238100 DECENTRALIZED UNITARY HVAC EQUIPMENT.pdf

UPGRADE EMERGENCY POWER IN BUILDING 138

VAMC, MARION, IN PROJECT: 610-16-104

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SECTION 23 81 00

DECENTRALIZED UNITARY HVAC EQUIPMENT

PART 1 - GENERAL

1.1 DESCRIPTION

A. This section specifies , split-systems, and roof top air conditioners with electric heat.

B. Definitions:

1. Energy Efficiency Ratio (EER): The ratio of net cooling capacity is

Btu/h to total rate of electricity input in watts u nder designated operating conditions (Btu hour/Watt).

2. Seasonal Energy Efficiency Ratio (EER): The rati o of the total cooling output of an air conditioner during its nor mal annual usage period for cooling in Btu/h divided by total electr ic energy input in watts during the same period (Btu hour/Watt).

3. Unitary: A Unitary Air Conditioner consists of o ne or more factory-made assemblies which normally include an evaporato r or cooling coil, a compressor and condenser combination, and m ay include a heating function as well.

4. Where such equipment is provided in more than on e assembly the separated assemblies shall be designed to be used t ogether and the requirements of rating are based upon use of matche d assemblies.

1.2 RELATED WORK

A. Section 01 00 00, GENERAL REQUIREMENTS.

B. Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, a nd SAMPLES

C. Section 03 30 00, CAST-IN-PLACE CONCRETE.

D. Section 23 05 11, COMMON WORK RESULTS FOR HVAC.

E. Section 23 05 12, GENERAL MOTOR REQUIREMENTS FOR HVAC and STEAM

GENERATION EQUIPMENT

F. Section 23 05 41, NOISE and VIBRATION CONTROL FO R HVAC PIPING and

EQUIPMENT.

G. Section 23 05 93, TESTING, ADJUSTING, and BALANC ING FOR HVAC.

H. Section 23 07 11, HVAC and BOILER PLANT INSULATI ON.

I. Section 23 09 23, DIRECT-DIGITAL CONTROL SYSTEM FOR HVAC.

J. Section 23 23 00, REFRIGERANT PIPING.

K. Section 23 31 00, HVAC DUCTS and CASINGS.

1.3 QUALITY ASSURANCE

A. Refer to specification Section 23 05 11, COMMON WORK RESULTS FOR HVAC.

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B. Safety Standards: ASHRAE Standard 15, Safety Cod e for Mechanical

Refrigeration.

1.4 SUBMITTALS

A. Submit in accordance with specification Section 01 33 23, SHOP

DRAWINGS, PRODUCT DATA, and SAMPLES

B. Manufacturer’s literature and data:

1. Sufficient information, including capacities, pr essure drops, and piping connections clearly presented, shall be incl uded to determine compliance with drawings and specifications for uni ts noted below:

a. Unitary air conditioners:

1) Split systems

2) Rooftop units

2. Unit Dimensions required clearances, operating w eights accessories and start-up instructions.

3. Electrical requirements, wiring diagrams, interl ocking and control wiring showing factory installed and portions to be field installed.

C. Certification: Submit proof of specified ARI Cer tification.

D. Performance Rating: Submit catalog selection da ta showing equipment ratings and compliance with required sensible-to-he at-ratio, energy efficiency ratio (EER), and coefficient of performa nce (COP).

E. Operating and Maintenance Manual: Submit three c opies of Operating and

Maintenance manual to COR three weeks prior to fina l inspection.

1.5 APPLICABLE PUBLICATIONS

A. The publications listed below form a part of thi s specification to the extent referenced. The publications are referenced in the text by the basic designation only.

B. Air-Conditioning, Heating, and Refrigeration Ins titute (AHRI):

210/240-2017............Performance Rating of Unita ry Air-Conditioning and Air-Source Heat Pump Equipment

270-2015................Sound Rating of Outdoor Uni tary Equipment

310/380-2017............Standard for Packaged Termi nal Air-Conditioners and Heat Pumps (CSA-C744-04)

340/360-2015............Performance Rating of Comme rcial and Industrial

Unitary Air-Conditioning and Heat Pump

Equipment

520-2004................Performance Rating of Posit ive Displacement

Condensing Units

C. Air Movement and Control Association (AMCA):

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210-2016................Laboratory Methods of Testi ng Fans for

