SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 1 OF 17
SECTION 23 73 00
Indoor Central-Station Air-Handling Units
PART 1 - GENERAL
1.01
1.02
1.03
1.04
102313
SECTION INCLUDES
A.
Packaged air handling units.
B.
Makeup air units.
C.
Fan coil units.
RELATED SECTIONS
A.
Section 23 05 00 - Common Work Results for HVAC.
B.
Section 23 05 48 - Vibration and Seismic Controls for HVAC Piping and Equipment.
C.
Section 23 31 00 - HVAC Ducts and Casings.
D.
Section 23 08 00 - Commissioning Requirements
E.
Division 26 - Electrical.
REFERENCES
A.
ABMA STD 9 - Load Ratings and Fatigue Life for Ball Bearings.
B.
AFBMA STD 11 - Load Ratings and Fatigue Life for Roller Bearings.
C.
AMCA 99 - Standards Handbook.
D.
ARI 410 - Forced-Circulation Air-Cooling and Air-Heating Coils.
E.
ARI 430 - Central-Station Air-Handling Units.
F.
ARI 435 - Application and Installation of Central Station Air-Handling Units.
G.
NEMA MG1 - Motors and Generators.
H.
NFPA 70 - National Electrical Code.
I.
SMACNA - HVAC Duct Construction Standards - Metal and Flexible.
J.
UL 900 - Test Performance of Air Filter Units.
SUBMITTALS FOR REVIEW
A.
Submit under provisions of Division 1.
B.
Shop Drawings: Indicate assembly, unit dimensions, weight loading, required
clearances, construction details, field connection details, and electrical characteristics
and connection requirements.
PROJECT NO, BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 2 OF 17
C.
Product Data:
1.
2.
Published Literature: Indicate dimensions, weights, capacities, ratings, fan
performance, gages and finishes of materials, and electrical characteristics and
connection requirements.
Provide data of filter media, filter performance data, filter assembly, and filter
frames.
D.
1.05
1.06
1.08
102313
4.
Submit sound power level data for both fan outlet and casing radiation at rated
capacity.
5.
Submit electrical requirements for power supply wiring including wiring diagrams
for interlock and control wiring, clearly indicating factory-installed and fieldinstalled wiring.
Manufacturer's Installations Instructions.
A.
Submit under provisions of Division 1.
B.
Maintenance Data: Include instructions for lubrication, filter replacement, motor and drive
replacement, spare parts lists, and wiring diagrams.
QUALITY ASSURANCE
Manufacturer: Company specializing in manufacturing the Products specified in this
section with minimum three years documented experience.
DELIVERY, STORAGE, AND PROTECTION
A.
Deliver, store, protect and handle products to site under provisions of Division 1.
B.
Accept products on site in factory-fabricated protective containers, with factory-installed
shipping skids and lifting lugs. Inspect for damage.
C.
Store in clean dry place and protect from weather and construction traffic. Handle
carefully to avoid damage to components, enclosures, and finish.
ENVIRONMENTAL REQUIREMENTS
A.
1.09
Provide fan curves with specified operating point clearly plotted.
OPERATION AND MAINTENANCE DATA
A.
1.07
3.
Do not operate units for any purpose, temporary or permanent, until ductwork is clean,
filters are in place, bearings lubricated, and fan has been test run under observation.
EXTRA MATER IALS
A.
Furnish under provisions of Division 1
B.
Provide one set of extra filters for each unit.
PROJECT NO, BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 3 OF 17
PART 2 - PRODUCTS
2.01
AIR HANDLING UNITS
A.
2.02
Manufacturers:
1.
McQuay.
2.
Trane
3.
Carrier.
4.
York.
AIR HANDLING UNITS - INDOOR MOUNTED
A.
GENERAL
1.
Unit layout and configuration shall be as defined in project plans and schedule.
Provide factory-installed external support kit on the base of the unit. External
support kit shall be used for ceiling suspension, external isolation, or with
housekeeping pad. Unit mounting devices not constructed of galvanized steel
shall be chemically cleaned and coated with both a rust-inhibiting primer and
finished coat of rust-inhibiting enamel.
3.
B.
Units shall be double wall construction.
UNIT CASING
All panels shall be double wall construction. Interior and exterior panels shall be
constructed of galvanized steel. Insulation shall have a minimum R-Value of 8
and shall be UL listed. The installation shall comply with NFPA-90A and B
requirements.
Unit shall be constructed of a complete structural frame with removable panels.
Unit manufacturer shall ship separate segments so unit can be broken down for
ease of installation in tight spaces. The entire air handler shall be constructed of
galvanized steel. Casing finished to meet ASTMB 117 250-hour salt-spray test.
