viewable from a DVD. The MPEG video shall be ISO-MPEG Level 1 (MPEG-1) coding with a resolution of 352 pixels (x) by 240 pixels (y) and an encoded frame rate of 29.97 frames per second. System shall perform an automatic disk image/file naming structure to allow saved video/data sections to be "burned" to digital format. It shall have the capability of "burning" a minimum of 120 minutes of recording to digital media. The video recording shall be free of electrical interference and shall produce a clear and stable image. The audio recording shall be sufficiently free of background and electrical noise as to produce an oral report that is clear and discernable. The digital recordings and inspection data shall be cross-referenced to allow instant access to any point of interest within the digital recording.

(k)

Television inspection.

Additional requirements.

[a]

Sewer lines and manholes are required to be clean. Prior to the television inspection, any sewer line or manhole found to be dirty during the TV inspection process will be cleaned by the contractor.

[b]

Televise the sewer line to document the condition of the line. Provide a color recording showing the completed work.

[c]

For mainline inspections, inspections shall be from center of the starting manhole to the center of the ending manhole. Distances along the pipe should be measured from the center of the upstream manhole.

The contractor shall be responsible to repair all defects observed in the camera and television inspection prior to final acceptance by the Town of Middletown.

As-built drawings. Upon completion of all sanitary sewer, and prior to acceptance, as-built drawings shall be submitted to the Town of Middletown for review and approval. One electronic copy in pdf format shall be submitted bearing the signature and seal of a Delaware-registered surveyor or engineer with the same scale as the original approved drawings.

Minimum size. No sewer main shall be less than eight inches in diameter. The minimum size of a sewer lateral shall be six inches. Apartments/condominiums up to four units per cluster may use a six-inch-diameter sewer lateral. Clusters with more than four units shall use a lateral size based on a computation of the flow to be generated from the cluster.

Minimum slope.

All sewers shall be designed and constructed to provide mean velocities, when full, of not less than two feet per second. Based on Kutter's formula or Manning's formula, an "n" value of 0.013 is generally used. Use of other practical "n" values may be permitted if the available research or field data show justification. The following are the minimum slopes that should be provided; however, slopes greater than these figures are desirable:

Sewer Size (inches)	Minimum Slopes (feet/feet)
8	0.0050
10	0.0028
12	0.0022
15	0.0015
18	0.0012
21	0.0010
24	0.0008
27	0.00067
30	0.00058
36	0.00046

All sewer laterals shall have a minimum slope of 2%, or in accordance with the adopted plumbing code, whichever is stricter. Excessive slopes should be avoided to prevent the separation of solids and liquids in the pipe.

Backflow preventers.

All sewer laterals between individual residential buildings and the sewer main shall have a backflow preventer installed prior to any branch line or internal cleanout. Sewer laterals serving nonresidential buildings may be required to install a backflow preventer subject to review by the Town's Engineer.

They shall be located inside the foundation wall for buildings with basements and just prior to the base wall in buildings with crawl spaces or no basements.

The backflow preventer shall remain accessible to and installed ahead of any and all service lines or cleanouts.

Cleanouts.

All sewer laterals shall have cleanouts installed on the exterior located at or within two feet of the property line and every 50 feet between the property line and building.

Only flush-type cleanouts will be installed.

No cleanout will be allowed to extend more than 1/2 inch above finished grade.

Cleanouts shall, by means of a sweeping 45° elbow, be connected in the direction of flow to an installed Y on the lateral.

Cleanouts installed in driveways or other roadway surfaces (blacktop areas) must be installed per the Town of Middletown standard details.

§ 46-12 Sanitary sewer force mains.

Description.

This section shall consist of sanitary sewer force mains within the right-of-way or a Town-maintained easement of ductile iron pipe (DIP), polyvinyl chloride (PVC) pipe or of high-density polyethylene (HDPE) of the diameter shown on the plans, laid on a firm bed true to line and grade in accordance with these specifications and details.

Force mains shall be installed at the elevations indicated on the construction drawings. Force mains shall maintain a minimum of 42 inches of cover.

Materials.

Polyvinyl chloride (PVC) pressure pipe.