Aerodynamic Performance Rating (ANSI)

410-1996................Recommended Safety Practice s for Users and

Installers of Industrial and Commercial Fans

D. American National Standards Institute (ANSI):

S12.51-2017.............Acoustics - Determination o f Sound Power Levels of Noise Sources Using Sound Pressure -

Precision Method for Reverberation Rooms (same as ISO 3741:1999)

E. American Society of Civil Engineers (ASCE)

ASCE 7-2017.............Minimum Design Loads for Bu ildings and Other

Structures

F. American Society of Heating, Refrigerating, and Air-Conditioning

Engineers (ASHRAE):

Handbook 2016...........HVAC Systems and Equipment

15-2019.................Safety Standard for Refrige ration Systems

(ANSI)

62.1-2016...............Ventilation for Acceptable Indoor Air Quality

(ANSI)

G. American Society of Testing and Materials (ASTM) :

B117-2018...............Standard Practice for Opera ting Salt Spray

(Fog) Apparatus

H. Federal Specifications (Fed. Spec.):

A-A-50502-2009.......... Air conditioner (Unitary H eat Pump) Air to Air

(3000-300,000 Btu)

I. Military Specifications (Mil. Specs.):

MIL-PRF-26915D..........Primer Coating, for Steel S urfaces

J. National Electrical Manufacturer's Association ( NEMA):

ICS 1-2005..............Industrial Controls and Sys tems: General

Requirements

MG 1-2019...............Motors and Generators (ANSI )

K. National Fire Protection Association (NFPA) Publ ications:

90A-2018................Standard for the Installati on of Air-

Conditioning and Ventilating Systems

PART 2 - PRODUCTS

2.1 UNITARY AIR CONDITIONERS - GENERAL

A. Applicable ARI Standards:

1. Cooling Capacity 39.6 kW (135,000 Btu/h) and Mor e: AHRI 340/ 360.

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2. Cooling Capacity Less Than 39.6 kW (135,000 Btu/ h): AHRI 210/240.

Units shall be listed in the ARI Directory of Certi fied Unitary Air-

Conditioners.

B. Performance Rating: Cooling capacity of units sh all meet the sensible heat and total heat requirements shown in the contr act documents. In selecting unit size, make true allowance for "sensi ble to total heat ratio" to satisfy required sensible cooling capacit y.

C. Machinery Guards: Provide guards as shown in AMC A 410 for belts, chains, couplings, pulleys, sheaves, shafts, gears and other moving parts regardless of height above the floor. Drive g uards may be excluded where motors and drives are inside factory fabricated casings.

D. Corrosion Prevention: Unless specified otherwise , equipment fabricated from ferrous metals that do not have a zinc coating or a duplex coating of zinc and paint shall be treated for prevention o f rust with a factory coating or paint system that will withstand 125 hours in a salt-spray fog test, except that equipment located outdoors shall be tested for 500 hours. The salt-spray fog test shall be in accordance with ASTM B117 using a 20 percent sodium chloride s olution. Immediately after completion of the test, the coating shall sho w no signs of blistering, wrinkling or cracking, no loss of adhes ion, and the specimen shall show no signs of rust beyond 3 mm (1 /8-inch) on both sides from the scratch mark.

2.2 SPLIT-SYSTEM AIR CONDITIONERS

A. Description: Factory assembled and tested, wall- mounted unit, with an air-cooled remote condensing unit, and field-instal led refrigeration piping.

B. Wall-Mounting, Evaporator-Fan Components:

1. Cabinet: Enameled steel with removable panels o n front and ends in color selected by Architect, and discharge drain pa ns with drain connection.

2. Airstream Surfaces: Surfaces in contact with th e airstream shall comply with requirements in ASHRAE 62.1. Drain Pan and Drain

Connection: Comply with ASHRAE 62.1-2007.

3. Refrigerant Coil: Copper tube, with mechanicall y bonded aluminum fins, complying with AHRI 210/240, and with thermal -expansion valve.

4. Fan: Direct drive, centrifugal fan.

5. Fan Motors: Comply with requirements in Section 23 05 12, GENERAL

MOTOR REQUIREMENTS FOR HVAC and STEAM GENERATION EQUIPMENT for

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238100-5 multi-tapped, multi-speed motors with internal ther mal protection and permanent lubrication.

