SECTION __________
CUSTOM PACKAGED DX AIR HANDLING UNIT SPECIFICATION
PART 1 GENERAL
1.1
1.2
DESCRIPTION OF WORK
A.
Custom Packaged DX air handling units.
B.
Economizer sections where noted on drawings.
C.
Supply fan section.
D.
Return fan section where noted on drawings.
E.
Internal vibration isolation.
F.
Filter section.
G.
Cooling coils.
H.
Heating coils.
I.
Accessories.
J.
Mechanical variable volume devices.
REFERENCES
A.
AFBMA 9 - Load Ratings and Fatigues Life for Ball Bearings.
B.
AFBMA 11 - Load Ratings and Fatigue Life for Roller Bearings.
C.
AMCA 99 - Standards Handbook.
D.
AMCA 210 - Laboratory Methods of Testing Fans for Rating Purposes.
E.
AMCA 300 - Test Code for Sound Rating Air Moving Devices.
F.
AMCA 301 - Method of Publishing Sound Ratings for Air Moving Devices.
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1.3
G.
AMCA 500 - Test Methods for Louver, Dampers, and Shutters.
H.
ARI 410 - Forced-Circulation Air-Cooling and Air-Heating Coils.
I.
ARI 430 - Central Station Air Handling Units.
J.
ARI 435 - Application of Central Station Air Handling Units.
K.
ARI 610 - Central System Humidifiers.
L.
NEMA MG1 - Motors and Generators.
M.
NFPA 70 - National Electrical Code.
N.
SMACNA - HVAC Duct Construction Standards - Metal and Flexible.
O.
UL 900 - Test Performance of Air Filter Units.
SUBMITTALS
A.
Submit under provisions of General Conditions and Division 1 as applicable.
B.
Shop Drawings: Indicate assembly, unit dimensions, weight loading, required
clearances, construction details, field connection details and electrical
characteristics and connection requirements.
C.
Product Data:
1.
Provide literature which indicates dimensions, weights, capacities, ratings,
fan performance, gauges and finishes of materials and electrical
characteristics and connection requirements.
2.
Provide data of filter media, filter performance data, filter assembly, and
filter frames.
3.
Provide fan curves with specified operating point clearly plotted.
4.
Submit sound power level data for both fan outlet, fan inlet 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 field installed wiring.
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Packaged DX Air Handling Unit Specification
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6.
1.4
1.5
OPERATION AND MAINTENANCE DATA
A.
Submit under provisions of General Conditions and Division 1 as applicable.
B.
Maintenance Data: Include instructions for lubrication, filter replacement, motor
and drive replacement, spare parts lists and wiring diagrams.
C.
Manufacturer’s Installation Instructions.
QUALIFICATIONS
A.
1.6
1.7
A.
Deliver, store, protect and handle products to site under provisions of General
Conditions and Division 1 as applicable.
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
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 MATERIALS
A.
1.9
Manufacturer: Company specializing in manufacturing the products specified in
this section with minimum ten (10) years documented experience, who issues
complete catalog data on total product.
DELIVERY, STORAGE, AND HANDLING
A.
1.8
Submit performance, noise and vibration test results of the laboratory air
handling unit and office air handling unit. Provide test results for review
prior to any air handling unit shipment to the jobsite.
Furnish under provisions of General Conditions and Division 1 as applicable.
QUALITY ASSURANCE
A.
Conform to space and access requirements; units will not be accepted which do
not conform to space and access requirements.
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PART 2 PRODUCTS
2.1
MANUFACTURERS
A.
Energy Labs.
B.
Governair Corporation
C.
Webco, Inc
Manufacturers listed by name does not imply that their standard method of unit manufacture is
acceptable or approved. All manufacturers shall meet or exceed all requirements of this
specification without exception.
2.2
CUSTOM PACKAGED DX AIR HANDLING UNITS
A.
Units shall be factory built, double wall construction with components listed in
attached schedule.
B.
Arrangement: Refer to the plan drawing.
C.
Unit Construction: The following sections describe in detail construction
requirements for the unit base, cabinet, access doors, insulation and paint finish.
