Section
Trench Excavation and Backfill
152.01 Scope
152.02 Materials
152.03 Workmanship
Gravity Sanitary Sewers
152.15 General provisions
152.16 Products
152.17 Execution
Sanitary Sewer Force Mains
152.30 General provisions
152.31 Products
152.32 Execution
Precast Concrete Structures
152.45 General provisions
152.46 Products
152.47 Execution
Lift Station Equipment
152.60 General provisions
152.61 Products
152.62 Diagrams
Cross-reference:
Building Codes, see Ch. 150
Flood hazard areas, see Ch. 154
Town policies, see Ch. 33
TRENCH EXCAVATION AND BACKFILL
This subchapter covers the work necessary for the trench excavation and backfill, complete, including but not limited to: clearing the right-of-way; protection of private property during construction; disposal of cleared materials; excavation of trench for the pipe and appurtenances; foundation stabilization; backfilling the pipe zone; removal, replacement, and rehabilitation of all fences, drainage ditches, waterways, culverts, concrete curbs, and sidewalks, or other features moved or damaged during construction; removal of all obstructions; removal of all existing pavement; locating and protecting existing utilities; repair of damaged utilities; the maintenance of access to public thoroughfares and to private property; the maintenance of adequate barricades, lights, and warning signs for the protection of the public; the public highways, county roads, streets and private drives; shoring, cribbing, bracing, sheeting, and dewatering as may be required; hauling and disposal of waste excavation, including temporary hauling and disposal of soil which cannot be accommodated within the designated right-of- way; repair of public and private property damaged during construction; final cleanup of the construction area; restoration of the landscape in public rights-of-way including replacement lawns, grasses, trees, shrubs, and mulches; and all miscellaneous items of work required to complete the construction specified hereunder.
(Ord. passed - -)
(A) Trench excavations. Trench excavation shall be classified as either common excavation or rock excavation as classified below.
COMMON EXCAVATION. Removal of all materials, which is not classified as rock excavation.
ROCK EXCAVATION. Removal of all materials which, by actual demonstration, cannot be the Town Engineer’s or Superintendent’s opinion, be reasonably excavated with a backhoe equipped with a general duty dipper and rock points, or similar approved equipment and which is in fact, systematically drilled or blasted. The Town Engineer or Superintendent reserves the right to waive the demonstration of the material encountered as well defined rock. The term ROCK EXCAVATION shall be understood to indicate a method of removal and not geological material. In addition, ROCK EXCAVATION may include removal of a well-defined rock by the method of systematic drilling and mechanical splitting.
(B) Trench backfill. Placement of native backfill material for Class A and C backfill shall include the working of material to achieve suitable moisture content and compaction to the specified density. In lieu of using native material excavated from the trench for Class A and C backfill, the contractor at his or her option may place and compact to specified density and approved imported backfill material. Imported material must be approved by the Town Engineer or Superintendent prior to placement. Material shall be earth, gravel, rock, or combinations thereof, free of humus, organic matter, vegetative matter, frozen material, clods, sticks, and debris and containing no stones having a dimension greater then four inches. Sand or pea gravel will not be an approved backfill material.
(1) Foundation stabilization. Gravel for trench foundation stabilization shall be clean pit-ran gravel, crushed rock or gravel, having reasonably even gradation from coarse to fine. The maximum size shall be four inches.
(2) Crushed gravel pipe base. Material for pipe base and pipe zone shall be three- fourth inch minus crushed gravel, having reasonably even gradation from coarse to fine.
(3) Gravel for trench, backfill. Gravel for trench backfill shall be clean pit run gravel, crushed rock, or gravel having a reasonable even gradation from coarse to fine. The maximum size shall be four inches.
(4) Bituminous cements. Bituminous cement for use in tacking the edges of existing asphaltic concrete pavement shall be RC-1 asphaltic road materials conforming to the applicable specifications of the Asphalt Institute, or shall be an asphalt emulsion.
(5) Asphaltic concrete. Asphaltic concrete shall not be hot plant mix, Class C material.
