Sewer Use Regulations

Appendix B.  Construction Technical Specifications

The owner of the property, the developer, and/or Licensed Utility Installer, shall construct and install all sanitary sewers and all building sewers in accordance with the following rules and regulations:                                                                 

Section 1.  The owner, developer, or L.U.I. shall submit to the Director (for approval) plans and profiles of the proposed public sewer extensions and/or building sewer connections.

Section 2.  The owner, developer or L.U.I. of a subdivision shall submit to the Director, a subdivision plan approved by the Harwich Planning Board along with the plans and profiles of the proposed public sewer extension.

Section 3.  The Contractor doing all the work shall be approved by the Director as a Licensed Utility Installer (L.U.I.) as described in Article II-Building Sewers and Connections, Sections 13a through 13g.

Section 4.  All materials, including pipe and manhole structures, shall be of the same make and quality used by the Harwich Sewer Department and approved by the Director.

Section 5.  Public sewers and building sewers shall be laid using a transit or laser level.  All sewer pipes shall be laid on a bed of crushed stone of at least six inches (6”) in depth under the pipe and crushed stone shall extend at least halfway up the side of the pipe.  Approved gravel, with no stones larger than two inches (2”) in any dimension, shall be used to cover pipe to one foot above pipe.  The rest of the backfill material must be approved by the Director, Massachusetts Highway Department or Town of Harwich Department of Public Works.  The approved backfill material shall be placed in mechanically compacted lifts of no more than six inches (6”) deep or as specified by the Harwich Surveyor of Highways, Massachusetts Highway Department, or other specifications more stringent than the above. The approved backfill material above the gravel shall contain no stones greater than 6 inches in any dimension.         

Section 6.  Impervious dams shall be considered every 300 feet to control the flow of groundwater within the pipe bedding material when:

Section 7.  Sewers may be deep enough to drain basement fixtures, and shall be deep enough to prevent freezing.  Watertight insulation shall be provided for sewers that cannot be placed deep enough to prevent freezing.

House connections chimneys (vertical pipe) preformed block shall be used when the sewer main is greater than or equal to 12 feet deep.

Section 8.  Where high groundwater conditions are anticipated, the buoyancy of sewers shall be considered, and the floatation pipe of pipe shall be prevented with appropriate design and construction of the sewer.

Section 9.  No mud, gravel or debris shall be allowed to enter the sewer pipes at any time.  All pipes shall be capped at end of day’s laying and water shall be pumped out of excavation prior to removing the cap.

Section 10.  Building sewer connection to the public sewer shall have a wye branch fitting, as approved by the Director, made of the same type of materials as the sewer main being tapped.

Section 11.  Minimum size of gravity public sewer pipe diameter shall be eight (8”) inches and building sewer pipes shall not be less than four (4”) inches in diameter.  Minimum sizes of low-pressure sewer mains shall be in accordance with Article IV-Design of Sewers, Section 9. Details of Low-Pressure Sewer Design and Construction.

Section 12.  Sewer pipe and building sewer pipe material shall be:

A.  Reinforced Concrete Pipe shall meet the following specification:

             Note:  non-reinforced concrete pipe shall not be used.

B.  Extra Heavy Cast Iron Pipe shall meet the following specifications:

Pipe, fittings, and appurtenances shall conform to the requirements of ASTM Specification A-74 or ANSI A-21.11 and gaskets shall conform to ASTM Specification C-564.

C.  Heavy Wall Polyvinyl Chloride (PVC) Pipe shall meet the following specifications:

Pipe shall be made from Class 12454-B materials or better in accordance with ANSI/ASTM Specification D-1784, and shall ultraviolet light (UV) protected.

The pipe and accessories shall conform to the requirements of the following, with a minimum pipe stiffness of 46 PSI at a maximum deflection of five percent (5%):

                        ANSI/ASTM               D 3034                        (4” – 15”)
                        ASTM                         F 679 Type I               (18” – 27”

D.  Ductile Iron Pipe shall meet the following specifications:

All pipe and fittings shall be cement mortar lined in accordance with ANSI Specification A-21.4 at twice the specified thickness, and have an internal and external bituminous seal coating and closure pieces shall be jointed by means of a mechanical coupling of the cast sleeve type.