6. Filters: Disposable, with MERV rating of 7 or hi gher according to

ASHRAE 52.2.

C. Air-Cooled, Compressor-Condenser Components:

1. Casing: Steel, finished with baked enamel in co lor selected by

Architect, with removable panels for access to cont rols, weep holes for water drainage, and mounting holes in base. Se rvice valves, fittings, and gage ports shall be brass and located outside of the casing.

2. Compressor: Hermetically sealed scroll with cra nkcase heater and mounted on vibration isolation. Compressor motor s hall have thermal- and current-sensitive overload devices, st art capacitor, relay, and contactor.

3. Compressor motor with manual-reset, high-pressur e switch and automatic-reset, low-pressure switch.

4. Refrigerant: R-410A unless otherwise indicated.

5. Refrigerant Coil: Copper tube, with mechanicall y bonded aluminum fins, complying with AHRI 210/240, and with liquid subcooler.

6. Fan: Aluminum, propeller type, directly connect ed to motor.

7. Motor: Permanently lubricated, with integral th ermal-overload protection.

8. Low Ambient Kit: Permit operation down to minus 18 deg C (0 deg F).

9. Mounting Base: Polyethylene.

10. Minimum Energy Efficiency: Comply with ASHRAE/ IESNA 90.1 "Energy

Standard for Buildings except Low-Rise Residential Buildings."

2.3 ROOFTOP AIR CONDITIONERS

A. Casing: Formed and reinforced double-wall insula ted panels, fabricated to allow removal for access to internal parts and c omponents, with joints between sections sealed. Exterior casing of galvanized steel with factory-painted finish, with pitched roof pane ls and knockouts with grommet seals for electrical and piping connec tions and lifting lugs. Galvanized inner casing. Casing insulation and adhesive shall comply with NFPA 90A or NFPA 90B and comply with AS TM C 1071, Type I and shall be minimum 13 mm (1/2 inch) thick. Space between double wall panels filled with foam insulation and sealed moist ure tight.

Removable cam latched access panel to allow access to internal parts.

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B. Corrosion Prevention: Paint shall be treated for prevention of rust with a factory coating or paint system that will wi thstand 500 hours in a salt-spray fog test. The salt-spray fog test shal l be in accordance with ASTM B117 using a 20 percent sodium chloride s olution.

C. Airstream Surfaces: Surfaces in contact with th e airstream shall comply with requirements in ASHRAE 62.1.

D. Supply-Air Fan: Direct driven centrifugal; wit h permanently lubricated, ECM motor resiliently mounted in the fan inlet. Fan wheel shall be aluminum or painted-steel, and fan scroll shall be galvanized- or painted-steel.

E. Condenser-Coil Fan: Propeller, mounted on shaft of permanently lubricated motor.

F. Seismic Fabrication Requirements: Fabricate f an section, internal mounting frame and attachment to fans, fan housings , motors, casings, accessories, and other fan section components with reinforcement strong enough to withstand seismic forces defined in Secti on 23 05 41, NOISE and VIBRATION CONTROL FOR HVAC PIPING and EQUIPMENT when fan-mounted frame and RTU-mounted frame are anchored to buildin g structure.

G. Fan Motor: Comply with requirements in Section 2 3 05 12, GENERAL MOTOR

REQUIREMENTS FOR HVAC and STEAM GENERATION EQUIPMENT.

H. Supply-Air Refrigerant Coil: Aluminum-plate fins and seamless internally grooved copper tube in steel casing with equalizing-type vertical distributor. Polymer strip shall prevent all copper coil from contacting steel coil frame or condensate pan. Coi l split shall be interlaced.

I. Condensate Drain Pan: Formed sections of stainle ss-steel sheet, a minimum of 50 mm (2 inches) deep and complying with ASHRAE 62.1. Drain connections shall be threaded nipple.

J. Outdoor-Air Refrigerant Coil: Aluminum-plate fin s and seamless internally grooved copper tube in steel casing with equalizing-type vertical distributor. Polymer strip shall prevent copper coil from contacting steel coil frame or condensate pan.

K. Electric-Resistance Heating Coil: Resistance wir e of 80 percent nickel and 20 percent chromium, supported and insulated by floating ceramic bushings recessed into casing openings, fastened to supporting brackets, and mounted in galvanized-steel frame.

