HomeMy WebLinkAbout233113 DUCTWORKTHE KENT
23 31 13 - 1
THE KENT Issue Date 05.09.18 DUCTWORK
THE KENT
SECTION 23 31 13 - DUCTWORK
PART 1 - GENERAL
1.01 RELATED SECTIONS:
A. Drawings, general provisions of the Contract, including General and Supplementary
Conditions, and Division-1 Specification Sections and Division 20 and 23 Specification
Sections, apply to work of this Section.
1.02 DESCRIPTION OF WORK:
A. Scope of Work:
1. Furnish and install ductwork as shown or implied on the Contract Documents.
2. Extent of the work is indicated on the Drawings and in the schedules, and by
requirements of this section.
a. Low pressure ductwork is hereby defined as ductwork subjected to velocities
of less than 2500 fpm or less and operating pressure of 2” water column (w.c.)
or less, positive or negative.
B. Work Included:
1. Combined heating and air conditioning supply and return air duct systems.
2. Mechanical exhaust ducts.
3. Outdoor air intake systems.
4. Return air runouts from trunk to register or grille.
1.03 QUALITY ASSURANCE:
A. Construction Standards:
1. All ducts shall be fabricated in accordance with SMACNA "HVAC Duct Construction
Standards”.
2. Where SMACNA standards provide no guidance, comply with ASHRAE Handbook of
Fundamentals chapter on Duct Construction.
3. Comply with ANSI/NFPA 90A “Standard for the Installation of Air-Conditioning and
Ventilating Systems” and ANSI/NFPA 90B “Standard for the Installation of Warm Air
Heating and Air-Conditioning Systems”.
4. All ductwork furnished with factory installed insulation and vapor barriers shall be UL
listed and labeled for a flame spread and smoke producing rating of 25 and 50
respectively and listed Class I.
B. Pressure Classifications:
1. Supply, return, and relief ducts in penthouses and mechanical rooms shall be
constructed to 2" water column classification.
2. All other supply ducts shall be constructed to 2" water column classification.
3. All other return air ducts shall be constructed to 2" water column classification.
4. All other exhaust air ducts shall be constructed to 2" water column classification
THE KENT
23 31 13 - 2
THE KENT Issue Date 05.09.18 DUCTWORK
THE KENT
1.04 SUBMITTALS:
A. Submit descriptive literature and shop drawings for manufactured products and factory
fabricated ductwork in accordance with Division 1 requirements.
B. Submit complete dimensioned layouts of ductwork showing both the accurately scaled
ductwork and its relation of space enclosure. At a minimum, the following items will be
required to be indicated on the duct layout submittals:
1. Drawings shall be submitted in AutoCAD or Revit format. Hand drawn documents are
not acceptable.
2. Ductwork layout on reflected ceiling plans to 1/4" = 1'-0" scale.
3. Fire damper and smoke damper installation and locations. Where fire dampers and
smoke dampers are located in walls and floors, provide details of installation.
4. Access door installations and locations. Where access doors are required in walls
provide details of installation.
5. Duct sizes and fabrication methods.
6. All required transitions and noted whether they are flat on top, flat on bottom, or
concentric.
7. All field seams required and the proper method of joint shall be indicated.
8. All sections to be internally lined shall be indicated, and the increased dimensions
shall be noted.
9. All sections that are to be installed with flexible ductwork shall be indicated.
10. Volume dampers, motorized dampers, turning vanes, and extractor installation,
fabrication and locations.
11. Hanging and supporting details.
12. Drawings shall show ductwork elevations in relation to ceiling height with clearance
worked out between ductwork, piping, electrical fixtures, and structure.
1.05 RECORD DRAWINGS:
A. Submit Record Drawings in accordance with Division 1 requirements.
1.06 DELIVERY, STORAGE AND HANDLING:
A. Protect shop fabricated and factory fabricated ductwork, accessories and purchased products
from damage during shipment, storage, and handling. Prevent end damage and prevent dirt
and moisture from entering ducts and fittings.
B. Where possible, store ductwork inside and protect from the weather. Where necessary to
store outside, store above grade and enclosed with waterproof wrapping.
PART 2 - PRODUCTS
2.01 MANUFACTURERS:
A. Subject to compliance with requirements, provide products of one of the following:
1. Metal duct:
a. U.S. Steel
b. Republic Steel
c. Wheeling Steel
d. Norfolk
THE KENT
23 31 13 - 3
THE KENT Issue Date 05.09.18 DUCTWORK
THE KENT
2. Metal duct accessories:
a. Ductmate Industries, Inc.