E.  Extra Strength Vitrified Clay Pipe shall meet the following specifications:

Pipe shall conform to the current requirements of NCPI Specification ER 3300 – 67 and meet the requirements of ASTM Specification C 700.

Note:  standard strength vitrified clay pipe shall not be used.

F.  Acrylonitrile – Butadiene - Styrnee (ABS) Pipe shall meet the following specifications:

Pipe and fittings shall conform to the requirements of ASTM Specification D 2661.

G.  Plastic Pipe, sizes 4 inches through 12 inches, shall be ANSI/ASTM D3034, SDR-35 Type PSM Poly (Vinyl Chloride) (PVC) material; minimum pipe stiffness (F/^Y) is 46 psi; bell and spigot style and rubber gasket conforming to ASTM F477.

H.  Low Pressure Mains and Services for 1-1/4-inch pipe through 4-inch pressure pipe shall be polyethylene pipe with material conforming to ASTM D3350, Type PE-3408 pressure Class PC 160, SDR-11.  Fittings for use with polyethylene pipe and tubing shall be manufactured and furnished by the pipe supplier and in conformance with AWWA C901 requirements.  Joints for polyethylene pipe shall be jointed by the butt fusion method in a manner recommended by the pipe manufacturer.

Pipe sizes 1-1/4 inches through 4 inches shall be Polyvinyl Chloride (PVC) pipe ASTM D2241 PVC pressure pipe material conforming to ASTM D1784, minimum class SDR 21 for pipe 1-1/4-inch, push-on joint conforming to ASTM D3139 with flexible elastomeric gaskets conforming to ASTM F477.

Fittings for use on PVC pressure pipe of 4-inch nominal inside diameter or greater shall be ductile iron with mechanical joints as described in ANSI 21.10/AWWAC110.  The coatings and linings of the fittings shall be as specified for ductile iron pipe.

I.  Other pipe materials:

Other pipe materials shall require prior written approval of the Director before being installed.

Materials for sewer construction shall be appropriate for local conditions, including the character of industrial wastes, septicity, soil characteristics, external loadings, and problems such as abrasion and corrosion. All sewers shall be able to withstand damage from superimposed loads.  Proper allowances for soil and potential groundwater conditions, as well as the width and depth of the trench shall be used. Where necessary, special bedding, haunching and initial backfill, concrete cradles, or other special construction elements shall be used.

The minimum internal pipe diameter shall be eight (8) inches for gravity sewers.

Joints for the selected pipe shall be designed and manufactured such that “O” ring gaskets of the “snap-on” type are used.

Gaskets shall be continuous, solid, natural or synthetic rubber, and shall provide a positive compression seal in the assembled joint.

Joint preparation and assembly shall be in accordance with the manufacturer’s recommendations.

Wye branch fittings, as approved by the Director, shall be installed for connection of laterals.

Bedding, Haunching, and Initial Backfill

Based on the bedding support of the type of soil and potential groundwater conditions, use the following for the anticipated loads:

Safety and Load Factors

Selection of pipe class shall be predicated on the following criteria:

Safety factor - 1.5
Load factor - 1.7
Weight of soil - 120 lbs/cu.ft.
Wheel loading - H-20

Section 13.  Manholes and Cleanouts 

Manhole and Cleanout Size

Cleanouts

Cleanouts shall be constructed of the same material as the building sewer. The size of the cleanout shall be the same size as the building sewer up to six (6”) inches in diameter, for building sewers larger than six (6”) inches in diameter manholes shall be used. Cleanouts shall be sealed with removable, re-useable threaded screw-in plug or screw-on cap.

Manholes

Manholes shall be minimum of four (4’) feet in diameter with a minimum access diameter of 30 inches (76 cm). Larger diameter manholes may be required by the Director. A minimum drop of 0.10 foot shall be used between entrance and exit inverts.

