531-24-106 Spec Section 23 31 00.pdf

03-01-23

AHU-2 REPLACEMENT, BUILDING 85, BOISE VAMC (CD SET)

PROJECT # 531-24-106

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SECTION 23 31 00

HVAC DUCTS AND CASINGS

PART 1 - GENERAL

1.1 DESCRIPTION

A. A complete listing of common acronyms and abbreviations are included in

Section 23 05 11, COMMON WORK RESULTS FOR HVAC.

B. Ductwork and accessories for HVAC including the following:

1. Supply air, return air, outside air, exhaust, make-up air, and relief systems.

C. Definitions:

1. Seal or Sealing: Use of liquid or mastic sealant, with or without compatible tape overlay, or gasketing of flanged joints, to keep air leakage at duct joints, seams and connections to an acceptable minimum.

2. Duct Pressure Classification: SMACNA HVAC Duct Construction

Standards, Metal.

1.2 RELATED WORK

A. Section 01 00 00, GENERAL REQUIREMENTS.

B. Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, and SAMPLES.

C. Section 01 81 13, SUSTAINABLE CONSTRUCTION REQUIREMENTS.

D. Section 07 84 00, FIRESTOPPING.

J. Section 23 05 11, COMMON WORK RESULTS FOR HVAC.

K. Section 23 05 41, NOISE AND VIBRATION CONTROL FOR HVAC PIPING and

EQUIPMENT.

L. Section 23 05 93, TESTING, ADJUSTING, and BALANCING FOR HVAC.

M. Section 23 07 11, HVAC and BOILER PLANT INSULATION.

N. Section 23 09 23, DIRECT-DIGITAL CONTROL SYSTEM FOR HVAC.

O. Section 23 34 00, HVAC FANS.

S. Section 23 73 00, INDOOR CENTRAL-STATION AIR-HANDLING UNITS.

U. Section 23 82 16, AIR COILS.

1.3 APPLICABLE PUBLICATIONS

A. The publications listed below form a part of this specification to the extent referenced. The publications are referenced in the text by the basic designation only.Where conflicts occur these specifications and the VHA standards will govern.

B. American Society of Civil Engineers (ASCE):

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7-2016..................Minimum Design Loads for Associated Criteria for Buildings and Other Structures

C. American Society for Testing and Materials (ASTM):

A653/A653M-2020.........Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-

Coated (Galvannealed) by the Hot-Dip Process

A1011/A1011-2018a.......Standard Specification for Steel, Sheet and

Strip, Hot-Rolled, Carbon, Structural, High-

Strength Low-Alloy, High Strength Low-Alloy with Improved Formability, and Ultra-High

Strength

B209-2021...............Standard Specification for Aluminum and

Aluminum-Alloy Sheet and Plate

C1071-2019..............Standard Specification for Fibrous Glass Duct

Lining Insulation (Thermal and Sound Absorbing

Material)

E1-2014(R2020)..........Standard Specification for ASTM Liquid-in-Glass

Thermometers

E77-2014(R2021).........Standard Test Method for Inspection and

Verification of Thermometers

E84-2021a...............Standard Test Method for Surface Burning

Characteristics of Building Materials

D. National Fire Protection Association (NFPA):

90A-2021................Standard for the Installation of

Air-Conditioning and Ventilating Systems

96-2021.................Standard for Ventilation Control and Fire

Protection of Commercial Cooking Operations

E. Sheet Metal and Air Conditioning Contractors National Association

(SMACNA):

006–2020................HVAC Duct Construction Standards, Metal and

Flexible, 4th Edition

016-2012................HVAC Air Duct Leakage Test Manual, 2nd Edition

2016....................Fibrous Glass Duct Construction Standards, 7th

Edition

F. Underwriters Laboratories, Inc. (UL):

181-2013(R2017).........Standard for Factory-Made Air Ducts and Air

Connectors

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G. Department of Veterans Affairs (VA):

PG-18-10-2015...........Physical Security Design Manual for VA Mission

Critical Facilities

1.4 SUBMITTALS

A. Submittals, including number of required copies, shall be submitted in accordance with Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, AND

SAMPLES.

B. Information and material submitted under this section shall be marked

“SUBMITTED UNDER SECTION 23 XX XX, SECTION TITLE”, with applicable paragraph identification.

