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.01 General Owner Requirements and Design Intent
  1. The Professional shall design each HVAC water treatment application with all the required equipment, materials and labor to achieve the functional intent of effective and safe operation, high reliability, and minimizing maintenance costs on those piping systems.
    1. Construction documents hall include all drawings and specifications necessary to clearly define the scope of work for the contractor to furnish and install all the components and materials required to meet the functional intent above.
      1. Ensure details comply with manufacturer's installation instructions.
      2. Locate in safe and convenient area and provide convenient means for frequently inspecting and cleaning.  Maintain manufacturer's recommended clearance.
      3. Coordinate requirements between Specifications and Drawings.
    2. Guide Specifications are included at the end of this section.
  2. At University Park Campus, OPP's Water Treatment Contractor or authorized Mechanical Water Treatment representative shall be given adequate advance notification (minimum 4 weeks) in order to supervise the introduction of the chemical treatment into the system.
  3. The Professional shall discuss provisions of the chemical treatment program at Commonwealth Campus projects with the University.
  4. All closed systems (hot water and chilled water) shall be provided with chemical treatment.
  5. All open recirculating systems (cooling towers) shall be provided with chemical treatment.
  6. All steam boilers shall be provided with chemical treatment.
  7. Guidelines for the use of glycol are also covered in this section.
  8. Minimum requirements for flushing and cleaning of new and existing systems are covered in the Guide Specifications.

.02 Closed Systems Water Treatment (Hot & Chilled Water)
  1. Equipment: All closed loops shall have a Bypass Feeder (Pot Feeder) piped into the circulation line, so that chemical treatment can be introduced into the system.  A flow indicator shall be installed to show indication of flow through the bypass feeder.
  2. Equipment Installation: Bypass feeder shall be installed across the re-circulation pump to allow for a minimum 5 psi pressure drop.  The discharge side of the pump shall be piped to the bottom of the feeder and the suction side piped to the top.  This will allow an upward flow of material in the feeder.  The shot feeder shall be located at least 12 inches off the floor, and manual ball valves shall be conveniently located near the bypass feeder to isolate and drain the bypass feeder. One ball valves shall include a memory stop set to keep a trickle flow through feeder to keep seals wetted.
  3. Pre-operational Cleaner: All systems shall be flushed with water prior to chemical cleaning.  Use water meter to fill, record, and tag (permanent tag) the system with the actual system volume.  Chemical cleaner shall be added to remove grease, mill oil, organic soil, flux, iron oxide etc.  All terminal control valves and valves at end of runs (“dead legs”) shall be opened so that cleaner is circulated through the whole system.  After cleaning, all strainers shall be flushed, and strainer screens cleaned or replaced.  Once closed loop is chemically cleaned, system shall be dumped and flushed with water so that all cleaning chemical is removed from the system.
  4. Chemical treatment: Shall be an alkaline, buffered, nitrite-based corrosion inhibitor, maintained at proper levels to prevent corrosion to the system. 