The removal of side panels shall not affect the structural integrity of the unit. All
removable panels shall be gasketed to minimize air leakage. All doors shall have
gasketing around full perimeter to prevent air leakage. Contractor shall be
responsible to provide connection flanges and all other framework that is needed
to properly support the unit.
3.
Construct casing sections capable of operating from -4"wg to +6"wg.
Access panels and/or access doors shall be available on both sides of the unit in
all sections to allow easy access to drain pan, coil(s), motor, drive components
and bearings for cleaning, inspection, and maintenance. If panels are not
removable, then manufacturer shall provide access sections with doors between
all internal components to ensure access and cleanability of the air handler.
Access doors shall be double wall construction to prevent damage to insulation
during routine maintenance.
102313
PROJECT NO, BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 4 OF 17
Access panels and doors shall be fully removable without the use of specialized
tools to allow complete access of all interior surfaces.
Door hardware shall be surface mounted to minimize penetrations in the door
casing that could lead to air leakage paths.
All joints between exterior panels and structural frames, as well as joints between
module frames, shall be properly sealed and gasketed to provide an air seal.
FANS
Fan shafts shall be solid, coated with a rust-inhibiting coating, and properly
designed so that fan shaft does not pass through first critical speed as unit
comes up to rated RPM. All fans shall be statically and dynamically tested by the
manufacturer for vibration and alignment as an assembly at the operating RPM
to meet design specifications. Fans controlled by variable frequency drives shall
be statically and dynamically tested for vibration and alignment at speeds
between 25% and 100% of design RPM. If fans are not factory-tested for
vibration and alignment, the contractor shall be responsible for cost and labor
associated with field balancing and certified vibration performance. Fan wheels
shall be keyed to fan shafts to prevent slipping.
Provide grease lubricated ball bearings selected for L-50 200,000-hour average
life per ANSI/AFBMA 9. Greasable bearings shall have lubrication lines extended
to the drive side of the unit. Lubrication lines shall be a clear, high-pressure,
polymer to aid in visual inspection. Extend both grease lubrication lines to drive
side of unit and rigidly attach to drive side bearing support with zerk fittings. If
extended lubrication lines are not provided, manufacturer shall provide
permanently lubricated bearing with engineering calculations for proof of bearing
life.
Fans shall be mounted on isolation bases. Internally-mounted motor shall be on
the same isolation base. Fan and motor shall be seismically restrained and
internally isolated with spring isolators. Flexible canvas ducts shall be installed
between fan and unit casing to ensure complete isolation. Flexible canvas ducts
shall comply with NFPA 90A and UL 181 requirements. Statically and
dynamically balance fan section assemblies.
Fan sections shall have full height, double wall, hinged doors on drive side for
inspection and maintenance of internal components.
Belts shall be enclosed as required by OSHA standard 29 CFR 1910 to protect
worker from accidental contact with the belts and sheaves.
For fan sections controlled by variable frequency drives, balance at speeds
between 25% and 100% of design RPM.
MOTORS AND DRIVES
Fan motors shall be heavy duty, high efficiency per Section 15050, open dripproof.
2.
102313
V-Belt Drive shall be variable pitch rated at 1.2 times the motor nameplate.
PROJECT NO, BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 5 OF 17
All motors and drives shall be factory-installed and run tested. All motors shall be
installed on a slide base to permit adjustment of belt tension. Slide base shall be
designed to accept all motor sizes offered by the air-handler manufacturer for
that fan size to allow a motor change in the future, should airflow requirements
change.
Motors shall be selected to operate continuously at 104 F (40 C) ambient without
tripping of overloads. Motors shall have a +/- 10 percent voltage utilization range
to protect against voltage variation. Motors shall be in compliance with EPACT
when applicable.
Manufacturer shall provide for each fan a nameplate with the following
information to assist air balance contractor in start up and service personnel in
maintenance:
Fan and motor sheave pa•t number
Fan and motor bushing pa•t number
Number of belts and belt pa•t numbers
Fan design RPM and motor HP
Belt tension and deflection
Center distance between shafts
COILS
1.
Install coils such that headers and return bends are enclosed by unit casing to
ensure that if condensate forms on the header or return bends, it is captured by
the drain pan under the coil.
Coils shall be manufactured with plate fins to minimize water carryover and
maximize airside thermal efficiency. Fin tube holes shall have drawn and belled
collars to maintain consistent fin spacing to ensure performance and air pressure
drop across the coil as scheduled. Tubes shall be mechanically expanded and
bonded to fin collars for maximum thermal conductivity. Use of soldering or
tinning during the fin-to-tube bonding process is not acceptable due to the
inherent thermal stress and possible loss of bonding at that joint.
