The town must be notified at least 24 hours in advance of the completion of any testing. All testing must be witnessed by the town's representative.
(A) Gravity sewers.
(1) Mandrel testing.
(a) All flexible sanitary sewer pipe shall be mandrel deflection tested after installation. The mandrel (go/no-go) device shall be cylindrical in shape and constructed with nine evenly spaced arms of prongs. The mandrel dimension shall be 95% of the flexible pipe's published ASTM average inside diameter. Allowances for pipe wall thickness tolerances of ovality (from shipment, heat, shipping loads, poor production, etc.) shall not be deducted from the ASTM average inside diameter, but shall be counted as part of the 5% allowance. The contact length of the mandrel arm shall equal or exceed the nominal diameter of the sewer to be inspected. Critical mandrel dimensions shall carry a tolerance ± 0.001 inch.
(b) The mandrel inspection shall be conducted no earlier than 30 days after reaching final trench backfill grade; provided, in the opinion of the town, sufficient water densification or rainfall has occurred to thoroughly settle the soil throughout the entire trench depth. Short-term (i.e., tested within 30 days after installation) deflection shall not exceed 3% of the pipe's average inside diameter. The mandrel shall be hand pulled by the contractor through all sewer lines. The test shall not be performed with the aid of a mechanical pulling device. Any sections of the sewer not passing the mandrel test shall be uncovered and the contractor shall replace and recompact the backfill material to the satisfaction of the engineer and/or Utility Director. These repaired sections shall be retested with the go/no-go mandrel until passing.
(2) Leakage testing.
(a) The pipeline shall be made as nearly watertight as practicable, and leakage tests and measurements shall be made. All apparatus and equipment required for testing shall be furnished by the contractor.
(b) Where the groundwater level is more than one foot above the top of the pipe at its upper end, the contractor shall conduct either infiltration tests or low pressure air tests on the completed pipeline.
(c) Where the groundwater level is less than one foot above the top of the pipe at its upper end, the contractor shall conduct either exfiltration tests or low pressure air tests on the completed pipeline.
(d) Low pressure air tests shall be made using equipment specifically designed and manufactured for the purpose of testing sewer lines using low pressure air. The equipment shall be provided with an air regulator valve or air safety valve so set that the internal pressure in the pipeline cannot exceed eight PSI.
(e) The test shall be made on each manhole-to-manhole section of pipeline after placement of the backfill. The town or its designated representative must be present to witness each satisfactory air test before it will be accepted as fulfilling the requirements of these specifications.
(f) Pneumatic plugs shall have a sealing length equivalent to or greater than the diameter of the pipe to be tested. Pneumatic plugs shall resist internal test pressures without requiring external bracing or blocking.
(g) Low pressure air passing through a single control panel, shall be introduced into the sealed line until the internal air pressure reaches four PSI greater than the maximum pressure exerted by groundwater that may be above the invert of the pipe at the time of test. However, the internal air pressure in the sealed line shall not be allowed to exceed eight PSI. When the maximum pressure exerted by the groundwater is greater than four PSI, the contractor shall conduct only an infiltration test.
(h) At least two minutes shall be allowed for the air pressure to stabilize in the section under test. After the stabilization period, the low-pressure air supply hose shall be quickly disconnected from control panel. The time required in minutes for the pressure in the section under test to decrease from 3.5 to 2.5 PSI (greater than the maximum pressure exerted by groundwater that may be above the invert of the pipe) shall not be less than that shown in the following table:
Pipe Diameter in Inches | Minutes |
Pipe Diameter in Inches | Minutes |
4 | 2.0 |
6 | 3.0 |
8 | 4.0 |
10 | 5.0 |
12 | 5.5 |
15 | 7.5 |
18 | 8.5 |
21 | 10.0 |
24 | 11.5 |
30 and larger | 13 |
(i) When the sewer section to be tested contains more than one size of pipe, the minimum allowable time shall be based on the largest diameter pipe in the section, and shall be the time shown in the table reduced by 0.5 minutes.
(j) Reinforced concrete pipe shall be tested in accordance with ASTM C 924 (joint testing shall be in accordance with ASTM C 1103). Test time shall be a function of pipe diameter and the length of installed line to be tested as provided in ASTM C 924.
(k) Infiltration tests shall be made after underdrains, if present, have been plugged and other groundwater drainage has been stopped such that the groundwater is permitted to return to its normal level insofar as practicable.
(l) Upon completion of a section of the pipeline, the line shall be dewatered and a satisfactory test conducted to measure infiltration for at least 24 hours. The amount of infiltration, including manholes, tees and connections, shall not exceed 100 gallons per nominal inch diameter per mile of sewer per 24 hours.
(m) Exfiltration tests which subject the pipeline to an internal pressure, shall be made by plugging the pipe at the lower end and then filling the line and manholes with clean water to a height of two feet above the top of the sewer at its upper end. Where conditions between manholes may result in test pressures which would cause leakage at the plugs or stoppers in branches, provisions shall be made by suitable ties, braces and wedges to secure the plugs against leakage resulting from the test pressure.