All buried PVC pressure pipe shall be polyvinyl chloride pipe (PVC). Class 253 SDR-18 meeting the requirements of ASTM D-2241 for force mains up to 12 inches in diameter. Fittings shall be in accordance with ASTM D-2466 of the same color and pressure rating. Joints at the fittings shall be of the mechanical-joint-type. At the remaining joints push-on type joints with concrete buttresses may be used in accordance with ASTM 3139. The elastomer seals used for joining the pipe shall meet ASTM F477 specifications. Lubricant shall be as recommended and supplied by the pipe manufacturer.

Provide a joint restrainer for the connection to ductile iron pipe if thrust forces present dictate this requirement. Provide a joint restrainer at all locations where a transition to HDPE pipe is required. The restrainer shall provide a full 360-degree contact with a serrated inside surface to secure the clamp to the pipe. The restrainer shall be UNI-FLANGE Series 1300 or an approved equal for PVC to ductile iron transitions. The restrainer between PVC and HDPE pipe shall be per the recommendations of the HDPE pipe manufacturer.

Ductile iron (DIP) pipe. All buried ductile iron piping shall be Pressure Class 52 ductile iron meeting the requirements of AWWA C151. The pipe shall be double-cement-lined per AWWA C104 and have an internal coating system. The internal coating shall be a ceramic epoxy and shall be an amine cured novalac epoxy containing at least 20% by volume of ceramic quartz pigment. The coating shall be US Pipe and Foundry Protecto 401 or an approved equal. Pipe intended for buried installation shall receive an external standard bituminous foundry coating in accordance with ANSI A21.4. All buried ductile iron pipe shall have mechanical joints in accordance with AWWA C111.

All fittings shall be ductile iron compatible fittings with mechanical joints meeting the requirements of AWWA C153. All fittings shall be double-cement-lined per AWWA C104 and coated on the exterior with an asphaltic coating. The interior coating shall be the same as for the pipe, as noted above.

Provide restrained joints for all buried ductile iron pipe. Joints shall be suitable for use with AWWA C111 mechanical joints. The follower gland shall include a restraining mechanism which, when actuated, imparts multiple wedging action against the pipe, increasing its resistance as the pressure increases. Flexibility of the joint shall be maintained after burial. Glands shall be manufactured of ductile iron conforming to ASTM A536-80. Restraining devices shall be of ductile iron heat treated to a minimum hardness of 370 BHN. Dimensions of tie gland shall be such that it can be used with standard mechanical joint with tee bolts. Twist-off nuts, sized same as tee-head bolts, shall be used to insure proper torque and actuating of restraining devices. The mechanical joint restraining device shall have a working pressure of at least 250 psi with a minimum safety factor of 2, and shall be EBAA Iron, Inc. MEGALUG, Mueller Aqua Grip, or approved equal.

High density polyethylene (HDPE) pipe. HDPE pipe used for force main construction, shall be PE3408 high density polyethylene meeting cell classification 345444C or 345444E per the requirements of ASTM D-3350 and shall be listed in the name of the pipe and fitting manufacturer in the Plastics Pipe Institute TR-4, Recommended Hydrostatic Strengths and Design Stresses for Thermoplastic Pipe and Fittings Compounds, with a standard HDB rating of 1600 psi at 73° F. Pipe and fittings shall be from the same manufacturer. Pipe shall be manufactured in accordance with ASTM F714 or ASTM D 3035 and shall be so marked. The pipe shall have a standard dimension ratio (SDR) suitable for the design operating condition means of installation and depth of burial, as approved by the Town Engineer. HDPE force mains installed via the directional bore method shall be SDR 11.0, minimum.

Pipe detection. Force mains shall have tracer wire and detectable tape installed continuously along its length. Detectable tape shall be installed in accordance with the specifications outlined in the section entitled "Sanitary Sewer Gravity Mains and House Connection." The tape shall be a minimum of two inches wide, green in color, and imprinted with the words "Caution-Sewer Line Below." Tracer wire shall be installed in accordance with the Town of Middletown "Supplemental Tracer Wire Specification."[1]

Editor's Note: Said specification is included as an attachment to this chapter.

Thrust blocks. Thrust blocks shall be provided on all force main plugs, caps, tees, and bends deflecting 22 1/2 degrees or more either vertically or horizontally.

Thrust blocks shall be concrete with a compressive strength of 3000 psi in 28 days.

Thrust blocking shall be located between solid ground and the fitting to be anchored.

Unless otherwise shown or directed by the Town, place the base and thrust bearing sides of thrust blocking directly against undisturbed earth.