.03 Open Re-circulating Systems Water Treatment (Cooling Towers) 
  1. Equipment:
    1. All towers (including Evaporative Condenser type Towers) shall be equipped with an automatic blowdown controller, LMI, model DC4000, or approved equivalent.  Controller shall have flame retardant, molded TPFE housing and clear polycarbonate cover that can be secured with a padlock.  Controller shall be capable of feeding chemicals 4 ways: Pulse, Percent of time, Limit timer, and Percent of bleed.  Controller shall have LED indicators for all functions and shall have a 4 to 20 mA output.  Controller shall be supplied with a flow assembly to include the conductivity probe as well as a flow switch.  The flow switch shall be capable of preventing the controller from operating the blow down valve or feeding chemical if no flow is indicated.  Flow assembly shall be able to be isolated by manual ball valves so that assembly can be repaired or replaced.
    2. The fresh water make-up line to the tower shall have an electrical contacting water meter, Carlon, model JSJ, or approved equivalent.  This water meter must be capable of sending an electronic pulse to the controller to allow the controller to feed chemical based on the volume of fresh water to the tower.   The water meter shall be installed with a by-pass that is capable of being valved off so that water can still feed the tower and meter can be taken out for repairs.
    3. Chemical feed pump shall be LMI, model P131-392SI, or approved equivalent capable of pumping 10 gal/day maximum.  Pump shall be supplied with an integral anti-siphon/priming valve.  All tubing shall be clear polyethylene.  Pump shall be capable of modulating its stroke and speed.  Pump shall have a liquid end construction of Polypropylene/Flourofilm/Polyprel.
    4. If the condenser water volume is greater than 800 gallons, a solid halogen feeder (brominator) shall be installed to provide a controlled distribution of tableted, approved bromine and chlorine donors.  The brominator shall have an integrally mounted flow meter for accurate feeding and manual valve with the capacity to adjust the flow from 0 to 5 gal/min.  A pressure relief valve shall be used on those applications where the brominator is used on a pressure discharge or if the unit will be used in with conjunction with a solenoid and timer.   For systems with less than 800 gallons, a simple water filter housing shall be provided for the feeding of the solid holagen.
  2. Equipment Installation:
    1. Blow down valve shall be installed so that the valve can be isolated by conveniently located ball valves so that blow down valve can be removed, repaired, and or replaced.  A Strainer shall be installed up stream of the blow down valve to catch any dirt or debris that may prevent the blow down valve from functionally properly.  Strainer shall be capable of easily being cleaned and replaced.
    2. The chemical inhibitor shall be injected into an area of high flow and shall use an injection nozzle that has a check valve to prevent the flow of condenser water into the chemical injection line.
    3. All new systems shall have a corrosion coupon rack installed, so that coupons can be used to help diagnose any potential corrosion problems.  The rack shall be located so that coupons can be easily removed and installed.
  3. Pre-operational Cleaner: All condenser water systems shall be flushed with water prior to chemical cleaning.  Use water meter to fill, record, and tag (permanent metal tag) the system with the actual system volume.  Chemical cleaner shall be added to remove grease, mill oil, organic soil, flux, iron oxide etc.  Once condenser water system is chemically cleaned, the system shall be dumped and flushed with water so that all cleaning chemical is removed from the system.  After cleaning, all strainers shall be flushed, and strainer screens cleaned or replaced.
  4. Chemical Treatment: Inhibitor shall be designed to control corrosion of all metals, as well as inhibit the formation of scale. The chemical inhibitor shall be a blend of organic inhibitors and dispersants that contain no molybate, zinc, or heavy metals.  The use of the chemical inhibitor shall be in compliance with all local discharge regulations.  The chemical treatment program shall maintain proper levels of chemical inhibitor to sustain a LSI of 2.5 to 3.0.   PH of the condenser water shall not be below 8.0 and not exceed 9.5.   Biocide program shall be limited to solid halogen feed chemicals. These chemicals shall be fed in a manor that prohibits the growth of bacteria, especially Legionella prevention. 

