CHAPTER 1700. Testing of Pipelines.

 

1701. General. All waterlines shall be tested, flushed and disinfected as outlined in this section.

 

1702. Testing. Tests shall be made upon completion of system installation or any valved portion thereof. All tests shall be made at the expense of the contractor and in the presence of the Engineer.

 

Lines shall be slowly filled with water, venting off all air. If required, taps shall be provided at line high points to bleed off the air, and after testing these shall be plugged. A minimum pressure fifty percent (50%) in excess of the maximum line operating pressure shall be maintained on the portion being tested for a minimum period of two hours, using either pneumatic or hydraulic means to maintain the pressure. Maximum leakage during the test shall not exceed one‑half gallon per inch of diameter per 1000 feet of pipe. Suitable means shall be provided by the contractor for determining the quantity of water lost by leakage under the test pressure. No pipe installation will be accepted until the leakage is less than allowable.

 

1703. Flushing. After pressure testing, all pipelines shall be flushed. Flushing shall be accomplished through hydrants or, if a hydrant does not exist at the end of the line, the contractor shall install a tap sufficient in size to provide for a 2.5 foot per second flushing velocity in the line. The following is the flow quantity required to provide a 2.5 foot per second flushing velocity:

 

Pipe Size (in.)

Flow (gpm)

2

26

4

100

6

220

8

390

10

610

12

880

 

1704. Dis-infection. After flushing, all culinary waterlines shall be disinfected by chlorination. Chlorination shall provide a minimum of 25 ppm residual after 24 hours contact in the pipe‑ line. This may be expected with an application of 50 ppm, although some conditions may require more. Chlorine in the form of a one percent slurry of high‑test calcium hypochlorite (HTH, Perchloron, Pittchlor, etc. which are 70 available chlorine by weight) shall be fed into the pipeline in such a manner as to mix with the water flowing in the pipeline. (A one percent slurring ‑ 10,000 ppm ‑ results from mixing one pound of calcium hypochlorite with 8.40 gallons of water.)


 

The following table provides information as to the required quantity of slurry to be used per 100 feet of pipe to provide a chlorine concentration of 50 ppm:

 

.

Pipe Size (in.)

Vol. of 100 ft Length (gal.)

Required Amount of Slurry/100 ft. of pipe (gal.)

1 1/2

9.18

0.07

2

16.32

0.12

2 1/2

25.50

0.18

3

36.73

0.26

4

65.28

0.47

6

146.90

1.05

8

261.10

1.87

10

408.10

2.92

12

587.60

4.20

 

 

During the process of chlorinating the pipeline, all valves and other pipeline appurtenances shall be operated several times to provide sufficient contact with the chlorinating agent. Following chlorination, the waterline shall be drained and thoroughly flushed and, if necessary, re‑chlorinated until a satisfactory bacteriological test is obtained.

 

1705. Sewer Acceptance Tests. All sanitary sewer pipe and appurtenances shall be cleaned, video inspected and tested for leaks prior to acceptance by city officials. Inspection shall be accomplished by video camera in accordance with paragraph 1707. Testing shall be accomplished by either an air test or infiltration test described in paragraphs 1708 and 1709. Unless otherwise provided in the special provisions, a developer must accomplish the air test: excepting however, that if the conditions where the ground water table is such as to preclude a proper exfiltration test, the City Engineer may require the infiltration test. Service lines for any section of pipe being tested will also be included in the testing of that section. (Ord. 96-08)

 

1706. Cleaning. After the sewer lines have been laid and the trench backfilled, they shall be thoroughly cleaned by jetting and tested for leakage and alignment in the presence of the Engineer before acceptance by the city. Cleaning shall be performed by an approved sewer jet by introducing pressurized water at the upper end of the trunks and laterals and flushing to remove all foreign material. Waste water and debris shall not be permitted to enter sewer lines in service, but shall be removed at the lowest manhole of the extension. Other methods of cleaning may be used subject to approval by the Engineer. After the lines have been thoroughly cleaned, they shall be tested between all manholes for displacement.