Construct coil casings of galvanized steel. End supports and tube sheets shall
have belled tube holes to minimize wear of the tube wall during thermal
expansion and contraction of the tube.
All coils shall be completely cleaned prior to installation into the air handling unit.
Complete fin bundle in direction of airflow shall be degreased and steam cleaned
to remove any lubricants used in the manufacturing of the fins, or dirt that may
have accumulated, in order to minimize the chance for water carryover.
On stacked cooling coils, intermediate drain pans shall be installed between the
coils. Intermediate drain pans shall have drop tubes to guide condensate to the
main drain pan, thus preventing flooding of lower coils that would result in
moisture carryover.
102313
PROJECT NO, BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 6 OF 17
LEVEL DRAIN PANS
Units with cooling coils shall have drain pans under complete cooling coil section
that extend beyond the air-leaving side of the coil to ensure capture of all
condensate in section. Drain pans shall be constructed of interior and exterior
panels. Insulation shall be encased between exterior and interior walls. Drain
pans shall be stainless steel and shall be sloped in 2 planes, pitched toward
drain connections to ensure complete condensate drainage when unit is installed
level and trapped per manufacturer's requirements.
Units with heating coils shall have a galvanized steel drain pan under complete
heating coil section sloped in 2 planes and pitched toward drain connections to
ensure proper drainage during cleaning and to capture water in the event of a
coil failure.
All drain pan connections supplied by unit manufacturer including, piping, and
piping connections extending from stainless steel drain pans shall be constructed
of stainless steel.
Sections after each coil shall have galvanized steel flat drain pans which shall be
accessible for cleaning.
FILTERS
Provide factory-fabricated filter section of the same construction and finish as
unit casings. Filter section shall have filter guides and access door(s) extending
the full height ofthe casingto facilitate filter removal. Provide filter blockoffs as
required to prevent air bypass around filters.
Pre-filter shall be minimum MERV 7, 2" pleated media. Filters shall be
removable from one side of filter section(s).
DAMPERS
All dampers shall be internally mounted. Dampers shall be premium ultra low
leak and located as scheduled. Dampers shall be Ruskin CD60 double-skin
airfoil design or equivalent for minimal air leakage and pressure drop. Leakage
rate shall not exceed 5 CFM/square foot at one inch water gauge and 9
CFM/square foot at 4 inches water gauge. All leakage testing and pressure
ratings shall be based on AMCA Publication 500. Manufacturer shall submit
brand and model of damper(s) being furnished.
Provide low leak face and bypass dampers as scheduled on drawings. Dampers
shall be Ruskin CD60 double skin airfoil design or equivalent. Construct damper
blades and damper frames of galvanized steel. Provide opposed blade action
with metal compressible jamb seals and extruded vinyl blade edge seals. Blades
shall rotate on stainless steel sleeve bearings. Mechanically link face dampers
to bypass dampers and provide end driven control shafts. Damper blade lengths
shall not exceed 60 inches. Leakage rate shall not exceed 5 CFM/square foot at
one inch water gage and 9 CFM/square foot at 4 inch water gage.
3.
102313
For specification of damper actuators, refer to Specification Section 23 09 23.
PROJECT NO, BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 7 OF 17
2.03
ROOFTOP UNITS AND ENERGY RECOVERY VENTILATORS - ROOF MOUNTED AIR
HANDLING UNITS
A.
GENERAL
1.
Fabricate draw-thru type air handling units with fan sections.
Factory fabricate air handling units of sizes, capacities, and configurations as
scheduled on drawings.
The unit shall be able to withstand up to 1.5 times design static pressure, or 8inch wc whichever is less, with no more than 0.005 inch deflection per inch of
panel span.
B.
UNIT BASE
Base shall be welded supporting the entire length and width of the unit. Units
shipped in one piece shall have at a minimum six points of lift. These lift points
shall be designed to accept standard rigging devices.
The unit base design shall allow unit to rest on top of roofcurb when field
installed. Entire length and width under base shall be sealed in the field with
curb gasketing for weather tight seal.
C.
CASING
All panels shall be double wall construction. Interior and exterior panels shall be
constructed of galvanized steel. Panel insulation system shall provide a
minimum R value of 12. Insulation shall conform to NFPA 90 requirements.
Panels shall be fully removable to allow for a proper way to thoroughly clean
panels and to access internal parts. If panels are not removable, then
manufacturer shall provide access sections with doors between all internal
components to ensure access and cleanability of the air handler.
Access doors shall be constructed with a double-wall of solid G90 galvanized
steel interior panel. Gasketing around the full perimeter of the access door shall
be used to prevent air and water leakage. Preferred door handle shall not
penetrate door casing with single-handle latch.
