Common Work Requirements
Equipment schedules shall indicate electrical power requirements.
- Specify NEMA class F insulation with Class B temperature rise and 1.15 service-factors in an ambient temperature of 40 °C maximum.
- Specify 480V, three phase electrical service for motors 1/2 hp and larger. Specify single phase protection for multiphase motors.
- Enclosures for motors shall have hinged covers. Bolt on covers are not acceptable.
- For frames 284 or larger, bearings shall be capable of lubrication. Extend grease lines to an accessible location.
- For frames 140T – 280T, bearings shall be re-lubricated or equipped with double shields.
- Base plates for motors shall be constructed to NEMA standards and shall have a minimum of 2 belt tensioning bolts.
- Terminations for motors 5 hp or greater shall be made proprietary connectors and shall be made with split bolts wrapped with a layer of glass tape and then black electrical tape.
- Specify that all motors conform to the latest IEEE or NEMA standards relating to characteristics, dimensions, tolerances, temperature rise, insulation, and ratings for noise and vibration.
- Indicate the horsepower rating on both Division 15 and Division 16 construction drawings.
For motors 1 hp and larger:
- The following manufactures are approved: Baldor Super-E EM/XE (general purpose family) with optional cast iron frame, TECO/Westinghouse ASHH or Max-PE, WEG W22, or Toshiba. In cases of shipping delays, severe duty and IEEE 841 motors shall be considered. Rolled steel frames and aluminum end bells are not acceptable.
- Motor frames and end-bells shall be cast iron for motors 1 hp and larger. Specify premium efficiency motors, as defined by NEMA MG-1, for all motors 1 hp and larger.
- Belt drives shall be equipped with fixed pitch sheaves.
For motors equipped with VFDs:
- Motors shall meet the requirements of NEMA MG-1, part 31 “Definite Purpose Inverter-Fed Motors”.
- Provide solid shaft grounding rings (Aegis SGR or equal). Soft carbon brushes shall not be accepted. Split grounding rings shall not be accepted.
Synchronous belt drives
- Synchronous belts and gears shall be provided for belt-driven motors 3 hp and larger.
- Synchronous drives shall be designed for quiet, energy efficient operation. Eagle NRG is approved (or equivalent).
- Prior to start-up, shafts shall be laser alignment. Provide a printed report for review by UNC prior to start-up.
- Synchronous driven motors shall be equipped with soft start or a VFD.
- VFDs shall be stand-alone and fed from electrical panels.
- VFDs shall not be installed within or fed from MCCs.
- VFDs shall not be mounted inside or directly to AHU casings.
- VFDs shall be located as close as feasible to the motor controlled and in accordance with manufacturer’s installation instructions.
- Show VFDs on the drawings.
- VFDs should not be located outdoors. When absolutely necessary and approved by UNC Engineering Services, outdoor installations may be considered and generally shall be covered and protected to allow maintenance during adverse weather.
Approved brands and labeling requirements
- The approved manufacturer shall be manufactured by ABB, Schneider (Square D) and Danfoss. No other manufactures will be accepted.
- VFDs shall bear the original and approved manufacturer’s label and shall not be re-branded.
- The entire project shall provide VFDs by one manufacture. This is typically accomplished through specification of an owner preferred alternate. The owner preferred alternate or basis of design shall be ABB.
- Provide an IEEE 519-2014 (or most recent) analysis. For typical buildings, the total harmonic distortion shall not exceed 5%. For buildings with sensitive research or medical equipment, the total harmonic distortion shall not exceed 3% on both normal and emergency power. The VFD manufacturer shall provide mitigation as part of the VFD package. (The designer may specify an alternate harmonic mitigation method).
- The method of mitigation must be provided to the owner for approval (either through submittal or design review).
- Specify a dV/dT filter if the motor is greater than 50 hp.
The AC Drive system shall consist of an AC Drive and a Bypass circuit. These circuits shall operate independently of each other, and have completely separate switch mode power supplies operating off AC line Voltage. The bypass shall provide motor functionality with the drive removed. The bypass shall automatically respond to the BAS for start and stop while operating in bypass.
- Bypass package shall include a main input circuit breaker, disconnect or fused disconnect.
- Bypass shall include a service switch or line isolation contactor to disconnect power to the drive, but not the bypass.
- Drive and bypass package shall be UL listed and have a labeled, short circuit current rating (SCCR) of 100,000 amps.
- Start, stop, speed reference, and safeties to the drive are hard wired. Provide a LonTalk or BACnet compatible transceiver, whichever is compatible with the building for BAS
- For any VFD located out of site of the equipment served, provide a disconnect within sight of the equipment served.
- Disconnections shall be equipped with auxiliary contactors and wired to the VFD enable circuit. This eliminates the possibility of a hard start when the disconnect is closed.
Specify one VFD for each fan in a fan array.
- VFDs must go into fail safe mode during generator testing.
