SECTION 15891

HVAC DUCTWORK

PART 1 - GENERAL

1.1 SECTION INCLUDES

A. The Work shall consist of furnishing and installation of all HVAC ductwork as
shown on the drawings and specified herein.

1.2 QUALITY ASSURANCE

A. Ductwork shall comply with the requirements of NFPA 90A; Standard for the
Installation of Air Conditioning and Ventilation System.

B. Comply with NFPA 96; Standard for the Installation of Equipments for the
Removal of Smoke and Grease-laden Vapors of Commercial Cooking
Equipment - Chapter 3; Duct System for kitchen hood duct systems.

C. SMACNA Standards: Comply with SMACNA "High and Low Pressure

Duct Construction Standards" for fabrication and installation of ductwork,
as well as "HVAC Duct Construction Standards, Metal and Flexible."

D. Fabricator and Installer: Firm(s) with a minimum of five (5) years of

successful fabrication/installation experience on projects similar to that
required for the project.
.

PART 2 - PRODUCTS

2.1 DUCTWORK MATERIALS

A. General: HVAC duct design shall be in accordance with applicable

requirements of ASHRAE, SMACNA, SASO, NFPA or UL codes and
Standards. Shop fabricate ductwork of gages and reinforcement complying
with SMACNA - HVAC Duct Construction Standards and/or ASHRAE
Handbook, Equipment Volume, Chapter 16 - Duct Construction, and as
shown on drawings. Ducts shall be low pressure ducts with 500 Pa pressure
rating and seal Class B as per SMACNA Standards, unless indicated
otherwise on drawings. Ductwork shall be constructed in sizes and
configuration as shown on drawings.

B. Exposed Ductwork Materials: Where ductwork is indicated to be exposed to

view in occupied spaces, provide materials which are free from visual
imperfections including pitting, seam marks, roller marks, oil canning, stains
and discolorations, and other imperfections, including those which would
impair painting.

C. Sheet Metal: Unless indicated otherwise indicated, fabricate ductwork from

galvanized sheet steel complying with ASTM A 653 and A 924, lock-forming
quality, with G90 zinc coating; and ducts shall have mill-phosphatized finish

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 for surfaces exposed to view.

D. Kitchen Hood Exhaust Ducts: Kitchen hood exhaust ducts and supports
used for smoke and vapor removal from cooking equipment, exposed to
view, shall be fabricated from minimum 18 gage thick stainless steel sheet
conforming to ASTM A 240, type 304, and the rest of the duct shall be
fabricated of black sheet steel, welded construction. Shop fabricate ductwork
complying with SMACNA "HVAC Duct Construction Standards", and NFPA
96 "Removal of Smoke and Grease-Laden Vapors from Commercial
Cooking Equipments".

2.2 MISCELLANEOUS DUCTWORK ACCESSORIES

A. General: Provide manufacturer's standard materials and products of types

and sizes indicated and, where not otherwise indicated, provide type and
size required to comply with ductwork system requirements and SMACNA
Standards including all the necessary fittings, fasteners, sealant, duct
hardware i.e. test holes, quadrant locks and duct access doors for proper
connection to ductwork and equipment. Ducts shall be low pressure type as
per SMACNA Standards with static pressure rating of minimum 2 inches,
and with seal Class B.

B. Fittings: Provide radius type fittings fabricated of multiple sections with

maximum 15o change of direction per section. Unless specifically detailed
otherwise, use 45o laterals and 45o elbows for branch takeoff connections.
Where 90o branches are indicated, provide conical type tees.

C. Duct Sealant: Non-hardening, non-migrating mastic or liquid elastic sealant,

type applicable for fabrication/installation detail, as compounded and
recommended by manufacturer specifically for sealing joints and seams in
ductwork.

D. Duct Cement: Non-hardening migrating mastic or liquid neoprene based

cement, type applicable for fabrication/installation detail, as compounded
and recommended by manufacturer specifically for cementing fitting
components, or longitudinal seams in ductwork.

E. Ductwork Support Materials: Except as otherwise indicated, provide hot-

dipped galvanized steel fasteners, anchors, rods, straps, trim and angles for
support of ductwork.

F. Flexible Ducts: Either spiral-wound spring steel with flameproof vinyl

sheathing, or corrugated aluminum; complying with UL 181, Class 1,
complete with minimum 38 mm thick continuous flexible fiberglass sheath
insulation, 16 kg/m³ density, and vapor barrier jacket.

