CONSTRUCTION STANDARD SPECIFICATION

SECTION 02516

[FLUSHING AND DISINFECTION OF UNDERGROUND WATER LINES FOR DOMESTIC AND
FIRE PROTECTION SYSTEMS]{.underline}

Part 1 - General [2](#part-1---general)

1.01 Summary [2](#summary)

1.02 References [2](#references)

1.03 Submittals [2](#submittals)

1.04 Quality Assurance [2](#quality-assurance)

Part 2 -- Products [3](#part-2-products)

2.01 Acceptable Disinfectants [3](#acceptable-disinfectants)

2.02 Acceptable Dechlorination (Neutralizing) Agents
[3](#acceptable-dechlorination-neutralizing-agents)

Part 3 -- Execution [3](#part-3-execution)

3.01 Discharge Requirements [3](#discharge-requirements)

3.02 Flushing of Water Mains [4](#flushing-of-water-mains)

3.03 Disinfection of Water Mains [5](#disinfection-of-water-mains)

3.04 Disinfection for Repairs [7](#disinfection-for-repairs)

CONSTRUCTION STANDARD SPECIFICATION

SECTION 02516S

[FLUSHING AND DISINFECTION OF UNDERGROUND WATER LINES FOR DOMESTIC AND
FIRE PROTECTION SYSTEMS]{.underline}

# Part 1 - General

## 1.01 Summary

A.  Section Includes:

    1.  Discharge requirements

    2.  Flushing requirements for underground water mains

    3.  Disinfection requirements for the following new and repaired
        systems:

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a.  Underground Potable water distribution piping.

b.  Fire protection piping below grade to base of riser.

## 1.02 References

A.  American Water Works Association (AWWA)

    1.  C651 Disinfecting Water Mains

    2.  B300 AWWA Standard for Hypochlorites

## 1.03 Submittals

A.  General: Submit the following in accordance with conditions of
    Contract and Section 01330 \"Descriptive Submittals \".

B.  Flushing Plan.

## 1.04 Quality Assurance

A.  All work shall comply with the applicable portions of the most
    current edition of the International Plumbing Code and AWWA
    Standards.

B.  The materials and practices comprising the work shall conform to
    this and other referenced specifications. Where this specification
    conflicts with the requirements of another referenced specification,
    this specification shall prevail.

C.  All persons performing or supervising testing shall be qualified by
    either training or experience to perform such tests.

D.  SNL will perform water quality testing of water samples taken from
    piping systems for chlorine concentrations and bacteriological
    quality. The contractor must coordinate water quality testing with
    the SDR a minimum of 24 hours in advance.

# Part 2 -- Products 

## 2.01 Acceptable Disinfectants

A.  Sodium hypochlorite \[NaOCl\] conforming to AWWA B300 Standard for
    Hypochlorites.

B.  Calcium hypochlorite \[Ca(OCl)2\] granules and tablets conforming to
    AWWA B300 Standard for Hypochlorites. Calcium hypochlorite intended
    for use in swimming pools is not permitted.

C.  Disinfection with pure chlorine gas or liquid is not permitted.

## 2.02 Acceptable Dechlorination (Neutralizing) Agents

A.  Sodium thiosulfate (technical grade, prismatic rice) is acceptable
    for all discharges, except to an active watercourse.

B.  Vitamin C salt (sodium ascorbate, Vita-D-Chlor brand or equal) must
    be used when discharging to an active watercourse.

C.  Sulfur dioxide gas is not permitted.

# Part 3 -- Execution

## 3.01 Discharge Requirements 

A.  The Contractor shall obtain approval, through the construction
    observer, to discharge to the surface from the Environmental
    Management Department (3121) two days prior to any discharge.

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A.  Discharges to environment:

    1\. Discharges shall not cause or have the reasonable potential to
    cause or contribute to a violation of a water quality standard.

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2.  Employ Best Management Practices (BMPs) to prevent erosion from
    discharge of water during any construction activities including
    flushing and disinfection in accordance with an approved Storm Water
    Pollution Prevention Plan (SWPPP).

3.  Chlorinated water used for disinfection shall be dechlorinated with
    an approved dechlorination agent. If discharge is not to a
    watercourse (e.g., flat ground), then total chlorine concentration
    shall be reduced to less than 1 ppm (part per million). Discharges
    to a watercourse require approval from the Environmental Management
    Department (3121) prior to any discharge. Do not dose neutralizing
    chemical beyond the minimum required to neutralize the chlorine
    actually present in discharge. Allowable residual chlorine will vary
    depending on discharge avenue (watercourse, flat land, or sanitary
    sewer system).

4.  For discharges of less than 5,000 gallons, notify the Construction
    Observer at least 48 hours (2 working days) in advance of planned
    discharge.

5.  For discharges of 5,000 gallons or more, notify the Construction
    Observer at least 5 working days in advance of planned discharge.