(6) Crushed gravel. Material shall be one and one-half inch minus or three-fourths inch minus crushed gravel or rock, reasonably even graded from coarse to fine.
(7) Controlled density fill. Controlled density fill (CDF) shall be a mixture of cement, fly ash, aggregates, water and admixtures proportioned to provide a non-segregating, self-consolidating, free-flowing, and excavatable material that will result in a hardened, dense, non-settling fill. CDF is approved as an alternative for “gravel for trench backfill” and as an alternative to “crushed gravel” and must be used at any location on the project at the option of the contractor for foundation stabilization material, pipe base material, pipe zone material, trench backfill material and pavement base material.
(Ord. passed - -)
(A) Clearing the right-of-way. Where cleaning of the right-of-way is necessary, it shall be completed prior to the start of trenching. Trees and brush shall be cut as near to the surface of the ground as practicable and piled for disposal. The contractor shall observe all federal and state laws relating to fire permits and local regulations related to burning such materials. Under no conditions shall excavated materials be permitted to cover brush or trees prior to cleaning and disposal. Existing trees or tree limbs whether on public or private property, are not to be removed without permission from the Town Engineer or Superintendent or as designated on the plans.
(B) Obstructions. This item refers to obstructions which may be removed and do not require replacement. Obstructions to the construction of the trench such as, but not limited to, stumps, abandoned piling, abandoned concrete structures, logs, rubbish, and debris of all types shall be removed by the contractor at his or her own expense. The Town Engineer or Superintendent will, if requested by the contractor, make changes in the alignment to avoid major obstructions if such alignment changes can be made without adversely affecting the intended function of the facility.
(C) Asphaltic concrete pavement removal and replacement.
(1) All bituminous and concrete pavements, regardless of thickness, shall be cut prior to excavation of trenches. Width of the pavement cut shall be at least six inches greater than the required width of the trench at ground surface at each side. Pavement removed during excavation shall be piled separately from the earth spoil and removed from the site and shall not be used in backfilling the trench.
(2) Undercut pavement shall be cut at least six inches greater than the trench wall.
(3) After the trench has been backfilled and compacted according to the specifications, the contractor shall bring the trench to a smooth even grade at the proper depth below the existing surface to provide the required depth of pavement. The contractor shall cut the existing pavement to a straight line and remove any pavement that has been damaged.
(4) The entire existing paved surface shall be cleaned before resurfacing is begun.
(5) The contractor shall apply a prime coat of asphalt tack coat to the edges of the existing pavement and to the cast iron manhole frames below the grade. He or she shall then place the asphaltic concrete over the prepared trench. The finished surface of the new pavement shall conform to the grade, crown, and slope of the existing pavement.
(6) Pavement replacement within all streets shall be at least two lifts one and one-half inch thickness each for a total asphaltic concrete thickness of three inches but shall not be less than existing pavement thickness. Pavement thickness greater than three inches shall be placed in layers not greater than two and one-half.
(D) Blasting. Blasting of excavation shall be permitted only after securing approval of the Town Engineer or Superintendent and only when proper precautions are taken for the protection of persons and property. Any damage caused by the blasting shall be repaired by the contractor at his or her own expense. The contractor’s methods of procedure and blasting shall conform to state laws, county laws, and municipal ordinances.
(E) Trench width. Minimum width of unsheeted trenches in which pipe is to be laid shall be 18 inches greater than the inside diameter of the pipe, except by permission of the Town Engineer or Superintendent. The maximum width of the trench shall be limited to the pipe outside diameter exclusive of the bells plus 24 inches. Trench width required where CDF is used, as the entire backfill shall be as shown on the plans or as directed by the Town Engineer or Superintendent. In all cases, trench width shall be confined to dedicated right-of-way for public thoroughfares or within areas of which construction easements have been obtained, unless special arrangements have been made with the affected property owners.