C. Manufacturer's Literature and Data Including: Full item description and optional features and accessories. Include dimensions, weights, materials, applications, standard compliance, model numbers, size, and capacity.

1. Rectangular Ducts:

a. Schedules of duct systems, materials and selected SMACNA construction alternatives for joints, sealing, gauge and reinforcement.

b. Duct liner.

c. Sealants and gaskets.

d. Access doors.

2. Round and Flat Oval DuctS:

a. Manufacturer's details for duct fittings.

b. Sealants and gaskets.

c. Access sections.

d. Installation instructions.

3. Volume dampers, back draft dampers.

4. Upper hanger attachments.

5. Fire dampers, fire doors, and smoke dampers with installation instructions.

6. Sound attenuators, including pressure drop and acoustic performance.

7. Flexible ducts and clamps, with manufacturer's installation instructions.

8. Flexible connections.

9. Instrument test fittings.

10. Details and design analysis of alternate or optional duct systems.

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D. Coordination Drawings: Refer to paragraph SUBMITTALS in Section 23 05

11, COMMON WORK RESULTS FOR HVAC.

E. Complete operating and maintenance manuals including wiring diagrams, technical data sheets, information for ordering replaceable parts, and troubleshooting guide:

1. Include complete list indicating all components of the systems.

2. Include complete diagrams of the internal wiring for each item of equipment.

3. Diagrams shall have their terminals identified to facilitate installation, operation, and maintenance.

1.5 QUALITY ASSURANCE

A. Bio-Based Materials: For products designated by the USDA’s

Bio-Preferred Program, provide products that meet or exceed USDA recommendations for bio-based content, so long as products meet all performance requirements in this specifications section. For more information regarding the product categories covered by the

Bio-Preferred Program, visit http://www.biopreferred.gov.

B. Refer to Section 01 81 13, SUSTAINABLE CONSTRUCTION REQUIREMENTS for additional sustainable design requirements.

C. Fire Safety Code: Comply with NFPA 90A.

D. Duct System Construction and Installation: Referenced SMACNA Standards are the minimum acceptable quality.

E. Duct Sealing, Air Leakage Criteria, and Air Leakage Tests: Ducts shall be sealed as per duct sealing requirements of SMACNA HVAC Air Duct

Leakage Test Manual for duct pressure classes shown in the contract documents.

F. Duct accessories exposed to the air stream, such as dampers of all types (except smoke dampers) and access openings, shall be of the same material as he duct or provide at least the same level of corrosion resistance.

1.6 AS-BUILT DOCUMENTATION

A. Comply with requirements in paragraph AS-BUILT DOCUMENTATION of Section

23 05 11, COMMON WORK RESULTS FOR HVAC.

PART 2 - PRODUCTS

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2.1 DUCT MATERIALS AND SEALANTS

A. General: Except for systems specified otherwise, construct ducts, casings, and accessories of galvanized sheet steel, ASTM A653/A653M, coating G90; or, aluminum sheet, ASTM B209, alloy 1100, 3003 or 5052.

B. Joint Sealing: Refer to SMACNA HVAC Duct Construction Standards, Metal and Flexible.

1. Sealant: Elastomeric compound, gun or brush grade, maximum 25 flame spread, and 50 smoke developed (dry state) compounded specifically for sealing ductwork as recommended by the manufacturer. Generally, provide liquid sealant, with or without compatible tape, for low clearance slip joints and heavy, permanently elastic, mastic type where clearances are larger. Oil base caulking and glazing compounds are prohibited because they do not retain elasticity and bond.

2. Tape: Use only tape specifically designated by the sealant manufacturer and apply only over wet sealant. Pressure sensitive tape shall not be used on bare metal or on dry sealant.

3. Gaskets in Flanged Joints: Soft neoprene.

C. Approved factory-made joints may be used.

2.2 DUCT CONSTRUCTION AND INSTALLATION

A. Regardless of the pressure classifications outlined in the SMACNA

Standards, fabricate and seal the ductwork in accordance with the following pressure classifications:

B. Duct Pressure Classification:

1. 0 to 13 mm (0 to 1/2 inch)

2. 13 mm to 25 mm (1/2 inch to 1 inch)

3. 25 mm to 50 mm (1 inch to 2 inch)

4. 50 mm to 75 mm (2 inch to 3 inch)

5. 75 mm to 100 mm (3 inch to 4 inch)

C. Seal Class: All ductwork shall receive Class A Seal.

D. Duct for Negative Pressure Up to 750 Pa (3 inch WG): Provide for exhaust duct between HEPA filters and exhaust fan inlet including systems for Autopsy Suite exhaust.