- Provide a schedule /s for VFDs indicating equipment ID, equipment served, HP, minimum rated output amps, volts, phase, UL enclosure type, input disconnect means (circuit breaker or fused disconnect), etc.
Training and warranties
- The VFD manufacturer shall provide a factory certified technical representative to inspect the contractor’s installation, and to test and start-up the VFDs furnished under this specification.
- The VFD and bypass warranty shall be 24 months minimum from the date of startup and shall cover parts, travel, labor and shipping required for repair.
- Provide all required cables and copies of software required for adjustment of all user-adjustable parameters. Provide one Installation and Operations Manual and wiring schematic per VFD at the time of training.
- The manufacturer shall provide factory direct warranty and support service.
- A representative of the VFD manufacturer shall provide one-day on-site training. For large projects, provide factory training in addition to on-site training.
Disconnecting means furnished integrally with equipment is considered adequate if the disconnecting means is properly sized and fused.
- For starters located adjacent to the motor served, specify combination-type starters.
- Specify with integral control transformers, solid state thermal overload protection, 120 volt coils, low voltage protection, indicating pilot lights (neon or LED type), hand-off-automatic switches and all necessary auxiliary contacts. Starters shall be UL508 listed for the available short circuit current. All starters, including skid mounted starters, shall be NEMA rated. IEC rated starters are not acceptable. Specify phase loss protection and adjustable overloads.
BAS controls panels shall not contain wiring in excess of 24 volts. The division 26 designer shall specify 120 VAC controls circuits for powering BAS control panels. 120 VAC circuits shall terminate in central locations to the control panels served. The division 26 designer shall show the 120 VAC termination point on the electrical drawings which is typically within an ME or EE room. The division 23 controls contractor shall provide necessary step-down transformers and shall field route low voltage power from the 120 VAC termination point to the equipment served.
Provide a strainer and analog water totalizing meter for makeup water supplies.
Hydronic pressure gauges exposed to vibrations shall be liquid filled.
When providing pressure measurement on each side of equipment, specify a single gauge connected to both sides and equipped with isolation valves for measuring either side independently with the same gauge.
Combination balancing/shutoff valves shall be independent and using the shut off function shall not affect the system balance when the valve is reopened.
Butterfly valves are not acceptable valves for flow balancing.
Balance valves shall be tagged with the model #, terminal unit #, circuit gpm, balance governing head loss, calculated circuit head loss.
Specify the vibration isolator type and the static deflection limits. Limit the vibration transmissibility to the building structure at the lower driving frequency of the equipment to a maximum of 1%.
Equipment shall be clearly identified with engraved phenolic plates securely fastened to the equipment with sheet metal screws. Specify phenolic plates with tag and letter colors in compliance with the SCO electrical design guidelines. Indicate the equip ID number. When appropriate, such as for exhaust fans, indicate at the fan/s and the equipment served the equipment or system served, panel number, and breaker number.
All equipment requiring periodic maintenance or testing located in concealed spaces shall be clearly identified on an adjacent finished surface to identify the location of equipment.
For equipment mounted above ceilings, provide an ID label on the ceiling below the equipment. Typical concealed equipment includes air terminals, air valves, PRVs, mixing valves, duct and pipe differential pressure sensors, steam traps, fire smoke dampers, etc. Labels shall be clear or white with 0.375″ high black letters.
Pipe and Duct Identification
Completely paint piping systems in mechanical rooms with the applicable colors listed below.
Identification shall be provided no further than 30 feet apart, at major changes in direction, at each valve or equipment, and on both sides of penetrations.
For both piping and ducts, provide stencil or strap-on identification indicating the system and the direction of flow.
See table 1 for system colors and identifications. Pipe identification should contrast in color to the pipe colors and be easily readable. The width of color bands should be equal to the size of the stencil indicated.
For insulated pipe systems, stencil sizes are as follows:
- For pipes up to 1 inch, use 1 inch letters.
- For pipes 1 inch to 2 inches, use 2 inch letters.
- For pipes 2 inches to 6 inches, use 3 inch letters.
- For pipes above 6 inches, use 4 inch letters.
For un-insulated systems, stencil sizes are as follows:
- For pipe diameters up to 1 inch, use 1/2 inch letters.
- For pipe diameters from 1 inch to 2 inches, use 1 inch letters.
- For pipe diameters from 2 inches to 6 inches, use 2 inch letters.
- For pipe diameters over 6 inches, use 3 inch letters.
At each floor level and at roof level identify each exhaust air duct from safety cabinets and fume hoods by 2″ tall painted black lettering identifying the room it originates from.
- Specify brass valve tags with chains for isolation and control valves.
- Specify a valve tag chart in the O&M manual.
- Specify a valve tag chart to be mounted in the ME room in a frame with a clear, shatter-proof cover.
- Include the tag numbers in the as-built drawings.