Unit shall be built for outdoor installation.
1.
Unit Base: Each unit shall be constructed on a base fabricated from heavy
duty welded structural steel channel. Formed metal tubular bases or
formed metal channel bases are not acceptable. Channel bases shall be
sized as a function of air handling length as follows:
A.H. UNIT
LENGTH
UP to 15’..............................
10’ - 20’ ...............................
15’ to 25’..............................
20’ x 30’...............................
25’ x 40’...............................
MINIMUM
CHANNEL SIZE
4” x 1-5/8”
6” x 2”
8” x 2-1/2”
10” x 2-5/8”
12” x 3”
(5.4#/Lin.Ft.)
(8.2#/Lin.Ft.)
(11.5#/Lin.Ft.)
(15.3#/Lin.Ft.)
(20.7#/Lin.Ft.)
a.
Heavy welded lifting lugs shall be added to the perimeter channel
along the longest length of the unit section.
b.
The unit floor shall be fabricated of 16 gauge hot rolled galvanized
steel sheets. Each sheet of flooring material shall have a base
structural member centered under all edges for adequate support.
All floor seams shall be fully welded flush to maintain an air tight
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seal. The flooring shall be welded to the structural members
below. Welds from below the floor shall be spaced no greater than
4” on center. Drive screw attachment is not acceptable.
2.
3.
Unit Housing
a.
The unit housing side and roof panels shall be constructed of 16gauge galvanized steel, and shall utilize a standing seam modular
panel type construction. The panels shall be attached to each other,
to the roof, and to the floor using bolts. Drive screw attachment is
not acceptable. All seams shall be sealed with an acrylic latex
sealant prior to assembling the panels and after completion of the
assembly.
b.
All floor openings shall have 1” minimum flange up around the
entire perimeter.
c.
(Type F) Doors shall be double wall, insulated, man size, double
seal type with two separate gaskets closing to knife-edges.
Doorframe shall be powder coated extruded aluminum with
stainless steel powder coated adjustable hinges. Door handles and
hinges shall be fully adjustable. Door handles shall incorporate a
roller cam to insure airtight fit. Doors shall be operable from inside
as well as outside unit. Ventlock type handles are not acceptable.
d.
Door hinges and latches shall be easily adjustable, without the use
of shims or special tools, to allow for a tight seal between the door
and the unit as the gasketing material compresses over time.
e.
Latches shall utilize non-corrosive door handles on exterior and
roller cam type on interior.
f.
(Option) Include a 9” x 9” wire dual glazed reinforced glass view
window in each fan access door.
Insulation: Wall and Ceiling Insulation shall be 2” (Option 4”) thick, 1½#
(Option 3#) per cubic foot density, neoprene coated fiberglass and cover
all walls, ceilings and under floors. Insulation shall meet NFPA-90A
smoke and flame spread requirements.
There shall be no insulation
exposed to the air stream. All other sections shall have 20 gauge solid
steel liners. Each panel shall be individually removable and be used to
secure the insulation in place. (Option) All fan sections shall have a 20gauge perforated steel acoustical sheet metal liner covering all walls and
ceiling surfaces.
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F.
4.
Floor insulation shall be 2” minimal polyurethane continuous foam-inplace insulation applied to underside of floor liners. Fiberglass insulation
in bases is not acceptable as they do not prevent oil-canning and have
inherent gaps between batts which compromise the r-factor of the
insulation.
5.
Paint Finish: After final assembly the unit exterior shall be coated with an
industrial grade polyurethane paint. In addition, all fan bases, springs and
structural steel supports shall be coated with the same finish. The paint
system shall meet ASTM B Salt fog test for a minimum 2000 hours.
Internal Components
1.
2.
Fan Assembly (Arrangement #1 Plenum Fan or Direct Drive)
a.
All fan assemblies supplied for the air handlers shall be
manufactured by the air handling unit manufacturer for the purpose
of sole source responsibility.
b.