 

1707 Video Inspection. Sewer line video inspection shall be conducted by the developer or his representative and shall consist of the following: A video camera will be passed through each sewer line section from manhole to manhole after the line has been flushed with a sewer jet. A video tape recording of the inspection will be made of all sewer lines and a copy of the tapes will be provided to the City. If the illuminated interior of the pipe shows broken, misaligned or displaced pipe or other defects, the defects designated by the City Engineer shall be remedied by the developer. After cleaning and inspection have been completed, the line shall be tested for leakage. All cleaning, video inspection and tests shall be made at the expense of the developer and with observance by the appropriate city official. (Ord. 96-08)

 

1708. Infiltration Test. The infiltration test is the only hydrostatic test acceptable when the natural groundwater table is above the crown of the higher end of the test section. The maximum allowable limit for infiltration shall be 200 gallons/inch/mile/day with no allowance for external hydrostatic head.

 

1709. Air testing.

 

(1) The reach of pipe to be tested shall be isolated by completely blocking all outlets in the section under test. Careful attention must be given to blocking all plugs. Prior to installing the lower and upper plugs, the pipe must be wetted to minimize any loss of air through the pipe wall as a result of permeability in the dry condition. One of the plugs used at the manhole must be equipped for an air inlet to fill the line from an air compressor. The air compressor which feeds air into the pipe section must be equipped to control the air entry rate and to prevent the pressure from exceeding five P.S.I.G. - this can be done by means of a blow-off valve set to operate at five P.S.I.G.

 

(2) After the pipe has been wetted and plugs installed, the air should be allowed to slowly fill the pipe until a constant pressure of four P.S.I.G. is maintained. At this point, control the compressor so that the internal pressure in the line is maintained between four and three and one‑half P.S.I.G. for at least two minutes to permit the temperature of the entering air to equalize with the temperature of the pipe wall. Check during this two minutes stabilization period with a soap solution, all plugs and exposed fittings. If a leak is found, bleed off the air, repair the leak and start a new two minute stabilization period. When the temperature of the air has reached equilibrium with that of the pipe wall, bring the air pressure to four P.S.I.G. and disconnect the air supply. The gauge is then watched.

 

1710. Air Permeable Pipe Material. Pipe constructed of air‑permeable material shall be considered acceptable when the time required for pressure to decrease from 4 to 3 psig greater than average pressure of any ground water above the pipe shall less than the time shown in the following Tables for the condition of the pipe. A pipe will be considered saturated if it has been full of water for a period of 4 hours or more:


 

TABLE 17‑l

 

TIME IN SECONDS REQUIRED FOR PRESSURE DROP

FOR A SATURATED PIPE CONDITION

 

Length (ft)

 

Pipe Diameter in Inches

 

 

4

6

8

25

4

10

18

50

9

20

35

75

13

30

53

100

18

40

71

125

22

50

88

150

26

59

106

175

31

69

123

200

35

79

141

225

40

89

158

250

44

99

176

275

48

109

194

300

53

119

211

350

62

139

227

400

70

158

227

450

79

170

227

500

88

170

227

550

97

170

227

600

106

170

227

650

113

170

227

 

 


 

TABLE 17‑2

 

TIME IN SECONDS REQUIRED FOR PRESSURE DROP

FOR A DRY PIPE CONDITION

 

Length (ft)

 

Pipe Diameter in Inches

 

 

4

6

8

50

5

11

20

75

8

17

30

100

10

23

41

125

13

29

51

150

15

34

61

175

18

40

71

200

20

46

81

225

23

51

91

250

25

57

102

275

28

63

112

300

31

69

122

325

33

74

132

350

36

91

142

375

38

103

142

400

40

103

142

425

43

103

142

450

46

103

142

475

48

103

142

500

51

103

142

525

53

103

142

550

56

103

142

575

58

103

142

600

61

103

142

 

 


 

1711. Non Air‑Permeable Pipe Material. Pipe constructed of non air‑permeable material shall be considered acceptable when the time required for pressure to drop from 4.0 to 3.9 psig greater than the average pressure of any groundwater above the pipe shall be not less than twice the time specified in the table for a dry pipe condition.

 

If the installation fails to meet test requirements, the Contractor shall immediately determine and repair at his own expense the source of leakage.

 

1712. Deflection Test for Plastic Pipe. The Contractor shall test sections of sewer line selected by the Engineer by an approved method to insure that circumferential deflection of plastic pipe does not exceed 5 percent. The Contractor shall re‑bed or replace all pipe that does not meet this requirement at his own expense.