Place thrust blocking so the fitting joints will be accessible for repair.

Protect steel rods and clamps by galvanizing or by coating with bituminous paint.

Valves.

Plug valves for force main isolation service shall be the nonlubricated-type designed for a minimum working pressure of 175 psi and suitable for buried service. The valve shall be suitable for tight closure with pressure on either side of the plug. Buried valves shall have mechanical joint ends. Valves installed in vaults shall have flanged ends unless otherwise noted. The body shall be semisteel. The plug shall be semisteel, resilient-type neoprene faced for use in raw sewage service. The plug seat shall have an overlay of mechanical nickel, fusion-bonded Nylon II, or other suitable material on all surfaces in contact with the plug face. The port area of the valve shall not be less than 100% of the pipe area. The upper trunnion shall be sealed with either permanent O-ring-type seals, or packing held in place by an adjustable packing gland. Packing shall be replaceable without disassembly of operator or valve. The upper and lower journals shall be fitted with replaceable permanently lubricated stainless steel sleeve type bearings. Valves shall be either hand wheel or two-inch square nut operated as indicated on the plans. Plug valves shall be manufactured by the DeZurik Unit of General Signal Corp., or an approved equal.

All plug valves shall be furnished with buried-service-type gear operators. Buried valves shall be furnished with a roadway valve box and an extension stem securely fastened to the operator to position a two-inch square operating nut welded to the top of the stem within 12 inches of the ground surface. An open and closed indicator shall be provided on all valves at the operating nut. Valves shall open left (counterclockwise). Spacer discs or rods shall be installed in the valve box as required to center the extension stem. Extension stem shall be of the size recommended by the valve manufacturer.

The exterior of the valve, operator, and extension stem shall be bituminous coated unless otherwise noted.

Valve boxes. Valve boxes shall be cast iron, three-piece screw-type installed over the valve bonnet and operating nut. Valve boxes shall be capable of being adjusted to reach the surface of the existing or proposed grade but not to extend above the finished grade at any time. Valve boxes shall be manufactured by Mueller or approved equal.

Couplings and wall seals.

Couplings shall be provided where required to facilitate the installation or removal of valves and equipment, in addition to the couplings shown on the drawings. All couplings shall be designed for the same pressure rating as of the pipes on which installed. In addition:

The pipe couplings shall be of gasketed, sleeve-type, with diameter to properly fit the pipe. Each coupling shall consist of one steel middle ring 0.154 inches thick and five inches in length, two steel followers, two rubber-compounded wedge section gaskets and sufficient track-head steel bolts to properly compress the gaskets. Field joints shall be made with this type of coupling.

The middle ring and followers of the coupling shall be true circular sections free from irregularities, flat spots, or surface defects. They shall be formed from mill sections with the follower-ring section of such design as to provide confinement of the gasket. After welding, they shall be tested by cold expanding a minimum of 1% beyond the yield point.

The coupling bolts shall be of the elliptic-neck track head design with rolled threads. The manufacturer shall supply information as to the recommended torque to which the bolts shall be tightened. All bolt holes in the followers shall be oval.

The gaskets of the coupling shall be composed of a crude or synthetic rubber base compounded with other products to produce material, which will not deteriorate from age, from heat, or exposure to air under normal storage conditions. It shall also possess the quality of resilience and ability to resist cold flow so that the joint will remain sealed and tight when subjected to shock, vibration, pulsation and temperature or other adjustments of the pipeline.

The couplings shall be assembled on the job in a manner to insure tight joints under all reasonable conditions of expansion, contraction, shifting and settlement, unavoidable variations in trench gradient, etc. The coupling shall be Dresser, Style 38, as manufactured by Dresser Manufacturing Division, Bradford, Penna., or approved equal.

(7)

Wall seals shall be provided at all penetrations in concrete structures. In addition:

The contractor shall determine the required inside diameter of each individual wall opening or sleeve before ordering, fabricating or installing. The inside diameter of each wall opening shall be sized as recommended by the manufactured to fit the pipe and seal to assure a watertight joint.

Seals shall be Link-Seal, as manufactured by Thunderline Corporation, or approved equal.

Acceptance testing.

Prior to acceptance, all new pressure pipes shall be tested as specified herein. The contractor shall be responsible for furnishing all labor, tools, equipment, materials, including water, pumps, compressors, pressure gauges, meters, and stopwatch subject to the approval of the Town.