Fan performance shall be based on tests run in an AMCA certified
laboratory and administered in accordance with AMCA Standard
210. Fan performance tests shall be taken with fans running inside
the cabinet to include any affects from the unit cabinet and other
internal components.
c.
Fans shall be configured so that both fan bearings are on the same
side of the wheel with the wheel over hung (Arrangement #1) or
direct drive as shown on plans. There shall be no obstructions (i.e.,
bearings or bearing supports, etc.,) at the inlet of the fan. All
Plenum fan wheels shall be aluminum construction.
d.
Each fan shall be sized to perform as indicated on the equipment
schedule. The wheel diameter shall not be less than that shown on
the equipment schedule. The fan shall be constructed to AMCA
Standards for the Class Rating as indicated on the Equipment
Schedule.
e.
For belt driven fans, provide pressure relief type grease fittings and
extend lubrication lines to the motor side of the fan just inside its
access door.
Fan Base, Spring Isolation, and Support Framing
a.
Mount fan and motor on an internal, fully welded, rigid structural
steel channel base. Base shall be free-floating at all four corners on
spring type isolators with earthquake restraints. The fan assembly
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shall be isolated from the cabinet by steel springs with deflection
as indicated in schedules.
b.
3.
The fan discharge shall be isolated from the cabinet by means of a
neoprene-coated flexible connection. If belt driven, L10- 200,000
Hr. operating life bearings shall be mounted on a structural steel
channel or machined surface. The structure supporting the bearing
bar shall be fabricated from structural steel and detachable to allow
for removal of the fan wheel and shaft as one piece.
Balancing
a.
The shafting of the fan shall be sized not to exceed 75% of the first
critical speed for maximum RPM of Class specified. The critical
speed will refer to the top of the speed range of the fans’ AMCA
class. The lateral static deflection shall not exceed 0.003” per foot
of the length of the shaft.
VIBRATION - [BELT DRIVE] Fan wheels and shaft assemblies
shall be factory dynamically balanced and shall meet or exceed
guidelines in AMCA 204-96 for Balance Quality and Vibration
Levels for Fan Application Category BV-3. Following fan
assembly, the complete spring isolated fan assembly shall be tested
using an electronic balance analyzer with tunable filter and
stroboscope. Vibration measurements shall be taken on each fan
bearing housing in the vertical, horizontal, and axial planes (6 total
measurements, 3 each fan bearing). The maximum allowable peak
velocity shall not exceed 0.125 inches per second peak amplitude
(filter in) on any of 6 readings and sum of all readings shall not
exceed 1.5 mils displacement when fan is running at 1135 rpm. A
copy of the Vibration test report (Vibration Nomograph) shall be
provided with the Operation and Maintenance Manual upon
request. The fan assembly shall also be vibration tested at design
RPM with the spring isolators at the specified deflection, with the
tunable filter utilized and frequencies from 500 cpm to 50,000 cpm
shall be scanned to detect misalignment, bearing defects,
mechanical looseness or foundation weakness.
VIBRATION - [DIRECT DRIVE] Fan wheel shall be factory
dynamically balanced and shall meet or exceed guidelines in
AMCA 204-96 for Balance Quality and Vibration Levels for Fan
Application Category BV-3. Following fan assembly, the complete
spring isolated fan assembly shall be tested using an electronic
balance analyzer with tunable filter and stroboscope. Vibration
measurements shall be taken on each motor bearing housing in the
vertical, horizontal, and axial planes (5 total measurements, 2 each
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motor bearing and 1 Axial). The maximum allowable velocity shall
not exceed 0.125 inches per second peak amplitude (filter in) on any
of 5 readings and the sum of all readings shall not exceed .5 mils @
1170 rpm. A copy of the Vibration test report (Vibration
Nomograph) shall be provided with the Operation and Maintenance
Manual upon request. The fan assembly shall also be vibration
tested at design RPM with the spring isolators at the specified
deflection, with the tunable filter utilized and frequencies from 500
cpm to 50,000 cpm shall be scanned to detect misalignment, bearing
defects, mechanical looseness or foundation weakness.
b.
4.
5.
