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City of Plymouth
STANDARD SPECIFICATIONSTABLE OF CONTENTS

WW.902 INSPECTION & TESTING - WASTEWATER

  1. GENERAL INSPECTION AND TESTING
    1. All materials and equipment used in the construction of projects shall be subject to adequate inspection and testing in accordance with generally accepted standards.
    2. The Owner shall provide notice to the City and his representative of the planned commencement of construction thirty (30) days prior to such commencement. The Owner shall reimburse the City for all inspection and testing expenses incurred by the City throughout the course of the project.
    3. City Representatives will at all times have access to the work, materials, invoices of materials, and other relevant data and records. The Contractor will provide proper facilities for such access and observation of the work and also for any inspection or testing thereof.
    4. If any work is covered contrary to inspections by the City Representative, it must, if requested by the City of Plymouth be uncovered for the City Representative observation and replaced at the Contractor's expense.
    5. If the City Representative considers it necessary or advisable that covered work be inspected or tested by others, the Contractor, at the request, will uncover, expose, or otherwise make available for observation, inspection, or testing as the City Representative requires, that portion of the work in question, furnishing all necessary labor, materials, tools, and equipment. If it is found that such work is defective, the Contractor will bear all expenses of such uncovering, exposure, observation, and testing and of satisfactory reconstruction.

  2. TESTS
    1. Construction
      1. Sewers twenty-four (24) inches (61cm) or less shall be laid with straight alignment between manholes using an inline laser. The alignment shall be checked by using either a laser or lamping.
    2. Deflection Test
      1. Deflection tests shall be performed on all flexible pipe. The test shall be conducted after the final backfill has been in place at least thirty (30) days.
      2. No pipe shall exceed a deflection of five percent (5%).
      3. If the deflection test is to be run using a certified mandrel, it shall have a diameter equal to ninety-five percent (95%) of the inside diameter of the pipe. The test shall be performed without mechanical pulling devices.
      4. Televising, if deemed necessary by the City Representative, shall be a part of this testing process.

  3. LOW PRESSURE AIR TESTING FOR SANITARY SEWERS
    1. General Instructions
      1. The City will require low pressure air testing to verify the integrity of the sewers, joints, and connections. If the City Representative deem necessary, televising of the sewers may be required. The Contractor shall furnish the labor, equipment, and materials necessary for these test at his expense.
      2. The section of the sewer line to be tested is plugged. Low pressure air is introduced into the plugged line. The amount and rate of air loss is used to determine the acceptability of the section being tested.
      3. Flush and clean the sewer line prior to testing, thus serving to wet the pipe surface as well as clean out any debris. A wetted interior pipe surface will produce more consistent results. Plug all pipe outlets to resist the test pressure. Give special attention to stoppers and laterals.
    2. Procedures
      1. Determine the test duration for the section under test by computation from the applicable equations shown in ASTM C 828, or from prepared air test tables. The pressure holding time is based on an average holding pressure of three (3) psi (21 kPa) gage or a drop from 3.5 psi (24 kPa) to 2.5 psi (17 kPa) gage.
      2. Add air until the internal air pressure of the sewer line is raised to approximately 4.0 psi (28 kPa) gage. After an internal pressure of approximately 4.0 psig is obtained, allow time for the air pressure to stabilize. The pressure will normally show some drop until the temperature of the air in the test section stabilizes.
      3. When the pressure has stabilized and is at or above the starting test pressure of 3.5 psi gage, commence the test. Before starting the test, the pressure may be allowed to drop to 3.5 psig. Record the drop in pressure for the test period. If the pressure has dropped more than 1.0 psi (17kPa) gage during the test period, the line is presumed to have failed. The test may be discontinued when the prescribed test time has been completed even though the 1.0 psig drop has not occurred.
      4. The test procedure may be used as a presumptive test which enables the installer to determine the acceptability of the line; prior to backfill and subsequent to construction activities.
      5. If the pipe to be tested is submerged in ground water, a water infiltration test should be used.
    3. Safety
      1. The air test may be dangerous if, because of lack of understanding or carelessness, a line is improperly prepared.
      2. It is extremely important that the various plugs be installed and braced in such a way as to prevent blowouts. Inasmuch as a force of 250 lb (1112N) is exerted on an eight (8) inch (203 mm) plug by an internal pipe pressure of five (5) psi (34 kPa), it should be realized that sudden expulsion of a poorly installed plug or of a plug that is partially deflated before the pipe pressure is released can be dangerous.
      3. As a safety precaution, pressurizing equipment may include a regulator or relief valve set at perhaps ten (10) psi (69 kPa) to avoid over-pressurizing and damaging an otherwise acceptable line. No one shall be allowed in the manholes during testing.
    4. Table
      1. The Air Test Table has been prepared utilizing applicable equations from ASTM C 828. It is based on an allowable air loss of 0.003 ft3/min ft2 of internal pipe surface, a maximum air loss per test section of 3.5 ft3/min and a minimum significant air loss per test section of 2.0 ft3/min. (Test sections of such length that an air loss of 3.5 ft3/min would be exceeded using the allowable loss of air per square foot of internal pipe surface may be tested in segments where total air loss would be between 2.0 and 3.5 ft3/min.)

