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Chilled Water Bridge

A specification of an item in this or any other sections shall not relieve Contractor from providing all items, articles, materials, operations, methods, labor, equipment and incidentals necessary for a complete and functional system.

Where size for a pipe segment is not indicated, the pipe segment size shall be equal to the largest pipe segment to which it is connected. Transition to smaller size shall occur on the side of fitting where smaller size is indicated.

All pipe, valves, fittings and pumps shall be installed as indicated on the drawings and according to the manufacturer’s instructions and installation drawings. All welding shall be performed to meet ASTM B31.1 unless noted by designer as otherwise.

General Locations and Arrangements Drawings (plans, details, schematics, and diagrams) indicate the general location and arrangement of the piping systems. Location and arrangement of piping layout shall take into consideration pipe sizing, friction loss, pump sizing, maintenance accessibility and other design considerations. So far as possible, install piping as indicated.

Design Note: Design of the bridge piping shall place bridge inside mechanical room and install bridge controller cabinet, all instruments, valves and meter between building isolation and utility isolation valves, excluding the end of line differential pressure transmitter.
The Engineer must approve the contractor performing building piping work. Submit contractor qualifications and references for five (5) similar projects performed in the last 5 years. The contractor must also meet the following minimum requirements:

  • Performed a minimum of three (3) institutional building piping installations within the last 5 years.
  • Has been in the institutional building piping business and has been performing this type of work for a minimum of 5 years.
  • Is licensed to perform work in the State of North Carolina.
Submit shop drawings for all pipe sizes including, but not limited to, the following:

  • Pipe: ASTM/ANSI number, grade if known, class, type, wall thickness, material.
  • Fittings: ASTM/ANSI number, grade if known, class, type, wall thickness, material.
  • Flanges: ASTM number, grade, class, type, material.
  • Isometric drawings showing routing, sensor location, valve location and hanger locations.
  • Test Pressure and media.
  • Pipe cleaning method.
  • Valves: manufacturer cut sheets, size, materials, actuator size, pressure rating.
  • Pumps: manufacturer cut sheets, pump curves, including design capacity and head, motor cut sheets, pump base design, pump installation requirements, pump manufacturers alignment specifications, flexible coupling design and cut sheet.
  • Welder certifications.
  • Thermometer: manufacturer cut sheet, size, range.

Install mag meter, supplied by the University, as per flow diagram and manufacturer installation requirements. The preferred meter installation is in horizontal pipe runs. For a meter being installed in same size bridge piping, there shall be a minimum of five (5) pipe diameters before the meter and two (2) pipe diameters after the meter. If installing smaller meter than the bridge piping or any fittings adjacent to the meter, have four (4) pipe diameters between the meter flanges and the reducers or fittings on both sides of the meter. For horizontal installation, the probes inside the meter must be installed in the three o’clock and nine o’clock positions, with the control read-out on the top at the 12 o’clock position. The meter must not be installed downstream from the control valve. The meter must not be installed in the highest point of pipe system.

Control Valves

Manual Utility and Building Isolation Valves

Use high performance butterfly valves. The valve shall have a lugged wafer style body of carbon steel or ductile iron rated for ANSI class 150 service. The seat material shall be fluoropolymer-based blend with no fillers, nor PTFE filled. Disk and shaft shall be 316 Stainless Steel construction. Shaft shall be full-length. Stub shafts are NOT allowed. Disk to shaft connection shall be non-shear tangential pinning. Disk shall be offset from the shaft centerline. The valve shall have upper and lower shaft bushing/bearings of a 316 stainless steel carrier and PTFE liner. Shaft seal shall be multiple rings of V-flex style PTFE packing with 316 stainless steel packing- ring.

Approved Manufacturers: Jamesbury, Milwaukee, or approved equal

Pump Isolation Valve

Valves shall be full lug type permitting removal of downstream piping while using valve for system shut-off. Bi-directional dead-end pressure rating to be a minimum of 150 psig with no downstream flange/piping attached. Standard applications shall use 10-position lever operators for valve sizes 5” and smaller, gear operator for larger sizes.

Approved Manufacturers: Nibco, Apollo, Milwaukee, Jamesbury, or approved equal

Valve Installation

Install butterfly valves as shown on plans, details and according to valve manufacturer’s installation recommendations.