3. Factory Fabricated Round or Oval Ductwork
a. C & R (Pinnacle)
b. Dixie Sheetmetal
c. Eastern Sheetmetal
d. JTD Spiral(Indiana Supply)
e. Lapine Metal Products
f. SPIROsafe; Div of Lindab
g. Semco (L.J. Fiesel)
h. Tangent Air (Doug Studebaker?)
i. U. S. Air Duct
j. United Sheetmetal Div. United McGill Corp.
4. Duct sealant:
a. Polymer Adhesives
b. Ductmate
c. Fosters
d. United Duct Sealant
e. Hardcast
B. General: Where ductwork is indicated to be exposed to view in occupied spaces, provide
materials which are free from visual defects and imperfections including fittings, seam
markings, roller marks, stains and discolorations, and other imperfections, including those
which would impair painting.
C. Sheet Metal: Except as otherwise indicated, fabricate ductwork from galvanized sheet metal
steel complying with ANSI/ASTM A 653, lockforming quality and ANSI/ASTM A 653M, G90
zinc coating; mill phosphatized for exposed locations.
D. Painted Sheet Metal: Where architectural or mechanical drawings, schedules, details or
specifications call for ductwork to be finish painted in exposed locations, galvanized sheet
metal shall be pre-etched type known as "galvaneal" or "paint-grip." Clarify with Engineer
before fabrication.
E. Stainless Steel Sheet: Where indicated, provide stainless steel complying with ANSI/ASTM A
480; AISI Type 304, with No. 4 directional polish where exposed to view in occupied spaces.
Protect finished surfaces with mill-applied adhesive protective paper, maintained through
fabrication and installation. Where concealed, provide mill finish on sheets.
F. Aluminum Sheet: Where indicated, provide aluminum complying with ANSI/ASTM B209, Alloy
3003, Temper H14.
G. Rectangular Ductwork:
1. Ductwork shall be fabricated of gages and reinforcement complying with SMACNA
Standards, and shall be of sizes as shown on Drawings. Dimensions as shown are
inside measurements indicating free area required.
2. Ducts noted to receive liner shall be increased in size to maintain the inside
dimensions noted.
THE KENT
23 31 13 - 4
THE KENT Issue Date 05.09.18 DUCTWORK
THE KENT
H. Round Ductwork:
1. Round ducts shall be factory fabricated zinc coated steel of spiral lockseam
construction.
2. Round duct fittings shall be factory fabricated zinc coated steel for 45 or conical
take-off from the main trunk.
I. Shop Fabricated Ductwork:
1. Shop fabricate ductwork in 4, 8, 10 or 12 - foot lengths, unless otherwise indicated or
required to complete runs. Fabricated to pressure standards per SMACNA guidelines.
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.
2. Shop fabricate ductwork of gages and reinforcement complying with SMACNA
standards.
3. Fabricate duct fittings to match adjoining ducts, and to comply with duct requirements
as applicable to fittings.
a. Except as otherwise indicated, fabricate elbows with centerline radius equal to
1.5 times the duct width in the plane of the turn; and fabricate to include
factory manufactured turning vanes in elbows where shorter radius is
necessary.
b. Limit angular tapers to 30 degrees for contracting tapers and 20 degrees for
expanding tapers.
4. General: Longitudinal joints shall be shop or field sealed Pittsburgh or Snap-Lock
Joints. Snap-lock joints are permitted in all ductwork of 144 square inch or less. Use
Pittsburgh joints only on all ducts larger than 144 square inches.
5. Transverse joints shall be per SMACNA standards for pressure class. Seal in field
after erection.
6. Fittings:
a. Round and flat oval duct fittings shall be factory fabricated zinc coated steel
for 45 or conical take-off from the main trunk.
b. Do not use bull head fittings.
7. Duct Configuration:
a. Ducts in chases shall have concentric offsets.
b. Ducts above ceilings (horizontal) shall have eccentric offsets to provide
maximum clearances.
2.02 METAL GAUGES SINGLE WALL ROUND AND FLAT OVAL DUCTWORK:
ROUND DUCTS WITH MAXIMUM 2” W.G. POSITIVE STATIC PRESSURE
Duct Diameter Spiral Duct Fittings and Longitudinal Seam Duct
3” thru 26” 26 24
28” thru 36” 24 22
38” thru 50” 22 20
52” thru 60” 20 18
62” thru 78” 18 16
THE KENT
23 31 13 - 5
THE KENT Issue Date 05.09.18 DUCTWORK
THE KENT
Notes:
1. Reinforce with 1” x 1” x 1
/8” girth rings every 6 ft.