A copy of the above balance test data for this project showing
calculations for deflection and critical speed of the shaft and wheel
assembly shall be submitted to the engineer and a copy forwarded
to the Owner.
Motors and Drive
a.
Furnish high-efficiency open drip proof standard NEMA frame
rigid ball bearing type motors. Reliance “Alpha”, Century “EPlus”, or Marathon “ZRI” with grease lubricated bearings and
alemite fittings. Horsepower as shown on the schedule are
minimum allowable.
b.
The motor shall be mounted on an adjustable slide rail motor base.
The fan motors shall be factory wired to an external junction box
with flexible conduit of adequate length so that it will not have any
affect on the vibration isolation.
c.
If belt driven, provide V-belt type, cast-iron sheaves, and
reinforced rubber belts. The belts shall be selected for 150% of the
motor nameplate horsepower. Drives shall be “Browning” or equal
by “Woods.”
Coils
a.
Cooling coils shall be the plate fin extended surface type. The
primary surface shall be a minimum of 5/8” outside diameter
seamless copper with a 0.020” minimum wall thickness. Each coil
shall have individually replaceable return bends of 0.025 wall
thickness minimum on both sides of the coil. Coils incorporating a
“hairpin” type design are not acceptable. Tubes shall be expanded
into the fin collars to provide a permanent mechanical bond.
b.
The secondary surface shall be flat or formed of 0.008” aluminum
fins and shall be spaced not closer than 12 fins per inch with
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integral spacing collars that cover the tube surface. Headers shall
be non-ferrous seamless copper. Chilled water coil coils shall be
tobin bronze brazed steel male pipe connections and 1/8” pipe vent
and drain connection extended to outside of unit casing.
6.
c.
Direct Expansion Coils shall have copper sweat suction
connections and refrigerant distributor liquid connections, and
shall be provided with adjustable superheat controls and external
equalizer lines.
d.
Cooling coil casing shall be minimum 16-gauge, 304 stainless steel
with double formed 1/2” stacking flanges and 3/4” flanges on the
side plates. Flanged tube sheets shall have extruded tube holes.
Reinforcing rods shall be furnished so that the unsupported length
is not over 60”. All coil assemblies shall be tested under water at
300 psi and rated for 150-psi working pressure. Provide diverter
plates at both ends of the coil to divert the condensate drip from the
headers and return bends into the drain pan. Headers are to be
located inside the cabinet casing with only the pipe connections
extending through the casing.
e.
Coils shall be fully blanked to ensure all air passes through the
coil. Intermediate condensate pans are to be furnished on multiple
coil units with copper down tubes to the main drain panel.
f.
304 Stainless steel IAQ double sloped recessed drain pans shall be
provided as an integral part of the unit base in all cooling coil
sections. Pans shall be 16-gauge minimum with 1”-1½ lb. density,
neoprene coated fiberglass insulation and a 16-gauge under liner.
Stainless steel condensate connections shall be provided on one
side of the unit.
g.
All chilled water coils shall be certified in accordance with ARI
Standard 410.
Filters
a.
Filter sections shall be fabricated as part of the air handling unit.
Filters shall be arranged for upstream, downstream, or side loading
as shown on the drawings. Provide filter holding frames to
accommodate scheduled filters.
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b.
7.
8.
G.
Factory install at each filter bank a Dwyer Magnehelic “Series
2000” pressure gauge complete with static pressure tips, hardware
and fittings. Enclose the gauges in a protective sheet metal box
with a hinged inspection door. Paint to match unit. Provide
separate filter gage for each pre and each final filter bank.
Economizer
a.
Economizer section shall include dampers for return air, fresh air
and exhaust air. Dampers shall be opposed blade type. Dampers
shall be sized for approximately 1200 fpm face velocity based
upon gross damper area. Furnish full height 24” wide access doors
for damper and linkage service.
b.
Dampers shall be extruded aluminum type with rubber edge seals
and stainless steel arc end seals. Dampers shall be low leak and
incorporate nylon bearings.
c.