Valves may be used to facilitate the fit-up of weld neck flanges, but the valve must be removed before the flanges are welded. During fit-up, metal pancakes or solid pieces of gasket material shall be used to ensure that valve is not damaged from sparks or spatter.

Valves with gear operators or actuators are to be installed with stems at or above centerline wherever possible, but in no case with the stems straight down. Valves with actuators and position indicators shall be installed so that the indicator is visible from the floor. Any valve installed with reducers nearby must have appropriate spacing to remove any bolt without pipe disassembly.

Before tightening flange bolts, adjust the disc of the valve to the full-open position. Tighten bolts to specification in crisscross pattern. After tightening, rotate disc to closed position to assure proper operation.

After piping systems have been pressure tested and put into service, but before final adjusting and balancing, inspect valves for leaks. Adjust, replace packing or replace valves to stop leaks.

Gear Operator

Provide gear operator for manually operated butterfly valves 6” and larger.

Chain Wheel Operators

Provide chain operators for manually operated butterfly valves 6” and larger, located more than 8 ft. above equipment room floor.

Cast iron or ductile iron adjustable sprocket rims and chain guides are required. Use galvanized or brass chain and chain closure links to form continuous loop of chain at each operator.

Ball Valves

Ball valves for use in chilled water systems must have a performance rating of CWP 600psi with two (2) piece design. Provide valve neck extensions of sufficient length to allow for insulation. Three (3) piece valves are NOT allowed.

Approved Manufacturers: Apollo 70-100 series or approved equal

Check Valves

Check valves used for Duplex pump system should be 150 Class Dual Disc Wafer Style. Check Valves for the Pump Bypass should be 150 Class flanged swing check.

Remove scale, slag, dirt, and debris from both inside and outside of piping and fittings before assembly. Install valves, control valves and piping specialties, including items furnished by others, as specified and/or detailed. Refer to drawings and/or manufacturer’s recommendations. Use fittings for all changes in direction and all branch connections. Mitered ells, welded branch connections, notched tees and “orange peel” reducers are NOT allowed. Weld-o-lets® may be used in lieu of fittings for branch take-offs from mains 2” or larger provided that the branch take-offs are two (2) or more sizes smaller than the main. Do not use “stub-ins” for making pipe connections.

Thread-o-lets must be used at vent and drain connections, thermowells and/or other instrument locations. Materials of Weld-o-lets® and Thread-o-lets® shall match the material of the piping. All holes shall be made with a drill bit or hole saw. Holes may NOT be cut with a torch.

Reducers in horizontal piping shall be the eccentric type with the top level. Reducers in vertical piping shall be concentric. All reducers must be installed to allow bolt installation and removal after all equipment is in place.

Provide drain valves at all low points and vents at high points of piping systems (even if not shown on drawings) for complete drainage of systems. This includes, but is not limited to, all low points, bases of all risers, at each branch take-off and between isolation valves. See drain and vent sizing chart on the next tab.

Use only new materials, free from defects, rust, scale and guaranteed for services intended.

Pipe

All Chilled Water piping lines shall be seamless, standard weight, Schedule 40 black steel ASTM A53 GR B. Chilled Water pipes larger than 2” shall have welded joints. Threaded nipples shall be Schedule 80 black steel.

Welded Fittings

Pipe fittings shall be standard weight Schedule 40 black steel. Use only long radius elbows.

Flanges

ASTM A105, ANSI B16.5, hot forged steel, weld neck pattern flanges are to be used whenever possible. Slip-on flanges are not allowed without Chilled Water Director’s prior consent. Bore dimension of weld neck flange shall match inside diameter of connected pipe. Full face gaskets must be used with flat face flanges, and ring-type gaskets must be used with raised face flanges. For example, pump connections and strainers. Valves may be used to facilitate the fit-up of flanges; but valves must be removed before the flanges are welded. During fit-up, metal pancakes or a solid piece of gasket material shall be used to ensure that the valve is not damaged from weld sparks or weld splatter while tacking flanges.

Bolts/Fasteners

Bolts and nuts shall be Grade 5 NC. Bolts, bolt studs, nuts and washers shall have zinc/cadmium plate finish. Note: Threaded rods are not allowed as fastening elements. If studs are to be used, they are to be individually factory stamped with grade identification.