Any defective work, which shows up while conducting tests or before acceptance, shall be replaced or repaired by the developer at his own cost and expense. Any leaks due to either blown joints or cracked pipe or fittings shall be repaired by the developer at his own expense.

All new force mains shall undergo a hydrostatic pressure test prior to acceptance by the Town of Middletown.

Test restrictions:

All tests shall be conducted in the presence of a Town inspector.

Testing of all pressure pipes shall be conducted in accordance with AWWA C600 testing requirements.

Test pressure shall be 150 psi.

The hydrostatic pressure test shall be of at least a two-hour duration.

Valves shall not be operated in either direction at a differential pressure exceeding the rated valve working pressure. The test pressure shall not exceed the rated pressure of the valves when the pressure boundary of the test section includes closed, resilient-seated gate valves or butterfly valves.

Pressurization.

After the pipe has been laid, all newly laid pipe or any valved section thereof shall be subjected to a hydrostatic pressure of 150 psi. Each valved section of pipe shall be slowly filled with water, and the specified test pressure (based on the elevation of the highest point of the line or section under test and corrected to the elevation of the test gauge) shall be applied by means of a pump connected to the pipe. Valves shall not be operated in either the opening or closing direction at differential pressures above the rated pressure. It is good practice to allow the system to stabilize at the test pressure before conducting the test.

Before applying the specified test pressure, air shall be expelled completely from the section of piping under test. If permanent air vents are not located at all high points, corporation cocks shall be installed at such points so that the air can be expelled as the line is filled with water. After all the air has been expelled, the corporation cocks shall be closed and the test pressure applied. At the conclusion of the pressure test, the corporation cocks shall be removed and plugged or left in place as directed by the Town.

All exposed pipe, fittings, valves, and joints shall be examined carefully during the test. Any damage or defective pipe, fittings, valves, or joints that are discovered following the pressure test shall be repaired or replaced with sound material, and the test shall be repeated until satisfactory results are obtained.

No drop in pressure will be allowed for the minimum two-hour duration. The contractor shall be responsible to repair all defects in the event the pipe is unable to maintain pressure.

Construction methods. The construction methods for sanitary sewer force mains shall be as described in the specifications outlined in the section entitled "Sanitary sewer gravity mains and house connections."[2]

Editor's Note: See § 46-11.

Alignment/separation. The alignment and separation requirements for sanitary sewer force mains shall be as described in the specifications outlined in the section entitled "Sanitary sewer gravity mains and house connections."[3]

[3]

Editor's Note: See § 46-11.

As-builts drawings. Upon completion of all sanitary sewer force mains, and prior to acceptance, as-built drawings shall be submitted to the Town of Middletown for review and approval. One electronic copy in pdf format shall be submitted bearing the signature and seal of a Delaware-registered surveyor or engineer with the same scale as the original approved drawings.

§ 46-13 Sanitary sewer manholes and miscellaneous stuctures.

Description. The work described in this section involves sanitary sewer manholes and miscellaneous structures of concrete or brick masonry built to the shapes and dimensions in accordance with these specifications and details as shown in the standard details, at the location indicated on the plans or as directed by the Town.

Material.

Precast manholes.

Precast reinforced concrete risers, eccentric cones and bases shall be as detailed on the drawings and in conformance with ASTM Designation C 478. Joints between riser sections shall be fitted with an O-ring rubber gasket, meeting the requirements of ASTM Designation C 443.

All pipe to manhole connections shall be made by means of an integrally cast flexible connector.

Manhole steps. Manhole steps shall be made of 3/8-inch diameter (No. 3) steel reinforcing bars, ASTM Designation A 615, Grade 60, encased in polypropylene plastic. Manhole steps shall have notched tread ridge with retainer lug on each side. Steps shall be spaced vertically and aligned as shown on the standard detail drawing and set to provide a minimum of six-inch tread. Manhole steps shall be OSHA approved.

Manhole frames and covers. Manhole frames and covers shall be furnished and set by the contractor as the work progresses as shown in the standard detail drawing. Frames shall be well-bedded in a concrete collar. Material for frames and covers shall be in accordance with the standard specifications for gray iron castings ASTM Designation A 48 for Class No. 35. The manhole frame and cover shall be as shown in the standard details, or approved equal.

The cover shall have written on it "Town of Middletown Sanitary Sewer."