.04 Steam Boilers Water Treatment
  1. Equipment:
    1. The fresh water make-up to the feed water tank shall be softened to remove calcium and magnesium particles from the water.  The softeners shall be regenerated automatically based on a water meter. The unit shall be sized so that softener regenerates approximately twice per week.
    2. The feed water tank shall be sized to allow for a minimum of 10-20 minutes residence time of the feed water to allow sufficient time for pre-warming of the feed water.  The feed water tank shall be fitted with a stainless steel sparge line. The sparge shall be located on the bottom of the tank to allow for sufficient contact with the feed water.  Holes in the sparge line shall be positioned to the center of the tank away from the tank walls. The oxygen scavenger shall be fed directly into the feed water tank below the water line with a Stainless Steel injection nozzle.  The feed water tank shall have a factory-installed coating to help prevent corrosion on the tank walls.
    3. A conductivity controller, LMI, model DC-4000, or approved equivalent shall be used to maintain conductivity limits within the boiler.  Controller shall have flame retardant, molded TPFE housing and clear polycarbonate cover, which can be secured with a padlock. Controller shall have LED indicators for all functions and shall have a 4 to 20 mA output. The controller will actuate a motorized ball valve when conductivity reaches above the set point.  The controller shall then close the motorized ball valve when the conductivity goes below the deadband.  The controller must be easily calibrated and come with a high-pressure conductivity probe.  Controller shall be provided with a motorized ball valve and globe valve to prevent flashing.
    4. Two mixing tanks shall be provided: one for the dispersant and phosphate liquid chemical, another mix tank for the oxygen scavenger.  The mix tank pumps shall be relayed to the feed water pump so they are both activated when the feed water pumps are on.  Each mix tank shall have a mixer to allow suitable mixing of chemicals.  The water for the mix tanks shall be soft water, and if possible from either condensate or feed water tank.  Chemical pumps shall be sized to overcome the boiler pressure as well as pressure in the feed water line.  All connections from the chemical pump to the point of injection shall be hard piped, with check valves to prevent the feed/boiler water being pushed back into the chemical pump.
    5. Stainless Steel Injection nozzles should be used to feed chemicals into the feed water line (or feed water tank for the oxygen scavenger). The injection nozzle for the inhibitor shall be in the feed water line, and after the feed water pumps but as far as possible from the boiler.   Each injection nozzle shall be installed with an isolation valve in case any repairs are needed to chemical feed system.   Provide check valves on all chemical feed lines to prevent the feed water from pushing back into the chemical injection line.
  2. Pre-operational Cleaner:  (Boil out)  All steam boilers shall to be flushed with water prior to chemical cleaning.  Specially formulated, liquid boil-out solution containing inorganic and organic surfactant materials, iron sequestrates, and corrosion inhibitors shall be used.  The product shall be designed to remove oil, grease, and mill scale from new boiler surfaces and shall clean water-side surfaces that have become contaminated with oil or grease during service.
  3. Chemical Treatment:  The dispersant and inhibitor shall be liquid blend of polymeric dispersants, phosphate conditioning agents for control of deposit formation and improved iron and sludge dispersion.  Product shall be suitable for FDA/USDA regulated facilities. The dispersant shall be mixed and maintained in a poly mix tank with mixer and high-pressure pump.  This pump shall be activated whenever the feed water pumps are turned on.  These chemicals shall be injected into the feed water line down stream from the feed water pumps and as close to the boiler as possible.  Oxygen scavenger shall be a powdered sodium sulfite, used to protect the feed water tank, piping and boiler from dissolved oxygen attack.  The oxygen scavenger shall be mixed and maintained in a poly mix tank with mixer and pump.  The pump shall be activated whenever the feed water pump is turned on. A check valve must prevent any back flow to the pump from the feed water tank.

.05 Glycol Systems
  1. Equipment:  Glycol systems shall be equipped with a mix and fill tank with manual fill capabilities, hose bibb from domestic water for tank filling, and tank level alarm interconnected with the BAS.
  2. Equipment Installation:
    1. Do not direct-connect makeup lines to glycol systems.
    2. Glycol systems should be configured so that small sections of the system can be isolated with valves and drained to a local floor drain.  Alternatively, a tank should be installed at the glycol system fill point that is large enough to capture the entire system’s contents.
  3. Pre-Operational Cleaning
    1. All systems that are to be filled with a glycol solution shall be cleaned as outlined under “Closed Systems Water Treatment (Hot & Chilled Water)” above.
  4. Chemical Treatment
    1. Take reading of Glycol concentration in system.  Required concentration may vary depending on the specific application.  Refer to concentration and tolerances in the associated specification.
    2. Shutdown circulation pumps prior to adding additional glycol.
    3. Open air vents at top of system to allow air to escape as system fills.
    4. Use Glycol pump and add Glycol mixture until desired pressure is achieved.  (If correct pressure level is unknown, use 5 lb. Per floor as rule of thumb).
    5. Turn on pumps and circulate system mixture.
    6. Continue to bleed air until system is free of air.
    7. Close valves to air vents once all air is out of system.
    8. Recheck Glycol concentration and system pressure.  Add additional Glycol or water if needed to bring system to correct concentration level and correct pressure.
  5. If you are not sure of proper fill procedures or how to determine correct concentration of mixture, please contact Mike Kelleher or one of the Environmental System technicians.