Drains/Vents

Provide drain valves at all low points and vents at high points of piping systems (even if not shown on drawings) for complete drainage and venting of systems between isolation valves and elsewhere as noted on flow diagram, plans and details. Where the vent lines cannot be reached from floor level, or be easily reached using an 8’ ladder, the vent lines shall be run with a second isolation valve accessible from floor level and the discharge to be run to the sanitary sewer system.

Connections to the pipe shall be made using thread-o-lets and Schedule 80 nipples. For drains and vents, provide ball valves of type specified above and size specified below with hose thread adapter and cap.

Pipe Size Drain Size Vent Size
6” and less Minimum ¾” Minimum ½”
8” to 10” Minimum 1” Minimum ¾”
12” to 14” Minimum 1¼” Minimum ¾”
16” and greater Minimum 2” Minimum ¾”

Use ¾” Thread-o-lets® for the installation of temperature sensor and thermometer thermowells. Temperature sensors are to be installed on the sides of horizontal run piping. Position the outlet connection so the sensor has enough room to be installed without damage and removed for calibration.

Differential Pressure Sensor/Transmitters

Thread-o-lets® are to be used for differential pressure sensor/transmitters. Taps are to be a minimum ½” with ½” valve reduced down to 3/8”. Taps should be on the side of the horizontal run pipe at the three o’clock or nine o’clock position to avoid sediment and/or air trapping. After the valve, lines shall be run in a manner so as not to trap air. Compression fittings allowed only at the transmitter and isolation valves. Isolation valves to be ball valves installed at DP taps. The tubing for differential pressure instrument shall be installed with continuous runs from isolation valve to transmitter connection.

Pump/Strainer Differential Pressure Gauge

Provide a single pressure gauge connected to both sides of strainers, pump suction, pump discharge, and pump discharge after check or balancing valve (whichever is farthest downstream). Gauge is not to be connected to the system through a manifold system where each branch can be isolated, and pressure relieved from the gauge. Thread-o-lets® are to be ½” when connecting to pump piping.

Gauges should be 2-1/2” face, liquid-filled with maximum reading of 150 psi (high readings may be required at certain parts of campus, like Dean Smith Center). Install gauges with ½” or ¾” Thread-o-let®, bushing ½” Schedule 80 carbon steel nipple and ¼” ball valve.

Approved Manufacturer: Weksler or other approved equal

Control Air

Compressed air tubing must be copper or stainless steel from isolation valve to instrument or control valve. Tubing shall be run in a manner that will not promote trapping of water. Each end-user of compressed air shall have individual isolation valves and control valves with positioners, which shall have filters and separators with fully automatic drains. Compressed air lines must be sized for all components using their delivery rates. Branch lines shall be 3/8” minimum with no more than five (5) feet from the isolation valve to the pressure set or solenoid. If more than two (2) components are being served, the main line size should be run to the last component served.

Install two (2) thermometers, two (2) temperature sensors, flow meter, pressure differential transmitter with local digital readout and remote pressure differential transmitter as per flow diagrams between the four (4) bridge isolation valves.

All welding shall be performed to meet standard ASTM B31.1 unless noted by designer as otherwise. Inspect pipe and pipe fittings for roundness before they are fit-up or set in place. Properly clean fittings; clean and bevel plain ends of steel pipe before fit-up.
All welding shall be performed by a certified welder who is regularly engaged in welding of piping systems. All welder’s certifications must be on file with the contractor and available to Owner upon request. Owner’s representative will perform any observations deemed necessary before, during, or after fabrication to assure, to the Owner’s satisfaction, the proper welding is provided. Owner reserves the right to perform independent testing of welds. If results of such examination are unsatisfactory, Owner reserves the right to stop in progress welding work, without any cost to Owner, until a satisfactory resolution with Owner is reached.

Unless otherwise indicated, welding shall be done using only the following processes:

  1. Shielded Metal Arc Welding (SMAW), also known as “stick” welding
  2. If approved, Gas Tungsten Arc Welding (GTAW), also known as “TIG” and Heliarc welding.

For any welding performed after the pipe cleaning is completed, “TIG” welding is required. For repairs and replacement of existing pipe, pipe will be hand cleaned prior to installation and root pass will be installed using “TIG” process. This is for small sections of piping and repairs.

