Department of Facilities Services Chilled Water Distribution System Chilled Water Design Specifications Chilled Water Services 2013 Design Guidelines 1|P a g e
Department of Facilities Services Chilled Water Distribution System Contents Contents ......................................................................................................................................................................2 DESCRIPTION OF CHILLED WATER SYSTEM ..................................................................................................5 BUILDING SYSTEM - GENERALLY .............................................................................................
Department of Facilities Services Chilled Water Distribution System Welded Pipe Joints .................................................................................................................................. 27 Pipe Welding ........................................................................................................................................... 27 PIPE HANGERS AND SUPPORTS ............................................................................................................
Department of Facilities Services Chilled Water Distribution System Instrumentation Cables ........................................................................................................................... 44 Pneumatic or Instrumentation Lines ....................................................................................................... 44 Conduit for Power and Instrumentation .................................................................................................. 44 APPENDIX ..
Department of Facilities Services Chilled Water Distribution System DESCRIPTION OF CHILLED WATER SYSTEM The University of North Carolina - Chapel Hill owns, maintains and operates a district cooling system comprised of 5 production plants and a thermal energy storage system, distribution system consisting of over 25 miles of underground piping, and building bridge systems consisting of over 150 bridges controlling chilled water in over 140 buildings or locations.
Department of Facilities Services Chilled Water Distribution System Chilled water is centrally produced and distributed throughout the campus, and this district cooling system shall be utilized wherever possible. The district cooling system is comprised of four major subsystems; the production system, the distribution system, the building bridge system, and the building cooling system. The Designer responsible for connecting to this system is primarily concerned with the last two subsystems.
Department of Facilities Services Chilled Water Distribution System PRIMARY/SECONDARY BUILDING BRIDGE SYSTEM – GENERALLY By definition a primary secondary bridge connection exists when the primary circuit (distribution mains) is connected to the secondary circuit (building system) by means of a low pressure loss pipe common to both circuits. The correct operation of the district cooling system is dependent on the design and operation of the primary/secondary bridge.
Department of Facilities Services Chilled Water Distribution System GPM LENGTH (ft) PIPE SIZE 0-150 0-400 4” 150-250 0-200 4” 200-1000 6” 0-250 6” 250-1000 8” 0-400 8” 400-1000 10’ 0-500 10” 500-1000 12” 0-800 12” 800-1200 14” 0-500 14” 500-1000 16” 250-600 600-1000 1000-1500 1500-2000 2000-4000 BRIDGE RETURN TEMPERATURE CONTROL VALVE (TCV-A) DESIGN CRITERIA The operation of the Bridge Return Temperature Control Valve (TCV-A) is of critical importance to the efficient op
Department of Facilities Services Chilled Water Distribution System The degree to which the valve will cavitate: Cavitation is a performance limit that fluid properties, pressure drop, and trim design impose upon valve operation. The designer shall follow these specifications when specifying this valve: The Bridge Return Temperature Control Valve (TCV-A) shall have a low sensitivity through the first part of its travel with increasing sensitivity as 100% of travel is approached.
Department of Facilities Services Chilled Water Distribution System CHW Bridge flow 449 – 545 GPM Press differential at mains Max: 20 psi Min: 5 psi Pipe flow resistance from mains to bridge bypass tees at CHW Bridge flow 3 psi. The bridge return temperature control valve table shall have the following information: Column 1 shall be percent of valve rotation with increments of 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%.
Department of Facilities Services Chilled Water Distribution System 70 114% 1.68 3.32 262 285.00 0.92 80 127% 2.09 2.91 312 351.00 0.89 90 138% 2.47 2.53 364 418.00 0.87 100 143% 2.67 2.33 394 475.00 0.83 UNDERGROUND CHILLED WATER DISTRIBUTION PIPING GENERAL Use only new material, free from defects, rust, scale, and guarantee for services intended. Use material meeting the latest revision of the ASTM specifications as listed in this specification.
Department of Facilities Services Chilled Water Distribution System Record Documentation Prior to acceptance of installation and use, contractor shall deliver two (2) copies of survey quality as built construction drawings for UNC to review and approve. Drawing to include GIS survey of points including change of directions, valves & tie in locations. A photograph library of the installation prior to backfilling is required.