1. Round Duct: Galvanized steel, spiral lock seam construction with standard slip joints.

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2. Rectangular Duct: Galvanized steel, minimum 1.0 mm (20 gauge), Pittsburgh lock seam, companion angle joints 32 mm by 3.2 mm (1-1/4 by 1/8 inch) minimum at no greater than 2.4 m (8 feet) spacing.

Approved pre-manufactured joints are acceptable in lieu of companion angles.

E. Round and Flat Oval Ducts: Furnish duct and fittings made by the same manufacturer to ensure good fit of slip joints. When submitted and approved in advance, round and flat oval duct, with size converted on the basis of equal pressure drop, may be furnished in lieu of rectangular duct design shown in the contract documents.

1. Elbows: Diameters 75 through 203 mm (3 through 8 inches) shall be two sections die stamped, all others shall be gored construction, maximum 18 degree angle, with all seams continuously welded or standing seam. Coat galvanized areas of fittings damaged by welding with corrosion resistant aluminum paint or galvanized repair compound.

2. Provide bell mouth, conical tees or taps, laterals, reducers, and other low loss fittings as shown in SMACNA HVAC Duct Construction

Standards, Metal and Flexible.

3. Ribbed Duct Option: Lighter gauge round/oval duct and fittings may be furnished provided certified tests indicating that the rigidity and performance is equivalent to SMACNA standard gauge ducts are submitted.

a. Ducts: Manufacturer's published standard gauge, G90 coating, spiral lock seam construction with an intermediate standing rib.

b. Fittings: May be manufacturer's standard as shown in published catalogs, fabricated by spot welding and bonding with neoprene base cement or machine formed seam in lieu of continuous welded seams.

4. Provide flat side reinforcement of oval ducts as recommended by the manufacturer and SMACNA HVAC Duct Construction Standards, Metal and

Flexble. Because of high pressure loss, do not use internal tie-rod reinforcement unless approved by the COR.

F. Casings and Plenums: Construct in accordance with SMACNA HVAC Duct

Construction Standards, Metal and Flexible, including curbs, access doors, pipe penetrations, eliminators and drain pans. Access doors shall be hollow metal, insulated, with latches and door pulls, 508 mm

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(20 inches) wide by 1219 to 1372 mm (48 to 54 inches) high. Provide view port in the doors where shown. Provide drain for outside air louver plenum. Outside air plenum shall have exterior insulation. Drain piping shall be routed to the nearest floor drain.

G. Volume Dampers: Single blade or opposed blade, multi-louver type as detailed in SMACNA Standards. Refer to SMACNA for Single Blade and

Multi-blade Volume Dampers.

2.4 DUCT ACCESS DOORS, PANELS AND SECTIONS

A. Provide access doors, sized and located for maintenance work, in the following locations:

1. Fan array inlet side.

2. Fan arry outlet side.

3. Upstream of cooiling coil.

4. Front and back of Hot deck (See New Air Handling Unit Front elevation and Back elevation details).

5. Front and back of Cold deck (See New Air Handling Unit Front elevation and Back elevation details).

6. Upstream of filters, front and back (See New Air Handling Unit Front elevation and Back elevation details).

7. Upstream of Primary heating coil.

B. Openings shall be as large as feasible. Access door specifications regardless of swing direction:

1. Frame:

a. 0.080 6063-T55 Extruded Aluminum with structural thermal break.

b. 304 Stainless Stee Piano Hinge

c. Continous single seam, closed cell EPDM primary gasket.

d. Thermoplastic elastomer secondary gasket.

2. Door Panel: 20ga galvanized 304 or 316 stainless steem skins

a. Polyurethane Foam Insulation – R-14 minimum.

b. Galvanized, Galvannealed 304 or 316 – 20ga Stainless steel.

c. Through Door, compression latching mechanisms

d. Tool or key locking with internal release handles and linkage.

e. Test ports

f. ASTM E283/E283M-19 compliant

3. Viewport:

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a. 0.062 6063-T5 Extruded Aluminum

b. Extruded polyvinyl bulb gasket and butyl mounting tape.

c. Clear Laminated glass with thermal break.

