COOLTWR-Q Cooling Tower, Cleaning - Quarterly

                                             50 Tons & Under  Man Hours 6
                                                  50-500 Tons Man Hours 30
                                                500-1000 Tons Man Hours 50
                                               Over 1000 Tons Man Hours 60

This applies to all cooling towers and evaporative condensers.  Those located on
the mezzanine or lower levels and near fresh air intakes are particularly

Special Instructions:

1.  Perform work before seasonal start-up (unless system has remained clean and
    free of biodeposits), before seasonal shutdown, and quarterly during the
    cooling season.
2.  Review the Procedure for "Controlling Hazardous Energy
3.  Review manufacturer's instructions.
4.  Deenergize, tag, and lock electrical circuits.
5.  Review the Procedure for "Selection, Care, and Use of
    Respiratory Protection".
6.  Ensure that there are safe and sturdy ladders and platforms to perform the
    lifting and cleaning required.
7.  If biological growth is excessive, have a qualified water treatment
    specialist review your treatment program.
8.  Refer to information on chlorine use.
9.  Check the building's asbestos management plan to see if the wet deck panels
    have been tested for asbestos.  If they are suspect but have not been tested,
    have them tested.  Manage asbestos in accordance with the plan.

Items to Check & Initial Completion:

1. ___ Close building air intake vents within the vicinity of the cooling tower
       until the cleaning procedure is complete.
2. ___ Shut down, drain, and flush the cooling tower with water (check with state
       to determine if there are any restrictions on discharging the water).
       Isolate the cooling tower from the rest of the condenser water system
       where applicable.
3. ___ Clean the wet deck, remove all debris, and dispose of properly.  If the
       wet deck panels contains asbestos, follow the asbestos management plan for
       isolation, notification, work practice, and waste disposal.
4. ___ Inspect the tower, the tower basin and holding tank for sediment and
       sludge, and any biological growth.
5. ___ Using low pressure water hose or brushes, clean the tower, floor, sump,
       fill, spray pans and nozzles and removable components such as access
       hatches, ball float, and other fittings until all surfaces are clean and
       free of loose material.  Porous surfaces such as wooden and ceramic tile
       towers will require additional cleaning and brushing.  Clean cracks and
       crevices where buildup is not reached by water treatment.
6. ___ Clean all system strainers and strainer housings.
7. ___ Remove drift eliminators and clean thoroughly using a hose, steam, or
       chemical cleanser.
8. ___ Check fan and air inlet screens and remove any dirt or debris.
9. ___ Reassemble components, and fill tower and cooling system with water.
10.___ Monitor the water pH and maintain pH within a range of 7.5 to 8.0.  The pH
       can be monitored with litmus paper or a pH meter.

If a more thorough disinfectant cleaning is needed;

11.___ Add a silicate-based low or non-foaming detergent as a
       dispersant at a dosage of 10-25 pounds per thousand gallons of water in
       the system.
    a.___ Use a silicate-based low or non-foaming detergent such as Cascade ,
          Calgonite , or equivalent product.  (Trade names mentioned do not imply
          endorsement by the government).
    b.___ If the total volume of water in the system is not known, it can be
          estimated to be ten (10) times the recirculating rate (gallons per
          minute) or 30 gallons per ton of refrigeration capacity.
    c.___ The dispersant is best added by first dissolving it in water and adding
          the solution to a turbulent zone in the water system, such as the
          cooling tower basin near the pump suction.
    d.___ Contact a professional water treatment specialist for a dispersant
          which may be safely used without interfering with the operation of the
12.___ Add chlorine disinfectant to achieve 25 parts per million
       (ppm) of free residual chlorine.
    a.___ Maintain 10 ppm of free residual chlorine in water returning to the
          cooling tower for 24 hours.
    b.___ A swimming pool test kit may be used to monitor the chlorine.  Follow
          the manufacturer's instructions.  Test papers such as those used to
          monitor restaurant sanitizing tanks may also be used.
    c.___ Monitor every 15 minutes for two hours to maintain the 10 ppm level.
          Add chlorine as needed to maintain this level.
    d.___ Two hours after the slug dose or after three measurements are stable at
          10 ppm of free residual chlorine, monitor at two hour intervals to
          maintain the 10 ppm of free residual chlorine.
    e.___ Some kits cannot measure 10 ppm.  In this case dilute the test sample
          with distilled water to bring it within the test set range.
13.___ After 24 hours, drain the system (check with state to
       determine if there are any restrictions on discharging the water).
14.___ Adjust bleed, float, central valve for desired water level.
15.___ Open any building air vents that were closed prior to the
       cleaning of the cooling tower.
16.___ Implement an effective routine treatment program for
       microbial control.
17.___ Document all maintenance and cleaning procedures by date and
       time.  Record the brand name and the volume or weight of chemicals used.

Tools & Materials:

1.  Standard Tool Kit
    Plus Pipe wrenches to 24"
         Tubing cutters
         Flaring tool
         Small acetylene outfit
         Packing tool kit and packing
         3/4" socket set
         Crescent wrenches to 14"
2.  Pressure washer with hose and nozzle.
3.  Cleaning tools and materials.  Consult the Material Safety Data Sheets (MSDS)
    for hazardous ingredients and proper personal protective equipment (PPE).
4.  Appropriate chemicals and detergents (see guide card for details).  Consult
    the Material Safety Data Sheets (MSDS) for hazardous ingredients and proper
    personal protective equipment (PPE).
5.  Respirator with acid/gas/mist/HEPA filters.  For other chemicals, refer to
    the Material Safety Data Sheet (MSDS) for recommended respirator).
6.  Safety goggles.
7.  Waterproof clothing (while working inside a wet tower).
8.  Gloves (refer to MSDS on chemicals used for the type of gloves required).
9.  Rubber boots if wet.
10. Litmus paper or pH meter.
11. Swimming pool test kit.


Chlorine Compounds*           Percent Available   Weight per**
                              Chlorine            1,000 gallons

  Calcium, Ca(OCl)2 (HTH)              70         0.3 lb.
  Sodium, NaOCl
    Industrial grade                 12-15        1.5 lb.
    Domestic grade (bleach)           3-5         5.25 lb.

Potassium or sodium
chlorinated isocyanurates***          55-65        0.4 - 0.33 lb.
                                     66-90        0.33 - 0.25 lb.

*    Only those compounds commonly available in most communities are listed.
Other appropriate compounds may be suggested by a water treatment specialist.

**   These weights are approximate and are calculated to attain a free chlorine
level of 25 ppm in a theoretical cooling tower system with no biodeposits.  If
biodeposits are present, additional chlorine will be required.  Calculate the
volume of the entire cooling tower system, including the cooling tower water and
the recirculating water; it should be several times more than the holding
capacity of the tower.

***  Select only fast-release compounds, which are available in pellets, granular
or extra granular forms in the 55-65% available chlorine category.  Compounds
with higher percentages of available chlorines (66-90%) release more slowly; use
only the granular or extra granular forms.

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