External surface of unit casing shall be prepared and factory coated with a
minimum 1.5 mil enamel finish or equal. Unit casing exterior with factory coating
shall be able to withstand a salt spray test in accordance with ASTM Bl17 for a
minimum of 500 consecutive hours. Unit casing will be provided with
manufacturer's standard color.
Unit roof shall be sloped a minimum .25 inch per foot either from one side of unit
to other or from center to sides of the unit. Roof assembly shall overhang all
walls of units by 2 inch minimum.
For units with outside air requirements, manufacturer shall provide inlet hood
with high performance sine wave moisture eliminator to prevent water carryover
into unit casing from outside air. Hoods shall be sized for 100% economizer
cycle.
102313
PROJECT NO, BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 8 OF 17
FANS SECTIONS
Provide fans of type and class as specified on the schedule. Fan shafts shall be
solid, coated with a rust-inhibiting coating, and properly designed so that fan
shaft does not pass through first critical speed as unit comes up to rated RPM
All fans shall be statically and dynamically tested by the manufacturer for
vibration and alignment as an assembly at the operating RPM to meet design
specifications. Fans controlled by variable frequency drives shall be statically and
dynamically tested for vibration and alignment at speeds between 25% and
100% of design RPM If fans are not factory-tested for vibration and alignment,
the contractor shall be responsible for cost and labor associated with field
balancing and certified vibration performance. Fan wheels shall be keyed to fan
shafts to prevent slipping.
Provide grease lubricated ball bearings selected for L-50 200,000-hour average
life per ANSI/AFBMA 9. Greasable bearings shall have lubrication lines extended
to the drive side of the unit. Lubrication lines shall be a clear, high-pressure,
polymer to aid in visual inspection. Extend both grease lubrication lines to drive
side of unit and rigidly attach to drive side bearing support with zerk fittings. If
extended lubrication lines are not provided, manufacturer shall provide
permanently lubricated bearing with engineering calculations for proof of bearing
life.
Fans shall be mounted on isolation bases. Internally-mounted motor shall be on
the same isolation base. Fan and motor shall be seismically restrained and
internally isolated with spring isolators. Flexible canvas ducts shall be installed
between fan and unit casing to ensure complete isolation. Flexible canvas ducts
shall comply with NFPA 90A and UL 181 requirements. Statically and
dynamically balance fan section assemblies.
Fan sections shall have full height, double wall, hinged doors on drive side for
inspection and maintenance of internal components.
Belts shall be enclosed as required by OSHA standard 29 CFR 1910 to protect
worker from accidental contact with the belts and sheaves.
For fan sections controlled by variable frequency drives, balance at speeds
between 25% and 100% of design RPM
MOTORS AND DRIVES
Fan motors shall be heavy duty, high efficiency per Section 15050, open dripproof.
2.
V-Belt Drive shall be variable pitch rated at 1.2 times the motor nameplate.
All motors and drives shall be factory-installed and run tested. All motors shall be
installed on a slide base to permit adjustment of belt tension. Slide base shall be
designed to accept all motor sizes offered by the air-handler manufacturer for
that fan size to allow a motor change in the future, should airflow requirements
change.
Motors shall be selected to operate continuously at 104 F (40 C) ambient without
tripping of overloads. Motors shall have a +/- 10 percent voltage utilization range
102313
PROJECT NO. BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 9 OF 17
to protect against voltage variation. Motors shall be in compliance with EPACT
when applicable.
Manufacturer shall provide for each fan a nameplate with the following
information to assist air balance contractor in start up and service personnel in
maintenance:
Fan and motor sheave part number
Fan and motor bushing part number
Number of belts and belt part numbers
Fan design RPM and motor HP
Belt tension and deflection
Center distance between shafts
COILS SECTION
Coils shall be manufactured by the same company as the supplier of the air
handling unit. Install coils such that headers and return bends are enclosed by
unit casings.
The wet section of the unit, defined as the entering air side of the
dehumidification coil to the leaving edge of the drain pan, shall be insulated. The
insulated shall meet UL 181 requirements. The air stream surface of the
insulation shall be constructed or coated such that it is not biodegradable, repels
water and it can be cleaned to prevent microbial growth. The manufacturer's
maintenance instructions shall describe the proper cleaning procedure for the
unit.
Construct coils of plate fins and seamless tubes. Fins shall have collars drawn,
belled and firmly bonded to tubes by means of mechanical expansion of tubes.
Do not use soldering or tinning in bonding process.
Construct coil casings of galvanized steel with formed end supports and top and
bottom channels. If two or more coils are stacked in unit, install intermediate
drain channels between coils to drain condensate to main drain pans without
flooding lower coils or passing condensate through airstream.