(n) The rate of leakage from the sewers shall be determined by measuring the amount of water required to maintain the level two feet above the top of the pipe.
(o) Leakage from the sewers under test shall not exceed the requirements for leakage into sewers as hereinbefore specified.
(B) Manholes.
(1) All manholes must be vacuum tested after installation, repair, or modification.
(2) Installation and operation of vacuum equipment and indicating devices must be in accordance with manufacturer's recommendations and performance specifications that have been provided by the manufacturer and accepted by the town.
(3) All manholes shall be tested by negative air pressure (vacuum) testing methods in accordance with ASTM C1244. These tests shall be performed by the contractor and observed and confirmed by a representative of the town.
(4) Stub outs, manhole boots, and pipe plugs must be secured to prevent movement while the vacuum is drawn.
(5) Installation and operation of vacuum equipment and indicating devices must be in accordance with manufacturer's recommendations and performance specifications.
(6) Procedures. With the vacuum tester set in place:
(a) Inflate the compression band to 40 PSI to affect a seal between the vacuum base and the structure. Connect the vacuum pump to the outlet port with the valve open. Draw a vacuum ten inches of Hg and close the valve.
(b) Acceptance standards for leakage will be established from the elapsed time for a negative pressure change from ten inches to nine inches of mercury. The maximum allowable leakage rate for a four-foot diameter manhole must be in accordance with the following table:
Minimum Test Times for Various Manhole Diameters | ||||||
Depth (feet) | Diameter (inches) | |||||
42 | 48 | 54 | 60 | 66 | 72 | |
Time (seconds) | ||||||
Minimum Test Times for Various Manhole Diameters | ||||||
Depth (feet) | Diameter (inches) | |||||
42 | 48 | 54 | 60 | 66 | 72 | |
Time (seconds) | ||||||
8 | 17 | 20 | 23 | 26 | 29 | 33 |
10 | 21 | 25 | 29 | 33 | 36 | 41 |
12 | 25 | 30 | 35 | 39 | 43 | 49 |
14 | 30 | 35 | 41 | 46 | 51 | 57 |
16 | 34 | 40 | 46 | 52 | 58 | 67 |
18 | 38 | 45 | 52 | 59 | 64 | 73 |
20 | 42 | 50 | 53 | 65 | 72 | 81 |
22 | 46 | 55 | 64 | 72 | 79 | 89 |
24 | 51 | 59 | 64 | 78 | 87 | 97 |
26 | 55 | 64 | 75 | 85 | 94 | 105 |
28 | 59 | 69 | 81 | 91 | 101 | 113 |
30 | 63 | 74 | 87 | 98 | 108 | 121 |
(7) Retest:
(a) If the manhole fails the test, necessary repairs must be made and the vacuum test and repairs must be repeated until the manhole passes the test.
(b) If manhole joint seals are pulled out during the vacuum test, the manhole must be disassembled and the joints replaced.
(8) Visual: Manholes will be subject to visual inspection with all visual leaks being repaired.
(C) Sanitary sewer lift stations and force mains.
(1) General. All new and replacement sanitary sewer force mains will be approved on a case by case basis by the Department. All design, construction and testing must meet ASTM, 10 States Standards and IDEM standards. An IDEM Construction Permit must be issued prior to any approval being given. The following additional requirements will apply.
(2) Location.
(a) Force mains shall be placed in the right-of-way if at all possible. If there is not enough room in the right-of-way, then a separate 20-foot wide sanitary sewer easement will be required.
(b) Pump stations shall be built on land that is town owned in fee simple.
(3) Pump station wet wells.
(a) All wet wells shall either be constructed or lined with non-corrosive materials.
(b) Safety hatches shall be made of metal material; fabric hatches will not be allowed.
(c) There shall be a minimum of six inches of clearance between the pump volute and hatch opening.
(4) Pumps. All pumps shall be manufactured by Flight unless otherwise approved by the Utility Director or their designee.
(D) Air relief valves.
(1) All new or replacement ARVs shall be A.R.1. Combination Air Valves-Short Version, 0-025; Stainless Steel Body and Bases or comparable as approved by the Utility Director or their designee.
(2) ARVs shall be placed inside of square doghouse structures measuring at least 48 inches by 48 inches with metal hatches with an appropriate load rating. A minimum of 12 inches of gravel must be placed underneath and surrounding the ARV inside of the structure.
(E) Inspections. All work must be inspected by the Clarksville Wastewater Department and copies of all appropriate documentation, permits and applications must be presented at time of inspection. Inspections must be scheduled by contacting the wastewater treatment plant. Inspections will be made within 24 hours of time of request. All inspections will be completed Monday through Friday; weekend inspections will not be scheduled.
(Ord. 2020-SW-02, passed 3-3-20) Penalty, see § 51.999