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The developer shall furnish all facilities and personnel for conducting tests. Methods other than low pressure air test shall be subject to the approval of the district. Pressure gauge to be oil filled to zero to 30 psi read range.

(1) Preparation for Testing for Leakage. The developer shall be required, prior to testing, to clean and flush all gravity sewer lines. The completed gravity sewer, including side sewer stubs, after completion of backfill and cleaning shall be televised. This will be permitted prior to paving. The sewer shall then be tested by the low pressure air test method and/or an infiltration test. Except, however, that in certain conditions an exfiltration test may be required by the district.

The first section of pipe not less than 300 feet in length installed by each crew shall be tested, in order to qualify the crew and/or the material. A successful installation of this first section shall be a prerequisite to further pipe installation by the crew. At the developer’s option, crew and/or material qualification testing may be performed at any time during the construction process after at least two feet of backfill has been placed over the pipe.

(2) Low Pressure Air Test. The sewer pipe shall be tested for leaks through the use of air (unless exfiltration test is approved) in the following manner:

Following the pipe cleaning, utility installation, and paving, the pipe installation shall be tested with low pressure air. Air shall be slowly supplied to the plugged pipe installation until the internal air pressure reaches four pounds per square inch greater than the average back pressure of any ground water that may submerge the pipe. Two-fifths pounds per square inch to be added per one foot of water table over the pipe to a maximum of six psi. At least two minutes shall be allowed for temperature stabilization before proceeding further.

The rate of air loss shall then be determined by measuring the time interval required for the internal pressure to decrease from three and one-half to two and one-half pounds per square inch while maintaining the stipulated pressure greater than the pipe section’s average adjacent groundwater back pressure.

The pipeline shall be considered acceptable if the total rate of air loss from any section tested in its entirety between manholes, cleanouts or pipe ends does not exceed the following table:

Length of 6" Pipe (ft)

Length of 8" Pipe

0

50

100

150

200

250

300

350

400

100

5:00

5:00

5:00

5:00

5:00

5:38

6:14

6:12

6:08

150

5:00

5:00

5:00

5:30

6:10

6:30

6:26

6:22

6:18

200

5:00

5:22

6:00

6:40

6:44

6:38

6:34

6:30

6:26

250

5:52

6:32

6:48

6:58

6:50

6:44

6:40

6:36

6:32

300

7:02

7:20

7:10

7:02

6:56

6:50

6:44

6:40

6:36

350

7:34

7:22

7:14

7:06

7:00

6:54

6:50

6:44

6:42

400

7:34

7:24

7:16

7:08

7:02

6:58

6:52

6:48

6:44

Test time in minutes and seconds. Minimum test period is five-minute duration.

Test times will be provided by the engineer for combinations other than eight-inch mains and six-inch laterals.

If the pipe installation fails to meet these requirements, the developer shall determine at his own expense the source or sources of leakage, and shall repair (if the extent and type of repairs proposed by the developer appear reasonable to the district) or replace all defective materials or workmanship. The completed pipe installation shall meet the requirements of this low pressure air test or the alternative water exfiltration test before being considered for acceptance.

Plugs used to close the sewer pipe for the air test shall be securely braced to prevent the unintentional release of a plug. Gauges, air piping manifolds and valves shall be located at the top of the ground. No one shall be permitted to enter a manhole where a plugged pipe is under pressure. Air testing apparatus shall be equipped with a pressure release device such as a rupture disk or a pressure relief valve designed to relieve pressure on the pipe under test at six psi.

(3) Deflection Test. Deflection tests shall be performed on all ASTM D3034 PVC gravity sewer mains by pulling a mandrel through the pipe. The allowable deflection test limit shall be five percent of the base inside diameter in accordance with APWA test procedures and the nominal mandrel size shown in the following table:

Nominal Pipe Size (in.)

Base Inside Diameter (in.)

Mandrel Size, Diameter (in.)

6

5.74

5.45

8

7.67

7.28

10

9.56

9.08

12

11.36

10.79

Deflection testing is not required for AWWA C900 PVC or ductile iron pipe.

Deflection testing is also not required for pipe diameters of 15 inches and greater.

The sewer lines shall be thoroughly cleaned prior to the deflection test. [Res. 735 § 1, 2017.]