Department of Facilities Services Chilled Water Distribution System Restrained type joint fittings shall be equal to EBBA Iron Series 1100 Megalug restraint systems for mechanical joint ductile iron piping, fittings and valves. Series 1100 solid ring restraints shall have a rated working pressure of 350 psi up to 16” pipe and 250 psi for 18” to 36” pipe. Series 1100 split ring restrains shall have a rated working pressure of 300 psi up to 16” and 200 psi for 18” to 36” pipe. Gasket material shall be SBR.
Department of Facilities Services Chilled Water Distribution System Vent valve boxes shall be 2-piece cast iron, 12 inch diameter box with a cover with a highway H20 rating. Boxes shall be located directly above the installed corporation stop. Mark cover as “Chilled Water”. Tapping Sleeves NOTE: Tapping sleeves can be used if approved by Chilled Water Manager.
Department of Facilities Services Chilled Water Distribution System All pipe, valves and fittings shall be installed as indicated on the drawings and according to the manufacturers’ instructions and UNC Chilled Water details. Provide vents at all high points of pipe sections. Coordinate location of drains with Chilled Water Engineer. Whenever possible the drain lines shall be run to the sanitary sewer system. If sanitary sewer is not available provide a pump out manhole (see Standard Details).
Department of Facilities Services Chilled Water Distribution System Coordinate the limitations and requirements of hydro-jet process with the flushing subcontractor such that the piping is installed in a sequence and manner that allows every section of the new pipeline to be cleaned and flushed.
Department of Facilities Services Chilled Water Distribution System L = S * D SQRT (P) / 200,000 L = allowable leakage in gallons per hour S = length of pipe tested, in feet D = nominal diameter of pipe in inches P = average test pressure during leakage test in pounds per square inch The Contractor is required to furnish all pumps, gauges, instruments, test equipment, and personnel required for tests and make provisions for removal of test equipment and draining of pipes after tests have been made.
Department of Facilities Services Chilled Water Distribution System CHILLED WATER BRIDGE GENERAL 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.
Department of Facilities Services Chilled Water Distribution System Submittals (Copies to Chilled Water Engineer) 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.
Department of Facilities Services Chilled Water Distribution System VALVES Butterfly Valves For Control Valves see Chilled Water Control Valves Specifications, starting on page 45. For the Chilled Water Bridge System, other than Control Valves, provide 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 or PTFE filled.
Department of Facilities Services Chilled Water Distribution System Chain Wheel Operators Provide chain operators for manually operated valves 6" and larger, located more than 8 ft. above equipment room floor. Cast iron or ductile iron adjustable sprocket rims and chain guides. 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 system to be rated for 250 psig at 100°F.
Department of Facilities Services Chilled Water Distribution System Compressed air tubing must be copper or stainless steel from isolation valve to instrument or control valve and 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 have fully automatic drains. Compressed air lines must be sized for all components using their delivery rates.
Department of Facilities Services Chilled Water Distribution System Furnish each pump and motor with name plate giving manufacturer’s name, serial number of pump, capacity in GPM and head in feet at design condition, horsepower, voltage, frequency, speed, and full load current. Test all pumps hydraulically at 150% of rated pressure, clean and paint before shipment. Manufacturer shall certify all pump ratings and contractor will supply performance information as part of the submittal.
Department of Facilities Services Chilled Water Distribution System Motors shall have 1.15 service factor in 40ºC 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. Motors vibration shall not exceed 0.15 inch per second, unfiltered peak.
Department of Facilities Services Chilled Water Distribution System Level the base and bolt down prior to grouting. Fill entire base with non-shrinking grout. Use end caps during 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 completed in the presence of the Chilled Water representative.
Department of Facilities Services Chilled Water Distribution System PIPE MATERIALS Use only new material, free from defects, rust, scale, and guarantee for services intended. All Chilled Water piping lines shall be standard weight, Schedule 40 black steel ASTM A53 GRB. Chilled Water pipes larger than 2" shall have welded joints and fittings that shall be standard weight Schedule 40 black steel. Threaded nipples shall be Schedule 80 black steel. Use only long radius elbows. Flanges ASTM A105, ANSI B16.