2.3 DAMPERS:

A. Low Pressure Manual Dampers: Provide dampers of single blade type or

multiblade type, constructed in accordance with SMACNA - Low Pressure
Duct Standards -with static pressure rating of minimum 2 inches.

B. Motorized Dampers: Provide dampers with parallel blades for 2-position

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 control, or opposed blades for modulating control. Construct blades of 16
gage steel, 13 mm diameter steel axles spaced on 229 mm centers.
Construct frame of 50 x 13 x 3 mm steel channel for face areas 2.32 m² and
under; 100 x 32 x 16 gage channel for face areas over 2.32 m². Provide
galvanized steel finish with aluminum touch-up.

C. Fire Dampers: Fire Dampers: Provide fire dampers, of types and sizes as
indicated on Drawings where required. Construct casings of 20 gage
galvanized steel with bonded red acrylic enamel finish. Provide fusible link
rated at 71-74oC unless otherwise indicated. Provide damper with positive
lock in closed position, and with the following additional features:

1. Damper Blade Assembly: Single-blade type or multi-blade type as

required.

2. Blade Material: Steel, match casing.

D. Motor-Driven Fire Dampers: Provide motor-driven fire dampers, of types

and sizes indicated or required. Construct casings of 20 gage galvanized
steel with bonded red acrylic enamel finish. Provide fusible link rated at 71-
74oC unless otherwise indicated, and curtain type stainless steel interlocking
blades, with motor equipped with instant closure cluch, stainless cable
damper blade linkage, motor mounting bracket and 800 mm long wire leads
for connecting to smoke/heat detector, and with motor mounted
outside/inside air stream.

E. Smoke Dampers: Smoke damper shall be designed for the smoke isolation
of sections of ducting in ventilation systems, basically consisting of a flanged
casing, shut off blades with overlapping interlocking joints. Blades are
connected by internal linkage for parallel action. External linkage parallel
action also available. Smoke dampers to be leakage tested as appropriate to
the requirements of UL555S.

Casing and blades shall be of a galvanized sheet steel to BS EN 10142 or

equivalent. Casing bearing made from sintered bronze. Blades shall have
standard face linkage for parallel blade operation. Size and type of damper
shall be as shown on drawings. Dampers shall be electrically operated and
controlled through BMS. All accessories required for electric operation shall
be provided.

F. Combination Fire and Smoke Dampers: Combination fire/smoke dampers

shall be designed for the fire/smoke isolation of sections of ducting in
ventilation systems, basically consisting of a flanged casing, shut off blades
with overlapping interlocking joints, with side seals to close off gap between
case and blades. Blades are connected by internal linkage for parallel
action. Damper is fitted with internal jack shaft incorporating fusible link
assembly.

Fire dampers to be independently tested as appropriate to the requirements

of UL555 (Fire rating 3 hours). Additional leakage tested as appropriate to
the requirements of UL555S.

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 Casing and blade shall be of galvanized sheet steel to BS EN 10142 or
equivalent. Casing bearings made from sintered bronze. Blades shall have
standard face linkage parallel blade operation. Size of dampers shall be as
shown on drawings. Dampers shall be electrically operated and controlled
through BMS. All accessories required for electric operation shall be
provided

2.4 TURNING VANES:

A. Provide turning vanes constructed of 38 mm wide curved blades set at 20

mm o.c., supported with bars perpendicular to blades set at 50 mm o.c., and
set into side strips suitable for mounting in ductwork.

2.5 DUCT HARDWARE:

A. Test Holes: Provide in ductwork at fan inlet and outlet, and elsewhere as
indicated, duct test holes, consisting of slot and cover, for instrument tests.

B. Quadrant Locks: Provide for each damper, quadrant lock device on one end
of shaft; and end bearing plate on other end for damper lengths over 300
mm. Provide extended quadrant locks and end extended bearing plates for
externally insulated ductwork.

2.6 DUCT ACCESS DOORS:

A. General: Provide where indicated, duct access doors of sizes indicated.

B. Construction: Construct of same or greater gage as ductwork served,

provide insulated doors for insulated ductwork. Provide flush frames for un-
insulated ductwork, extended frames for externally insulated duct. Provide
one side hinged, otherwise with one handle-type latch for doors up to 300
mm high and smaller, 2 handle-type latches for larger doors.