Location

Manholes and cleanouts shall be installed at the end of each line; at all changes in grade, size, or alignment; and at all intersections.  Distances shall not be greater than 300 feet for sewers measuring 15 inches (38 cm) or less in diameter, or 400 feet for sewers 18-30 inches (46-76 cm) in diameter.  Greater distances may be permitted for larger sewers or for those carrying a settled effluent, but only with prior approval of the Director.  The top of the manhole cover shall be no lower than one (1’) foot above the 100-year flood elevation level.  Junction manholes on low pressure sewers shall be installed at all intersections

Drop Type

A drop pipe for a sewer pipe with an invert entering a manhole of more than 24 inches (61 cm) above the manhole invert shall be provided.  Where the difference in elevation between the incoming sewer and the manhole invert is less than 24 inches (61 cm), the invert shall be filleted to prevent solids deposition.

Drop manholes shall be constructed with an outside drop connection.  Outside drop connections shall be encased in concrete, and shall provide access for cleaning as the sewer enters the manhole at the top of the drop connection.

Inside drop connections may be used provided the manhole has the area to facilitate safe access into the manhole with the inside drop in place, and shall be approved by the Director.  The inside drop connection shall be secured to the interior wall of the manhole, and shall provide access for cleaning as it enters the manhole at the top.  Internal drop pipes and fittings shall be PVC plastic sewer pipe in compliance with ASTM D2241.  Corrosion resistant anchors shall be used to attach the drop pipe to the inside surface of the manhole barrel. 

Structural Base

Manhole bases shall be constructed or placed on a minimum of twelve (12) inches of crusher run with a maximum stone diameter in all directions of one half ½ inch and free of organic materials.

Diameter

The manhole’s minimum diameter shall be 48 inches (122 cm) for standard manholes and 60 inches (153 cm) for inside drop manholes.  A minimum access diameter of 30 inches (76 cm) shall be provided.  Larger openings shall be provided for manholes that house equipment, as specified by the Director.

Materials

Manholes shall be precast concrete with barrel sections, cones, and bases, manufactured in compliance with ASTM C 478, and shall have an O-ring or bituminous-based gasketed joints.  “Precast concrete walls shall be made up using straight, circular barrel sections and eccentric cone sections if manhole steps are required, and concentric cone sections where no steps are required.  Manholes can also be poured-in-place concrete.  Other types are allowed subject to the approval of the Director.

All tongue-and-grove (or male and female joints in the precast wall, including the joint at the top of the base, shall be made up using the “Snap-On” type O-ring gasket, and shall conform to ASTM C443; except that joint taper shall not exceed 3-1/2 degrees.  The precast sections shall be provided with a special groove (cast into the male end) to receive and hold the gasket in position during joint assembly.  After joint assembly, the gap between sections shall be packed on the inside and outside with Anti-Hydro “Azpandcretes,” Masterflow 713 by Master Builders; or Five Star Grout by U.S. Grout Corp., and shall be troweled smooth so that no projections remain on the inside.

Manhole bases shall be constructed of 4,000 psi (28 day) concrete 8 inches thick, or shall be precast bases properly bedded in the excavation.  Field constructed bases shall be monolithic, properly reinforced, and extend at least 6 inches beyond the outside walls of lower manhole sections.  Precast manhole bases shall extend at least 6 inches beyond the outside walls of lower manhole sections.

Manholes shall be constructed using minimum 4-foot diameter, precast concrete manhole barrel sections, and an eccentric top section, conforming to ASTM Specification C-478, with the following exceptions on wall thickness: 

Manhole Diameter Wall Thickness
in Feet in Inches
4 5
5 6
6 7
6-1/2 7-1/2
7 8
8 9

All Sections shall be cast solid, without lifting holes.  Flat top slabs shall be a minimum of 8 inches thick and shall be capable of supporting a H-20 wheel loading. 

All joints between sections shall be sealed with “O” ring rubber gasket, meeting the same specifications as pipe joint gaskets, or butyl joint sealant completely filling the joint.

All joints shall be sealed against infiltration.  All metal parts shall be thickly coated with bitumastic or elastomeric compound to prevent corrosion.

No holes shall be cut into the manhole sections closer than 6 inches from joint surfaces.

Manholes which extend above grade shall not have an eccentric top section.  The top plate shall be large enough to accommodate the cover lifting device and the cover.

Manhole Covers

The elevation of the top section shall be such that the cover frame top elevation is one (1) foot above the 100-year flood elevation (in a field), 0.5 foot above a lawn elevation, or at finished road or sidewalk grade.                                 

