SECTION 5030 - TESTING AND DISINFECTION

 

PART 1 - GENERAL

 

1.01����� SECTION INCLUDES

 

A.�� Pressure and Leak Testing of Water System

 

B.�� Disinfection of Potable Water Systems

 

1.02����� DESCRIPTION OF WORK

 

Test and disinfect water mains, valves, fire hydrants, and appurtenances.

 

1.03����� SUBMITTALS

 

Follow the General Provisions (Requirements) and Covenants.

 

1.04����� SUBSTITUTIONS

 

Follow the General Provisions (Requirements) and Covenants.

 

1.05����� DELIVERY, STORAGE, AND HANDLING

 

Follow the General Provisions (Requirements) and Covenants.

 

1.06����� SCHEDULING AND CONFLICTS

 

Follow the General Provisions (Requirements) and Covenants, as well as the following:

 

A.�� Notify the Engineer two working days in advance of testing or disinfection operations to coordinate the operations.

 

B.�� The Engineer or his/her representative is required to be in attendance during testing or disinfection.

 

1.07����� SPECIAL REQUIREMENTS

 

None.

 

1.08����� MEASUREMENT AND PAYMENT

 

Testing and disinfection of water systems is incidental to the construction of pipe and fittings.

 

PART 2 - PRODUCTS

 

2.01����� DISINFECTION AGENT - CHLORINE

 

A.�� Liquid Chlorine complying with AWWA B300 and AWWA B301.

 

B.�� Sodium Hypochlorite complying with AWWA B300.

 

C.�� Calcium Hypochlorite complying with AWWA B300.

 

D.�� All disinfecting agents to be NSF 60 certified.� Supply and store in the original container.

 

PART 3 - EXECUTION

 

3.01����� SEQUENCE OF TESTING AND DISINFECTION

 

Perform operations according to AWWA C651 in the sequence below.��Successfully complete each operation before continuing to the next operation.� The Jurisdiction will provide reasonable quantities of water for flushing and testing.

 

A.�� Continuous-Feed or Slug Method (After Water Main Installation):� The sequence of testing and disinfection may be modified with approval of the Engineer.

 

1.�� Perform initial flush.

 

2.�� Perform disinfection.

 

3.�� Flush after disinfection.

 

4.�� Perform pressure and leak testing.

 

B.�� Tablet Method (Concurrent with Water Main Installation):� Use this method only if approved by the Engineer.� Modify the procedure for flushing, disinfection, and pressure and leak testing as needed if tablet method is used.

 

1.�� Perform disinfection.

 

2.�� Flush after disinfection.

 

3.�� Perform pressure and leak testing.

 

3.02����� INITIAL FLUSHING

 

A.�� Flushing:

 

1.�� Coordinate flushing with the Jurisdiction.

 

2.�� Flush pipe prior to disinfection using potable water.

 

3.�� Measure flushing velocity.

 

4.�� Obtain a minimum flushing velocity of 2.5 feet per second in the pipe to be disinfected.

 

B.�� Minimum Flushing Rate:� According to AWWA C651, Table 3, based on 40 psi residual pressure (see table below).

 

Table 5030.01:� Minimum Flushing Rate

 

Pipe Diameter

(inches)

Flow Rate for Flushing

(gpm)

Number of Taps2

Number of 2 1/2� Fire Hydrant Outlets1

1�

1 1/2�

2�

4

100

1

-

-

1

6

200

-

1

-

1

8

400

-

2

1

1

10

600

-

3

2

1

12

900

-

-

2

2

16

1,600

-

-

4

2

1With a 40 psi pressure in the main with the fire hydrant flowing to atmosphere, a 2 1/2 inch fire hydrant outlet will discharge approximately 1,000 gpm; and a 4 1/2 inch fire hydrant outlet will discharge approximately 2,500 gpm.

2Number of taps on pipe based on discharge through 5 feet of galvanized iron pipe with one 90elbow.

 

C.�� Property Protection:� Protect public and private property from damage during flushing operations.

 

3.03����� DISINFECTION

 

A.�� General:

 

1.�� Disinfect according to AWWA C651.� The tablet method contained in AWWA C651 is not to be used unless approved by the Engineer.

 

2.�� Keep piping to be chlorinated isolated from lines in service and from points of use.

 

3.�� Coordinate disinfection and testing with the Engineer.