.06 Side Stream Filters
  1. Closed Systems (Heating and Cooling)
    1. All new closed circulating systems shall have a side stream filter.  This shall include all heating hot water, chilled water, dual temperature, and glycol solution piping distribution systems.
  2. Open Re-circulating Systems (Cooling Towers)
    1. All new open circulating condenser water systems shall have a side stream filter.
    2. Equipment:  All open circulating systems shall have a side stream filter piped into the circulation line, so that suspended solids can be removed from the system.  All filters shall be bag filter type so that bags can be either taken out and cleaned and reused or replaced.  All bags shall be 100 micron size.  Filters shall be sized to handle a minimum of 10% of the system flow (gallons per minute) that the circulating pumps are capable of producing.
    3. Filter Vessel:  Material of construction shall be 304 Stainless Steel, with removable cap and swing-out bolts with eyenuts.  Units shall be capable of 150 psi working pressure.  Pressure gauges shall be mounted so that pressure can be read on both sides of the filter. Gauges shall be capable of showing pressures from 0-100 psi.
    4. Filter Bags:  Construction shall be polyester fiber, felt material.  Bags shall be capable of operating temperatures between 275 – 325 ?F.  Bags shall be a standard size to fit into the filter vessel.
    5. Equipment Installation:  Filter shall be installed across the circulation pump to allow for a minimum of a 5 psig pressure drop across the filter unit.  Manual valves shall be conveniently located near the filter to isolate, balance, and drain the filter.  A ball valve shall be installed in the inlet pipe to the filter.  A combination shut-off/balancing valve shall be installed in the discharge pipe from the filter, and set for 10% system flow at all times.  The drain line shall be piped to the sanitary sewer.
  3. Manufacturer (open loop only, refer to specification for closed loop)
    1. Filter Vessels:  Filter Specialists, Inc.
      1. BFN 11:
        1. 2” inlet and 2” outlet
        2. Uses one #1 bag
        3. Maximum 100 GPM water flow
      2. BFN 12:
        1. 2” inlet and 2” outlet
        2. Uses one #2 bag
        3. Minimum 4.4 square ft bag surface area
        4. Maximum 220 GPM water flow
      3. BFN 13:
        1. 1” inlet and 1” outlet
        2. Uses one #3 bag
        3. Minimum 0.5 square ft bag surface area
        4. Maximum 25 GPM water flow
      4. BFN 14:
        1. 1” inlet and 1” outlet
        2. Uses one #4 bag
        3. Minimum 1.0 square ft bag surface area
        4. Maximum 45 GPM water flow
    2. Filter Bags:  Filter Specialists, Inc.
      1. Bag Size #1:
        1. Minimum 2.0 square ft bag surface area
        2. Minimum 2.1 gallon bag volume
        3. 7” diameter x 16.5” long bag
      2. Bag Size #2:
        1. Minimum 4.4 square ft bag surface area
        2. Minimum 4.6 gallon bag volume
        3. 7” diameter x 32” long bag
      3. Bag Size #3:
        1. Minimum 0.5 square ft bag surface area
        2. Minimum 0.37 gallon bag volume
        3. 4” diameter x 8.25” long bag
      4. Bag Size #4:
        1. Minimum 1.0 square ft bag surface area
        2. Minimum 0.67 gallon bag volume
        3. 4” diameter x 14” long bag