When located in a traveled area (road or sidewalk), the manhole frame and cover shall be heavy duty cast iron.  When located in a lawn or in a field, the manhole frame and cover may be light duty cast iron.  The cover shall provide a minimum access diameter of 30 inches (76 cm). The mating surfaces shall be machined, and painted with tar pitch varnish.  The cover shall not rock in the frame.  Infiltration between the cover and frame shall be prevented by proper design and construction.  Covers shall have “Sewer” cast into them.  Covers shall be designed so that infiltration is prevented.

Manhole frames, installed at grade, shall be set in a full bed of mortar with no less than two nor more than four courses of brick underneath to allow for later elevation adjustment.  In lieu of brick, grade rings may be used for elevation adjustment.  Grade rings shall not exceed 6 inches in depth.  The total number of grade rings shall not exceed 12 inches in height, however, in no event shall more than 3 grade rings be used.

Manholes which extend above grade, shall have the frames cast into the manhole top plate.  The top plate shall be securely anchored to the manhole barrel, by a minimum of six, ½ inch diameter, corrosion resistant anchor bolts, to prevent overturning when the cover is removed.  The anchor bolts shall be electrically isolated from the manhole frame and cover.

Ladders

Manhole steps are to be provided in manholes.  Steps are to be cast in or grouted solid into the precast units at intervals of 12 inches.  Steps shall be in conformance with OSHA requirements having drop front or equivalent.  Bolted-on type is not acceptable.  Manhole steps to be M.A. Industries, Inc. copolymer polypropylene reinforced with ½-inch steel rod or equal.

Flow Channel or Invert

The flow channel through the manholes shall conform in shape and slope to that of the sewers entering and leaving the manholes.  Construct the top of the flow channel so that the flow will remain in the channel under peak conditions.  Form or shape the channel walls to the full height of the crown of the outlet sewer and so as not to obstruct maintenance, inspection, or flow in the sewers.  When curved flow channels are required, including branch inlets, increase minimum slopes to maintain acceptable velocities.  Provide a minimum 0.1-foot drop through the manhole.     

Bench or Shelf

Provide a bench on each side of every manhole channel.  The bench should have a slope of no less than 0.1 inch per foot or no greater than 0.5 inch per foot.  No lateral sewer, service connection, or drop manhole pipe should discharge onto the surface of the bench.

Manhole Inverts

Manhole inverts shall be constructed by laying sewer bricks on their long side with their water structured face up, in straight line or sweeping arch to from the bottom of the invert, from pipe to pipe.  Additional sewer bricks will fan out with their water structure facing towards the center of the invert from the invert brick.  The invert’s width will be the same diameter of the effluent pipe of the manhole.  The minimum height of the shelf shall be equal to the crown of the manhole’s effluent pipe and it shall be constructed from sewer brick with their water structured face up.

Buoyancy

Where high groundwater conditions are anticipated, the manholes shall be designed and constructed to prevent floatation.

Watertightness

Solid or watertight manhole covers shall be used in areas subject to flooding.  All manhole lift holes and grade adjustment rings shall be sealed with a nonshrinking mortar or other material approved by the Director.  A bituminous coating shall also be used on the exterior.  Inlet and outlet pipes shall be joined to the manhole with a gasketed, flexible watertight connection or with another watertight connection arrangement that allows for differential settlement of the pipe and the manhole.

The Contractor shall furnish manholes waterproofed over the entire exterior surface that will be below finished grade.  The water proofing shall not mar or interfere with the specified exterior finish for these structures.  Waterproofing shall be accomplished prior to structure installation for precast sections, and shall be applied to dry surfaces under proper weather conditions.

Waterproofing shall consist of a two-coat application of coal tar compound as manufactured by Koppers Bitumastic Super Service Black; Tnemec Heavy Duty Black 46-449; Preco Nitroproof 600; or equal, and shall be applied according to manufacturer’s specification.  Total thickness of the two-coat application shall not be less than 16 mils.

Pipe Connections

Pipes being connected to new manholes shall be connected to the manhole with cast-in-place rubber boot with clamp around gasket.  Pipes being connected to existing manholes shall be core drill opening and seal with link seal water stop between pipe and manhole wall.

