SECTION 23 31 00
HVAC DUCTS AND CASINGS
PART 1 GENERAL
1.01 SECTION INCLUDES
A.
Metal ductwork.
B.
Nonmetal ductwork.
C.
Kitchen hood ductwork.
D.
Duct cleaning.
1.02 RELATED REQUIREMENTS
A.
Section 01 61 16 - Volatile Organic Compound (VOC) Content Restrictions.
B.
Section 07 84 00 - Firestopping.
C.
Section 09 90 00 - Painting and Coating: Weld priming, weather resistant, paint or coating.
D.
Section 11 40 00 - Foodservice Equipment: Supply of kitchen range hoods for placement by
this Section.
E.
Section 23 07 13 - Duct Insulation: External insulation and duct liner.
F.
Section 23 33 00 - Air Duct Accessories.
G.
Section 23 36 00 - Air Terminal Units.
H.
Section 23 37 00 - Air Outlets and Inlets.
I.
Section 23 05 93 - Testing, Adjusting, and Balancing for HVAC.
1.03 REFERENCE STANDARDS
A.
ASHRAE (FUND) - ASHRAE Handbook - Fundamentals; 2009.
B.
ASTM A36/A36M - Standard Specification for Carbon Structural Steel; 2008.
C.
ASTM A240/A240M - Standard Specification for Chromium and Chromium-Nickel Stainless
Steel Plate, Sheet, and Strip for Pressure Vessels and General Applications; 2011a.
D.
ASTM A480/A480M - Standard Specification for General Requirements for Flat-Rolled
Stainless and Heat-Resisting Steel Plate, Sheet, and Strip; 2011a.
E.
ASTM A653/A653M - Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or
Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process; 2010.
F.
ASTM A666 - Standard Specification for Annealed or Cold-Worked Austenitic Stainless Steel
Sheet, Strip, Plate, and Flat Bar; 2010.
G.
ASTM E84 - Standard Test Method for Surface Burning Characteristics of Building Materials;
2010b.
H.
ICC-ES AC01 - Acceptance Criteria for Expansion Anchors in Masonry Elements; 2009.
I.
ICC-ES AC106 - Acceptance Criteria for Predrilled Fasteners (Screw Anchors) in Masonry
Elements; 2006.
J.
ICC-ES AC193 - Acceptance Criteria for Mechanical Anchors in Concrete Elements; 2010.
K.
ICC-ES AC308 - Acceptance Criteria for Post-Installed Adhesive Anchors in Concrete
Elements; 2009.
L.
NFPA 90A - Standard for the Installation of Air-Conditioning and Ventilating Systems; National
Fire Protection Association; 2009.
M. NFPA 90B - Standard for the Installation of Warm Air Heating and Air Conditioning Systems;
National Fire Protection Association; 2009.
N.
NFPA 96 - Standard for Ventilation Control and Fire Protection of Commercial Cooking
Operations; National Fire Protection Association; 2011.
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HVAC DUCTS AND CASINGS
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O.
SMACNA (LEAK) - HVAC Air Duct Leakage Test Manual; Sheet Metal and Air Conditioning
Contractors' National Association; 1985, First Edition.
P.
SMACNA (DCS) - HVAC Duct Construction Standards - Metal and Flexible; Sheet Metal and
Air Conditioning Contractors' National Association; 2005.
Q.
SMACNA (FGD) - Fibrous Glass Duct Construction Standards; Sheet Metal and Air
Conditioning Contractors' National Association; 2003.
R.
SMACNA (KVS) - Kitchen Ventilation Systems and Food Service Equipment Fabrication &
Installation Guidelines; 2001.
S.
UL 181 - Standard for Factory-Made Air Ducts and Air Connectors; Underwriters Laboratories
Inc.; Current Edition, Including All Revisions.
1.04 SUBMITTALS
A.
See Section 01 33 00 - Administrative Requirements, for submittal procedures.
B.
Product Data: Provide data for duct materials and duct liner.
C.
Shop Drawings: Indicate duct fittings, particulars such as gages, sizes, welds, and configuration
prior to start of work for 1" pressure class and higher systems.
D.
Test Reports: Indicate pressure tests performed. Include date, section tested, test pressure,
and leakage rate, following SMACNA (LEAK) - HVAC Air Duct Leakage Test Manual.
E.
Manufacturer's Certificate: Certify that installation of glass fiber ductwork meet or exceed
specified requirements.
F.
Project Record Documents: Record actual locations of ducts and duct fittings. Record changes
in fitting location and type. Show additional fittings used.
1.05 QUALITY ASSURANCE
A.
Installer Qualifications: Company specializing in performing the type of work specified in this
section, with minimum 3 years of documented experience.
1.06 REGULATORY REQUIREMENTS
A.
Construct ductwork to NFPA 90A and NFPA 90B standards.
1.07 FIELD CONDITIONS
A.
Do not install duct sealants when temperatures are less than those recommended by sealant
manufacturers.