2. Reinforce with 11/4” x 11/4” x 3/16” girth rings every 4 ft.
3. When companion flange joints are used as reinforcement,
44” to 48” diameter shall be 2” x 2” x 3/16”
50” to 60” diameter shall be 21/2” x 21/2 x 3/16”
2.03 MISCELLANEOUS DUCTWORK MATERIALS:
A. General: Provide miscellaneous materials and products of types and sizes indicated and,
where not otherwise indicated, provide type and size required to comply with ductwork system
requirements including proper connection of ductwork and equipment. All adhesives and
sealants shall be water based. Contractor may use solvent based sealants for specific cases
when requested in writing and approved by the Engineer.
B. Duct Sealant: Water based 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.
C. Ductwork Support Materials: Except as otherwise indicated, provide hot-dipped galvanized
steel fasteners, anchors, rods, straps, trim and angles for support of ductwork.
D. For exposed stainless steel ductwork, provide matching stainless steel support materials.
E. For aluminum ductwork, provide aluminum support materials except where materials are
electrolytically separated from ductwork.
2.04 SEALANT AND GASKETS:
A. General Sealant and Gasket Requirements: Surface-burning characteristics for sealants and
gaskets shall be a maximum flame-spread index of 25 and a maximum smoke-developed
index of 50 when tested according to UL 723; certified by an NRTL.
B. Two-Part Tape Sealing System:
1. Tape: Woven cotton fiber impregnated with mineral gypsum and modified
acrylic/silicone activator to react exothermically with tape to form hard, durable, airtight
seal.
2. Tape Width: 3 inches, 4 inches, or 6 inches.
3. Sealant: Modified styrene acrylic.
4. Water resistant.
5. Mold and mildew resistant.
6. Maximum Static-Pressure Class: 10-inch wg, positive and negative.
7. Service: Indoor and outdoor.
8. Service Temperature: Minus 40 to plus 200 deg F.
9. Substrate: Compatible with galvanized sheet steel both PVC coated and bare,
stainless steel, or aluminum.
THE KENT
23 31 13 - 6
THE KENT Issue Date 05.09.18 DUCTWORK
THE KENT
10. For indoor applications, sealant shall have a VOC content of 250 g/L or less when
calculated according to 40 CFR 59, Subpart D (EPA Method 24).
11. Sealant shall comply with the testing and product requirements of the California
Department of Health Services' "Standard Practice for the Testing of Volatile Organic
Emissions from Various Sources Using Small-Scale Environmental Chambers."
C. Water-Based Joint and Seam Sealant:
1. Application Method: Brush on.
2. Solids Content: Minimum 65 percent.
3. Shore A Hardness: Minimum 20.
4. Water resistant.
5. Mold and mildew resistant.
6. VOC: Maximum 75 g/L (less water).
7. Maximum Static-Pressure Class: 10-inch wg, positive and negative.
8. Service: Indoor or outdoor.
9. Substrate: Compatible with galvanized sheet steel (both PVC coated and bare),
stainless steel, or aluminum sheets.
D. Flanged Joint Sealant: Comply with ASTM C 920.
1. General: Single-component, acid-curing, silicone, elastomeric.
2. Type: S.
3. Grade: NS.
4. Class: 25.
5. Use: O.
6. For indoor applications, sealant shall have a VOC content of 250 g/L or less when
calculated according to 40 CFR 59, Subpart D (EPA Method 24).
7. Sealant shall comply with the testing and product requirements of the California
Department of Health Services' "Standard Practice for the Testing of Volatile Organic
Emissions from Various Sources Using Small-Scale Environmental Chambers."
E. Flange Gaskets: Butyl rubber, neoprene, or EPDM polymer with polyisobutylene plasticizer.
F. Round Duct Joint O-Ring Seals:
1. Seal shall provide maximum leakage class of3 cfm/100 sq. ft. at 1-inch wg and shall
be rated for10-inch wg static-pressure class, positive or negative.
2. EPDM O-ring to seal in concave bead in coupling or fitting spigot.
3. Double-lipped, EPDM O-ring seal, mechanically fastened to factory-fabricated
couplings and fitting spigots.