AIR TEST TABLE
Based on Equations from ASTM C 828
SPECIFICATION TIME (MIN:SEC) REQUIRED FOR PRESSURE DROP FROM 3 1/2 TO 2 1/2 PS/G WHEN TESTING ONE PIPE DIAMETER ONLY

PIPE DIAMETER, INCHES
Length of
Line, Feet		 4 6 8 10 12 15 18 21 24 27 30 33 36 39
25 0:04 0:10 0:18 0:28 0:40 1:02 1:29 2:01 2:58 3:20 4:08 4:59 5:56 6:58
50 0:09 0:20 0:35 0:55 1:19 2:04 2:58 4:03 5:17 6:41 8:15 9:59 11:53 13:57
75 0:13 0:30 0:53 1:23 1:59 3:06 4:27 6:04 7:55 10:01 12:23 14:58 17:00 18:25
100 0:18 0:40 1:11 1:50 2:38 4:08 5:56 8:05 10:39 12:45 14:11 15:35
125 0:22 0:50 1:28 2:18 3:18 5:09 7:26 9:55 11:20
150 0:26 0:59 1:46 2:45 3:58 6:11 8:30
175 0:31 1:09 2:03 3:13 4:37 7:05
200 0:35 1:19 2:21 3:40 5:17
225 0:40 1:29 2:38 4:08 5:40
250 0:44 1:39 2:56 4:35
275 0:48 1:49 3:14 4:43
300 0:53 1:59 3:31
350 1:02 2:19 3:47
400 1:10 2:38
450 1:19 2:50
500 1:28
550 1:37
600 1:46
650 1:53

  1. JOINT TESTING
    1. Sanitary Sewer
      1. Sanitary sewer pipe and joints furnished shall be capable of meeting the following laboratory tests of assembled joints on random sample of each class, size, and type of pipe required.
      2. The installed system shall meet the infiltration and exfiltration requirements for the system.
      3. All pipe and joints shall be capable of withstanding a hydrostatic pressure of 20 feet of water (8.6 psi) for two hours with no visible leakage.
      4. Assembled joint tests shall be required if the infiltration/exfiltration tests are failed or if the joint system and assembly is unsatisfactory to the City Representative.
      5. Assembled joint tests shall be performed by an independent testing laboratory approved by the City Representative. Tests shall be performed on not more than one (1) percent of the total length of pipe of each class, size, and type utilized, except that at least two specimens shall be used for each test. The expense of the testing shall be borne solely by the Contractor. Testing shall conform to the applicable procedures of the ASTM specifications for the joint under test.
    2. Storm Sewers
      1. Storm sewer pipe and joints shall meet the same requirements as sanitary sewers, except when unusual site conditions exist and special permission is granted by the Department Superintendent.

  2. MANHOLE TESTING
    1. All sanitary sewer manholes shall be tested prior to backfilling; utilizing ASTM C1244-93 Standard Test Method for Concrete Sewer Manholes by the Negative Air Pressure (Vacuum) Test. All sanitary sewer manholes shall conform to the standards set therein.
    2. The City Representative shall be notified a minimum of two working days prior to the testing of the manholes.
    3. The Contractor shall be responsible to perform the tests. The City Representative shall be present during all tests.
    4. The Contractor shall document the tests and submit this documentation to the City of Plymouth Wastewater & Sewer Department and any other agency requiring such information.
    5. Preparation of the manhole:
      1. All lift holes shall be plugged.
      2. All pipes entering the manhole shall be temporarily plugged, taking care to securely brace the pipes and plugs to prevent them from being drawn into the manhole.
    6. Procedure:
      1. The test head shall be placed at the top of the manhole in accordance with the manufacturer's recommendations.
      2. A vacuum of 10 inches of mercury shall be drawn on the manhole, the valve on the vacuum line of the test head closed, and the vacuum pump shut off. The time shall be measured for the vacuum to drop to 9 inches of mercury.
      3. The manhole shall pass if the time for the vacuum readings to drop from 10 inches of mercury to 9 inches of mercury meets or exceeds the values indicated in Table 1.
      4. If the manhole fails the initial test, necessary repairs shall be made by an approved method. The manhole shall then be retested until a satisfactory test is obtained.

TABLE 1 MINIMUM TEST TIME FOR VARIOUS MANHOLE DIAMETERS
Diameter (in.)
Depth
(ft.)		 30 42 48 33 36 54 60 66 72
Time (min.)
8 11 12 14 17 20 23 26 29 33
10 14 15 18 21 25 29 33 36 41
12 17 18 21 25 30 35 39 45 49
14 20 21 25 30 35 41 46 51 57
16 22 24 29 34 40 46 52 58 67
18 25 27 32 38 45 52 59 65 73
20 28 30 35 42 50 53 65 72 81
22 31 33 39 46 55 64 72 79 89
24 33 36 42 51 59 64 78 87 97
26 36 39 46 55 64 75 85 94 105
28 39 42 49 59 69 81 91 101 113
30 42 45 53 63 74 87 98 108 121

END OF SECTION TABLE OF CONTENTS



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