2.7 FLEXIBLE CONNECTIONS:

A. Provide flexible duct connections wherever ductwork connects to vibration

isolated equipment. Construct flexible connections of neoprene-coated
flameproof fabric crimped into duct flanges for attachment to duct and
equipment. Make airtight joint. Provide adequate joint flexibility to allow for
thermal, axial, transverse, and torsional movement, and also capable of
absorbing vibrations of connected equipment.

2.8 VARIABLE AIR VOLUME (VAV) BOXES (Relief or By-Pass Type):

A. VAV boxes shall be completely factory-assembled. Units designed shall be

of sizes as shown on drawings and shall have factory catalog rating for L/S.,
static pressure and noise criteria as required. Units shall have damper shaft
with optional location of linkage arrangement (left or right of unit) for single
damper control actuator to be mounted on exterior of unit. Static pressure
loss through the unit shall be consistent at all times regardless of air volume
damper position.

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 B. Cabinet shall be constructed of not less than 22 gauge, zinc-coated steel.
Internal surfaces shall be acoustically and thermally insulated as required
with glass fiber, surface-treated to prevent erosion. Insulation material shall
meet NFPA and NBFU 90A.

C. Performance of unit shall be based on tests conducted in accordance with

ASHRAE Standard 36-72 and with ADC Standard 1062R4 with no ductwork
between unit discharge and sound room.

D. Control Actuator: Factory-mounted electric/electronic actuator with

appropriate linkages in accordance with box requirements. Control actuator
shall be furnished by the air volume control box manufacturer.

E. Room Temperature Controls: To be furnished by the air volume control box

manufacturer, as indicated on the drawings, in accordance with the air
volume control box requirements. Thermostat shall be a wall-mounted
electric/electronic type with appropriate mounting hardware supplied by the
controls supplier.

F. Box identification: Each airflow control box shall be clearly marked with an
identification label and airflow indicator. Identification label shall include
such information as unit nominal L/S, maximum factory-set L/S, minimum
factory-set L/S, and coil type and coil hand when supplied.

2.9 CONSTANT AIR VOLUME BOXES (Mechanical)

A. Shall be single duct terminal box for constant volume systems for supply or
extract application, casing with acoustic and thermal lining, erosion resistant
to approx. 20 m/s, with circular inlet spigot suitable for DIN circular duct
sizes, outlet suitable for fixing of angle flange or slide on flanges, inspection
cover sealed by a quick release clamping bar, casing air leakage to Class II
VDI 3803 and DIN 24194, box complies with clean room Class 3 VDI 2083
and Class 100 of US Standard 209b.

B. Volume flow rate controller mechanical system powered without external

power supply, with integral bellows doubling as an oscillation damper, high
accuracy on set volume flow rates, differential pressure range 50 to 1500
Pa, volume flow range 5:1.

C. Constructed of galvanized sheet steel casing, lining of attenuator and

regulator section with mineral wool density 30 to 40 kg/m³, erosion protected
with laminated glass fiber scrim up to air velocity of 20 m/s non-flammable to
DIN 4102, material Class A2. Aluminum regulator, polyurethane bellows and
stainless steel control spring. Additional Acoustic Cladding, consisting of 40
mm mineral wool and outer casing of 1 mm galvanized sheet steel to reduce
casing radiated noise.

D. Reheat coil (Where shown on drawings) shall be fixed to box discharge, to

heat the volume flows, flanged both sides. Attenuator provided to fit box or
reheat coil, to reduce air regenerated noise, with angle flange or slide on
flanges on both ends. Boxes shall be of type and size as shown on
drawings.

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2.10 SOUND ATTENUATORS:

A. Refer to Section 15240 - VIBRATION ISOLATION AND NOISE CONTROL.

2.11 DUCT INSULATION:

A. Refer to Section 15250 - MECHANICAL INSULATION.

2.12 DUCTWORK FABRICATION

A. Ductwork shall be fabricated in factory qualified for the fabrication of ducts

and shall be subject to approval of the Engineer. Rectangular ducts shall be
fabricated in 1200, 2400, 3000, or 3600 mm lengths, unless otherwise
indicated or required to complete runs. Round ducts (if used) shall be
provided in manufacturer’s standard lengths. Pre-assemble work in shop to
greatest extent possible, so as to minimize field assembly of systems.
Disassemble systems only to extent necessary for shipping and handling.
Match-mark sections for reassembly and coordinated installation.
B. Shop fabricate ductwork of gages and reinforcement complying with
SMACNA - HVAC Duct Construction Standards -and/or ASHRAE
Handbook, Equipment Volume, Chapter 16; Duct Construction; for
appropriate static pressure rating classification.