Section 14.  Force main pipe shall be either

A.  Ductile Iron Pipe

B.  Polyvinyl Chloride (PVC) Plastic Pipe C.  Other pipe materials Trenching, bedding, and backfilling shall be as approved by the authority having jurisdiction over the property, such as but not limited to: the Massachusetts Highway Department, Town of Harwich Department of Public Works, or Harwich Wastewater Superintendent.

Joint preparation and assembly shall be in accordance with the manufacturer’s written instructions.

Anchorages, concrete blocking, and/or mechanical restraint shall be provided when there is a change of direction of 7-1/2 degrees or greater.

When the daily average design detention time, in the force main, exceeds 20 minutes, the manhole and sewer line receiving the force main discharge or the sewage shall be treated so that corrosion of the manhole and the exiting line are prevented.  The corrosion is caused by sulfuric acid biochemically produced from hydrogen sulfide anaerobically produced in the force main.

The force main shall terminate, in the receiving manhole, at a PVC plastic sewer pipe “T”.   The vertical arms of the “T” shall be twice the diameter of the force main.  The upper arm shall be at least 4 feet long; the lower arm shall terminate in a PVC plastic sewer pipe 90-degree elbow in a flow channel directed to the manhole exit pipe.  The “T” and its arms shall be securely fastened to the inside surface of the manhole wall using corrosion resistant anchors. 

Force mains shall have a minimum velocity of three feet per second, 3ft/Sec.

Section 15.  No sanitary sewer pipe shall be left open into an unfinished house or cellar hole.  All pipes must be capped to prevent the flow of surface water or debris from entering the sanitary sewer.

Section 16.  All sewer works located in the flood plain district area, established under the zoning by-law, shall require that new and replacement sewer works be designed and constructed to minimize or eliminate infiltration of flood waters into the system or discharge sewerage from the system into the floodwater.

Section 17.  Sewer Pipe Testing

A.  General

The L.U.I. shall test the first section of pipeline as soon as it is installed to demonstrate that the work conforms to these specifications.  The initial section shall not be less than five hundred (500) feet and not more than one thousand (1000) feet of pipeline.  Testing of pipe shall closely follow pipe laying. 

For all sewer pipe tests, the L.U.I. shall furnish an air or water test pump, an air or water meter, and suitable pressure gauge.  The L.U.I. shall also furnish all labor and materials required to install suitable temporary testing plugs or caps for the pipeline and perform the test.  The meter and gauge shall be installed by the L.U.I. in such a manner that all air or water entering the section under the test will be measured and the pressure in the section indicated and they shall be kept in use throughout all tests. 

The scheduling of deflection and pressure and leakage tests shall be as approved and attended by the Town of Harwich’s Sewer Department or Town Inspector.

Before accepting any sewer segment, the L.U.I. shall provide a television tape of the entire sewer including point of connection an existing sewer or pumping station. Television inspection shall be performed by a firm specializing in this work and shall produce the following information:

  1. A continuous videotape recording of the entire length of pipe being inspected.  The tape shall include location of each section, direction of camera travel, a commentary of the pipe’s condition, and various irregularities found and lateral connections.
  2. The section of pipe being televised shall be identified at least once every 50 ft.

  3. Documentation on television logs and voice recorded on tape shall consist of the following information:

a.  Distance from the numbered manhole point of beginning on each sewer section to the location of thespecific condition being inspected

b.  Angular orientation of all above conditions inside pipe (i.e., leak at 10:00, service connection at 3:00).

c.  Sewer size, material, and joint spacing. 

B.  Deflection

Deflection tests shall be performed on all flexible pipes.  The tests shall be conducted after the final backfill has been in place at least 30 days to permit stabilization of the pipe system.

No pipe shall exceed a deflection of 5 percent.  If deflection exceeds 5 percent, the pipe shall be replaced.

The rigid ball or mandrel used for the deflection test shall have a diameter of not less than 95 percent of the base inside diameter or the average inside diameter of the pipe as specified by ASTM D 2122 Standard Test Method of Determining Dimensions of Thermoplastic Pipe and Fittings.  The tests shall be performed without mechanical pulling devicess.