5.
DX Cooling Coils: Refer to Section 15790.
CONDENSING SECTION
The condensing section shall be open on the sides and bottom to provide access
and to allow airflow through the coils. Condenser coils shall be multi-row and
fabricated from 3/8" high efficiency rifled copper tubing mechanically bonded to
high efficiency aluminum fins. Each condenser coil shall be factory leak tested
with high-pressure air under water. Condenser coil guards shall provide
protection from incidental contact to coil fins. Coil guards to be constructed of
cross wire welded steel with PVC coating. Provide acoustic fan shrouds.
Condenser fans shall be direct drive, propeller type designed for low tip speed
and vertical air discharge. Condenser fans shall have airfoil blades, discharge
shrouds for quiet operation, and shall run at 850 maximum rpm. Fan blades
shall be constructed of steel and riveted to a steel center hub. Condenser fan
motors shall be heavy-duty, inherently protected, three-phase, non-reversing
type with permanently lubricated ball bearing and integral rain shield.
102313
PROJECT NO. BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 10 OF 17
Each circuit shall have fan cycling of at least one condenser fan to maintain
positive head pressure. An ambient thermostat shall prevent the refrigeration
system from operating below 45°F. SpeedTrol TM condenser fan speed control
shall be added to the last fan off on each refrigeration circuit to provide cooling
operation to ambient temperatures down to 32°F. Fan speed control shall be field
adjustable (size 36-75C only).
Each unit shall have multiple, heavy-duty Copeland scroll compressors. Each
compressor shall be complete with gauge ports, crankcase heater, sight-glass,
anti-slug protection, motor overload protection and a time delay to prevent short
cycling and simultaneous starting of compressors following a power failure.
Compressors shall be isolated with resilient rubber isolators to decrease noise
transmission.
Each unit shall have two independent refrigeration circuits. Each circuit shall be
complete with a liquid line solenoid valve, low pressure control, filter-drier, liquid
moisture indicator/sight-glass, thermal expansion valve, liquid line shutoff valve
with charging port, discharge line shutoff valve, a manual reset high pressure
safety switch, high pressure relief device and pump down switch. The thermal
expansion valve shall be capable of modulation from 100% to 25% of its rated
capacity. Sight-glasses shall be accessible for viewing without disrupting unit
operation. Each refrigerant circuit shall include a subcooling circuit to provide 15
degrees of liquid subcooling. Each circuit shall be dehydrated and factory
charged with Refrigerant 407C and oil.
Refrigeration capacity control shall be accomplished by staging of the unit's
multiple compressors. To maintain desired temperature control, the unit shall
have a minimum of four steps of capacity control.
All compressor capacity control staging shall be controlled by the factory installed
main unit control system.
All compressor capacity control staging shall be controlled by the factory installed
main unit control system.
DRAIN PANS
Units with cooling coils shall have drain pans under complete cooling coil section
that extend beyond the air-leaving side of the coil to ensure capture of all
condensate in section. Drain pans shall be constructed of interior and exterior
panels. Insulation shall be encased between exterior and interior walls. Drain
pans shall be stainless steel and shall be sloped in 2 planes, pitched toward
drain connections to ensure complete condensate drainage when unit is installed
level and trapped per manufacturer's requirements.
Units with heating coils shall have a galvanized steel drain pan under complete
heating coil section sloped in 2 planes and pitched toward drain connections to
ensure proper drainage during cleaning and to capture water in the event of a
coil failure.
All drain pan connections supplied by unit manufacturer including, piping, and
piping connections extending from stainless steel drain pans shall be constructed
of stainless steel.
102313
PROJECT NO. BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 11 OF 17
Sections after each coil shall have galvanized steel flat drain pans which shall be
accessible for cleaning.
EXTERNAL PIPING ENCLOSURE
All units shall be provided with external piping enclosure. Piping enclosure shall
be supplied by the manufacturer factory assembled and shall be of the same
construction as the main unit casing. Piping enclosure shall be external to the
unit and be shipped separate for field installation in order to facilitate piping of the
unit coil(s). Piping enclosure shall be mounted on a roof curb.
Each piping enclosure shall have a hinged access door, minimum 36" wide and
full height of the unit.
3.
Piping enclosures shall be full height of unit and minimum 34" deep.
Length of enclosure shall completely enclose the cooling coil section, access
section, heating coil section and face and bypass damper section of each unit.
FILTERS
Provide factory-fabricated filter section of the same construction and finish as
unit casings. Filter section shall have filter guides and access door(s) extending
the full height ofthe casingto facilitate filter removal. Provide filter blockoffs as
required to prevent air bypass around filters.
