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

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

B. Reference is made to the Iowa Department of Transportation Standard Specifications for Highway and Bridge Construction, Series 2001, and all current General Supplemental Specifications and Materials Instructional Memorandum by the term "Iowa DOT Specifications" and/or " Iowa DOT I.M."

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.

1.036 SCHEDULING AND CONFLICTS

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

B. The Jurisdictional Engineer or his/her representative must be in attendance during testing or disinfection.

1.047 REGULATORY SPECIAL REQUIREMENTS

A. Conform to Comply with the standards of the Iowa Department of Natural Resources.

1.058 MEASUREMENT FOR AND PAYMENT

All measurements for payments will be made by the Jurisdictional Engineer or authorized representative. Testing and disinfection of water systems is incidental to the construction of pipe and fittings.

A. Testing and inspection of water systems is incidental to construction.  Include the costs in the prices bid for pipe and fittings.

PART 2 - PRODUCTS

2.01 DISINFECTION AGENT - CHLORINE

A. Meet Requirements:

1. Calcium Hypochlorite, per ANSI/AWWA B300.

2. Sodium Hypochlorite, per ANSI/AWWA B300.

B. Chlorine containers must have AWWA stamp.

A. Liquid Chlorine, per AWWA B300 and AWWA B301.

B. Sodium Hypochlorite, per AWWA B300.

C. Calcium Hypochlorite, per 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 OPERATION TESTING AND DISINFECTION

A. New Water System Construction: Perform operations according to AWWA C651 in the following sequence:

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

1.a. Perform initial flush.
4.b. Perform disinfection.
5.c. Flush after disinfection.
3.d. Perform pressure and leak testing.
2. Make all service taps.

2. 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.

a. Perform disinfection.
b. Flush after disinfection.
c. Perform pressure and leak testing.

B. Water System Rehabilitation:  Perform operations in the following sequence:

1. Perform initial flush.

2. Perform pressure and leak testing.

3. Perform disinfection.

4. Flush after disinfection.

5. Make all service taps.

C.B. Successfully complete each operation before commencing continuing to the next operation.

D.C. The Jurisdiction will provide reasonable quantities of water for flushing and testing.

3.032 INITIAL FLUSHING

A. Flushing:

1. Coordinate flushing with Jurisdiction.

1.2. Flush pipe prior to disinfection using potable water.

2.3. Use pitot tube to measure Measure flushing velocity.

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

B. Minimum Flushing Rate per AWWA C651, Table 3, based on 40 psi residual pressure:

Pipe Diameter (inches)

Flow Rate for Flushing
(gpm)

Pipe Diameter
(inches)

Flow Rate for Flushing
(gpm)

4

100

16

1,600

6

220

18

2,000

8

390

20

2,500

10

600

24

3,500

12

870

30

5,500

14

1,200

36

8,000

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 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 90º elbow.

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

3.043 DISINFECTION

A. General:

1. Applicable standard: ANSI/AWWA C651. Disinfect according to AWWA C651. The tablet method contained in AWWA C651 is not to be used unless approved by the Engineer.

2. Disinfect only after satisfactory pressure testing has been completed.

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

4.3. Coordinate disinfection and testing with Jurisdictional the Engineer.

5.4. Jurisdictional Engineer will Obtain and test water samples, unless otherwise provided by the Engineer.

B. Disinfection Procedure:

1. Induce 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 minimum until the entire new pipe contains a minimum of 25 mg/L free chlorine minimum.

4. Retain chlorinated water in pipe for at least 24 hours and not no more than 48 hours.

5. If test is not successful, repeat disinfection procedure.

3.054 FINAL FLUSHING AFTER DISINFECTION IS COMPLETE

A. Maintain isolation of the new pipe from the existing potable water system until test results have been approved, but not less than 24 hours after flushing has been completed.

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

C. Discharge chlorinated water in a safe manner.

D.B. Disposal of heavily chlorinated water Dispose of chlorinated water, which is flushed from the new piping, to prevent damage to the environment. Comply with any other state or federal requirements. De-chlorinate highly-chlorinated water from testing before releasing into the ground or sewers. Obtain Jurisdiction approval prior to any 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 Table C.1 the following table:

Table C.1 Amounts of chemicals required to neutralize various residual chlorine concentrations in 100,000 gal (378.5 m3) of water*

Residual Chlorine Concentration

Sulfur Dioxide
(SO2)

Sodium Bisulfite
(NaHSO3)

Sodium Sulfite
(Na2SO3)

Sodium Thiosulfate
(Na2S2O3 +5H2O)

Mg / L

lb

(kg)

lb

(kg)

lb

(kg)

lb

Kg

1

0.8

(.36)

1.2

(.54)

1.4

(.64)

1.2

(.54)

2

1.7

(.77)

2.5

(1.13)

2.9

(1.32)

2.4

(1.09)

10

8.3

(3.76)

12.5

(5.67)

14.6

(6.62)

12.0

(5.44)

50

41.7

(18.91)

62.6

(28.39)

73.0

(33.11)

60.0

(27.22)

* Except for residual chlorine concentration, all amounts are in pounds (kilograms).
Residual Chlorine
Concentration		 Sulfur Dioxide
(SO2)		 Sodium Bisulfite
(NaHSO3)		 Sodium Sulfite
(Na2SO3)		 Sodium Thiosulfate
(Na2S2)3 + 5H2O)		 Ascorbic Acid
(C6O8H6)
mg/L lb lb lb lb 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

3.025 PRESSURE AND LEAK TESTING

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

B. Secure any 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 that 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 five 5 psi over the test pressure at the highest point in the isolated system.

F. Test and monitor the completed piping system at 1½ 1.5 times the system working pressure or 150 psi, whichever is greater, for two continuous hours.

G. Monitor the pressure in the line for a period of not less than two hours.

H. G. If at any time during the test the pressure drops to five 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.

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

J. I. Maximum Allowable Leakage Rate allowable leakage rate at 150 psi (not applicable at other pressures) per AWWA C600.

L = (N)(D)(P)½
          7,400

Where:
L = allowable leakage, in gallons per hour.
N = number of joints in pipe test section.
D = pipe diameter, in inches.
P = average test pressure, psig.

The following table assumes an average test pressure of 150 psi, 18 feet pipe lengths, and no fittings:

Pipe Diameter
(inches)

Maximum Allowable Leakage Rate, (gallons per hour per 1,000 feet of pipe)

4

0.37

6

0.55

8

0.74

10

0.92

12

1.10

14

1.29

16

1.47

18

1.66

20

1.84

24

2.21

30

2.76

36

3.31

Note: For unusual conditions or for water lines shorter than 500 feet, consult
Jurisdictional Engineer for allowable leakage rate.  The following formula shall apply:

L = (S)(D)(P)½
         133,200

Where:
L = leakage allowable, in gallons per hour.
S = length of pipe test section, in feet.
D = pipe diameter, in inches.
P = average test pressure, psig.

K.J. If the average measured leakage per hour exceeds the Maximum Allowable Leakage Rate maximum allowable leakage rate, repair and retest the water line main.

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

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

3.06 BACTERIA SAMPLING

Test water mains according to AWWA C651. If the initial disinfection procedure fails to produce satisfactory bacteriological results or if other water quality is affected, repeat the disinfection procedure.

3.067 PUTTING WATER MAIN IN SERVICE

A. Obtain Jurisdictional Engineer's approval to pPut the completed water system in service only after obtaining permission from the Engineer.

END OF SECTION