Provide louvers for outside air and exhaust for units located
outdoors. Louvers shall be sized for a maximum face velocity of
450 fpm based on gross louver area. Hoods in lieu of louvers are
not acceptable.
(Option) Marine Service Lights: Vapor proof marine lights shall be
factory wired to individual switches located next to access doors for fan
sections, filter sections, and economizer sections.
(Option) Air Flow Measuring Stations – Fans and OSA
1.
Fans shall be supplied with a complete flow measuring system capable of
supplying a 4 - 20 mA output signal to the EMS system that is
proportional to air flow. The flow measuring station and a flow
transmitter, both factory mounted and piped.
2.
The flow measuring station shall consist of total and static pressure pickups located in the inlet cone(s) of each fan. OSA measurement device shall
be located at the OSA (minimum) damper. OSA measurement device shall
be based on thermal dispersion and be 2% to 5% accurate from 0 to 10000
FPM velocity. OSA measurement station shall be NIST traceable. OSA
measurement station shall be Ebtron “Gold” series or prior approved
equal. (No know equal)
3.
Provide a Magnehelic gauge with CFM scale on external side of the fan
sections which indicates the fan volume.
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Packaged DX Air Handling Unit Specification
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4.
The electronic flow transmitter shall be capable of receiving signals of
total and static pressure from a flow element, of amplifying, extracting the
square root, and scaling to produce a 4 - 20 mADC output signal linear
and scaled to air volume or velocity. The flow transmitter shall be capable
of the following performance and application criteria.
a.)
H.
Calibrated spans from 0 - 896 FPM, in eight flow range
increments. Output signal 4 - 20 mADC standard. Integral zeroing
means 3-way zeroing valve with manual switch. Temperature
effect ± 2.0% of full span from 40° to 120°F
5.
The transmitter shall not be damaged by over-pressurization up to 200
times greater than span, and shall be furnished with a factory calibrated
span and integral zeroing means. The transmitter shall be housed in a
NEMA 12 enclosure with external signal tubing, power, and output signal
connections.
6.
The electronic differential pressure transmitter shall be Dwyer model 605,
Setra 264 or equal. OSA transmitter shall be Ebtron GTA116
DX Condensing Sections
1.
The DX Condensing Section shall be fully integrated with the air handling
section and shall be self manufactured by the air handling unit
manufacturer in the same facility as the air handling section. Third party
purchased condensing units skid mounted to the air handling section are
not acceptable due to the lack of single source responsibility and quality
control by the air handling unit manufacturer.
2.
Compressors shall be of the hermetic scroll or semi-hermetic screw type.
Reciprocating compressors are not acceptable due to their inherently
excessive noise and vibration characteristics. Each refrigeration circuit
shall include all specialties for proper operation, including liquid line filter
drier and sightglass, refrigerant distributor(s) with thermal expansion
valve(s), and charging/service ports.
a.
Scroll Compressors
Compressor shall be of compliant design for axial and radial
sealing of the scrolls. Motor shall be suction gas cooled, with
sufficient suction side free volume and oil sump to provide
liquid handling capability.
Compressor to include annular
discharge check valve to provide low pressure drop, silent
shutdown, and reverse rotation protection. (Option) compressors
to include belly band heaters for additional liquid migration
protection. Compressors may be arranged in tandem, triple and
quad configuration on a single refrigeration circuit.
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b.
3.
Screw Compressors
Compressors shall be of the single stage, positive displacement,
3550 RPM hermetic motor driven, rotary screw type, including an
integral oil separation system, oil sump, oil filter, and integral solid
state motor protection. Each screw compressor capacity control
shall be achieved by infinitely variable slide valve unloading.
Condensing unit
a.
Air Cooled Condensing Units
Air Cooled Condensing Units shall incorporate a V style coil
arrangement to minimize the footprint and height of the unit. The
entire condenser section shall be supported
Condenser coils shall be constructed of seamless copper tubing
mechanically expanded into aluminum (option copper) fins, and
incorporate an integral subcooling circuit. Fin spacing to be no
greater than 12 fpi.