(F) Grade. The bottom of the trench shall be carried to the lines and grades shown on the plans or as established by the Town Engineer or Superintendent, with proper allowance for pipe thickness and for gravel bedding. Any part of the trench excavated below grade shall be corrected with material of the type specified in § 152.02(B)(1), for the full width of the trench and thoroughly compacted layers not to exceed six inches, to the established grade. Unless otherwise specified, service laterals shall be laid at a slope of one-fourth inch per foot.
(G) Shoring, sheeting, and grading of trenches. Whenever necessary to prevent caving during excavation of gravel, sandy soil, or other unstable material, the trench shall be adequately sheeted and braced. Where sheeting and bracing are used, trench widths shall be increased accordingly. Trench sheeting shall remain in place until pipe has been placed, backfilled at the pipe zone, tested for defects, and repaired, if necessary.
(H) Location of the excavated materials. During trench excavation, the contractor shall locate the excavated material so it will not completely obstruct a traveled roadway or street; and, unless otherwise approved by the Town Engineer or Superintendent, all streets and roadways shall be kept open to at least one-way traffic.
(I) Removal of water. The contractor shall provide and maintain ample means and devices with which to promptly remove and dispose of all water, including flow from existing sewer lines, entering the trench excavation during the time the trench is being prepared for the pipe laying, during the laying of the pipe, and until the backfill at the pipe zone has been completed. The contractor shall dispose of the water and sewage in accordance with state and local regulations.
(J) Foundation stabilization. When, in the opinion of the Town Engineer or Superintendent, the material in the bottom of the trench is unsuitable for supporting the pipe, the contractor shall excavate below the flow line as directed by the Town Engineer or Superintendent and backfill to the required grade with gravel of the type specified in § 152.02(B)(1).
(K) Trench backfill. The pipe zone shall be defined as extending from the spring line to the pipe to a point 12 inches above the outside of the pipe and for the full width of the trench, for all classes of backfill. In areas of rock or other areas designated by the Town Engineer or Superintendent, the entire pipe zone shall backfilled with three-fourths inch minus “crushed gravel”. In all other areas, the pipe zone shall be backfilled with materials not exceeding one and one-half inches in size selected from the specified trench backfill and thereafter placed and hand-tamped in six-inch layers.
(L) Trench backfill compaction.
(1) After the contractor has backfilled the pipe zone of the trench as required, he or she shall then backfill the balance of the trench, with the type backfill specified, in one-foot layers, mechanically compacted each layer to 95% of maximum density in roadways and 85% to 90% in all other areas.
(2) Any subsequent settlement of the trench or ditch during the guarantee period shall be considered to be the result of improper compaction and shall be corrected at no expense to the district.
(M) Trench backfill above pipe zone. The following types of backfill shall be used on the project in the areas shown on the plans. The class of backfill used for service connections will generally be the same as that used for the sewer line, which they are connected.
(1) Class “A” backfill. The entire trench above the pipe zone shall be backfilled with native excavated material and compacted in accordance with the specifications.
(2) Class “B” backfill. With the exception of the last ten inches, the trench above the pipe zone shall be backfilled with gravel or trench backfill and compacted according to the specifications. The top ten inches of the trench shall be backfilled and compacted in successive layers with eight inches of one and one-half inch minus “crushed gravel”, and two inches of three-fourths inch minus “crushed gravel”.
(3) Class “C” backfill. With the exception of the top 11 inches, the trench above the pipe zone shall be backfilled with gravel for trench backfill and compacted according to the specifications. The top 11 inches of the trench shall be backfilled and compacted in successive layers with eight inches of one and one-half inches minus “crushed gravel”, and two one and one-half inch layers of asphaltic concrete.
(4) Class “D” backfill. With the exception of the top three inches, the entire trench shall be backfilled with controlled density fill (CDF). Pipe base will not be required or used. Provision approved by the Town Engineer or Superintendent shall be made for fixing the pipe in place above the trench bottom as specified until the CDF has become firm. The top three inches of the trench shall be backfilled and compacted in successive layers with two, one and one-half inch layers of aspaltic concrete.