1. Terminals: Stainless-steel machine-staked termi nals secured with stainless-steel hardware.

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2. Overtemperature Protection: Disk-type, automatic ally reset, thermal-cutout, safety device; serviceable through terminal box.

3. Overcurrent Protection: Manual-reset thermal cut outs, factory wired in each heater stage.

4. Control Panel: Unit mounted with disconnecting means and overcurrent protection and shall include magnetic c ontactors.

L. Refrigerant Circuit Components:

1. Number of Independent Refrigerant Circuits: One.

2. Compressor: Hermetic, scroll, mounted on vibrati on isolators; with internal overcurrent and high-temperature protectio n, internal pressure relief/protection, and crankcase heater (i f required by compressor manufacturer due to refrigerant charge l imits).

M. Refrigerant: R-410A.

N. Refrigeration Specialties:

1. Expansion valve with replaceable thermostatic el ement.

2. Refrigerant filter/dryer.

3. Manual-reset high-pressure safety switch.

4. Automatic-reset low-pressure safety switch.

5. Minimum off-time relay.

6. Automatic-reset compressor motor thermal overloa d.

7. Brass service valves installed in compressor suc tion and liquid lines.

O. Air Filtration: Minimum arrestance according to ASHRAE 52.1, and MERV rating according to ASHRAE 52.2.

1. Glass Fiber: Minimum 80 percent arrestanc e, and MERV 5. Disposable

2-in thick. Unit shall only use one filter size and be accessible through an access panel.

P. Outdoor-Air Damper: Linked damper blades, capabl e of up to 100% outdoor air.

Q. Damper Motor: Modulating with adjustable minimum position.

R. Relief-Air Damper: Gravity actuated or motorized , complying with

ASHRAE/IESNA 90.1, and having bird screen and hood.

S. Electrical Power Connection: A single connection of power to unit with unit-mounted disconnect switch accessible from outs ide unit and control-circuit transformer with built-in overcurre nt protection.

T. Controls:

1. Basic Unit Controls:

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a. DDC controller or programmable timer and interfa ce with HVAC instrumentation and control system and to digital d isplay outdoor-air temperature, supply-air temperature, re turn-air temperature, economizer damper position, indoor-air quality, and control parameters. Interface with BMS/DDC system v ia BACnet open protocol. Include any additional points required by points list or control sequence indicated on drawings.

2. Safety Control Operation:

a. Smoke Detectors: Stop fan and close outdoor-air damper if smoke is detected and with additional contacts for alarm interface to fire alarm control panel.

d. Low-Discharge Temperature: Stop fan and close ou tdoor-air damper if supply air temperature is less than 4 deg C (40 deg F).

c. Defrost Control for Condenser Coil: Pressure di fferential switch to initiate defrost sequence.

3. Scheduled Operation: System will be operated co ntinuously on a single schedule year round.

4. Supply Fan Operation:

a. Run fan continuously.

5. Refrigerant Circuit Operation:

a. Occupied Periods: Cycle or stage compressors to match compressor output to cooling load to maintain room temperature . Cycle condenser fans to maintain maximum hot-gas pressure .

6. Electric-Resistance Heating-Coil Operation:

a. Occupied Periods: Cycle coil to maintain room t emperature.

7. Outdoor-Air Damper Operation:

a. No outside air minimum.

8. Economizer Outdoor-Air Damper Operation:

a. Economizer Periods: Open to percent of the fan capacity to comply with ASHRAE Cycle II. Controller shall perm it air-side economizer operation when outdoor air is less than 27 deg C (80 deg F). Use mixed-air and outdoor-air to adjust mi xing dampers.

During economizer cycle operation, lock out mechani cal cooling until 80 deg F.

9. Interface Requirements for HVAC Instrumentation and Control System:

a. Interface relay for scheduled operation.

b. Interface relay to provide indication of fault a t the central workstation and diagnostic code storage.

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c. Compatible with BACnet for central HVAC control workstation for adjusting set points, monitoring supply fan start, stop, and operation, inquiring data to include outdoor-air da mper position, supply- and room-air temperature, monitoring consta nt and variable motor loads, monitoring cooling load, moni toring economizer cycles and monitoring air-distribution s tatic pressure and ventilation air volume.