Department of Facilities Services Chilled Water Distribution System 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 page 21. Welded Pipe Joints All welding shall be performed to meet ASTM B31.1 unless noted by designer as otherwise.
Department of Facilities Services Chilled Water Distribution System Bolts, Nuts, Studs and Washers Bolts, nuts, studs and washers shall have electro-plated zinc or hot dip 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.
Department of Facilities Services Chilled Water Distribution System PIPING SYSTEM PRESSURE TEST Coordinate pressure tests 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 test. If engineer is not present, conduct test in presence of Construction Manager's representative. Representative shall sign report-verifying results.
Department of Facilities Services Chilled Water Distribution System NOTE: The Contractor shall provide their flushing plan to the designer at least two 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: Detailed plans on performing the flushing and cleaning. The plan must include a strainer with opening no larger than 0.45 inches.
Department of Facilities Services Chilled Water Distribution System The Contractor shall install temporary piping to facilitate the flushing at the end of piping runs. The temporary piping will be line size or 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.
Department of Facilities Services Chilled Water Distribution System Final Fill If piping is to be isolated from the system for more than 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 7 days, Chilled Water Personnel will fill the system with water from the University Chilled Water System.
Department of Facilities Services Chilled Water Distribution System For pipes 1-1/2" and smaller, specified pipe insulation and jacket shall be continuous through hanger or support locations and insulation protection shields shall be provided to protect insulation from compressing. For pipes 2" and larger, where manufactured pre-insulated pipe supports are used at hanger or support locations, extend insulation to insulated pipe supports.
Department of Facilities Services Chilled Water Distribution System BRIDGE CONTROLS PRIMARY/SECONDARY BUILDING BRIDGE SYSTEM - DESCRIPTION OF OPERATION A chilled water bridge system shall fall into one of two categories, depending on the kind of building loads that are served. The building category will be designated when the designer/engineer have reviewed the building loads with the Chilled Water Engineer/Manager. These categories are: (1) essential loads, (2) non-essential loads.
Department of Facilities Services Chilled Water Distribution System Water flow across the bridge interface is controlled by a two position spring-return-to-closed valve (FV-B) in the bridge bypass line, a two-position spring-return-to-open valve (FV-P) in the pump bypass line and a temperature control valve (TCV-A) in the distribution return branch line, and a VFD on the pump. A multi-loop digital controller (MC-1) provides regulatory and discreet control of the bridge system components.
Department of Facilities Services Chilled Water Distribution System INTERLOCKS AND METERING BTU metering is available as an output of the MC-1 digital controller. The temperature difference of the distribution supply and return as sensed by TS-1 and TS-2 is multiplied by the flow rate as sensed by FE/FT-1. This value is integrated and becomes a digital output to totalizer NQI-l. INSTRUMENT SPECIFICATIONS The following field-mounted devices and functions shall be provided for all applications: TAG NO.
Department of Facilities Services Chilled Water Distribution System VFD Variable Frequency Drive Designer Note: The VFD must not be powered up or operated until it has been certified by the VFD supplier’s personnel and verified by Chilled Water Personnel.
Department of Facilities Services Chilled Water Distribution System Six (6) programmable digital inputs for maximum flexibility in interfacing with external devices. All digital inputs shall be programmable to initiate upon an application or removal of 24 VDC or a dry contact. Three (3) programmable digital Form-C relay outputs. The relays shall include programmable on and off delay times and adjustable hysteresis. Default settings shall be for run, not faulted (fail safe), and run permissive.
Department of Facilities Services Chilled Water Distribution System Startup – A certified start-up form shall be filled out for each drive with a copy provided to Chilled Water, a copy provided with project documentation and a copy kept on file at the drive manufacturer. Design Note: No auto transfer to bypass in case of drive fault. Design Note: No DCS start command required for bypass operation.
Department of Facilities Services Chilled Water Distribution System INSTALLATION NOTE: Bench-check valve action and travel limits before installation. Notify UNC-CM representative of bench-check so UNC-CW personnel can witness testing. Manufacturer: Jamesbury (valve size in inches), 815 L - 11 21 36 XZ – QP(n)C/M with ND9000 series positioner or approved equal.