Condenser Fans shall be direct drive propeller type with venturis
for efficient performance and low sound levels, and shall
incorporate an external fan guard for each fan to protect against
inadvertent contact with the moving fans. Head pressure control is
maintained by fan cycling (option – variable speed motor control.)
b.
Evaporative Cooled Condensing Units
Evaporative Cooled Condensing Units shall be of the draw through
type. Blow through designs are not acceptable due to higher fan
power requirements and the likelihood of outward water leakage
due to positive pressures inside the wet section. The condenser
sump shall be constructed of stainless steel, and shall be double
sloped to drain to facilitate cleaning and maintenance.
All make up water, recirculation water, and drain piping shall be
factory piped by the unit manufacturer. Water circulation system
shall incorporate a minimum of two pumps for redundancy. Single
pump designs shall not be acceptable due to the lack of redundancy
of a critical component. Spray nozzles shall be of the spiral type to
prevent clogging. Moisture eliminators shall be provided on the air
inlet and above the spray tree to prevent moisture carryover.
Evaporative Condenser Coils shall be constructed of seamless
copper tubing supported by non-metallic tube sheets supported in
stainless steel frames, to permit expansion and prevent contact
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between dissimilar metals and galvanic corrosion. Designs that
incorporate finned “desuperheater” coils are not acceptable due to
the inherent scaling and corrosion involved with the wet
environment inside the condenser. If a desuperheater circuit is
included, the manufacturer shall provide a lifetime warranty
against failure due to scaling and/or corrosion.
Condenser Fans shall be direct drive propeller type with venturis
for efficient performance and low sound levels, and shall
incorporate an external fan guard for each fan to protect against
inadvertent contact with the moving fans. Head pressure control is
maintained by fan cycling (option – variable speed motor control.)
c.
Water Cooled Condensing Units
Water Cooled Condensing Units shall incorporate ASME certified
cleanable shell & tube type condensers with removable heads.
Condenser water connections shall be grooved end pipe coupling
type (Victaulic) to facilitate head removal and tube cleaning with
minimal disruption to the piping system.
I.
Gas Heat
a.
b.
Heat Exchanger
The heat exchanger primary drum shall be constructed of 16-gauge
formed and welded series 300 stainless steel. Secondary tubes shall
be constructed of 14-gauge high carbon steel {option - series 400
stainless steel}.
Power Burner & Gas Train
The burner shall be of the power firing type and incorporate a
primary combustion air blower and spark ignition transformer. The
gas train shall be complete with all ETL approved controls and shall
be factory mounted in the unit heater vestibule. Standard controls
include main gas valve, flame supervision, positive burner safety
switch, pilot cock, main gas cock, adjustable main, and pilot pressure
regulators. The burner shall be factory fired and adjusted for proper
combustion. Final adjustment will be made in the field during unit
start-up by a factory representative or by a service organization
certified by the unit manufacturer. {option -The gas train shall be
complete with all components required to meet FM code or IRI
code.}
.
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Packaged DX Air Handling Unit Specification
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J. Controls
1.
All controls shall be factory mounted by the Air Handling Unit
manufacturer and be UL 705 certified. These controls shall include all
damper actuators, temperature sensors, pressure sensors, air flow
measuring sensors, filter switches, smoke and fire detectors as indicated on
the control drawings.
2.
Electric and electronic controls shall be wired in UL approved conduit to a
terminal block in a sheet metal UL Listed enclosure located at a common
location mounted on the air handling unit. All pressure sensing controls
shall be piped to a common point on the unit with 1/4” compression
fittings.
3.
All chilled water and hot water control valves shall be field mounted. In
addition, all necessary piping specialties including strainers, shut-off
valves, thermometers, pressure taps, air vents, etc. shall be field installed
as indicated on the piping diagram. Control valve wiring (electric) or
control tubing (pneumatic) shall be extended to a common point on the Air
Handling Unit by the air handler manufacturer.
(B) Electrical
1.
Unit manufacturer shall supply a single point power panel for main supply
voltage. Separate 115-volt power for lights and controls shall be provide by
Div 16.