C. Fabricate duct fittings to match adjoining ducts, and to comply with duct
requirements as applicable to fittings. Except as otherwise indicated,
fabricate elbows with centerline radius equal to associated duct width; and
fabricate to include turning vanes in elbows where shorter radius is
necessary. Limit angular tapers to 30o for contracting tapers and 20o for
expanding tapers.

D. Fabricate ductwork with accessories installed during fabrication to the

greatest extent possible.

E. Fabricate ductwork with duct liner in each section of duct where indicated.
Laminate liner to internal surfaces of duct in accordance with instructions by
manufacturers of lining and adhesive, and fasten with mechanical fasteners.

2.13 DIFFUSERS, REGISTERS AND GRILLES

A. General: Diffusers, registers and grilles shall be factory fabricated of

aluminum, type and finish as shown on the drawings or as approved by the
Engineer.

B. Submittal:

1. A schedule of all air inlets and outlets indicating location, types,

specified air quantity, neck or face velocity, sound power level
values, and maximum and minimum air quantity ranges.

2. Copies of manufacturer's technical specifications including detailed

installation instructions for ducts and hardware.

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 3. Certificates of compliance stating that the material used and
construction conform to all requirements of this specification.

4. The Contractor shall be responsible for diffusion, spread, drop and

throw. If, according to the certified data of manufacturer of the
proposed units, the sizes indicated on Drawings will not perform
satisfactorily, units shall be re-selected to perform quietly and
effectively in accordance with manufacturer's recommendation.

C. Diffusers shall distribute the specified quantity of air evenly over space
intended, without causing noticeable drafts, air movement in excess of 0.25
m/sec in occupied zones, or dead spots anywhere in the conditioned area.

D. Ceiling diffusers shall be of the square, round, perforated and/or linear slot,
bar type as shown on the drawings. The type of ceiling construction where
the diffusers are to be installed shall determine the type of compatible
diffuser rings or frames to be provided. Diffusers shall be sized in
accordance with the recommendations of the manufacturer. Diffusers shall
be equipped with baffles or other devices required to provide air distribution
pattern. Factory fabricated turning vanes, furnished by the diffuser
manufacturer, shall be provided at each diffuser, branch duct, or take-off,
except where flexible ductwork is used. Opposed blade volume damper and
separate pattern adjustment shall be provided by the diffuser manufacturer
and shall be installed so that it can be removed through the diffuser neck for
exhaust and shall be similar to diffusers used for supply, except that
elements used solely for air pattern control shall be omitted.

Diffuser shells, frames, perforated face plates, and all air volume controls
and air turning devices shall have baked-on flat enamel or equivalent finish.
Color of finish for shells and other component parts shall be gray or off-
white. Color of exposed frames and face plates shall be as approved by the
Engineer.

E. Registers shall be provided with factory fabricated volume dampers

furnished by the register manufacturer. Volume dampers shall be of the
group-operated, opposed blade type and shall be key and adjustable.
Supply registers shall have two sets (horizontal and vertical) of directional
blades or vanes. Exhaust and return registers shall be similar to supply
registers, except that they shall have a single set of non-directional face bars
or vanes having the same appearance as the supply registers. Registers
shall be factory primed, ready for finish painting. Volume dampers and
splitter assemblies shall be factory finished in baked black enamel or
equivalent.

F. Grilles shall be manufactured and finished in same manner as registers,

except that volume dampers shall be omitted. Grilles, volume adjusters and
air control devices made of steel (if required) shall be zinc-phosphate treated
prior to priming and finishing.

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 G. Security diffusers, grilles and registers:

1. Security diffusers, grilles and registers shall be manufactured to

meet all applications of highest security and safety while maintaining
the necessary air distribution requirements and Shall be constructed
using approved design that allows the grill to become an integral part
of the wall for additional strength and shall meet ASTM standard.

Security grade diffusers, grilles and registers shall be installed as

per the manufacturer instructions and recommendations to ensure
proper installation.

2.14 FRESH AIR INTAKE AND RELIEF OUTLET (VENT) HOOD:

A. Hood shall be constructed of heavy gauge extruded aluminum louvers.
Blades shall be of stormproof extruded aluminum with corners mitered and
welded. Roof and curb caps shall be formed by heavy gauge aluminum and
the assembly shall be braced by angular steel.
B. Provide birdscreen, built-up curb and cleanable filters, where required. Size
shall be as shown on the drawings.