PART 3 - EXECUTION

3.1 INSTALLATION

A. If an installation is unsatisfactory to the COR, the contractor shall correct the installation at no additional cost or time to the

Government.

B. Comply with provisions of Section 23 05 11, COMMON WORK RESULTS FOR

HVAC, particularly regarding coordination with other trades and work in existing buildings.

C. Fabricate and install ductwork and accessories in accordance with referenced SMACNA Standards:

1. Contract documents show the general layout of ductwork and accessories but do not show all required fittings and offsets that may be necessary to connect ducts to equipment, boxes, diffusers, grilles, etc., and to coordinate with other trades. Fabricate ductwork based on field measurements. Provide all necessary fittings and offsets at no additional cost to the Government. Coordinate with other trades for space available and relative location of HVAC equipment and accessories on ceiling grid. Duct sizes in the contract documents are inside dimensions which shall be altered by

Contractor to other dimensions with the same air handling characteristics where necessary to avoid interferences and clearance difficulties.

3. Construct casings, eliminators, and pipe penetrations in accordance with SMACNA Standards. Design casing access doors to swing against

D. Control Damper Installation:

1. Provide necessary blank-off plates required to install dampers that are smaller than duct size. Provide necessary transitions required to install dampers larger than duct size.

2. Assemble multiple sections dampers with required interconnecting linkage and extend required number of shafts through duct for external mounting of damper motors.

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3. Provide necessary sheet metal baffle plates to eliminate stratification and provide air volumes specified. Locate baffles by experimentation, and affix and seal permanently in place, only after stratification problem has been eliminated.

4. Install all damper control/adjustment devices on stand-offs to allow complete coverage of insulation.

E. Low Pressure Duct Liner: Install in accordance with SMACNA Standards.

F. Protection and Cleaning: Adequately protect equipment and materials against physical damage. Place equipment in first class operating condition or return to source of supply for repair or replacement, as determined by COR. Protect equipment and ducts during construction against entry of foreign matter to the inside and clean both inside and outside before operation and painting. When new ducts are connected to existing ductwork, clean both new and existing ductwork by mopping and vacuum cleaning inside and outside before operation.

3.2 DUCT LEAKAGE TESTS AND REPAIR

A. Existing ductwork leakage shall be performed by the Testing and

Balancing Contractor directly contracted by the General Contractor and independent of the Sheet Metal Contractor. This test shall occur prior to any demolition or repair work to determine the existing leakage rate of the system within the mechanical room.

B. Ductwork leakage testing shall be performed by the Testing and

Balancing Contractor directly contracted by the General Contractor and independent of the Sheet Metal Contractor.

C. Ductwork leakage testing shall be performed for the entire air distribution system within the mechanical room(including all supply, return, exhaust and relief ductwork), section by section, including fans, coils and filter sections. Based upon satisfactory initial duct leakage test results, the scope of the testing may be reduced by the

COR on ductwork constructed to the 500 Pa (2 inches WG) duct pressure classification. In no case shall the leakage testing of ductwork constructed above the 500 Pa (2 inches WG) duct pressure classification or ductwork located in shafts or other inaccessible areas be eliminated.

D. Test procedure, apparatus and report shall conform to SMACNA HVAC Air

Duck Leakage Test Manual. The maximum leakage rate allowed is 4 percent of the design air flow rate.

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E. All tests shall be performed in the presence of the COR and the Test and Balance agency. The Test and Balance agency shall measure and record duct leakage and report to the COR and identify leakage source with excessive leakage.

F. If any portion of the duct system tested fails to meet the permissible leakage level, the Contractor shall rectify sealing of ductwork to bring it into compliance and shall retest it until acceptable leakage is demonstrated to the COR.

G. All tests and necessary repairs shall be completed prior to insulation or concealment of ductwork.

H. Make sure all openings used for testing flow and temperatures by TAB

Contractor are sealed properly.

3.3 TESTING, ADJUSTING, AND BALANCING (TAB)

A. Refer to Section 23 05 93, TESTING, ADJUSTING, and BALANCING FOR HVAC.

3.4 OPERATING AND PERFORMANCE TESTS

A. Refer to Section 23 05 11, COMMON WORK RESULTS FOR HVAC.

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