.07 Water Analysis and Testing for Closed Loop Systems
  1. The purpose of this procedure is to outline the steps used to test any closed re-circulating loops on campus, (chilled water, hot water, glycol, etc.).  This procedure also outlines many implications of what might happen if a closed loop system is not properly chemically treated.
  2. The following tests will be run on each closed loop:
    1. Visual Inspection:
      1. After taking a sample of the water, the water analyst will visually inspect the water and see how clear the water is.  If the water is relatively clear the water analyst may continue with the remaining tests.
      2. If the water appears cloudy and dark brown in color, the analyst will check to see if any filtration system is on the closed loop.  If so, the filter may need to be changed or backwashed.
      3. The analyst may choose to take a water sample and let it set for a couple of hours.
        1. After the water sample had time to sit for a couple of hours, if the water starts to clear up and a deposit forms on the bottom of the container – this indicates the water contains high levels of suspended solids.
        2. If a filter is not already on the system the analyst may choose to recommend installation of some type of filter to help clear up the water.
        3. Suspended solid loading in a closed water circulating loop can lead to problems, the solids can settle out in low flow areas.  The resulting deposit can cause corrosion and provide conditions that promote bacteria growth.  Some bacteria can absorb the chemical inhibitors used to prevent corrosion, which will still leave the system untreated, even though chemical has been added.  Deposits can act as an insulator preventing good heat transfer.  Not maintaining good heat transfer will increase energy costs to any system.
    2. The analyst may choose to run an iron test using the Hach colorimeter based on the degree of water discoloration.
      1. The water analyst should record the readings so comparisons can be made to previous readings to help diagnose the system in the future.
      2. If the dissolved levels of iron are greater than 30 ppm, the analyst will recommend to have the system flushed and chemically cleaned.
      3. High levels of dissolved iron left in the system can lead to more corrosion problems, leaks, poor heat transfer efficiency, as well as bacteria problems.
    3. Conductivity:  Every system will have the conductivity measured.
      1. After reading the conductivity with the conductivity meter the analyst will record the current reading and review past readings.  A conductivity reading higher or lower than the previous reading generally indicates a number of situations.
        1. If the conductivity reading is higher than previous readings, this indicates that something has been added to the system, for example the water analyst may have added chemical to the system during the last service.  If chemical was not added and the conductivity has increased dramatically, the water analyst may need to check for potential areas of contamination.  If conductivity is above 5000 mmhos, it may be recommended that the system be drained and refilled with treated water.
        2. Extreme levels of high conductivity can lead to some types of corrosion problems.
        3. If the conductivity reading is lower than previously recorded, this indicates that some water was lost from the system.  (Most likely the chemical inhibitor levels will be low as well).  The water analyst may need to check with area maintenance to see if any work was done on the system to explain the water loss.  If the closed system inhibitor (NT403) has been added and conductivity levels have not risen from the last visit, this may indicate the system has a continuous leak.  If the conductivity levels remain low (approximately the same conductivity as the raw water), the analyst will need to check for leaks and report the problem to area maintenance.
        4. Running at low conductivity may cause a number of problems.  First, it is a huge waste of water, chemicals and energy.  Secondly, it may damage equipment.  Fresh water makeup brought into a leaking hot water boiler loop will deposit certain types of deposition on the  boiler tubes.  If the leak is not caught in time the tubes could fail and the boiler may need to be re-tubed.  Leaks in a chilled water system can lead to scale build up in heat exchangers and chillers, lowering the equipment efficiencies  and raising the Universities energy costs. It may also promote corrosion and may increase the chance of piping failures.
    4. Nitrite Test:  Each treated closed loop will be tested for Nitrite levels.
      1. The water analyst will check past history of the nitrite levels for each system being tested.  If nitrite levels are lower than what is required, the water analyst will add the appropriate amount of closed system inhibitor (GE Betz NT403) to the system.  The water analyst should record the approximate amount of closed system inhibitor added to the system.  Not maintaining the proper nitrite levels will lead to corrosion problems, which may require the system to be repaired or re-piped.  It may also lead to iron oxide deposition in piping causing low flows and reduced heat transfer efficiencies.
      2. If the nitrite levels remain low after adding the closed system inhibitor and conductivity has remained the same.  The analyst may choose to run a bacteria test on the system in question by using the GE Betz BioScan.
        1. If the readings for the closed system is above 25 RLU’s the water analyst may request that the system be flushed.
        2. If the water analyst discovers that the system does have a bacteria growth problem, he may choose to recommend the closed loop system be drained, refilled and treated with a closed system biocide as well as a bio-dispersant.  After the system has circulated for a couple of days the system should be dumped and refilled with fresh water retreated with closed system inhibitor (GE Betz NT403).
        3. Within 2 weeks of retreating, the water analyst should retest the closed loop system for bacteria levels again, to verify the bacteria growth problem is gone.  Some bacteria can feed off the nitrite in the closed system inhibitor and will in turn promote corrosion was well as increase the chance of slimes and biomasses growing within the system.  These bacteria could reduce the efficiencies of the equipment and could cause health and safety issues for employees and the general public.
      3. If the nitrite levels are high, it is not recommended to drain the system.  Rather, leave the system as is and record nitrite levels.  Additional chemical will not hurt the system.
      4. The analyst may choose to run a sulfate reducing bacteria test and may need to contact the GE Betz water treatment representative to do so.
    5. PH Measurement:  Every closed loop will have the pH tested and recorded.
      1. The water analyst will review the previous pH reading s and see if any big pH swing is evident.
        1. The pH of the closed loop should always be higher than the make up water pH.
        2. The pH of a closed loop should never be below 7.0.  If this ever arises, the closed loop should immediately be drained and retreated.  Any pH below 7.0  is considered to be a corrosive environment.
        3. It is important to have a properly calibrated pH meter.  If the meter is not functioning properly the results may not be helpful in any system diagnosis.
      2. If the pH reading has dropped dramatically from the previous service visit, it would indicate that there might be a bacteria growth problem.  Refer to the Nitrite Testing section of this procedure for testing and dealing with the potential of bacteria growth.
      3. If the pH reading is high (above a pH of 11) the system should be drained, refilled and retreated with closed system inhibitor.  Certain types of corrosion can occur at high pH levels.
    6. Glycol:  Each glycol system should have the glycol measured using a refractometer.
      1. This reading will indicate the level of freeze protection the closed loop is treated for.
      2. If lower than what is required for the system, the water analyst will contact Central Services for glycol addition.