2.15 AIR FILTERS

A. All outside air and recirculated air shall be filtered, except as noted. Filters
shall be underwriters' Laboratories, Inc. listed filters. Air flow shall not
exceed rated capacity at specified efficiency. Performance shall be tested
and certified per ASHRAE Standard 52-76.

B. Definitions:

1. Efficiency: as measured by the Dust Spot Method on Atmospheric

Air, per ASHRAE Test Standard 52-76, unless otherwise noted.
2. Arrestance: per ASHRAE Test Standard 52-76.

3. Dust holding capacity: per ASHRAE Test Standard 52-76.

C. Filter types, provide as follows:

1. Flat Panel Filter, Replaceable Type (F1).

2. Bag Filter, Extended Surface Type (F2).

3. Cartridge Filter (F3).

4. Inertial Filter (IF).

D. Flat Panel Filters, Replaceable Type (F1): Pleated media shall be blend of
cotton and synthetic fibers. Casing shall be double wall, rigid chipboard
frame with expanded metal media support, cross braced on both sides of
filter. Thickness shall be as noted.

1. Filter frames shall be metal with holding latches. The filter shall have
an average atmospheric dust spot efficiency of not less than 25 to

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 30% when tested in accordance with ASHRAE Test Standard 52-76.
Initial resistance at 2.7 m/s face velocity shall be maximum 50 kPa
for 50 mm thick unit.

2. Provide filters similar to American Air Filter, AM-AIR 301.

E. Bag Filters, Extended Surface, Non-Supported Type (F2): Provide

replaceable bag type. Glass fiber media shall be supported on leaving side
with flexible mesh. . The filter shall have an average atmospheric dust spot
efficiency of not less than 60 to 65% when tested in accordance with
ASHRAE Test Standard 52-76.

1. Side access housings (for low and medium efficiency filters): Filter
mounting section shall be fully factory assembled and dimensionally
compatible with factory fabricated air handling units, or as shown on
plans.

a. Provide hinged and recessed access doors on both sides of

each housing with hinged cast aluminum spring loaded
latches on opposite sides of each door and closed cell
neoprene rubber perimeter gasketing. Hinges shall be zinc
plated.

b. Provide molded polyvinyl chloride flexible filter sealing

gaskets with extruded aluminum retainers. Sealing pressure
shall be applied against entering air face of filter header. Seal
adjacent filters by vertical gasket strips attached to filter
header.

c. Housing shall be minimum 16 gauge galvanized steel

construction with 100 mm turned-in flanges for attachment to
adjacent equipment. Pre-drilled attachment holes shall be on
not more than 300 mm centers. Provide integral track, for 50
mm thick pre-filters.

d. Insulate internally the same as air handling unit casing.

F. Cartridge Filters (F3): Filter shall consist of water resistant media made from
ultra fine glass filters. Media shall be pleated and have crimped aluminum
separators to maintain uniform spacing. The pleated media pack shall be
inserted into galvanized steel cell sides with a 19mm galvanized sheet steel
header on the air entering side. The filters shall have crossed wire bracing
on air leaving side. . The filter shall have an average atmospheric dust spot
efficiency of not less than 80-85% when tested in accordance with ASHRAE
Test Standard 52-76.

G. Filter gauges shall be differential pressure type and dial type with range and
minor divisions as noted under Installation.

H. Filter gauges shall be differential pressure type and dial type with built-in
facility for transmitting a warning signal to the BMS when filter resistance has
reached twice original value or that recommended by air filter manufacturer.

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 Range and minor divisions shall be as noted under installation. Provide
indication lamps at following locations.

1. Before Filter.

2. After Filter.
3. Provide complete with static pressure taps and two way cocks to
permit calibration.

PART 3 - EXECUTION

3.1 INSTALLATION OF METAL DUCTWORK

A. General: Assemble and install ductwork in accordance with recognized

industry practices which will achieve air tight (5 percent leakage for systems
rated 75 mm and under; one percent for systems rated over 75 mm) and
noiseless (no objectionable noise) systems, capable of performing each
indicated service. Install each run with minimum number of joints. Align
ductwork accurately at connections, within 3 mm misalignment tolerance
and with internal surfaces smooth. Support ducts rigidly with suitable ties,
braces, hangers and anchors of type which will hold ducts true-to-shape and
to prevent buckling. Support vertical ducts at every floor.

B. Field Fabrication: Complete fabrication of work at project as necessary to

match shop-fabricated work and accommodate installation requirements.