C.  Air Testing

The Town requires air testing in lieu of the exfiltration or infiltration tests.  The L.U.I. shall submit the proposed method of air testing to the Director for approval.  All air testing shall be performed in accordance with the procedures described in ASTM C828-86 for Clay Pipe or ASTM C924 for or Concrete Pipe or those procedures approved by the Director, and shall be specifically designed and manufactured for testing pipelines with low-pressure air and shall be provided with an air regulator valve or air safety valve set to prevent the air pressure in the pipeline from exceeding ten (10) psi.  If the results of the air test are unsatisfactory, the L.U.I. shall repair the sewer pipe and perform the air tests until the sewer pipe passes the air test.  If site conditions are not conducive to air test, as determined by the Director, the L.U.I. will be required to perform an exfiltration and/or an infiltration test as outlined below.

Low pressure air tests shall conform to ASTM Specification C 828.  All sections to be tested shall be cleaned and flushed, and shall have been backfilled, prior to testing.  Air shall be added until the internal pressure of the test section is raised to approximately 4.0 PSIG.  The air pressure test shall be based on the time, measured in seconds, for the air pressure to drop from 3.5 PSIG.  Acceptance is based on limits tabulated in the “Specification Time Required for a 1.0 PSIG Pressure Drop” in the Uni-Bell PVC Pipe Association “Recommended Practice For Low-Pressure Air Testing of Installed Sewer Pipe”.

Before pressure is applied to the line all connections shall be firmly plugged.  Before the test period starts, the air shall be given sufficient time to cool to ambient temperature in the test section. 

If the test section is below groundwater, the test pressure shall be increased by an amount sufficient to compensate for groundwater hydrostatic pressure, however, the test pressure shall not exceed 10 PSI.  

The pressure test gauge shall have been recently calibrated, and a copy of the calibration results shall be made available to the Director prior to testing.

Exfiltration Test

If for any reason, approved by the Director, air testing cannot be performed, the Director shall require exfiltration testing.  Leakage tests by exfiltration shall be made before or after backfilling at the discretion and under the supervision of the Town Inspector.  The length of pipe to be tested shall not exceed 1,000 feet and be such that the head over the crown at the upstream pipe is not less than two (2) feet and the head over the downstream pipe crown is not more than six (6) feet.  The pipe shall be plugged, by pneumatic bags or mechanical plugs, in such a manner that the air can be released from the pipe while it is being filled with water.  Before any measurements are made, the pipe shall be kept full of water long enough to allow absorption of water and the escape of any trapped air.  Following this, a test period of at least two hours shall begin.  Provisions shall be made for measuring the amount of water required to maintain the water at a constant level during the minimum two (2) hours test period.  If any joint shows an appreciable amount of leakage, the joining material shall be removed and replaced.  If the water required to maintain a constant level in the pipe does not exceed twenty-five (25) gallons per nominal diameter, in inches, per 24 hours per mile of pipe and if all leakage is not confined to a few joints, workmanship shall be considered satisfactory.  If the amount of leakage indicates defective joints or broken pipes, they shall be corrected or replaced.

Infiltration Test

If for any reason, approved by the Director, air testing and exfiltration testing cannot be performed, the Director shall require infiltration testing be performed.  Pipe shall be tested for infiltration after backfill has been placed and the ground water allowed to return to normal elevation.  Infiltration tests shall be made only under the supervision of the Town Inspector, and the length of line to be tested shall be not less than the length between adjacent manholes and not more than the total length or each size pipe and shall not exceed 1000 feet.  The allowable infiltration shall be twenty-five (25) gallons per nominal diameter, in inches, per 24 hours per mile of pipe in each section tested as determined by means of V-Notch weirs, pipe spigots, or by plugs in the end of the pipe to be furnished and installed by the L.U.I., in an approved manner, and at such times and locations as may be directed by the Town Inspector. 

There shall be no gushing or spurting leaks.  If an inspection of the completed sewer or any part thereof shows pipes or joints which allow noticeable infiltration of water, the defective work or material shall be replaced or repaired.