.08 Water Treatment Test Control Limits
  1. Condenser Water
    1. 6 to 9 ppm of Phosphonate
    2. 0.5 to 1.0 ppm of Chlorine Residual
    3. 2.5 cycles of concentration
  2. Closed Loop Chilled Water System
    1. 300 to 600 ppm of Nitrite
  3. Closed Loop Hot Water System
    1. 600 to 900 ppm of Nitrite
  4. Glycol Systems
    1. Refer to concentration and tolerances in the guide specification.
  5. Hot Water Boilers
    1. 600 to 900 ppm of Nitrite
  6. Steam Boilers
    1. 30-60 ppm of Sulfite
    2. 30-60 ppm of phosphate
    3. 3000-4000 mmhos of neutralized conductivity

.09 Guide Specifications
  1. Design Professional shall carefully review and edit the guideline specifications below, adapting them as needed to achieve application-specific, fully developed specifications for each project.
  2. These shall be edited using the process described in the instructions contained at the beginning of the document.  Proposed modifications shall be reviewed with OPP staff.
  3. Finalized version shall be included in the project contract documents.  Use of other specifications is not acceptable.

    DocumentVersion DateDescription
    232500 HVAC WATER TREATMENT - CLOSED SYSTEMS - GUIDE SPECIFICATIONMarch 8, 2017OPP minimum specification requirements for HVAC Water Treatment for Closed Systems
    232500 HVAC WATER TREATMENT COMMONWEALTH - CLOSED SYSTEMS - GUIDE SPECIFICATIONMarch 8, 2017OPP minimum specification requirements for HVAC Water Treatment for Closed Systems for Commonwealth 

 

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