1.08 LEED CERTIFICATION
A.
Achievement of the US Green Building Council (USGBC) LEED (Leadership in Energy and
Environmental Design) Silver Certification is an essential part of this project.
B.
The list of LEED Credits applicable to this project is located in Specification Section 01 35
14.01.
C.
All bidding General Contractors, Subcontractors, and Material Suppliers must review all of the
applicable LEED Credits/Prerequisites and all of the LEED On-line Templates that are
necessary for documentation for the applicable LEED Credits prior to submitting a bid.
D.
The successful General Contractor, Subcontractors, and Material Suppliers are required to
provide all necessary documentation to prove compliance with the LEED Credits/Prerequisites
that are applicable to this project (both “Construction” and “Design” Credits).
E.
Submittal of LEED documentation and the review of the documentation by the Green Building
Certification Institute (GBCI) will extend past the conclusion of the construction. The General
Contractor, Subcontractors, and Material Suppliers must continue their documentation and
response to comments from the GBCI until the award of LEED Silver Certification for this
project.
F.
Shop Drawings, Submittals, and Product Data:
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1.
All submittals shall indicate the specific contribution of the product, assembly, or process
toward accomplishing the LEED Certification goal. Generic data or marketing information
is not acceptable.
PART 2 PRODUCTS
2.01 DUCT ASSEMBLIES
A.
All Ducts: Galvanized steel, unless otherwise indicated.
B.
Low Pressure Supply (Heating Systems): 2 inch w.g. pressure class, galvanized steel.
C.
Low Pressure Supply (System with Cooling Coils): 2 inch w.g. pressure class, galvanized steel.
D.
Return and Relief: 1 inch w.g. pressure class, galvanized steel.
E.
General Exhaust: 1 inch w.g. pressure class, galvanized steel.
F.
Kitchen Cooking Hood Exhaust: 1 inch w.g. pressure class, un-galvanized steel.
1. Construct of 16 gage un-galvanized steel using continuous external welded joints in
rectangular sections.
G.
Dishwasher Exhaust: 1 inch w.g. pressure class, galvanized steel or stainless steel.
1. Construct of 18 gage stainless steel using continuous external welded joints in rectangular
sections.
H.
Outside Air Intake: 1 inch w.g. pressure class, galvanized steel.
I.
Combustion Air: 1/2 inch w.g. pressure class, galvanized steel.
J.
Transfer Air and Sound Boots: 1 inch w.g. pressure class,.
2.02 MATERIALS
A.
Galvanized Steel for Ducts: Hot-dipped galvanized steel sheet, ASTM A653/A653M FS Type B,
with G90/Z275 coating.
B.
Un-Galvanized Steel for Ducts: ASTM A 1008/A 1008M, Designation CS, cold-rolled
commercial steel.
C.
Stainless Steel for Ducts: ASTM A 240/A 240M, Type 304.
D.
Joint Sealers and Sealants: Non-hardening, water resistant, mildew and mold resistant.
1. Type: Heavy mastic or liquid used alone or with tape, suitable for joint configuration and
compatible with substrates, and recommended by manufacturer for pressure class of
ducts.
2. VOC Content: Not more than 250 g/L, excluding water.
3. Surface Burning Characteristics: Flame spread of zero, smoke developed of zero, when
tested in accordance with ASTM E84.
E.
Hanger Rod: ASTM A36/A36M; steel, galvanized; threaded both ends, threaded one end, or
continuously threaded.
F.
Hanger Fasteners: Attach hangers to structure using appropriate fasteners, as follows:
1. Concrete Wedge Expansion Anchors: Complying with ICC-ES AC193.
2. Masonry Wedge Expansion Anchors: Complying with ICC-ES AC01.
3. Concrete Screw Type Anchors: Complying with ICC-ES AC193.
4. Masonry Screw Type Anchors: Complying with ICC-ES AC106.
5. Concrete Adhesive Type Anchors: Complying with ICC-ES AC308.
6. Other Types: As required.
G.
Flexible Ducts:
H.
Insulated Flexible Ducts for Pressure Classes 2" and under:
1. Manufacturers:
a. Flexmaster Model Type 5.
b. Technaflex Model WK.
c. Thermoflex Model M-KE.
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2.
UL 181, Class 1, aluminum laminate and polyester film with latex adhesive supported by
helically wound spring steel wire; fiberglass insulation; polyethylene vapor barrier film.
a. Pressure Rating: 10 inches WG positive and 1.0 inches WG negative.
b. Maximum Velocity: 4000 fpm.
c. Temperature Range: -20 degrees F to 210 degrees F.
I.
Joint Sealers and Sealants: Non-hardening, water resistant, mildew and mold resistant.
1. Type: Heavy mastic or liquid used alone or with tape, suitable for joint configuration and
compatible with substrates, and recommended by manufacturer for pressure class of
ducts.