Section 18.  Sewer Force Main Testing

The sewer force main pipe shall be given pressure and leakage tests in sections of approved length as approved by the Director.  For these tests, the L.U.I. shall furnish a water test pump, water meter, and a pressure gauge.  The L.U.I. shall also furnish all labor and equipment to install suitable temporary testing plugs or caps for the pipeline and to perform the tests.  The meter and gauge shall be installed by the L.U.I. in such a manner that all water entering the section under the test will be measured and the pressure in the section indicated and they shall be kept in use throughout all tests.

The scheduling of pressure and leakage tests shall be as approved and attended by the Town Inspector.

The section of pipe to be tested shall be filled with water by pumping water into it and opening the air release valves and expelling all air from the pipe.  If air release assemblies are not available at high points for releasing air, the L.U.I. shall perform:  all excavation(s); make the necessary tap(s) at such highpoint(s); plug said holes of the tapping saddles after completion of the test with brass or bronze plug(s); and backfill the excavation(s).

The L.U.I. shall make a leakage test by metering the flow of water into the pipe while maintaining (in the section being tested) a pressure equal to 1.5 times the highest pressure to which the pipe will be subjected under normal conditions of service or 150 psi, whichever is greater.  This shall be done by placing the section under pressure by pumping.

The lengths of joint to be used in determining the allowable leakage shall be based on the nominal diameter of the pipe.  The allowable leakage shall be less than 11.65 gallons per inch diameter per day per mile of force main tested, maintaining a pressure within 5 psi for a minimum of two (2) hours duration.  If the section shall fail to pass the pressure test, the L.U.I. shall locate and repair or replace the defective pipe, fitting, or joint, at the L.U.I.’s own expense.

If, in the judgment of the Director, it is impracticable to follow the foregoing procedure exactly, modifications in the procedures may be made if approved by the Director, but in any event the L.U.I. shall be responsible for the ultimate tightness of the line within the above leakage requirements with no allowances for leakage from valves.

Section 19.  Low Pressure Sewer Testing

The sewer low pressure pipe shall be given pressure and leakage tests in sections of approved length as approved by the Director.  For these tests, the L.U.I. shall furnish a water test pump, water meter, and suitable pressure gage.  The L.U.I. shall also furnish all labor and equipment required to install suitable temporary testing plugs or caps for the pipeline and perform the test.  The meter and gage shall be installed by the L.U.I. in such a manner that all water entering the section under the test will be measured and the pressure in the section indicated and they shall be kept in use throughout all tests.

The scheduling of pressure and leakage tests shall be as approved and attended by the Town Inspector.

The section of pipe to be tested shall be filled with water by pumping water into it and opening the air release valves and expelling all air from the pipe.  If air release assemblies are not available at high points for releasing air, the L.U.I. shall perform:  all excavation(s); make necessary tap(s) at such highpoint(s); plug said holes of the tapping saddles after completion of the test with brass or bronze plug(s); and backfill the excavation(s).

The L.U.I. shall make a leakage test by metering the flow of water into the pipe while maintaining (in the section being tested) a pressure equal to 1.5 times the highest pressure to which the pipe will be subjected under normal conditions of service or 150 psi whichever is greater.  This shall be done by placing the section under pressure by pumping.

The lengths of joint to be used in determining the allowable leakage shall be based on the nominal diameter or the pipe.  The allowable leakage shall be less than 11.65 gallons per inch diameter per day per mile of pipe tested, maintaining a pressure within 5 psi for a minimum of two (2) hours duration.  If the section shall fail to pass the pressure test, the L.U.I. shall locate and repair or replace the defective pipe, fitting, or joint at the L.U.I.’s own expense.

If, in the judgment of the Director, it is impracticable to follow the foregoing procedure exactly, modifications in the procedures may be made if approved by the Director, but in any event the L.U.I. shall be responsible for the ultimate tightness of the line within the above leakage requirements with no allowances for leakage from valves.

Section 20.  Cleaning Sewer Lines

At the conclusion of the work, the L.U.I. shall thoroughly clean all pipelines by washing with water or other means to remove all dirt, stones, pieces of wood, or other material which may have entered the pipes during the construction period.  Debris cleaned from the lines shall be removed from the low end of the pipeline by installing a screening device that will prevent any debris from entering the public sewer system or a section of the sewer works already approved.  If after this cleaning, obstructions remain, they shall be removed.  After the pipelines are cleaned and if the groundwater level is above the pipe or following a heavy rain, the Town Inspector will examine the pipes for leaks.  If any defective pipes or joints are discovered, they shall be repaired or replaced as directed by the Town Inspector.         

