15-10 Water Service Line will be paid per linear foot for pipes less than 2 inches . 1
Valve boxes, meter boxes, hot boxes, vaults and manholes for protecting and servicing utility 2 controls are incidental to the appropriate pay item. 3 A __" Line Stop with Bypass consists of installing line stops o n opposite ends of the piping to 4 be isolated, tapping the piping beyond the line stops and providing temporary bypass piping 5 between the taps. The entire assembly of valves and piping will be measured as one unit and 6 paid per each. 7 Corporation stops or ot her items to aid in testing and flushing of the piping are incidental 8 items. 9 If the contract does not include such pay items, measurement will not be done and the items 10 will be incidental to other contract pay items. All piping, controls, certifications, 11 appurtenances and other miscellaneous items necessary to place the new or relocated item in 12 proper working condition are incidental. 13 Payment will be made under: 14 Pay Item Pay Unit __" Valve Each __" Insertion Valve Each __" Plug Valve Each __" Tapping Sleeve and Valve Each __" Air Release Valve Each __" Combination Air Valve Each __" Blow Off Each __" Water Meter Each Relocate Water Meter Each Reconnect Water Meter Each __" DCV Backflow Prevention Assembly Each Relocate __" DCV Backflow Prevention Assembly Each __" RPZ Backflow Prevent ion Assembly Each Relocate __" RPZ Backflow Prevention Assembly Each Fire Hydrant Each Relocate Fire Hydrant Each __" Line Stop Each __" Line Stop with Bypass Each Fire Hydrant Leg Linear Foot __" Water Service Line Linear Foot Water Service Line Linear Foot SECTION 1520 15 SANITARY SEWER 16 1520 -1 DESCRIPTION 17 Provide sanitary sewers suitable for transporting sewage. 18 1520 -2 MATERIALS 19 Refer to Division 10. 20 Item Section Sanitary Sewer Pipe and Fittings 1034
15-11 Use any pipe specified under Section 1034 except where a particular type pipe is specified in 1
the plan s or required by environmental regulations or Departmental policy. Verify the pipe is 2 appropriate for the test pressure of the system and the external lo ading. 3 For sewer services and laterals use pipe conforming to the current requirements of the North 4 Carolina State Building Code: Plumbing Code for building sewer pipe. 5 Use ductile iron fittings on pressurized (force main) pipelines 4 inches or larger. 6 Use screw type plastic or brass clean -out covers. 7 Use #12 AWG solid- copper wire with green insulation for the utility locator wires. 8 Use 2 inch plastic marking tape colored green with “Caution Sewer Line,” or similar wording, 9 permanently printed at 36 inch centers. 10 1520 -3 CONSTRUCTION METHODS 11 Apply Section 1505 for excavation, trenching, pipe laying and backfill to sanitary sewer 12 installation. 13 Assemble pipe in accordance with the r ecommendations of the manufacturer. 14 Install PVC pipe in accordance with approved bedding methods. 15 Install vitrified clay sewer pipe in accordance with ASTM C12. 16 Install 4 inch minimum diameter sanitary sewer clean -outs flush with finished grade on 4 inch 17 and 6 inch service lines. Provide clean -outs at the right -of-way line and at changes in 18 direction. Do not locate clean -outs within the roadway pavement or shoulders. Provide 19 clean -outs no more than 50 feet apart when beyond the roadway shoulders. 20 Use ductile iron pipe for sewers with 10% or greater slope. 21 Install sewer lines entering manholes with the crown at or higher than the sewer line leaving 22 the manhole. 23 Install small diameter pipe (4 inches or less) under existing pavement by a trenchless method 24 at no additional compensation. 25
A.Gravity Sanitary Sewer 26 Construct gravity sanitary sewers in conformance with NCDEQ Gravity Sewer Minimum 27 Design Criteria . 28
1.Pipe Installation 29 Use fittings or saddles to connect service lines to the sewer main. 30 Maintain sewer flow at all times. Use temporary diversions or pumping to maintain 31 flow when connecting proposed sewers to existing sewers. Use engineered 32 temporary pumping systems capable of handling full pipe flow. Use pumping 33 systems with automatic reliable operation or constantly tended manual operation. 34
2.Testing 35 Perform tests on newly installed sewers and altered sewers before placing into 36 service. Provide all equipment, piping, controls, pumps, water and safety devices 37 necessary for performing the tests. 38 Test all 24 inch es and smaller gravity sewer lines for leakage using infiltration, 39 exfiltration, or air test. Perform visual inspection on gravity sewer lines larger than 40 24 inches. Perform line and grade te sting and deflection testing on all gravity sewer 41 lines. 42
15-12 (a) Infiltration 1
For sewer lines greater than 3 f eet below groundwater, measure the amount of 2 water infiltrating into the pipeline between manholes in at least 24 hours. Repair 3 leaks or replace piping when the rate of infiltration exceeds the following 4 equation: 5 W = LD 000789.0 Where: W = maximum allowable leakage in gallons per hour L = length of pipeline tested, in feet D = nominal diameter of the pipe, in inches