Backing rings (chill rings) or consumable inserts are not allowed, unless specifically requested by Owner and/or Engineer.

Ground clamp must be placed as close as possible to work, to ensure no damage to electronic equipment in this system or elsewhere in the mechanical room.

Repair any welds not meeting the acceptance criteria at no cost to the Owner.

Hanger and Support Spacing

Space pipe hangers and supports for steel pipe in accordance with the following schedule, with exceptions as indicated herein:

Pipe Size Max Spacing
Up through 1 ¼” 7’-0”
1 ½” 9’-0”
2” 10’-0”
2 ½” 11’-0”
3” 12’-0”
4” 14’-0”
5” 16’-0”
6” 17’-0”
8” 19’-0”
10” 22’-0”
12” 23’-0”
14” 24’-0”
16” 27’-0”
18” 28’-0”
20” 30’-0”
24” 32’-0”
30” 33’-0”

Spacing less than indicated above may be required to conform with building structure design and/or loading limitations. If pipe size changes between support points, maximum spacing shall be based on the smaller pipe size. Install hangers and supports to bear on outside of insulation. Place hangers and supports within one (1) foot of either side of each fitting, such as elbow and tee, each valve, strainer, and other piping specialty for piping 4” and above.

Hanger Rods (Metallic)

Rods shall have electro-plated zinc or hot dipped galvanized finish.

Bolts, Nuts, Studs and Washers

Bolts, nuts, studs and washers shall have electro-plated zinc or hot dipped galvanized finish.

Installation

Support all piping from building structural members using beam clamps, ceiling plates, wall brackets, or floor stands. At no time shall hangers and supports overload building structural members. Fasten ceiling plates and wall brackets securely to structure and test to demonstrate adequacy of fastening.

Coordinate hanger and support installation to properly group piping of all trades.

Suspend hangers by means of hanger rods. Perforated band iron or flat wire (strap iron) is not allowed.

Piping shall not be supported by other piping, ductwork, or conduit.

Pipe hangers or supports are not allowed to penetrate vapor barrier of pipe insulation.

Install adequate supports during erection of piping so as not to over stress either piping or equipment to which piping is connected.

All insulation material shall be delivered to the project site in original factory packaging and stored so materials are protected from moisture and weather, including long exposure to UV sunlight.
Install Expanded Polyisocyanurate Foam (Polyiso) or Phenolic Foam insulation as per manufacturer’s specifications. If conditions demand, an alternate insulation may be used after approval by Chilled Water Director.

Insulation

  1. Expanded Polyisocyanurate Foam is a continuously molded rigid foam insulation meeting requirements of ASTM C-591, with thermal conductivity of not more than 0.19 at 75°F mean temperature, minimum density of 2 lb/ft3, minimum compressive strength of 24 psi, maximum water vapor transmission of 4.0 perm-inch, and suitable for temperature of +300°F down to -297°F. Insulation shall have a factory- applied jacket with self-sealing lap (SSL). HiTHERM HT-300 or approved equal.
  2. Phenolic Foam insulation by ITW Trymer® Supercel Phenolic, Dyplast DyTherm® Phenolic or Resolco Insul-Phen® is an acceptable substitute provided insulation characteristics equal or exceed requirements specified for polyisocyanurate above.

Insulation Jacket

  1. Saran Vapor Retarder Film™ with self-sealing (SSL), ASTM C-755 and C-1136, 6 mil thickness. Permeance shall not exceed 0.01 perms, equal to Dow™ Saran 560. Elbows, fittings, valves, and butt joints shall be wrapped with three (3) layers of Dow™ Saran 520 Vapor Retarder tape.
  2. Provide PVC jacket over Dow™ Saran tapes for exposed elbows, fittings and valves.
All insulation installation methods shall be performed in accordance with the latest edition of National Commercial and Industrial Insulation Standards published by MICA (Midwest Insulation Contractors Association) and manufacturer’s installation instructions, except as modified in this Section of Specifications.

Install all products with good workmanship, smooth and even surfaces. Use full-length factory furnished material where possible. No scrap piecing is allowed. Apply insulation only on clean, dry surfaces after all rust and scale have been removed and hydro testing has been completed.