(N) Excess excavated material. All excess excavated materials shall be hauled and disposed of by the contractor. The contractor shall make his or her own arrangements for the disposal of the excavated material and shall bear all costs and retain any profit incidental to such disposal.
(O) Rock excavation. Before proceeding with rock excavation, the contractor shall have completed the common excavation to such depths that only rock excavation remains. At this time, the trench shall be made available to the Town Engineer or Superintendent and measurements will be taken to determine the amount of rock excavation remaining.
(Ord. passed - -)
GRAVITY SANITARY SEWERS
(A) Description. Work under this subchapter includes the installation and testing of gravity sanitary sewer pipe, fittings, and connections.
(B) Quality assurance.
(1) All similar components shall be manufactured and furnished by one manufacturer.
(2) Only one type of pipe may be used for the project unless otherwise approved by the town. The contractor shall select one type of pipe from those listed in this specification.
(Ord. passed - -)
(A) Polyvinyl chloride pipe.
(1) PVC pipe four inches through 15 inches in diameter.
(a) All PVC pipe four inches through 15 inches in diameter shall conform to ASTM D1784, “rigid poly (vinyl chloride) and chlorinated poly (vinyl chloride) compounds” and either:
1. ASTM F 794, “Poly (vinyl chloride) (PVC) ribbed gravity sewer pipe and fittings based on controlled inside diameter”;
2. ASTM F 949, “Poly (vinyl chloride) (PVC) corrugated sewer pipe with a smooth interior and fittings”;
3. ASTM D 3034, “Type PSM poly (vinyl chloride) (PVC) sewer pipe and fittings”; or
4. ASTM F-789, “Type PS- 46 poly (vinyl chloride) (PVC) plastic gravity flow sewer pipe and fittings”.
(b) PVC sewer pipe shall be SDR 35 with cell classification of 12454-B or 12454-C.
(c) Pipe joints shall be push-on type conforming to ASTM D3212, “Joint for drain and sewer plastic pipes using flexible elastomeric seals”.
(2) Gaskets shall be factory installed and chemically bonded to the bell end of the pipe.
(3) Each pipe shall be identified with the name of manufacturer, nominal size, cell classification, ASTM designation, Uni-Bell Plastic Pipe Association designation, the pipe stiffness designation, and the manufacturer’s date code.
(B) Ductile iron pipe.
(1) Ductile iron pipe shall be centrifugally cast in metal or sand lined molds and shall conform to the latest revisions of ANSI/AWWA C150/A21.50 and ANSI/AWWA C151/A21.51. Ductile iron pipe shall be Pressure Class 250 minimum. The interior surface of the ductile iron pipe and fittings shall be polyethylene line in accordance with ANSI/ASTM D1248. The minimum lining thickness shall be 35 mils.
(2) When used for underground service, ductile iron pipe shall have polyethylene encasements around the pipe exterior conforming to the latest revision of ANSI/AWWA C105/A21.5.
(3) Pipe joins and accessories shall be the type shown and shall conform to the following requirements and standards.
(a) Push-on joints.
1. ANSI/AWWA C110/A21.10.
2. ANSI/AWWA C111/A21.11.
(b) Mechanical joints.
1. ANSI/AWWA C110/A21.10.
2. ANSI/AWWA C111/A21.11.
a. Bolts and nuts. ANSI/AWWA C111/A21.11; tee-head bolts and hexagonal nuts.
b. Gaskets. ANSI/AWWA C111/A21.11.
(c) Flanged joints. ANSI/AWWA C111/A21.10, 250; psi working pressure rating and drilled to ASA 125 pounds standards.
1. Bolts. Table 1 10.14 of ANSI/AWWA C110/A21.10. ASTM A307, Grade B with heavy hex head. ANSI B18.2.1 as per Appendix A Attached to ANSI/AWWA C110/A21.10.