Pre-filter shall be minimum MERV 7, 2" pleated media.
removable from one side of filter section(s).
Filters shall be
DAMPERS
All dampers shall be internally mounted. Dampers shall be premium ultra low
leak and located as scheduled. Dampers shall be Ruskin CD60 double-skin
airfoil design or equivalent for minimal air leakage and pressure drop. Leakage
rate shall not exceed 5 CFM/square foot at one inch water gauge and 9
CFM/square foot at 4 inches water gauge. All leakage testing and pressure
ratings shall be based on AMCA Publication 500. Manufacturer shall submit
brand and model of damper(s) being furnished.
2.
For specification of damper actuators, refer to Specification Section 15975.
Provide low leak face and bypass dampers as scheduled on drawings. Dampers
shall be Ruskin CD60 double skin airfoil design or equivalent. Construct damper
blades and damper frames of galvanized steel. Provide opposed blade action
with metal compressible jamb seals and extruded vinyl blade edge seals. Blades
shall rotate on stainless steel sleeve bearings. Mechanically link face dampers
to bypass dampers and provide end driven control shafts. Damper blade lengths
shall not exceed 60 inches. Leakage rate shall not exceed 5 CFM/square foot at
one inch water gage and 9 CFM/square foot at 4 inch water gage.
ENERGY WHEEL SECTION
A. The air-handling unit shall have a total energy wheel sized per the ventilation
requirement of the unit. The energy wheel should be an integral part of the airhandling unit. An additional outside air unit, or other field assembled and ducted
102313
PROJECT NO. BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 12 OF 17
energy recovery device, is not acceptable. Mixed air units with economizing shall
be constructed with internal bypass dampers such that the pressure drop across
the wheel does not increase during economizing. External bypass and multiple
duct connections are not acceptable.
Performance & Certification. The air-handling unit shall be certified by ARI to
contain a rotary energy recovery wheel that is AR11060 certified. The airhandling unit nameplate shall bear the AR11060 certification label. Performance
characteristics of the energy wheel shall be provided as defined by AR11060.
The energy wheel shall be a total energy wheel, and the sensible and latent
effectiveness shall be reported. The calculated total net effectiveness of the
recovery device shall not be less than 70 percent when the specified ventilation
flow rate equals the exhaust flow rate. The amount of outside air transferred to
the exhaust air shall also be reported to ensure proper fan and damper sizing.
Wheel face velocity shall not exceed 900 fpm and pressure drops shall be less
than 1.25 in w.g. The energy recovery cassette shall be an Underwriters
Laboratories (UL) Recognized Component certified for mechanical, electrical,
and fire safety in accordance with UL Standard 1812.
Section Casing. Total energy recovery wheel modules shall be of solid doublewall construction. All exterior wall panels shall be made of galvanized steel. The
casing shall be able to withstand up to 1.5 times design static pressure, or 8 in
w.g., whichever is less, with no more than 0.005 linear unit of deflection per
linear unit of panel span. The unit shall be factory insulated and the panel
insulation system shall provide a minimum R-value of 12. The insulation shall
conform to NFPA 90 requirements.
Wheel Construction. The energy recovery component shall incorporate a rotary
wheel in an insulated cassette frame complete with seals, drive motor, and drive
belts. The total energy recovery wheel shall incorporate a desiccant without the
use of binders or adhesives, which may plug the desiccant aperture. Coated
segments shall be washable using standard detergent or alkaline-based coil
cleaners. The desiccant shall not dissolve in the presence of water or high
humidity. The rim shall be continuous rolled stainless steel to form an even
concentric circle to prevent leakage around the rim and to minimize wear of
components. All diameter and perimeter seals shall be provided as part of the
cassette assembly. Perimeter seals shall be self-adjusting; diameter seals shall
be adjustable. Seals shall be factory set. Wheel bearings shall be permanently
sealed and lubricated and have a minimum L-10 life of 400,000 hours.
Wheel Motor. The wheel drive motor shall be provided, mounted in the cassette
frame and supplied with a connector for field service. The wheel drive motor
shall be thermally protected and UL Component Recognized. Drive belts shall
require no belt tensioners. The wheel drive motor shall be no greater than 0.5
hp.
Maintenance. Energy recovery media for wheels larger than 25 inches in
diameter shall be provided in the form of removable segments. The segments
shall be removable without the use of tools to facilitate maintenance and cleaning
as required.
Access. Access doors shall be provided to allow for the removal of wheel
segments. Adequate space and access shall be provided for motor, bearing,
and belt removal.