C. Routing: Locate ductwork runs, except as otherwise indicated, vertically and

horizontally and avoid diagonal runs wherever possible. Locate runs as
indicated by diagrams, details and notations or, if not otherwise indicated,
run ductwork in shortest route which does not obstruct usable space or block
access for servicing building and its equipment.

Hold ducts close to walls, overhead construction, columns, and other

structural and permanent-enclosure elements of building. Limit clearance to
13 mm where furring is shown for enclosure or concealment of ducts, but
allow for insulation thickness, if any. Where possible, locate insulated
ductwork for 25 mm where furring is shown for enclosure or concealment of
ducts, but allow for insulation thickness, if any. Where possible, locate
insulated ductwork for 25 mm clearance outside of insulation. Wherever
possible in finished and occupied spaces, conceal ductwork from view, by
locating in mechanical shafts, hollow wall construction or above suspended
ceilings. Do not encase horizontal runs in solid partitions, except as
specifically shown. Coordinate layout with suspended ceiling and lighting
layouts and similar finished work.

D. Electrical Equipment Spaces: Do not route ductwork through transformer

vaults and their electrical equipment spaces and enclosures.

E. Penetrations: Where ducts pass through interior partitions and exterior walls,
conceal space between construction opening and duct or duct insulation with

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 sheet metal flanges of same gage as duct. Overlap opening on 4 sides by at
least 38 mm. Fasten duct and substrate.

F. Coordination: Coordinate duct installations with installation of accessories,

dampers, equipment, controls and other associated work of ductwork
system.

G. Installation: Install metal ductwork in accordance with SMACNA HVAC Duct

Construction Standards.

3.2 INSTALLATION OF FLEXIBLE DUCTS:

A. Maximum Length: For any duct run using flexible ductwork, do not exceed
1200 mm extended length.

B. Installation: Install in accordance with Section III of SMACNA - HVAC Duct

Construction Standards, Metal and Flexible.

3.3 INSTALLATION OF DUCTWORK ACCESSORIES

A. Install duct accessories in accordance with manufacturer's installation

instructions, with applicable portions of details of construction as shown in
SMACNA Standards, and in accordance with recognized industry practices
to ensure that products serve intended function.

B. Install turning vanes in square or rectangular 90o elbows in supply and

exhaust air systems, and elsewhere as indicated.

C. Install access doors to open against system air pressure, with latches
operable from either side, except outside only where duct is too small for
person to enter.

D. Coordinate with other work, including ductwork, as necessary to interface

installation of duct accessories properly with other work.

3.4 INSTALLATION OF DIFFUSERS, REGISTERS AND GRILLES

A. General: Install diffusers, registers and grilles in accordance with

manufacturer's written instructions and in accordance with recognized
industry practices to insure that products serve intended functions.

B. Coordinate with other work, including ductwork and duct accessories, as

necessary to interface installation of air outlets and inlets with other work.

C. Locate ceiling air diffusers, registers, and grilles, as indicated on Drawings.

3.5 FIELD QUALITY CONTROL

A. Leakage Tests:

1. After each duct system which is constructed for duct classes 75 mm

of w.g. and below is completed, test for duct leakage in accordance

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 with SMACNA Air Duct Leakage Test Manual. Repair leaks and
repeat tests until total leakage is less than 5% of system design air
flow.
2. Operate installed duct accessories to demonstrate compliance with
requirements. Test for air leakage while system is operating. Repair
or replace faulty accessories, as required to obtain proper operation
and leak-proof performance.

3.6 EQUIPMENT CONNECTIONS

A. General: Connect metal ductwork to equipment as indicated, provide flexible

connection for each ductwork connection to equipment mounted on vibration
isolators, and/or equipment containing rotating machinery. Provide access
doors as indicated.

3.7 ADJUSTING AND CLEANING

A. Clean ductwork internally, unit-by-unit as it is installed, of dust and debris.

Clean external surfaces of foreign substances which might cause corrosive
deterioration of metal or, where ductwork is to be painted, might interfere
with painting or cause paint deterioration.

B. Temporary Closure: At ends of ducts which are not connected to equipment

or air distribution devices at time of ductwork installation, provide temporary
closure of polyethylene film or other covering which will prevent entrance of
dust and debris until time connections are to be completed.

C. Adjusting: Adjust ductwork accessories for proper settings, install fusible

links in fire dampers and adjust for proper action.

3.8 SYSTEM TESTING AND BALANCING

A. Conform to the requirements of Section 15990 - TESTING, ADJUSTING

AND BALANCING.

END OF SECTION

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