Pipes 1-1/2” and smaller, specified pipe insulation and vapor barrier with jacket shall be continuous through hanger or support locations and protective shields shall be provided to protect insulation from compressing or being crushed.

Pipe 2” and larger, where manufactured pre-insulated pipe supports are used at hanger or support locations, extend insulation and vapor barrier to insulated pipe supports. Use 3” wide vapor barrier tape at pipe support. Contractor shall be responsible for continuity of vapor barrier at insulated pipe supports.

Piping 6” or larger shall use 1-1/2” insulation. Below 6”, the insulation shall be 1”.

Contractor fabricated anchors, secure insulation directly to pipe surface and extended from insulated pipe four (4) times insulation thickness. For pre-insulated anchors, cover entire surface of anchor with elastomeric foam insulation (Armaflex or equal). Take special care to assure a good vapor seal at anchor.

Identify piping with marker system. Markers shall be “snap-on” or “strap-on” type depending on applicable pipe size. Install pipe identification on all Chilled Water piping. Pipe should be identified at least once every 25 feet, at each branch off line, each access door or panel, each valve and where exposed piping passes through walls/floors. Place flow directional arrows at each pipe identification location.

Markers to comply with ANSI A13.1 for color, length of color field and include flow directional arrows integrated into the marker.

For insulated pipe systems, lettering sizes are as follows:

    • Pipes up to 1 inch: use 1-inch letters
    • Pipes 1-1/4” to 2 inches: use 2-inch letters
    • Pipes 2-1/2” to 6 inches: use 3-inch letters
    • Pipes over 6 inches: use 4-inch letters

Pipe identification labels shall be abbreviated as follows:

Piping System Identification Paint Color
Chilled Water Supply CHS Rustoleum Blue 925 Safety
Chilled Water Return CHR Rustoleum Blue 866 Marlin
Condenser Water Supply CWS Sherwin Williams Green 4085 Safety
Condenser Water Return CWR Sherwin Williams Green MC25 Marsh
Coordinate pressure test with Engineer and Chilled Water Engineer, in writing, at least 7 days in advance of its occurrence and conduct tests in presence of Engineer. Engineer has right to wave requirement for witnessing testing. If Engineer is not present, conduct test in presence of Construction Manager’s Representative. Representative shall sign report verifying results. Contractor shall notify Engineer of all tests to be performed.

Conduct pressure test prior to flushing and cleaning of piping systems. No systems shall be fully insulated until it has been successfully tested. Prior to the test being completed, insulation can be installed if it does not cover welds, joints, fittings or penetrations.

Conduct hydrostatic (HYDRO) test at 150psig with test medium of water unless otherwise indicated. For hydrostatic tests, remove air from piping being tested by means of air vents. If outlets are not available at high points, the Contractor shall make the necessary taps at points of highest elevation before the test is made.

The testing of the system shall be performed by a contractor experienced in pipe testing. The Contractor shall perform all phases of testing. S/he will provide supervision, pumps, calibrated gauges, instruments, test equipment, temporary piping and personnel required for tests, removal of test equipment and draining of pipes after tests have been successfully conducted.

Contractor should perform preliminary pressure test prior to witnessed record test to verify system will pass record test on first attempt. Pressure test may be made of isolated portions of piping systems to facilitate general progress of installation. Any revisions made in piping systems require re-testing of affected portions of piping systems. No pressure drop shall occur during test period. Any pressure drop during test period indicates leakage. If leaks are found, repair with new materials and repeat test; caulking or “JB Weld” is not acceptable.

Measure and record test pressure at high point in system. Where test pressure at high point in system causes excessive pressure at low point in system due to static head, portions of piping system may be isolated and tested separately to avoid undue pressure. However, every portion of piping system must be tested at the specified minimum test pressure.

Minimum test time shall be four (4) hours plus such additional time as Chilled Water Engineer may require insuring there are no air pockets in line, no broken pipe or defective materials in the line and no leaking joints.

Repair system and retest all portions of system when equipment or systems fails to meet minimum test requirements.

Submit results of each test for review to Engineer within three (3) days of test occurrence.