    A.  Notify the Construction Observer immediately in the event of any
        accidental discharge.

## 3.02 Flushing of Water Mains

A.  Preliminary flushing

    1.  Prior to flushing and disinfection, fill main with water to
        eliminate air pockets.

    2.  The Contractor shall flush all new installations in accordance
        with an approved flushing plan submitted by the Contractor. If
        no fire hydrants or other convenient outlets for flushing are
        available, the Contractor shall install flush points at no
        additional cost to SNL. All discharges must meet requirements in
        Section 3.01 of this specification. The Contractor shall
        coordinate operations by submitting a support request to the SDR
        a minimum of 24 hours in advance. Operations requiring a system
        outage must be coordinated a minimum of 2 weeks in advance.

    3.  Flush new mains, including fire service mains and lead-in
        connections to fire system risers, thoroughly before connection
        is made to system piping in order to remove foreign materials
        that might have entered the main during the course of the
        installation or that might have been present in existing piping.

    4.  Flushing shall be of sufficient magnitude and duration to flush
        all foreign material out of the lines, valves, and hydrants. The
        flushing velocity shall be a minimum of 2.5 feet per second
        (ft/s) for non-fire protection lines. Where the main supplies a
        fire protection system the velocity shall meet the NFPA 24
        requirement of 10 ft/s.

        Flow required to produce a velocity of 10 ft/s (3 meter per
        second \[m/s\]) in pipes (NFPA 24):

  ------------------------------------ ----------------------------------
  **Nominal Pipe Size**                

  Inches (in.)                         Gallons per Minute (gpm)

  4                                    390

  6                                    880

  8                                    1560

  10                                   2240

  12                                   3520
  ------------------------------------ ----------------------------------

5.  All valves and hydrants shall be fully opened and closed under water
    pressure to ensure proper operations during flushing and to dislodge
    foreign material. All valves on fire protection lines (except curb
    box valves) shall be sealed with a plastic seal in the normal
    position (opened or closed) at the conclusion of testing. During
    flushing operations, all valves or connections to existing systems
    shall be closed and backflow preventors or other approved equipment
    installed at the source to prevent contamination of existing
    systems.

6.  Contractor shall protect existing site improvements during flushing
    operation.

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B.  Final Flushing

    Clearing the main of heavily chlorinated water:

    1.  Contact the SDR or Sandia Construction Inspector to arrange for
        water quality testing for chlorine concentrations and
        bacteriological quality at minimum of 24 hours in advance of the
        final flushing.

    2.  After residual free chlorine concentration test has been
        completed by SNL, flush the piping system with potable water
        until total chlorine concentration in main is less than 1
        milligram per liter (mg/L) or 1 ppm. All discharges must meet
        requirements in Section 3.01 of this specification.

    3.  After final total chlorine concentration and bacteriological
        quality tests have been completed, Sandia Construction Inspector
        will furnish the test results to the Contractor. If the water
        quality tests do not show compliance with the applicable
        requirements of the Safe Drinking Water Act, the main shall be
        flushed, re-chlorinated, and retested until test results
        demonstrate compliance.

## 3.03 Disinfection of Water Mains

Disinfection shall follow the Requirements of AWWA Standard 651 for
Disinfecting Water Mains latest edition.

Disinfecting solutions containing chlorine shall not exceed 12% active
chlorine; greater concentrations can chemically attack and degrade
polyethylene.

A.  Disinfection by Chlorinated Water Injection

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1.  Inject chlorinated water with a free chlorine concentration no less
    than 25 mg/L, into the water line no more than 10 feet from the
    beginning of the new main. Provisions shall be taken to eliminate
    air pockets.

2.  Chlorinated water shall remain in the pipe for a minimum of 24hrs.
    If the water temperature is less than 41°F (5°C) it shall remain in
    the pipe for a minimum of 48 hours. Detectable chlorine residual
    should be found at each sampling point after the 24 hr or 48 hr
    period. Contact the Sandia Construction Observer to arrange for
    residual chlorine testing a minimum of 24 hours in advance.

    A.  Tablet Method: only applicable for projects where the pipes and
        appurtenances are kept clean and dry. This method must be
        indicated in the flushing plan. The flushing plan must clearly
        indicate the sequence of events to assure the line is
        disinfected properly and flushing requirements are met.

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1.  Warning: This procedure cannot be used on solvent-welded plastic or
    on screwed-joint steel pipe because of the danger of fire or
    explosion from the reaction of the joint compounds with the calcium
    hypochlorite.

2.  5-gram (g) calcium hypochlorite tablets shall be placed in each
    section of pipe, during construction. The number of tablets shall be
    .0012 d^2^L rounded to the next largest integer, where d is the
    inside diameter in inches and L is the length of pipe in feet. One
    tablet shall also be placed in each hydrant, hydrant branch, or
    other appurtenances. Tablets shall be secured using food-grade
    adhesive to the top of the main making sure that the number of
    tablets on each end is approximately equal. If the pipe is then to
    be placed in the trench, there must be markers indicating that the
    pipe has been installed with the tablets on top.