Department of Facilities Services Chilled Water Distribution System INSTALLATION NOTE: Bench-check valve action and travel limits before installation. Notify UNC-CM representative of bench-check so UNC-CW personnel can witness testing. Manufacturer type: Jamesbury (valve size in inches), 815 L - 11 21 36 XZ – QP(n)C/M or approved equal. Alternate FV-B, FV-P Bypass Valves For valves 1” to 6” in spaces where compressed air is not available, use a single V ball control valve with an electric actuator.
Department of Facilities Services Chilled Water Distribution System Thermowell for RTD Sensor The thermowell shall have 1.75”connection head length with ½” FNPT instrument mounting, ¾” MNPT process-mount, .5” outside diameter and .26” bore. The insertion depth shall be as stated in chart below. The thermowell shall be compatible with the specified temperature sensor and be constructed of 316 stainless. Pipe Size Insertion Depth 7” Up to 4” 6”-12” 12” and above Sensor Length 2.5” 4.5” 7.
Department of Facilities Services Chilled Water Distribution System PDT-2 shall provide a linear output signal proportional to process differential pressure (DP) for control of Chilled Water production. Sensor shall be capacitance-type. The instrument shall be microprocessor based. It shall be fully field configurable via the Highway Addressable Remote Transmitter (HART) communication protocol from the controller card.
Department of Facilities Services Chilled Water Distribution System The contractor shall provide all interfaces between starter or variable speed drive and bridge control panel. Contacts shall be rated for low level electronic signal loads. < = 10mA at 24vdc. This shall include a circuit to start and stop the pump(s) and an isolated circuit for pump(s) status indication. Installation Note: All power cables shall be installed in one continuous run. Instrumentation Cables Control cable type: Alpha no.
Department of Facilities Services Chilled Water Distribution System APPENDIX Appendix A Exposed Utility Temporary Support 2013 Design Guidelines 45 | P a g e
Department of Facilities Services Chilled Water Distribution System Appendix B Typical Chilled Water Trench thru Paved Area 2013 Design Guidelines 46 | P a g e
Department of Facilities Services Chilled Water Distribution System Appendix C Typical Chilled Water Trench thru Landscaped Area 2013 Design Guidelines 47 | P a g e
Department of Facilities Services Chilled Water Distribution System Appendix D Utility Butterfly Valve Installation 2013 Design Guidelines 48 | P a g e
Department of Facilities Services Chilled Water Distribution System Appendix E Chilled Water Drain Assembly 2013 Design Guidelines 49 | P a g e
Department of Facilities Services Chilled Water Distribution System Appendix F Chilled Water Air Vent Handhold 2013 Design Guidelines 50 | P a g e
Department of Facilities Services Chilled Water Distribution System Appendix G Ductile Iron/Steel Pipe Transition At Wall Penetration 2013 Design Guidelines 51 | P a g e
Department of Facilities Services Chilled Water Distribution System Appendix H Utility Piping Termination 2013 Design Guidelines 52 | P a g e
Department of Facilities Services Chilled Water Distribution System Appendix I Chiller Water Bridge Flow Diagram 2013 Design Guidelines 53 | P a g e
Department of Facilities Services Chilled Water Distribution System Appendix J Pump Differential Pressure Gauge Detail 2013 Design Guidelines 54 | P a g e
Department of Facilities Services Chilled Water Distribution System Appendix K Requesting Outage for Chilled Water Service Requests for planned outages of chilled water to any facility will only be accepted from the Facility Service Department involved in the work being done, Construction Management or a Contractor providing construction or renovation services on campus. All requests must be received no less than 5 business days in advance of the start date of the work.
Department of Facilities Services Chilled Water Distribution System Contact Information For any questions or concerns, please contact Chilled Water at 962-1448. Appendix L Request for Chilled Water Outage Request for a Chilled Water Outage A request for a chilled water outage needs to be submitted at least 5 working days before the outage is needed. This allows us to set the outage up with the proper contacts and arrange for any personnel needs that the outage may require.