UNC Chilled Water must approve the contractor performing the cleaning or supplying the chemicals. Submit contractor qualifications and references for five (5) similar projects performed within the last five (5) years. The contractor must also meet the following minimum requirements:

  • Performed a minimum of three (3) institutional pipe cleanings within the last 5 years,
  • Employed in the chemical pipe cleaning or treatment business, performing this type of work for a minimum of five (5) years,
  • Licensed to perform work in the State of North Carolina.
Note: The Contractor shall provide their flushing plan to the designer at least two (2) weeks before flushing is planned to begin. The designer shall verify the temporary piping is adequately sized to attain the required velocities in the piping.

Submit the following information:

  1. Detailed plans on performing the flushing and cleaning. The plan must include a strainer with opening no larger than 0.125 inches. The strainer will be removed several times during the process for inspection.
  2. Chemicals, description of chemicals, their composition and function
  3. Safety Data Sheets (SDS) for all chemicals to be used for pipe cleaning must be submitted to the Owner, including written notice of Owner’s responsibility to notify their employees of the use of those chemicals.
  4. Capacities/Ratings
  5. Materials of construction
  6. Dimensions and weights
  7. All other appropriate data

Approved Chemical Manufacturers: Nalco or approved equal

Use cleaning compound, similar to Nalco 2567, to remove organic soil, hydrocarbons, flux, pipe mill, varnish, pipe compounds, iron oxide, and lite deleterious substances – with or without inhibitor, suitable for system metals without deleterious effects. Cleaner shall contain no trisodium phosphate.
Provide bypass type batch feeder to receive chemicals in liquid or pellet form. Remove old feeder from ME room when process is completed.
Designer note: Designer shall provide contractor with flushing flow needed to ensure the velocities in any section of piping exceeds 3.0 fps. This will be the minimum flow required to properly flush the entire system. Contractor shall isolate the building chilled water pumps and supply temporary pump and piping to perform flushing. Ensure that the temporary 1/8” mesh strainer is in place before the cleaning begins.
Designer and Contractor note: The building chilled water pump may be use IF: approved for use by the Chilled Water Director, the pump has been aligned and verified by Chilled Water personnel, VFD has been certified by VFD supplier and checked by Chilled Water personnel, flow is deemed sufficient by the designing engineer, is requested in writing two (2) weeks in advance and a pump inspection is scheduled with the pump manufacturer’s service representative to determine no degradation is found. At a minimum the seal will be replaced during reassembly.

The Contractor shall install temporary piping to facilitate the flushing at the ends of piping runs. The temporary piping should be line size, but no less than 1/3 main line size depending upon location. The temporary piping will be installed off the bottom of the permanent piping, top take offs will not be allowed for flushing and cleaning. This will ensure that all foreign material is removed during cleaning. If horizontal connection is required for cleaning it must be line size and any reducers must be eccentric with the flat install on bottom edge of piping.

The Contractor shall bypass all necessary equipment and sensitive components. The Contractor shall verify all lines being flushed are open with no strainers or filters in any line.

Contractor to flush and clean all new chilled water piping systems after the system has been successfully pressure tested. Chilled Water personnel shall witness the flushing and cleaning procedures. The Contractor shall provide all water for flushing and cleaning. Flushing water and cleaning solutions shall be discharged to the sanitary sewer system.

Flush all chilled water pipe thoroughly for 30 minutes or longer, as required to remove all dirt and foreign matter from the system. UNC Construction Management representative will make determination if piping flush is complete before the Contractor can proceed to the cleaning step.
Drain the system.

Install temporary strainer. Strainer is to protect pump(s) and collect debris and foreign material.

Verify the strainer is clean before proceeding. Fill the system with water, vent and add recommended amount of cleaner. The cleaner should be diluted by at least a 3:1 ratio to prevent excessive attack on metal surfaces at the point of application. (Do not allow any chemicals to contact galvanized surfaces).

Circulate system for a minimum of 24 hours at the flow rate recommended by the chemical manufacturer. Remove the temporary mesh strainer and debris. If temporary mesh strainer was not clean, reinstall and continue cleaning.

If UNC Construction Management representative determines the temporary mesh strainer is clean, completely drain the system and continue to next step.

Fill system with clean water, vent and circulate for one (1) hour. Drain system.