The manhole frame and cover shall be as shown in the standard detail section.

The flow pipe channel through manholes shall be made to conform in shape and slope to that of the sewers. The top of the brick channel shall be at the same elevation as the crown of the main sewer line in the manhole. The channel shall drop a minimum of one inch from influent pipe to the effluent pipe.

All concrete for manhole base slabs and cradles, flow channels, encasements, blocking, etc., shall have a minimum compressive strength of 3,000 psi at 28 days. Type II Portland cement shall be used. All mortar and cement shall be nonshrink.

All new laterals tying into existing concrete manholes shall require the manhole to be core drilled for the connection. The lateral shall be installed and a watertight seal accomplished with the use of Link Seal wall seals, or approved equal.

Construction methods.

Precast manholes. Sanitary sewer manhole base and riser sections shall be precast reinforced concrete and shall be supplied by a manufacturer approved by the Town.

Manholes installed within the sewer distribution system shall conform to the requirements of the Town of Middletown, Type A-2 or A-3 precast manhole specifications.

In addition to the gasket material used within the joints between sections of the manhole, an external joint wrap is required. The wrap is to be applied to a clean/dry surface and placed with the manhole joint centered within the membrane strip with a minimum overlap distance of 18 inches when wrapped around manhole. Wrap shall be a self-adhered membrane consisting of two waterproofing materials with an aggressive rubberized asphalt adhesive backed by a layer of high-density cross-laminated polyethylene or approved equal. The membrane strips shall be a minimum of nine inches wide.

Lifting holes in the walls of precast reinforced concrete risers will be allowed but shall be plugged with rubber stoppers and grouted flush with face or manhole wall after installation of manhole riser sections. Not more than two holes shall be cast in the walls of each riser section for the purpose of handling.

The exterior surface of all precast manholes shall receive a minimum two-coat application of a 68% solids coal tar-type protective coating. The total average dry film thickness shall measure 24 mils with no single measurement to be less than 20 mils. Surfaces shall be prepared in accordance with the manufacturer's instructions and coatings applied in the field in a manner acceptable to the Town. The coating material shall be Bitumastic Super Service Black manufactured by Koppers Co., Inc., Pittsburgh, Pennsylvania, Tar-Jet Super Black XX-32-B-22 manufactured by Pennsbury Coatings Corp., New Britain, Pennsylvania, or approved equal.

Channels for receiving and passing water shall be formed in the bottom of manholes as shown in the standard details or as directed by the Town. All such channels shall be factory formed with concrete. Concrete channels poured in the field will not be permitted. Channels shall slope smoothly and evenly from the main pipe entering the manhole to the outlet pipe. Brick channels for future extensions shall be built into manholes where shown on the plans or where directed by the Town. Rubber gaskets approved by the Town shall be used to seal the pipe at all connections to the manholes.

(7)

Manholes shall be installed as pipe laying progresses. The Town may stop the contractor's work entirely on laying pipe until the manhole just passed has been completed.

Location. Manholes shall be installed at the end of each sewer line; at all changes in grade, size, or alignment; at all intersections; and at distances not greater than 300 feet. Manholes should not be located in the flow line of streets, within swales, nor within areas which may be subject to ponding conditions including low points which may periodically pond due to clogged stormwater inlets or other structures.

Drops. A drop pipe should be provided for a sewer entering a manhole at an elevation of 24 inches or more above the manhole invert. Where the difference in elevation between the incoming sewer and the manhole invert is less than 24 inches, the invert should be filleted to prevent the buildup of solids. Refer to standard details.

Minimum diameter.

The minimum diameter of public manholes (those owned and maintained by the Town) shall be 60 inches. A minimum access diameter of 24 inches shall be provided.

Private manholes may have a minimum diameter 48 inches.

Acceptance testing.

A vacuum test shall be performed on each manhole to assure watertightness in accordance with ASTM C 1244-05a and the following procedures.

Each manhole shall pass a vacuum test to be conducted after backfilling is complete.

The vacuum test shall include testing of the seal between the cast-iron frame and the concrete cone, slab or grade rings.

Plug all pipes entering the manhole at least eight inches into sewer pipe. The plug shall be inflated at a location past the manhole/pipe gasket.

Brace all plugs to prevent the plug or pipe from being dislodged and drawn into manhole.

A vacuum of at least 10 inches of mercury shall be drawn on the manhole.