b.Exfiltration 6 For sewer lines above groundwater, perform an exfiltration test on the pipeline 7 between manholes. Repair leaks or replace piping when the rate of exfiltration 8 exceeds maximum allowable leakage calculated in Subarticle 1520 -3(A)(2)(a). 9 The exf iltration test shall consist of securely plugging the pipe at the lower 10 manhole and filling the pipeline with water. Allow the water to s it for 24 hours 11 in clay or concrete pipes. Raise the water level in the upstream manhole 12 to 3 feet above the top of pipe. After 4 hours, measure the amount of water 13 required to bring the water level back to the level at the start of the test and 14 record the time. 15 Perform exfiltration tests through a series of manhole to manhole segments to 16 limit the length of pipe tested to between 300 f eet and 1, 500 f eet. Shorter 17 sections may be tested with longer test times. No additional leakage allowance 18 for manholes permitted. 19
c.Air Test 20 Instead of hydrostatic testing, sewer lines 24 inches in diameter or smaller may 21 be air tested in accordance with ASTM C828 and the following. Securely plug 22 the sewer pipe at the manholes. Fill the pipe with air to 4.0 psi and hold this 23 pressure for 5 minutes. Reduce the pressure to 3.5 psi. Measure the time for the 24 pressure to drop 1.0 psi to the new pressure of 2.5 psi. Exceed the minimum test 25 time shown in Table 1520- 1 for the appropriate nominal pipe diameter. 26 TABLE 1520 -1 AIR TEST TIME Pipe Size (Inches) Test Time (Minutes/100 ft) Pipe Size (Inches) Test Time (Minutes/100 ft) 8 1.2 18 2.4 10 1.5 21 3.0 12 1.8 24 3.6
d.Visual Inspection 27 Visually inspect sewer lines larger than 24 inches from the inside using 28 approved cameras. Correct any leakage, rolled gaskets or defects. 29
e.Line and Grade 30 Test all sewers for straight alignment by lamping or using a laser. 31
f.Deflection Testing 32 Perform deflection tests on all flexible pipes. Conduct the tes t after the final 33 backfill has been in place at least 30 days to permit stabilization of the soil -pipe 34 system. As an alternative to waiting 30 days to permit stabilization of the 35
15-13 soil-pipe system, provide certified soil testing verifying the backfill of the trench 1
has been compacted to at least 95% maximum density. 2 No pipe shall exceed a deflection of 5% . If deflection exceeds 5 %, relay the 3 pipe. 4 The rigid ball or nine -point mandrel used for the deflection test shall have 5 a diameter not less than 95 % of the base inside diameter or average inside 6 diameter of the pipe depending on which is specified in the ASTM, to which the 7 pipe is manufactured. The pipe shall be measured in compliance with 8 ASTM D2122. The test shall be performed without mechanical pulling devices. 9
B.Force Main Sanitary Sewer 10 Construct force main sewers in conformance with NCDEQ Minimum Design Criteria for 11 the Fast -Track Permitting of Pump Stations and Force Mains . 12
1.Installation 13 Install lines with 36 inches to 42 inches of cover to finished grade unless otherwise 14 directed or approved by the Engineer . Install lines with greater cover for short 15 distances to accommodate utility controls, to make tie -ins to existing facilities, to 16 eliminate high points in the pipeline or to provide clearance from existing or 17 proposed utilities, drainage, other obstacles or actual field conditions. 18 Provide automatic air release valves at all high points. 19
2.Testing 20 Perform pressure and leakage tests on newly installed force mains and altered sew ers 21 before placing such pipelines into service. Provide all equipment, piping, controls, 22 pumps, water and safety devices necessary for performing the tests and sterilization. 23 Test all new sewer force mains with clean water at 200 ± 5 psi for a 2 hour dura tion. 24 Vent all high points and expel all air. Provide certified results demonstrating leakage 25 less than : 26 W = LD 000106.0 Where: W = allowable leakage in gallons per hour L = length of pipeline tested, in feet D = nominal diameter of the pipe, in inches Repair leaks using approved methods or replace pipe, controls or appurtenances as 27 necessary to reduce leakage. Additionally, repair any leaks that are visible after 28 2 hours duration. 29 1520 -4 MEASUREMENT AND PAYMENT 30 __" Sanitary Gravity Sewer and __" Force Main Sewer will be measured and paid in actual 31 number of linear feet of sewer line that has been incorporated into the completed and accepted 32 work. Measurement of sewer line will be made by counting the number of joints used and 33 multiplyin g by the length of the joint to obtain the number of linear feet of sewer line installed 34 and accepted. Measurements of partial joints will be made along the length of the partial joint 35 to the nearest 0.1 foot. All fittings will be incidental on Sanitary Gravity Sewer . 36 Sanitary Sewer Clean -Out will be measured and paid per each. 37 Sewer Service Line will be paid per linear foot. 38 The quantity of D uctile Iron Sewer Pipe Fittings will be measured and paid per pound based 39 on the published weights for ductile iron fittings, exclusive of the weights of any accessories, 40 as listed in the “DI Fittings Weight Chart” located on the Utilities Unit website . If the 41 Contractor elects to use compact ductile iron sewer pipe fitt ings, measurement will be based 42
Source: North Carolina Standard Specifications for Roads and Structures, 2024 Edition. Pages 736–739 of 857.