 

4.�� Obtain and test water samples, unless otherwise provided by the Engineer.

 

B.�� Procedure:

 

1.�� Induce a flow of potable water through the pipe.

 

2.�� Introduce highly chlorinated water to the pipe at a point within 5 pipe diameters of the pipe's connection to an existing potable system, or within 5 pipe diameters of a closed end, if there is no connection to an existing system.

 

3.�� Introduce water containing a minimum of 25 mg/L free chlorine until the entire new pipe contains a minimum of 25 mg/L free chlorine.

 

4.�� Retain chlorinated water in the pipe for at least 24 hours and no more than 48 hours.

 

3.04����� FINAL FLUSHING

 

A.�� Flush pipe using potable water until chlorine residual equals that of the existing potable water system.

 

B.�� Dispose of chlorinated water to prevent damage to the environment.� Dechlorinate highly chlorinated water from testing before releasing into the ground or sewers.� Obtain Jurisdiction approval prior to flushing activities.

 

1.�� Check with the local sewer department for the conditions of disposal to the sanitary sewer.

 

2.�� Chlorine residual of water being disposed will be neutralized by treating with one of the chemicals listed in the following table.

 

Table 5030.02:� Amounts of Chemicals Required to Neutralize Various Residual Chlorine Concentrations in 100,000 Gallons of Water

 

Residual Chlorine Concentration

mg/L

Sulfur Dioxide

(SO2)

lb

Sodium Bisulfite

(NaHSO3)

lb

Sodium Sulfite

(Na2SO3)

lb

Sodium Thiosulfate

(Na2S2O3 + 5H2O)

lb

Ascorbic Acid

(C6O8H6)

lb

1

0.8

1.2

1.4

1.2

2.1

2

1.7

2.5

2.9

2.4

4.2

10

8.3

12.5

14.6

12.0

20.9

50

41.7

62.6

73.0

60.0

104

 

3.05����� PRESSURE AND LEAK TESTING

 

A.�� Remove debris from within the pipe.� Clean and swab out pipe, if required.

 

B.�� Secure unrestrained pipe ends against uncontrolled movement.

 

C.�� Isolate new piping from the existing water system.

 

D.�� Fill and flush all new piping with potable water.� Ensure all trapped air is removed.

 

E.�� Pressurize the new pipe to the test pressure at the highest point in the isolated system.� Do not pressurize to more than 5 psi over the test pressure at the highest point in the isolated system.

 

F.�� Test and monitor the completed piping system at 1.5 times the system working pressure or 150 psi, whichever is greater, for 2 continuous hours.

 

G.�� If at any time during the test the pressure drops to 5 psi below the test pressure, repressurize the pipe by pumping in potable water in sufficient quantity to bring the pressure back to the original test pressure.

 

H.�� Accurately measure the amount of water required to repressurize the system to the test pressure.

 

I.��� Maximum allowable leakage rate according to AWWA C600:

 

L = (S)(D)(P)0.5

148,000

 

Where:

L = allowable leakage, in gallons per hour

S = length of pipe tested, in feet

D = nominal pipe diameter, in inches

P = average test pressure, in pounds per square inch

 

The following table assumes an average test pressure (P) of 150 psi and 1,000 feet of test section.

 

Table 5030.03:� Maximum Allowable Leakage Rate

 

Pipe Diameter

�(inches)

Allowable Leakage Rate

(gallons/hour/1,000 feet of pipe)

4

0.33

6

0.50

8

0.66

10

0.83

12

0.99

14

1.16

16

1.32

18

1.49

20

1.66

24

1.99

30

2.48

36

2.98

 

J.�� If the average measured leakage per hour exceeds the maximum allowable leakage rate, repair and retest the water main.

 

K.�� If the measured pressure loss does not exceed 5 psi, the test will be considered acceptable.

 

L.�� Repair all visible leaks regardless of the amount of leakage.

 

3.06����� BACTERIA SAMPLING

 

Test water mains according to AWWA C651, including collection of two consecutive sets of acceptable bacteria samples 24 hours apart.� If the initial disinfection procedure fails to produce satisfactory bacteriological results or if other water quality is affected, repeat the disinfection procedure.

 

3.07����� PUTTING WATER MAIN IN SERVICE

 

Put the completed water system in service only after obtaining permission from the Jurisdiction.

 

END OF SECTION