102313
PROJECT NO, BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 13 OF 17
Wheel Control. Control of the energy wheel shall be incorporated into the air
handler control system and shall be as described under the air handler control
specifications. A secondary independent wheel controller is not acceptable. The
energy recovery device shall be designed with variable effectiveness control, to
vary the wheel's recovery capacity. The air handler manufacturer shall provide
an internal bypass damper for this control. The wheel's variable effectiveness
control shall have the ability to modulate the wheel's total energy recovery
effectiveness to 40 percent of the initial total recovery capacity.
Frost Control. Frost prevention shall be achieved using outside air bypass. The
air handler manufacturer shall provide frost set point temperatures, based on the
scheduled design air conditions. The air handler manufacturer shall provide any
de-rate in performance due to frost prevention measures for winter design supply
and exhaust air conditions leaving the energy wheel.
M.
FACTORY-INSTALLED VARIABLE FREQUENCY DRIVE/CONTROLLER
Variable Frequency Drive (VDD) shall be factory mounted, wired to the fan
motor, and commissioned by the AHU manufacturer. For specification, refer to
Section 23 29 23. Factory mounting will facilitate temporary heating, cooling,
ventilation, and / or timely completion of the project.
VFD/Disconnect shall be factory-mounted in a weatherproof, NEMA 3R
enclosure on the drive side of the air handling unit fan section. Ensure four feet
of clearance to access panel.
Factory Commissioning: Trained factory personnel shall ensure proper operation
of the VFD by a thorough factory test. Testing shall include "Hypot" test of unit
wiring to insure that no weaknesses exist in VFD, wiring, or motor. VFD should
be energized and fan run at 22Hz, 40Hz, and 60Hz to insure VFD will operate
throughout usable range of drive and that the fan rotation is correct. If VFD has
bypass, fan will additionally be tested in bypass position to insure bypass is
operational.
2.04
FAN COIL UNITS
A.
GENERAL UNIT DESCRIPTION
Unit layout and configuration shall be as defined in project plans and schedule.
Blow-through is only acceptable when consideration is given to capturing
downstream moisture carryover. Considerations include downstream moisture
eliminators and/or extended blank modules with condensate drain pans.
B.
UNIT CASING
The entire air handler shall be constructed of galvanized steel. The removal of
side panels shall not affect the structural integrity of the unit once the unit is
installed. Contractor shall be responsible to provide connection flanges and all
other framework that is needed to properly support the unit.
Access panels shall be on both sides of the unit in all sections to allow easy
access to drain pan, coil(s), motor, drive components and bearings for cleaning,
inspection, and maintenance.
102313
PROJECT NO, BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 14 OF 17
Units shall ship as one or two modules completely factory-assembled including
all coils, fans, motors, drives, dampers and filters.
Access Panels: Removable access panels shall be provided on both sides of the
unit to facilitate service access to drain pans, motors, drive components and
bearings. Panels shall be gasketed. Access panel for filter removal shall be
provided on both sides of the unit.
Cabinet: Casing shall be manufactured of heavy gauge galvanized steel. All
removable panels shall be gasketed to minimize air leakage.
INSULATION - High density, foil-faced - Interior surface of unit casing shall be
acoustically and thermally lined. Insulation shall be installed with adhesive.
Insulation shall have a minimum R-Value of 4, shall be UL listed, and shall meet
ASTM C 665 Bacteriological Standard requirements. The installation shall
comply with NFPA90A and B requirements. All exposed edges shall be sealed
to prevent erosion of fibers into the airstream. If edges of fiberglass insulation
are exposed, the manufacturer shall be responsible for sealing exposed edges
with mastic sealer to prevent erosion into the airstream.
COILS
Install coils such that headers and return bends are enclosed by unit casing to
ensure that if condensate forms on the header or return bends, it is captured by
the drain pan under the coil.
Coils shall be manufactured with plate fins to minimize water carryover and
maximize airside thermal efficiency. Fin tube holes shall have drawn and belled
collars to maintain consistent fin spacing to ensure performance and air pressure
drop across the coil are as scheduled. Tubes shall be mechanically expanded
and bonded to fin collars for maximum thermal conductivity. Use of soldering or
tinning during the fin-to-tube bonding process is not acceptable due to the
inherent thermal stress and possible loss of bonding at that joint.
Construct coil casings of galvanized steel. End supports shall have belled tube
holes to minimize wear of the tube wall during thermal expansion and contraction
of the tube.
4.
Hydronic Coils
Supply and return header connections shall be clearly labeled on outside
of units such that direction of coil water-flow is counter to direction of unit
air-flow
Coils shall be proof tested to 450 psig and leak tested to 300 psig air
pressure under water.
Headers shall be constructed of round copper pipe.
Tubes shall be 1/2 inch O.D. minimum 0.016 inch thick copper. Fins
shall be aluminum.