Equipment, ducting and piping installed on the exterior of the building shall blend in with the building. Specify appropriate paint colors and coordinate with the architect.
|Piping System||Color||Stencil Identification (Note 1)|
|Ductwork||Light Gray||Supply, Exhaust, Return|
|Chilled Water Supply||Marlin Blue (925) Note 2||CWS|
|Chilled Water Return||Marlin Blue (866) Note 2||CWR|
|Steam Condensate Return||Light Brown||COND|
|Domestic Cold Water||Dark Green||DOM CW|
|Domestic Hot Water||Red||DHW|
|Domestic Hot Water (RECIR)||Orange||DHWR|
|Heating Hot Water||Light Gray||HWS/HWR|
|Steam, High Pressure (25-75 psi)||Bright Red||HPS|
|Steam, Low Pressure (0-25 psi)||Dark Red||LPS #__|
|Condenser Water||Fed. Safety Green||CC|
|Pure water||Slate Gray||RO or RODI or DI|
|Compressed Air||Dark Gray||AIR|
|Fire Line||Safety Red||FIRE|
|Note 1: provide flow arrows.
Note 2: references the RUST-OLEUM® color
Specify insulation to provide an adequate thermal barrier as well as protection from moisture condensation on exterior of pipe or duct whose surface temperature drops below ambient conditions. In all cases the designer should confirm the size and type of insulation specified is sufficient to prevent surface condensation.
Do not insulate over tank and vessel labels.
Specify insulation for all valves, flanges, elbows, tees and other fittings with the same type and minimum thickness as adjoining pipe.
Specify insulation which provides access to circuit setters, control valves, strainers, unions and flexible connections and which may be removed and reinstalled without damage to the insulation.
Specify continuous insulation across pipe hangers, air handler casings, sleeves and walls.
Specify that the Contractor replace fiberglass and calcium silicate insulation which becomes wet during the construction period.
Insulation for devices on items requiring regular maintenance, such as steam traps, heating water devices, and chilled water devices should be easily removable and able to be reinstalled without damage to the insulation.
Insulate the following equipment items:
- Heating water air separator.
- Hot water converters.
- Steam traps.
- Insulate all cooling condensate drain piping. When necessary, insulate drain piping which collects large quantities of cold condensate.
Fiberglass insulation shall not be used on chilled water piping.
Insulate the body of the roof drains and piping a minimum of 10 ft. into the building.
See the insulation schedule below.
|domestic cold water||fiberglass or elastomeric|
|domestic hot water||fiberglass or elastomeric|
|interior roof leaders and overflow piping (note 2)||fiberglass or elastomeric|
|chilled water > 40 °F (note 1)||polyisocyanurate (nominal 2 lb. / ft3), elastomeric, or cellular glass|
|heating hot water||fiberglass, cellular glass, or calcium silicate|
|< 75 psi steam||fiberglass, cellular glass, or calcium silicate|
|75 to 200 psi steam||ellular glass or calcium silicate|
|low temperature piping ( < 39 °F)||elastomeric|
|hot gas refrigerant piping||fiberglass, cellular glass, or calcium silicate|
|heated fuel piping||fiberglass, cellular glass, or calcium silicate|
Corrugated aluminum jacketing or PVC jacketing is required on insulated piping at the following locations: in mechanical rooms from floor level to 8 ft. above finish floor, inside of AHUs, and exterior to the building.
Lined duct is not permitted. Sound attenuation liner may be considered on a case by case basis, but is generally NOT ALLOWED. The interior of ducts shall be smooth to avoid trapping dust and shall be a cleanable surface. In very limited cases fiberglass liner with a PSK jacket has been considered.
Specify rigid insulation for ductwork installed in mechanical rooms from floor level to 8 ft. AFF. Ductwork installed in mechanical rooms shall be with 8 oz. canvas lagging, minimum or PVC.
Externally insulate all exposed supply, return and outside air ducts with rigid fiberglass insulation.
Provide continuous insulation on supply duct at joints and throughout duct system from cooling coil to supply air grilles. Insulate all equipment including reheat coils, diffuser necks, fire dampers, and flexible connections.
Insulate the following duct systems in entirety:
- Outdoor air duct
- Supply duct
- Supply diffusers including the neck and back of the housing.
- Return ducts in areas that noise may be a problem such as large rectangular ducts within ceiling plenums of occupied areas and exposed rectangular duct in occupied areas.
- Return duct in mechanical rooms where the duct may take abuse.
- HVAC plenums and unit housings not pre-insulated at factory.
Insulate each ductwork system with one of the following:
- Rigid Fiberglass: 2″ minimum thickness in machine, fan and equipment rooms.
- Flexible Fiberglass
- Cellular Glass
- Flexible Unicellular
Insulate the following equipment
- Boilers (not pre-insulated at factory).
- Hot water storage tanks.
- Water heaters (not pre-insulated at factory).
- Heating hot water converters
- Heating water air separators.
Insulate each item of equipment specified above with one of the following
- Calcium Silicate.
- Flexible Unicellular: Do not use for equipment operating above 180 deg. F (82 °C).)