2.05 HANGERS AND SUPPORTS:
A. Indicate the extent of corrosive environment on Drawings.
B. Hanger Rods for Noncorrosive Environments: Cadmium-plated steel rods and nuts.
THE KENT
23 31 13 - 7
THE KENT Issue Date 05.09.18 DUCTWORK
THE KENT
C. Hanger Rods for Corrosive Environments: Electrogalvanized, all-thread rods or galvanized
rods with threads painted with zinc-chromate primer after installation.
D. Strap and Rod Sizes: Comply with SMACNA's "HVAC Duct Construction Standards - Metal
and Flexible," Table 5-1, "Rectangular Duct Hangers Minimum Size," and Table 5-2, "Minimum
Hanger Sizes for Round Duct."
E. Steel Cables for Galvanized-Steel Ducts: Galvanized steel complying with ASTM A 603.
F. Steel Cables for Stainless-Steel Ducts: Stainless steel complying with ASTM A 492.
G. Steel Cable End Connections: Cadmium-plated steel assemblies with brackets, swivel, and
bolts designed for duct hanger service; with an automatic-locking and clamping device.
H. Duct Attachments: Sheet metal screws, blind rivets, or self-tapping metal screws; compatible
with duct materials.
I. Trapeze and Riser Supports:
1. Supports for Galvanized-Steel Ducts: Galvanized-steel shapes and plates.
2. Supports for Stainless-Steel Ducts: Stainless-steel shapes and plates.
3. Supports for Aluminum Ducts: Aluminum or galvanized steel coated with zinc
chromate.
PART 3 - EXECUTION
3.01 GENERAL:
A. Assemble and install ductwork in accordance with recognized industry practices which will
achieve air tight (max. 5 % leakage) and noiseless (no objectionable noise) systems, capable
of performing each indicated service. Install each run with minimum of joints.
B. Align ductwork accurately at connections, within 1/8" misalignment tolerance and with internal
surfaces smooth.
C. Support ducts rigidly with suitable ties, braces, hangers and anchors of type which will hold
duct true-to shape and to prevent buckling.
D. Provide all necessary offsets and transformations as required in the installation of the work
although same may not be specifically shown on the plans. Offset all ducts as required to
increase head room under them, to improve the appearance of exposed ducts, and to avoid
interference with the work of other trades.
E. Locate ductwork runs, except as otherwise indicated, vertically and horizontally and avoid
diagonal runs wherever possible.
F. 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.
G. Hold ducts close to walls overhead construction, columns, and other structural and permanent
enclosure elements of building. Limit clearance to 1/2" where furring is shown for enclosure or
concealment of ducts, but allow for insulation thickness, if any.
THE KENT
23 31 13 - 8
THE KENT Issue Date 05.09.18 DUCTWORK
THE KENT
H. Where possible, in finished and occupied spaces, conceal ductwork from view, by locating in
mechanical shafts, furring, or above suspended ceilings. Do not encase horizontal runs in solid
partitions, except as specifically shown. Coordinate the layout with suspended ceiling and
lighting layouts and similar finished work.
I. Where ducts pass through interior partitions and exterior walls, conceal space between
construction opening and duct or duct-plus-insulation with sheet metal flanges of same gage
as duct. Overlap opening on four sides by at least 1-1/2".
J. Where ducts pass through time-rated fire resistive construction, all openings around the ducts
shall be sealed with fire stopping material as specified in Division 07, except where fire
dampers are shown, noted or required.
K. Provide angle, channel, or equal type frames for all manual and automatic dampers and install
as required.
L. In toilet exhaust systems serving two or more floors, install featherweight backdraft damper in
the branch ductwork to each floor.
M. Provide drain pans at built up air handling systems. Provide multiple drain pans at multiple
cooling coil sections.
N. Coordinate duct installations with installation of accessories, dampers, coil frames, equipment,
controls and other associated work of ductwork system.
O. Support ductwork in manner complying with SMACNA "HVAC Duct Construction Standards"
hanger and supports Section.
3.02 INSTALLATION OF RECTANGULAR DUCTWORK:
A. Field changes in duct dimensions shall result in equivalent cross-sectional areas to
dimensions shown. In no case shall the greater dimension be greater than four times the
lesser.
B. All transitions shall be made with long transition fittings. Ducts shall be flared to suit shape of
registers and grilles or openings for registers and grilles. Maximum angle of transition of 20 for
diverging air flow and 30 for contracting air flow.