If installed, remove the temporary piping and pump. If building chilled water pumps were used, commence inspection and seal replacement with pump manufacturer’s service representative. After pump is inspected, realign and have alignment verified. Re-inspect for leakage.

If piping is to be isolated from the system for more than seven (7) days, add inhibitor to prevent corrosion. Inhibitor shall be Nalco 3DT279. Molybdate inhibitor shall not be used. If the piping is being placed in service in less than seven (7) days, Chilled Water Personnel will fill the system with water from the University Chilled Water System.

Pump sizes, capacities, pressures and operating characteristics shall be as scheduled. Where pumps are indicated for parallel operation, each pump must be capable of delivering at least 100% of the building’s full load flow.

Pumps shall have a minimum clearance of 24” on sides and ends of pumps and motors to allow access for service and repair. Pumps shall have isolation valves to allow removal of pumps for repair. Pumps shall have bled valves and gauge ports at accessible locations. All pumps shall be serviceable without removing the volute from piping connections. Pumps shall meet or exceed operating efficiencies scheduled.

Furnish pumps complete with premium efficiency inverter-duty, motors, drive assemblies, coupling guard where required and accessories as specified. Select motor with sufficient horsepower rating for non-overloading operation over entire pump curve.

Furnish each pump and motor with name plate giving manufacturer’s name, pump serial number, pump capacity in GPM and head in feet at design condition, horsepower, voltage, frequency, speed, and full load current. Hydraulic testing of all pumps should be pressure tested at 150% of rated pressure, clean and painted before shipment. Manufacturer shall certify all pump ratings and contractor will supply performance information as part of the submittals.

All pumps shall operate without objectionable noise or vibration with maximum noise level of 85 dBA.

Furnish one (1) set of seals and bearings for each new pump to Owner.

Pumps to be base mounted and flexible coupled with working pressure of 175 psi and operating temperature of 250°F intermittent. Efficiency of the pump shall be greater than 85%. Pump design must allow for servicing without disturbing piping, motor or requiring shaft realignment. Pumps shall be designed and tested to Hydraulic Institute Standards.

Casings shall be cast iron having a minimum tensile strength of 35,000 psi. Removal of impeller or rotating assembly shall be accomplished without disconnecting suction and discharge piping. Casings to have tapped and plugged openings for vent, drain, and suction and discharge gauge connections.

Impellers to be made of cast bronze, hydraulically and dynamically balanced, keyed and locked to pump shafts with replaceable shaft sleeves. Rotating elements shall be mounted in heavy-duty ball bearings (greaseable preferred) and shall be equipped with water slingers on the side next to pump glands.

Chilled water pumps to be furnished with single inside, unbalanced mechanical seals with carbon rotating faces, ceramic stationary seats, Buna-N elastomer and 316 SS metal hardware, such as a John Crane Type 1 Seal or equivalent, rated up to 225°F continuous operation.

If pumps are supplied with couplings, drop-out spacer type couplings with flexible neoprene sleeves are to be used to allow for pump servicing. Diaphragm couplings may be used with high horsepower pumps.

Pumps shall be supplied with the groutable steel base plates with stainless steel drip pans under the pump assembly with threaded drain connections, to be field routed during installation. Provide drain pan constructed of 16-gauge stainless steel, all welded under pump heads and inlet/outlet flanges, including flanges of connection pipe. Drain pan shall be sized to accommodate entire pump head area from flange to flange. Provide silicone sealant between pump feet and drain pan to make pan leak-proof. Provide ½” drain opening in drain pan to be extended to nearest floor drain during the installation.

Inline pumps may be used in situations not allowing for base mounted pumps. The motors for inline pumps must not exceed 5 HP (unless approved by Chilled Water Director) and the pumps must be independently supported from the piping, either to the floor or from a wall structure.

Approved Manufacturers: Allis Chalmers, Aurora, Peerless, PACO, Worthington, Flowserve, Dresser-Rand, Bell & Gossett or other approved equal

Motor submittal shall include the manufacturer, horsepower, voltage, phase, hertz, RPM, motor type, motor enclosure type, frame type, insulation class, NEMA design designation, service factor, nominal full load efficiency, full load power factor, full load amps, weight and all other appropriate data.