2. Nuts. ASTM A307, Grade B, heavy hex: ANSI B18.2.2 as per Appendix A attached to ANSI/AWWA C110/A21.10.
3. Gaskets. Full-face ring type, one-eighth inch thick, vulcanized natural or synthetic rubber, free of porous areas, foreign materials, and visible defects as per Appendix A attached to ANSI/AWWA C110/A21.10.
(4) Pipe fittings shall not be short body pattern designed in accordance with ANSI/AWWA C110/A21.10. Fittings for pipe up to 12 inches in diameter shall be pressure Class 250 and pipes 14 inches and larger shall be pressure Class 150.
(5) Blind flanges, companion flanges, and flange filters shall conform toANSIB16.1 Class 125.
(Ord. passed - -)
(A) General construction requirements.
(1) Before installing piping, the contractor shall carefully verify location, depth, type of joint needed, and size of pipe to which connection is proposed. Contractor shall assure that the lines can be run as contemplated without interfering with footings, walls, other piping, fixtures, and the like.
(2) All lengths of pipe shall be dimensioned accurately to measurements established at the site and shall be worked into place without springing or forcing. Cut sections of pipe shall be reamed to remove all burrs.
(3) Utmost care shall be exercised in transporting and handling all pipe, fittings, valves, and the like, in order to avoid shock and damage to pipe coatings. Lifting shall be by hoist or skids when hand lifting is not feasible. Droppings will not be permitted. Pipe handled on skid ways must not be skidded or rolled against pipe already on the ground. Damaged or defective pipe and appurtenances shall be replaced.
(4) The pipe shall be thoroughly cleaned before being laid and kept clean during construction.
(5) The contractor shall cut all pipe and drill all holes that may be necessary.
(B) Pipe laying.
(1) The laying of pipe on the prepared bedding material shall commence from the lowest point, with the spigot ends pointing in the direction of flow. All pipes shall be laid true to line and grade. They shall be carefully centered so that when laid, they form a sewer with uniform invert.
(2) A pipe plug or bulkhead shall be used whenever pipe-laying operations are not in progress as required to protect the pipe ends from foreign material.
(3) Before making pipe joints, all surfaces of the joints shall be clean and dry. Lubricants, primers, and adhesives shall be used in accordance with the manufacturer’s recommendations. The pipe shall then be placed, fitted, and adjoined so as to obtain a watertight joint. In the event that previously laid pipe is disturbed, it shall be removed and re-laid.
(4) The contractor shall assure proper alignment and grade by proper use as lasers, batter boards, surveying instruments or other suitable means.
(C) Leakage tests.
(1) Generally. Prior to acceptance, all gravity sewers and manholes, including service laterals, shall be tested and pass a test for leakage. The contractor shall furnish all labor, materials, and equipment required for making the tests and groundwater level determinations. Testing shall not be performed until backfilling and compaction are completed. All gravity sewers shall pass one of the three following leakage tests as further specified by this section.
(a) Low pressure air test conforming to the requirements of the latest revision of ASTM C828 and ASTM C924 as minimum. The low pressure air test shall be used unless the contractor approves an infiltration or exfiltration test.
(b) Infiltration test with a maximum inward leakage of 100 gallons per inch of pipe diameter per mile per day.
(c) Exfiltration test with a maximum outward leakage of 100 gallons per inch of pipe diameter per mile per day. In addition, the contractor shall notify the town at least 48 hours in advance of any leakage tests as required to permit the town to witness such testing. The contractor shall keep documentation of leakage tests and their results with two copies submitted to the town upon completion and passage.
(2) Determination of groundwater level.
(a) Prior to and during all testing, the contractor shall determine all groundwater levels by backfill groundwater gauges or manhole groundwater gauges. In general, a sufficient number of groundwater gauges shall be installed to determine groundwater levels in the area of sewers being tested.
(b) In the case of newly installed groundwater gauges or the attachment of the temporary clear plastic tubing in the manhole groundwater gauge, the level of groundwater shall be allowed to stabilize before determining the groundwater level.
(3) Pipeline testing.