C. Provide engineered air foil blades turning vanes at square elbows, minimum 2 1-1/2" wide,
where shown on the drawings, and where changes in direction cannot be made as specified
above. Turning vanes shall be installed inside the insulation on internally lined ducts.
D. All rectangular sheet metal ducts over 18" in width shall be cross broken or mechanically
beaded to reduce vibration. Reinforcing angle and stiffeners shall be provided where required
to prevent sagging, buckling, vibration, sound transmission, etc.
E. Changes in direction shall be made with easy flowing curves. The minimum center line radius
of bends shall be at least 1-1/2 times the dimension of the duct in the plane of the turn unless
otherwise shown. Radius type elbows fabricated with the inside radius equal to width of duct;
short radius elbows will be permitted only by written approval of Architect/Engineer for specific
cause.
F. Ducts shall be fabricated to a minimum of SMACNA 2" pressure classification.
THE KENT
23 31 13 - 9
THE KENT Issue Date 05.09.18 DUCTWORK
THE KENT
G. All ducts shall be sealed to meet SMACNA Class B classification. Both longitudinal and
transverse joints are to be sealed.
3.03 PAINTING:
A. Paint interior of metal ducts that are visible through registers and grilles and that do not have
duct liner. Apply one coat of flat, black, latex paint over a compatible galvanized-steel primer.
3.04 FIRE DAMPERS, SMOKE DAMPERS, AND COMBINATION FIRE-SMOKE DAMPERS:
A. Fire dampers and combination fire-smoke dampers shall be installed in all ducts passing
through time rated fire resistive construction including but not limited to walls, floors, and
shafts, whether shown or not, and elsewhere as shown on the Drawings and as required by
the Building Code. All installations shall be in strict accordance with NFPA 90A and 101 and
manufacturer’s recommendations for compliance with their ratings.
B. Access sections, panels and/or doors shall be installed adjacent to each fire damper, smoke
damper or combination fire-smoke damper. Access openings shall be labeled.
3.05 LINTELS:
A. Mechanical Contractor shall be responsible for furnishing and installing lintels over all ducts
that pass through load bearing walls and any duct over 12" wide. Lintel size shall be sufficient
to support loads above. Lintel material shall be as approved by the Architect/Engineer. Lintels
shall be installed by craftsmen skilled in this particular trade.
3.06 FIELD QUALITY CONTROL:
A. Perform tests and inspections.
B. Leakage Tests:
1. Comply with SMACNA's "HVAC Air Duct Leakage Test Manual." Submit a test report
for each test.
2. Test the following systems:
a. Supply Ducts with a Pressure Class of 2-Inch wg or Higher: Test
representative duct sections selected by Engineer from sections installed,
totaling no less than 50 percent of total installed duct area for each designated
pressure class.
b. Return Ducts with a Pressure Class of 2-Inch wg or Higher: Test
representative duct sections, selected by Engineer from sections installed,
totaling no less than 50 percent of total installed duct area for each designated
pressure class.
c. Exhaust Ducts with a Pressure Class of 3-Inch wg or Higher: Test
representative duct sections, selected by Engineer from sections installed,
totaling no less than 50 percent of total installed duct area for each designated
pressure class.
d. Outdoor Air Ducts with a Pressure Class of 2-Inch wg or Higher: Test
representative duct sections, selected by Engineer from sections installed,
totaling no less than 50 percent of total installed duct area for each designated
pressure class.
3. Disassemble, reassemble, and seal segments of systems to accommodate leakage
testing and for compliance with test requirements.
THE KENT
23 31 13 - 10
THE KENT Issue Date 05.09.18 DUCTWORK
THE KENT
4. Test for leaks before applying external insulation.
5. Conduct tests at static pressures equal to maximum design pressure of system or
section being tested. If static-pressure classes are not indicated, test system at
maximum system design pressure. Do not pressurize systems above maximum
design operating pressure.
6. Give seven days' advance notice for testing.
C. Duct System Cleanliness Tests:
1. Visually inspect duct system to ensure that no visible contaminants are present.
2. Test sections of metal duct system, chosen randomly by Owner, for cleanliness
according to "Vacuum Test" in NADCA ACR, "Assessment, Cleaning and Restoration
of HVAC Systems."
a. Acceptable Cleanliness Level: Net weight of debris collected on the filter
media shall not exceed 0.75 mg/100 sq. cm.
D. Duct system will be considered defective if it does not pass tests and inspections.
E. Prepare test and inspection reports.
END OF SECTION