Section 21.  Sewer Manhole Leakage Tests

Leakage tests shall be made and observed by the Town Inspector on each manhole.  The test shall be the exfiltration test or vacuum test as described below:

For these tests, the L.U.I. shall furnish an air or water test pump, an air or water meter, and suitable pressure gage.  The L.U.I. shall also furnish all labor and materials required to install suitable temporary testing plugs or caps for the pipeline, and perform the test.  The meter and gage shall be installed by the L.U.I. in such a manner that all air or water entering the manhole under the test will be measured and the pressure in the manhole indicated and they shall be kept in use throughout all tests.

After the manhole has been assembled in place, all lifting holes and exterior joints surface shall be filled and pointed with an approved non-shrinking mortar.  The test shall be made prior to placing the shelf and invert and before filling and pointing the interior horizontal joints.  If the groundwater table has been allowed to rise above the bottom of the manhole, it shall be lowered for the duration of the test.  All pipes and other openings into the manhole shall be suitable plugged and the plugs braced to prevent blow out.

Exfiltration Testing

The manhole shall then be filled with water to the top of the cone section.  If the excavation has not been backfilled and observation indicates no visible leakage that is, no water visible moving down the outside surface of the manhole, the manhole may be considered to be satisfactory water-tight.  If the test, as described is unsatisfactory, as determined by the Town Inspector or if the manhole excavation has been backfilled, the test shall be continued.  A period of time may be permitted, if the Contractor so wishes, to allow for absorption.  At the end of this period the manhole shall be refilled to the top of the cone and the measuring time of at least two (2) hours shall begin. This amount shall be extrapolated to a 24-hour rate and the leakage determined on the basis of depth.  The leakage for each manhole shall not exceed one (1) gallon per vertical foot per day, a twenty-four (24) hour period shall equal one day.  If the manhole fails this requirement, but the leakage does not exceed three (3) gallons per vertical foot per day, repairs by approved methods may be directed by the Town Inspector to bring the leakage within the allowable rate of one (1) gallon per foot per day.  Leakage due to a defective section or joint or exceeding the three (3) gallon vertical foot per day, shall be the cause for the rejection of the manhole.  It shall be the L.U.I.’s responsibility to uncover the manhole, as necessary, and to disassemble, reconstruct, or replace it as directed by the Town Inspector.  The manhole shall then be retested and, if satisfactory, interior joints shall be filled and pointed and the invert constructed.

No adjustment in the leakage allowance will be made for unknown causes such as leaking plugs, absorptions, etc., it will be assumed that all loss of water during the test is a result of leaks through the joints or through the concrete.  Furthermore, the L.U.I. shall take any steps necessary to assure the Town Inspector that the water table is below the bottom of the manhole throughout the test.

If the groundwater table is above the highest joint in the manhole, and there is no leakage into the manhole, as determined by the Town Inspector, such a test can be used to evaluate the water-tightness of the manhole.  However, if the Town Inspector is not satisfied, the Contractor shall lower the water table and carry out the test as described hereinbefore.

Vacuum Testing

The vacuum test shall be based on the time, measured in seconds, for the vacuum to decrease from 10 inches of mercury to 9 inches of mercury for manholes.

Acceptance of manholes is based on the following:

Manhole

Manhole Diameter

Time to Drop 1” Hg

(10” to 9”)

10 ft or less

4 ft

120 seconds

10 ft to 15 ft

4 ft

150 seconds

15 ft to 25 ft

4 ft

180 seconds

NOTE:  For 5ft diameter manholes, add 30 seconds to the times above
             For 6ft diameter manholes, add 60 seconds to the times above

The vacuum test gauge shall have been recently calibrated, and a copy of the calibration results shall be made available to the Director prior to testing.

If the test on the manhole fails (the allowable gallons or the time is less than that tabulated above), necessary repairs shall be made and the vacuum test repeated, until the manhole passes the test.                                

Section 22.  Manhole Cleaning

All new manholes shall be thoroughly cleaned of all silt, debris and foreign matter of any kind, prior to final inspection.