U. Accessories:

1. Duplex, 115-V, ground-fault-interrupter outlet w ith 15-A overcurrent protection. Include transformer if required.

2. Filter differential pressure switch with sensor tubing on both sides of filter. Set for final filter pressure loss.

3. Coil guards of painted, galvanized-steel wire.

4. Hail guards of galvanized steel painted to match casing.

V. Roof curb (mounted on grade level equipment pad) : Vibration isolators and wind or seismic restraints shall be as specifie d in Section

23 05 41, NOISE and VIBRATION CONTROL FOR HVAC PIPI NG and EQUIPMENT.

Manufacturer's standard curbs constructed of galvan ized steel with corrosion-protection coating, watertight gaskets, a nd factory-installed wood nailer; complying with NRCA standards.

1. Curb Height: 355 mm (14 inches).

2. Wind and Seismic Restraints: Metal brackets com patible with the curb and casing, painted to match RTU, used to anch or unit to the curb, and designed for loads at Project site. Comp ly with requirements in Section 23 05 41, NOISE and VIBRATI ON CONTROL FOR

HVAC PIPING and EQUIPMENT for wind-load requirement s.

PART 3 EXECUTION

3.1 INSTALLATION

A. Rooftop Unit Support: Install unit level on cur b and then on reinforced concrete slab (see structural drawings f or details); 100 mm

(4 inches) larger on each side than unit. Concrete , reinforcement, and formwork are specified in Section 03 30 00, CAST-IN -PLACE CONCRETE.

Coordinate anchor installation with concrete base. Coordinate wall penetrations and flashing with wall construction. S ecure rooftop units to structural support with anchor bolts.

B. Install wind and seismic restraints according to manufacturer's written instructions. Wind and seismically restrained vibra tion isolation roof-

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238100-10 curb rails are specified in Section 23 05 41, NOISE and VIBRATION

CONTROL FOR HVAC PIPING and EQUIPMENT.

C. Install units level and plumb maintaining manufa cturer’s recommended clearances and tolerances.

D. Install vibration spring isolators under base of self-contained unit, with minimum static deflection of 25 mm (1 inch) un less otherwise indicated. Refer to Section 23 05 41, NOISE and VI BRATION CONTROL FOR

HVAC PIPING and EQUIPMENT

E. Install ground-mounting, compressor-condenser co mponents on a reinforced concrete base (see structural drawings f or details); 100 mm

(4 inches) larger on each side than unit. Concrete , reinforcement, and formwork are specified in Section 03 30 00, CAST-IN -PLACE CONCRETE.

Coordinate anchor installation with concrete base.

F. Install ground-mounting, compressor-condenser co mponents on polyethylene mounting base.

G. Install seismic restraints.

H. Install and connect precharged refrigerant tubin g to component's quick-connect fittings. Install tubing to allow access t o unit.

I. Install wall sleeves in finished wall assembly a nd weatherproof.

Install and anchor wall sleeves to withstand, witho ut damage seismic forces as required by code.

3.2 CONNECTIONS

A. Verify condensate drainage requirements.

B. Install condensate drain, minimum connection siz e, with trap and drain to grade.

C. Install piping adjacent to units to allow servic e and maintenance.

D. Connect ducts to units with flexible duct connec tors specified in

Section 23 31 00, HVAC DUCTS and CASINGS.

E. Install return-air duct continuously through wal l structure.

F. Ground equipment and install power wiring, switc hes, and controls for self contained and split systems.

G. Connect refrigerant piping to coils with shutoff valves on the suction and liquid lines at the coil and a union or flange at each connection at the coil and condenser.

H. Connect piping with shutoff duty valves on the s upply and return side of the coil and unions at all connections and with a throttling valve on the return piping near the coil.

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3.3 FIELD QUALITY CONTROL

A. Perform tests and inspections and prepare test r eports.

B. Tests and Inspections: After installing units an d after electrical circuitry has been energized, test units for compli ance with requirements. Inspect for and remove shipping bolts , blocks, and tie-down straps. After electrical circuitry has been en ergized, start units to confirm proper motor rotation and unit operation . Test and adjust controls and safeties. Replace damaged and malfunc tioning controls and equipment. Remove and replace malfunctioning units and retest as specified above.

3.4 STARTUP AND TESTING

A. Coordinate the startup and contractor testing sc hedules with the COR.

Provide a minimum of 7 days prior notice.

B. Provide services of manufacturer’s technical rep resentative for four hours to instruct VA personnel in operation and mai ntenance of units.

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