Motors driven by variable frequency drives (VFD) shall comply with the latest NEMA MG-1 Section IV, Part 31 unless otherwise noted and shall be inverter duty type. Starter insulation shall be designed to operate under maximum voltage peak of not less than 1600 volts with time reset not greater than 0.1 micro-seconds. Motor shall have corona resistant stator insulation. Motors shall be rated for 90°C temperature rise with 40°C ambient.

Motors shall have a 1.15 service factor in 40°C maximum ambient temperature. Select motors so they do not exceed nameplate rating nor operate into service factor to meet specified duty.

Motors shall have totally enclosed fan enclosures.

Motors shall have greaseable ball bearings with ANSI/AFBMA L-10 rating of 200,000 hours.

Motor vibration shall not exceed 0.15 inch per second, unfiltered peak.

Provide additional grounding of VFD driven motors to help protect the motor and its components from harmful transients generated by the VFD.

All motors driven by VFDs shall be grounded as specified:

  1. Mechanical contractor shall provide shaft grounding ring (AEGIS SGR or equal) on motor shaft. Soft carbon brushes are not acceptable. Install per
    manufacturer’s written instructions.
  2. The electrical contractor shall bond motor casing to local structural steel with braided straps of bare flat copper conductor cable, width to be specified by designing engineer.
  3. The electrical contractor shall bond motor feeder equipment grounding conductor to the motor terminal box. The contractor shall make sure to clean and prepare paint so that the connection for the ground will be clean and permanent. (Pertains to ALL motors)
Protect electric motors from premature failure by assuring that their windings are not subjected to concrete dust and other contaminants.

Set base mounted pumps on concrete bases (housekeeping pad), or concrete inertia base. The concrete pads must be dowelled to the floor at 12-inch intervals and have one mat of ¼” rebar to provide the base strength. Hold down bolts must penetrate the housekeeping pad and go into the existing floor pad a minimum of 5 inches. Level the base and bolt down prior to grouting. Fill entire base with non-shrinking grout. Use end caps during the grouting to prevent overflow when end caps are not integral with base plates. Housekeeping pad may be extended to allow for suction diffuser support.

Installation Note: Piping/pump alignment verification shall be performed by Chilled Water personnel.

Install all pumps in strict accordance with manufacturer’s instructions to avoid any stress and misalignment. Piping connections to pumps shall not create stress on pump casing. After final connections are completed, the contractor shall remove the bolts from the flanged connections at pumps. Piping shall remain aligned with pump connections after all bolts have been removed. If piping becomes misaligned after bolts have been removed, or if bolts cannot be removed by hand, the contractor shall revise piping to align piping with pump connection. If after completion of the strain free verification the piping system must be disassembled at any point in the future, the strain free verification shall be repeated. During final assembly after successful test the gaskets shall be replaced.

Contractor shall employ a technician certified by the selected pump manufacturer to field align flexible coupled pumps after the base has been grouted, the pipe/pump alignment check and flushing and cleaning procedures have been completed. Align pump and motor in all four planes: vertical angular, horizontal angular, vertical parallel, horizontal parallel. Alignment shall be within the recommended value by pump manufacturer (not coupler manufacturer), but not over 0.002” parallel and 0.003” angular per radius inch. Record and submit all results of alignment procedure to Engineer. Soft foot measurements must be less than 0.005” on each foot.

Installation Note: Pump/Motor alignment verification shall be completed independently by a Chilled Water representative.

Contractor shall produce a copy of the pump manufacturer’s alignment specifications (not pump coupler manufacturer’s specifications) at the time of Chilled Water verification or with pump submittals.

Where pump connection size and indicated line sizes are not identical, provide necessary concentric reducers/increasers for vertical piping at pump connection and eccentric reducers/increasers for horizontal piping at pump connection. Install eccentric reducers/increasers with top of pipe level. All isolation valves and flexible connections are to be full line size.

Note: To avoid damage to mechanical seals, never start or run pump in dry condition.

To perform pump startup:

  1. Verify that piping system has been tested, flushed, cleaned and filled.
  2. Verify that pipe/pump alignment has been verified by UNC Chilled Water representative.
  3. Verify that pump/motor alignment has been independently verified by UNC Chilled Water representative.
  4. Verify the VFD has been certified, with UNC Chilled Water technician present.
  5. Verify pump rotation.
  6. Prime pump and vent air from casing.