(a) Low pressure air test. Immediately prior to testing, the pipe shall be cleaned. After cleaning, all pipe outlets shall be plugged. The contractor must be aware that low pressure air testing may be dangerous. The contractor shall review the paragraphs entitled “Safety Precautions” in ASTM C828 and ASTM C924 before beginning pressurization of pipe. The sewer line shall then be slowly pressurized of 4.0 psig greater than the hydrostatic pressure head created by any groundwater over the pipe (i.e., the height of the groundwater above the invert of pipe, in feet, multiplied by 0.43). Where such internal pressure adjustment would result in a starting pressure greater than 9.0 psig, an infiltration test shall be performed. The method of pressurizing shall be such that the pressure shall be maintained until the temperature of the pipe and the air have equalized but in no case less than five minutes. After the temperature has stabilized, the air supply shall be discontinued and the pressure allowed to drop. When the pressure reached 3.5 psig (not including additional air pressure required by groundwater), a stopwatch shall be used to record the time it takes for the pressure to drop to 2.5 psig (or a one pound pressure drop). If the recorded time is more than the minimum test time as computed using Table 1 below, the section of pipe shall be considered to have passed the leakage test. If the recorded time is less than the minimum test time, the line shall be considered to have failed the test, shall be inspected for possible leaks, and retested upon correction until such time as the line passes the requirements.
Table 1 Low Pressure Air Test Minimum Test Time for Pressure to Drop from 3.5 to 2.5 PSIG | |
Nominal Pipe Diameter, Inches | Minimum Test Time, Minutes per 100 Feet |
Table 1 Low Pressure Air Test Minimum Test Time for Pressure to Drop from 3.5 to 2.5 PSIG | |
Nominal Pipe Diameter, Inches | Minimum Test Time, Minutes per 100 Feet |
4 | 0.3 |
6 | 0.7 |
8 | 1.2 |
10 | 1.5 |
12 | 1.8 |
15 | 2.1 |
18 | 2.4 |
21 | 3.0 |
24 | 3.6 |
27 | 4.2 |
30 | 4.8 |
33 | 5.4 |
36 | 6.0 |
39 | 6.6 |
42 | 7.3 |
(b) Infiltration test.
1. An infiltration test shall be used only when approved by the town or when the starting pressure for the low pressure air test would be greater than 9.0 psig. For an infiltration test to be performed, the ground water elevation must be at least 2.0 feet above the crown of the upstream pipe. The test shall require cleaning of the line and then plugging the pipe opening with a watertight plug with length equal to or greater than the pipe diameter.
2. A 90-degree V-notch weir shall be placed in the downstairs manhole of the section of pipe being tested. When performing an infiltration test with a weir, sufficient time will be allowed for the infiltration to crest the weir and stabilize. This time shall be determined based on the size of the sewer line, the slope of the line, and other pertinent information. In no case shall the time be less than one hour. The contractor shall measure the head (H) of water flowing over the weir. The measurement must be accurate and taken a minimum distance of 18 inches or four times the height of H upstream of the weir, whichever is greater. The measured infiltration over the weir can be calculated as: Q = 3204 H to the power of 2.5. Where H is inches and Q is gallons per day.
3. Where the infiltration allowances are very small, the measurement by weir inaccurate, the leakage measurement shall be made by timing the filling of a container of blown volume; The volume collected shall be converted to a 24-hour basis for comparison with specification requirements. If the measured infiltration is less than that allowed by Table 2 below, the pipe section shall be considered to have passed the leakage test.