2.
Single point power panel shall include all necessary fuses, non-fused
main disconnect, fan motor starters or VFD’s as specified in section
______, control transformer and terminals for remote control
interconnection
3. Power panel shall be UL508 labeled as a complete assembly. UL label for
enclosure only with UL internal components is not acceptable. Enclosure shall
be NEMA –4 construction UL listed.
4. All wiring shall be in compliance of the current National Electric Code. All
wiring shall be done by a UL705 certified shop at the factory. Field wiring is
not acceptable.
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Packaged DX Air Handling Unit Specification
Section _______, Page 14
K.
L.
Sound Power and Performance Certification
1.
Air handling unit sound power data shall be submitted for review by
Owner’s representative. Sound power data shall be given at the supply
connection(s) (outlet) and return connection(s) (inlet) in addition to
radiated sound power from the cabinet. Raw fan sound power data shall
be derived from tests done in accordance with AMCA Standard 300-85.
Data extrapolated from non-like fan sizes and types scheduled is not
acceptable. Attenuation assumed for the cabinet configuration, type of
insulation, opening locations and sizes, etc., shall be verified through
actual test measurements. The mechanical engineer may, at his option,
request copies of such tests.
2.
(Option) The manufacturer shall perform actual sound test on one selected
AHU in accordance with AMCA Standard 300-85. The mechanical
engineer shall select the test AHU after review of the submittal.
a.
Manufacturer shall perform the sound test in an AMCA lab
accredited for both AMCA 210 performance and AMCA 300
sound. Test lab accredited for just one or the other is not
acceptable.
b.
The mechanical and acoustics engineers shall be allowed to
witness the sound test. The AHU manufacturer shall notify the
mechanical engineer a minimum of ten (10) days prior to test as to
the location and date of the sound test. The travel costs incurred by
test witnesses shall be borne by the equipment manufacturer.
c
If the sound test indicates the AHU noise levels exceed levels of
units specified, the manufacturer shall take corrective measures to
reduce the sound. Any modifications that are necessary to meet
scheduled sound levels shall be applied to all AHU’s represented by
the test unit. Test results shall be submitted to the Owner’s
Representative for approval prior to shipment of any equipment.
Air Leakage Test (Option)
1.
Apparatus
a.
A U-Tube manometer shall be used to measure the static pressure
exerted on the unit cabinet. The manometer must have graduations
no larger than 0.2” (inches of water gauge).
b.
A pressure blower that is capable of producing the required
pressure without operating at a stall shall be used to perform the
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test. The pressurizing fan shall be attached to a flow metering
station which shall measure the volume flow rate by pressure drop
through one or more ASME long radius nozzles. The test
apparatus shall have a means of dampering such that the required
pressure may be exerted without over-pressurizing the cabinet.
c.
2.
M.
Air density shall be determined with wet and dry bulb
thermometers and a mercury barometer or equivalent.
Procedure
a.
The fan unit shall have all duct, damper, and louver openings
sealed with plywood or sheet metal and caulked or taped.
b.
The static pressure tap shall be arranged with one leg open to
atmosphere and one leg tapped to the cabinet interior.
c.
A static pressure load of 1.25 times the maximum calculated
system total static pressure or 12” whichever is less, will be exerted
on the cabinet.
d.
The leakage rate will be recorded at the flow measuring apparatus.
The air density at which the test was performed will be determined.
The test results will be corrected to standard air. An AHU will be
considered acceptable if it leaks at a rate of not more than one
percent of the design volume.
Warranty/Start-Up Service
1.
Manufacturer shall provide factory start-up service for each air handling
unit. Provide 18 month limited parts and labor warranty from date of unit
shipment.
PART 3 EXECUTION
3.1
INSTALLATION
A.
Install in accordance with manufacturer’s instructions.
B.
Install in conformance with ARI 435.
C.
Assemble high pressure units by bolting sections together. Isolate fan section
with flexible duct connections.
END OF SECTION
Energy Labs, Inc.
Packaged DX Air Handling Unit Specification
Section _______, Page 16