2. VOC Content: Not more than 250 g/L, excluding water.
3. Surface Burning Characteristics: Flame spread of zero, smoke developed of zero, when
tested in accordance with ASTM E84.
J.
Hanger Rod: ASTM A36/A36M; steel, galvanized; threaded both ends, threaded one end, or
continuously threaded.
2.03 DUCTWORK FABRICATION
A.
Fabricate and support in accordance with SMACNA HVAC Duct Construction Standards - Metal
and Flexible, and as indicated.
B.
Provide duct material, gages, reinforcing, and sealing for operating pressures indicated.
C.
Construct T's, bends, and elbows with radius of not less than 1-1/2 times width of duct on
centerline. Where not possible and where rectangular elbows must be used, provide air foil
turning vanes. Where acoustical lining is indicated, provide turning vanes of perforated metal
with glass fiber insulation.
D.
Increase duct sizes gradually, not exceeding 15 degrees divergence wherever possible;
maximum 30 degrees divergence upstream of equipment and 45 degrees convergence
downstream.
E.
Fabricate continuously welded round and oval duct fittings in accordance with SMACNA HVAC
Duct Construction Standards - Metal and Flexible.
F.
Fabricate continuously welded round and oval duct fittings two gages heavier than duct gages
indicated in SMACNA Standard. Joints shall be minimum 4 inch cemented slip joint, brazed or
electric welded. Prime coat welded joints.
G.
Provide standard 45 degree lateral wye takeoffs unless otherwise indicated where 90 degree
conical tee connections may be used.
H.
Where ducts are connected to exterior wall louvers and duct outlet is smaller than louver frame,
provide blank-out panels sealing louver area around duct. Use same material as duct, painted
black on exterior side; seal to louver frame and duct.
2.04 DUCT MANUFACTURERS
A.
Metal-Fab, Inc: www.mtlfab.com.
B.
SEMCO Incorporated: www.semcoinc.com.
C.
Eastern Sheet Metal, Inc: www.easternsheetmetal.com
2.05 MANUFACTURED DUCTWORK AND FITTINGS
A.
Manufacture in accordance with SMACNA HVAC Duct Construction Standards - Metal and
Flexible, and as indicated. Provide duct material, gages,reinforcing, and sealing for operating
pressures indicated.
B.
Double Wall Insulated Flat Oval Ducts: Machine made from round spiral lockseam duct with
light reinforcing corrugations, galvanized steel outer wall, 1-1/2" inch (25 mm) thick fiberglass
insulation, perforated galvanized steel inner wall; fittings manufactured with solid inner wall.
1. Manufacturers:
a. United McGill
b. SEMCO
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c.
Eastern Sheet Metal
2.06 KITCHEN HOOD EXHAUST DUCTWORK
A.
Fabricate in accordance with SMACNA HVAC Duct Construction Standards - Metal and
Flexible, SMACNA Kitchen Ventilation Systems and Food Service Equipment Fabrication &
Installation Guidelines and, and NFPA 96.
PART 3 EXECUTION
3.01 INSTALLATION
A.
Install, support, and seal ducts in accordance with SMACNA HVAC Duct Construction
Standards - Metal and Flexible.
B.
Install in accordance with manufacturer's instructions.
C.
Kitchen Hood Exhaust: Provide residue traps at base of vertical risers with provisions for clean
out.
D.
Duct sizes indicated are inside clear dimensions. For lined ducts, maintain sizes inside lining.
E.
Install and seal metal and flexible ducts in accordance with SMACNA HVAC Duct Construction
Standards - Metal and Flexible.
F.
Provide openings in ductwork where required to accommodate thermometers and controllers.
Provide pilot tube openings where required for testing of systems, complete with metal can with
spring device or screw to ensure against air leakage. Where openings are provided in insulated
ductwork, install insulation material inside a metal ring.
G.
Locate ducts with sufficient space around equipment to allow normal operating and
maintenance activities.
H.
Use crimp joints with or without bead for joining round duct sizes 8 inch and smaller with crimp
in direction of air flow.
I.
Use double nuts and lock washers on threaded rod supports.
J.
Connect terminal units to supply ducts directly or with one foot maximum length of flexible duct.
Do not use flexible duct to change direction.
K.
Connect diffusers or light troffer boots to low pressure ducts directly or with 5 feet maximum
length of flexible duct held in place with strap or clamp.
L.
Provide residue traps in kitchen hood exhaust ducts at base of vertical risers with provisions for
clean out.
M. Use stainless steel for ductwork exposed to view and stainless steel or carbon steel for ducts
where concealed.
N.
During construction provide temporary closures of metal or taped polyethylene on open
ductwork to prevent construction dust from entering ductwork system.
O.
At exterior wall louvers, seal duct to louver frame and install blank-out panels.
3.02 CLEANING
A.
Clean duct systems with high power vacuum machines. Protect equipment that could be
harmed by excessive dirt with filters, or bypass during cleaning. Provide adequate access into
ductwork for cleaning purposes.
END OF SECTION
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