Table 2 Infiltration and Exfiltration Tests Allowable Infiltration or Exfiltration Based on 100 Gallons per Day per Inch of Pipe Diameter per Mile of Pipe | |
Sewer Pipe Requirements | |
Nominal Pipe Diameter, Inches | Allowable Infiltration Gallons Per Foot of Pipe Per Hour |
Table 2 Infiltration and Exfiltration Tests Allowable Infiltration or Exfiltration Based on 100 Gallons per Day per Inch of Pipe Diameter per Mile of Pipe | |
Sewer Pipe Requirements | |
Nominal Pipe Diameter, Inches | Allowable Infiltration Gallons Per Foot of Pipe Per Hour |
4 | 0.0032 |
6 | 0.0047 |
8 | 0.0063 |
10 | 0.0079 |
12 | 0.0095 |
15 | 0.0118 |
18 | 0.0142 |
21 | 0.0166 |
24 | 0.0189 |
27 | 0.0237 |
30 | 0.0237 |
36 | 0.0284 |
42 | 0.0331 |
48 | 0.0379 |
Manhole Requirements | |
Nominal Manhole Diameter, Inches | Allowable Infiltration/Exfiltration, Gallons per Vertical Foot per Hour |
48 | 0.0379 |
60 | 0.0473 |
72 | 0.0568 |
(c) Exfiliration test.
1. An exfiltration test may only be performed in lieu of a low-pressure air test only as approved by the town.
2. Before beginning the exfiltration test, the pipe shall be cleaned. Once cleaned, the downstream pipe outlet shall be sealed at the manhole with a watertight plug. To assure a proper seal, the plug shall be at least equal to the diameter of the pipe being tested. (Note that if service laterals were connected, any opening lower in elevation than the static water level will also have to be plugged.)
3. The upstream manhole shall be filled with water to a static level not lower than four feet above the top of the sewer pipe (at its highest point) and not less than four feet higher than the existing groundwater table, whichever is greater. In lieu of using the upstream manhole, a standpipe can be used to develop the specific pressure head.
4. The water shall be allowed to stand for a period long enough to allow water absorption into the pipe (a minimum of six hours). After the absorption period, the pipe shall be refilled to the established level and the test begun. After a one-hour period, the exfiltration volume shall be calculated by either measuring the drop of water leveling the manhole or measuring the level in the manhole or measuring the volume of water to refill the standpipe to the original level, whichever applies. The measured exfiltration rate shall then be calculated and compared with the allowed by Table 2, the pipe tests, failure to meet the required limits will require correction, repair, and retesting the line.
(D) Deflection testing.
(1) Deflection testing shall be performed by the contractor in the presence of the town or its representative on all plastic pipes with nominal inside diameters of six inches or greater. Deflection testing shall be accomplished using on of the following devices: calibrated television or photography, or a properly sized “go no go” mandrel or sewer ball. Deflections of no more than 5% based on the base inside the diameters shown below will be allowed:
Table 1: Allowable Deflection | ||
Nominal Size, Inches | Base Inside Diameter, Inches | 5% Deflection Mandrel, Inches |
Table 1: Allowable Deflection | ||
Nominal Size, Inches | Base Inside Diameter, Inches | 5% Deflection Mandrel, Inches |
6 | 5.742* | 5.45 |
8 | 7.665* | 7.28 |
10 | 9.563* | 9.08 |
12 | 11.361* | 10.79 |
15 | 13.898* | 13.20 |
18 | 16.976** | 16.13 |
21 | 20.004** | 19.00 |
24 | 33.480** | 21.36 |
27 | 25.327** | 24.06 |
* From Tale 69 of Handbook of PVC Pipe, the Uni-Bell PVC Pipe Association, 1982 and/or Table XI.1 of ASTM Specification D3034. ** From Table 70 of the Handbook of PVC Pipe, the Uni-Bell PVC Pipe Association, 1982. | ||
(2) The deflection test shall be performed no sooner than 30 days following installation of the pipe (including backfill). Prior to testing, the pipeline shall be thoroughly cleaned.
(3) Prior to acceptance, pipes having deflections greater than 5% shall be excavated, rebedded, and/or replaced and retested (successfully)
(4) The contractor shall submit deflection test reports to the town within 30 days after the performance of each test. A separate report shall be submitted for each manhole-to-manhole sewer section. This report shall provide all pertinent data regarding the test including, but no limit to, the date of the test, details of the testing device used, diameter of pie, the date installation of the line was completed including backfill, and whether the line passed or failed the test.
(Ord. passed - -)
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