3.  When the installation has been completed, the main shall be filled
    with water at a rate to insure that the water within the main will
    flow at a velocity no greater than 1 ft/s (0.3m/s). Precautions
    shall be taken to eliminate air pockets with in the main. This water
    shall remain in the pipe for a minimum of 24hrs. If the water
    temperature is less than 41°F (5°C) it shall remain in the pipe for
    a minimum of 48 hours. Detectable chlorine residual should be found
    at each sampling point after the 24 hr or 48 hr period. Contact the
    Sandia Construction Observer to arrange for residual chlorine
    testing.

    A.  Calcium hypochlorite Granules, Granules shall be placed at the
        upstream end of the first section of pipe, at the upstream end
        of each branch main, and at 500-ft intervals. The granular
        quantity of calcium hypochlorite can be calculated using the
        table below:

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1.  Warning: This procedure cannot be used on solvent-welded plastic or
    on screwed-joint steel pipe because of the danger of fire or
    explosion from the reaction of the joint compounds with the calcium
    hypochlorite.

  --------------- ------------------- ------------------- -----------------
  **Calcium                                               
  Hypochlorite                                            
  Quantities per                                          
  500 linear                                              
  feet.**                                                 

  **Pipe Diameter                     **Calcium           
  (d)**                               Hypochlorite        
                                      Granules**          

  In.             \(mm\)              oz                  g

  4               100                 1.7                 57

  6               150                 3.8                 113

  8               200                 6.7                 200

  10              250                 10.5                300

  12              300                 15.1                430

  14\<            350\<               D^2^\*15.1          D^2^\*427.9

  Where D is the                                          
  inside pipe                                             
  diameter in                                             
  feet (D = d/12)                                         
  --------------- ------------------- ------------------- -----------------

2.  When the installation has been completed, the main shall be filled
    with water at a rate to insure that the water within the main will
    flow at a velocity no greater than 1 ft/s (0.3m/s). Precautions
    shall be taken to eliminate air pockets with in the main. This water
    shall remain in the pipe for a minimum of 24hrs. If the water
    temperature is less than 41°F (5°C) it shall remain in the pipe for
    a minimum of 48 hours. Detectable chlorine residual should be found
    at each sampling point after the 24 hr or 48 hr period. Contact the
    Sandia Construction Observer to arrange for residual chlorine
    testing.

    A.  After the residual chlorine testing had been accomplished, the
        contractor shall perform the "Final Flushing" as prescribed in
        Section 3.02 of this specification.

## 3.04 Disinfection for Repairs

Disinfection shall follow the Requirements of AWWA Standard 651 for
Disinfecting Water Mains latest edition.

A. Before Repair:

1.  Where practical, isolate a section of affected line and shut off all
    service connections.

2.  Swab or spray the inside of new pipe and fittings with a minimum of
    1 percent (10,000 ppm) hypochlorite solution before they are
    installed. Disinfect tools to be used in same manner.

    B. After Repair:

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1.  Prior to disinfection, flush affected line to remove any debris that
    may have been introduced during repairs. If possible, flush from
    both directions. Flush until discolored water is eliminated and
    water flows clear. If line segment cannot be isolated, thoroughly
    flush the segment to a tank or through a fire hydrant.

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3.  Obtain verification from the Sandia Construction Observer that
    affected line has been thoroughly flushed and is ready for
    chlorination.

4.  Apply chlorinated water to the interior surfaces of affected water
    line segment at the chlorine concentration and contact times as
    follows; verify total chlorine concentration by performing an
    initial total chlorine concentration test.

+-----------------------------------------+----------------------------+
| **[Chlorine Concentration (mg/L,        | ##                         |
| ppm)]{.underline}**                     | # **Minimum Contact Time** |
+-----------------------------------------+----------------------------+
| 300                                     | 15 minutes                 |
+-----------------------------------------+----------------------------+
| 250                                     | 1 hour                     |
+-----------------------------------------+----------------------------+
| 200                                     | 1.5 hours                  |
+-----------------------------------------+----------------------------+
| 150                                     | 2 hours                    |
+-----------------------------------------+----------------------------+
| 100                                     | 3 hours                    |
+-----------------------------------------+----------------------------+

5.  Flush affected line with potable water until total chlorine
    concentration in main is less than 1 mg/L (1 ppm) or the prevailing
    chlorine concentration in the water system is achieved. Follow the
    discharge requirements defined in Section 3.01 Discharge of this
    specification.

6.  After flushing, contact Sandia Construction Observer to arrange for
    final total chlorine concentration and bacteriological quality
    tests.

7.  After final total chlorine concentration and bacteriological quality
    tests have been completed, Sandia Construction Inspector will
    furnish disinfection report to Contractor. If water quality tests do
    not show compliance with water quality requirements repeat
    disinfection process until test results demonstrate compliance.

8.  Alternatively the "Slug Chlorination" procedure as defined in AWWA
    C651 may be followed for chlorination of the repair.

##### END OF SECTION