Coils shall be capable of being rotated in the field for left or right hand
connection.
DRAIN PAN
Cooling coil drain pan shall be constructed of 304 stainless steel. Units with
cooling coils shall have drain pans under complete cooling coil section that
102313
PROJECT NO. BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 15 OF 17
extend beyond the air-leaving side of the coil to ensure capture of all condensate
in section.
Drain pan shall be sloped in two planes, pitched toward drain connections to
ensure complete condensate drainage when unit is installed level and trapped
per manufacturer's installation instructions. Units without drain pans sloped in
two planes shall coat drain pans with anti-microbial treatment. Drain pan(s) shall
have main and auxiliary drain connections with auxiliary outlet higher than the
main connection.
Coil(s) shall be mounted above the drain pan to facilitate easy and complete
inspection, cleaning and removal.
The drain pan shall be capable of being rotated in the field between right and left
hand connections.
FANS
Provide single-wheel, forward curved centrifugal fans as specified on the
schedule. Fan shaft bearings shall be permanently sealed ball bearing with a
minimum L50 design life of 200,000 hours.
MOTORS AND DRIVES
All motors and drives shall be factory-installed and run tested. All motors shall
be installed on a slide base to permit adjustment of belt tension.
2.
Motors shall be open drip-proof.
Motors shall be selected to operate continuously at 130 F (55 C) ambient without
tripping on overloads. Motors shall have a +/- 10 percent voltage utilization range
to protect against voltage variation.
Manufacturer shall provide for each fan a nameplate with the following
information to assist air balance contractor in star-up and services personnel in
maintenance:
Fan and motor sheave pa•t number
Fan and motor bushing pa•t number
Number of belts and belt pa•t numbers
Fan design RPM and motor HP
Belt tension and deflection
Center distance between shafts
FILTERS
Provide removable two inch thick filters easily removable from a hinged access
door from either top or bottom of the unit. All units shall use standard filter sizes.
WIRING
Provide unit with fan motor power wiring extending to a junction box on the side
of the unit
102313
PROJECT NO, BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 16 OF 17
2.05
MAKEUP AIR UNIT
A.
Manufacturers:
1.
McQuay
2.
Other acceptable manufacturers offering equivalent products include:
a.
Modine.
b.
Trane.
GENERAL DESCRIPTION
1.
Configuration. Unit shall be comprised of the following components:
a.
Air intake section.
b.
Heating section.
c.
Fan and motor.
2.
Fan performance: As scheduled on the drawings
3.
Heating section: Capacity as scheduled on the drawings
CASING
1.
Construction: Sectionalized modules fabricated on channel base of welded
steel. Outside casing shall be minimum 20 gage galvanized steel. Assemble
sections with gaskets and bolts.
2.
Insulation: 1 inch thick; adhesive and coating shall comply with NFPA 90.
3.
Inspection Doors: Provide at each component requiring routine service including
fan and intake components with gasket, latch, and handle assembly.
FANS AND DRIVES
1.
Fan shall be forward curved, belt driven with open drip proof motor.
2.
For motor performance and electrical characteristics, refer to Section 15050.
FILTERS
102313
1.
Filter Box: Provide with filter guides, access doors, side loading, flat filter
arrangement.
2.
Filter Media: UL 900 listed, Class 2.
3.
Disposable Filters: 2 inch (50 mm) thick fiberglass, American Air Filter Model
5700 or approved equal.
PROJECT NO. BI-RT-844-CMR
SECTION 23 73 00
INDOOR CENTRAL-STATION AIR-HANDLING UNITS
PAGE 17 OF 17
PART 3 - EXECUTION
3.01
3.02
INSTALLATION
A.
Install in accordance with Division 1.
B.
Install in accordance with ARI 435.
C.
Assemble high pressure units by bolting sections together.
D.
Install assembled unit on vibration isolators. Refer to Section 23 05 48.
E.
Lubricate units before start-up.
F.
After testing and startup has been completed, replace filters with extra set of clean filters.
COMMISSIONING
A.
Engage a factory-authorized service representative, to perform startup service as per
functional test sheets and requirements of Section 17000 Commissioning.
B.
Verify that equipment is installed and commissioned as per requirements of Section
17000 and manufacturer's written instructions.
C.
Complete installation and startup checks and functional tests according to Section 23 08
00 and manufacturer's written instructions.
D.
Operational Test: After electrical and control systems have been energized, start units to
confirm proper unit operation. Rectify malfunctions, replace defective parts with new one
and repeat the start up procedure.
E.
Test and adjust controls and safety devices. Replace damaged and malfunctioning
controls and equipment.
END OF SECTION
102313
PROJECT NO, BI-RT-844-CMR