233100 HVAC DUCTS AND CASINGS seismic.pdf

UPGRADE EMERGENCY POWER IN BUILDING 138

VAMC, MARION, IN PROJECT: 610-16-104

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SECTION 23 31 00

HVAC DUCTS AND CASINGS

PART 1 - GENERAL

1.1 DESCRIPTION

A. Ductwork and accessories for HVAC including the following:

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

B. Definitions:

1. SMACNA Standards as used in this specification m eans the HVAC Duct

Construction Standards, Metal and Flexible.

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

3. Duct Pressure Classification: SMACNA HVAC Duct C onstruction

Standards, Metal and Flexible.

4. Exposed Duct: Exposed to weather.

1.2 RELATED WORK

A. Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, a nd SAMPLES.

B. Section 07 84 00, FIRESTOPPING: Fire Stopping Ma terial.

C. Section 13 05 41, SEISMIC RESTRAINT REQUIREMENTS FOR NON-STRUCTURAL

COMPONENTS: Seismic Reinforcing.

D. Section 23 05 11, COMMON WORK RESULTS FOR HVAC: General Mechanical

Requirements.

E. Section 23 05 41, NOISE AND VIBRATION CONTROL FO R HVAC PIPING and

EQUIPMENT: Noise Level Requirements.

F. Section 23 05 93, TESTING, ADJUSTING, and BALANC ING FOR HVAC: Testing and Balancing of Air Flows.

G. Section 23 07 11, HVAC, and BOILER PLANT INSULAT ION: Duct Insulation.

H. Section 23 09 23, DIRECT-DIGITAL CONTROL SYSTEM FOR HVAC: Duct Mounted

Instrumentation.

I. Section 23 34 00, HVAC FANS: Return Air and Exha ust Air Fans.

J. Section 23 82 00, CONVECTION HEATING and COOLING UNITS.

K. Section 23 81 00, DECENTRALIZED UNITARY HVAC EQU IPMENT.

1.3 QUALITY ASSURANCE

A. Refer to article, QUALITY ASSURANCE, in Section 23 05 11, COMMON WORK

RESULTS FOR HVAC.

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

C. Duct System Construction and Installation: Refer enced SMACNA Standards are the minimum acceptable quality.

D. Duct Sealing, Air Leakage Criteria, and Air Leak age Tests: Ducts shall be sealed as per duct sealing requirements of SMACN A HVAC Air Duct

Leakage Test Manual for duct pressure classes shown on the drawings.

E. Duct accessories exposed to the air stream, such as dampers of all types (except smoke dampers) and access openings, s hall be of the same material as the duct or provide at least the same l evel of corrosion resistance.

1.4 SUBMITTALS

A. Submit in accordance with Section 01 33 23, SHOP DRAWINGS, PRODUCT

DATA, and SAMPLES.

B. Manufacturer's Literature and Data:

1. Rectangular ducts:

a. Schedules of duct systems, materials and selecte d SMACNA construction alternatives for joints, sealing, gage and reinforcement.

b. Duct liner.

c. Sealants and gaskets.

d. Access doors.

2. Round and flat oval duct construction details:

a. Manufacturer's details for duct fittings.

b. Duct liner.

c. Sealants and gaskets.

d. Access sections.

e. Installation instructions.

3. Volume dampers, back draft dampers.

4. Upper hanger attachments.

5. Sound attenuators, including pressure drop and a coustic performance.

6. Flexible ducts and clamps, with manufacturer's i nstallation instructions.

7. Flexible connections.

8. Instrument test fittings.

9. Details and design analysis of alternate or opti onal duct systems.

10. COMMON WORK RESULTS FOR HVAC and STEAM GENERATION.

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C. Coordination Drawings: Refer to article, SUBMITT ALS, in Section 23 05

11-COMMON WORK RESULTS FOR HVAC AND STEAM GENERATION.

1.5 APPLICABLE PUBLICATIONS

A. The publications listed below form a part of thi s specification to the extent referenced. The publications are referenced in the text by the basic designation only.

B. American Society of Civil Engineers (ASCE):

ASCE7-2017..............Minimum Design Loads for Bu ildings and Other

Structures

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

A167-2009...............Standard Specification for Stainless and

Heat-Resisting Chromium-Nickel Steel Plate, Sheet, and Strip

A653-2019...............Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy coated (Galvannealed) by the Hot-Dip process

A1011-2018..............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

B209-2014...............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)

E84-2014................Standard Test Method for Su rface Burning

Characteristics of Building Materials

D. National Fire Protection Association (NFPA):

90A-2018................Standard for the Installati on of Air

Conditioning and Ventilating Systems

96-2018.................Standard for Ventilation Co ntrol and Fire

Protection of Commercial Cooking Operations

E. Sheet Metal and Air Conditioning Contractors Nat ional Association

(SMACNA):

3rd Edition –2006.......HVAC Duct Construction Stan dards, Metal and

Flexible

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

6th Edition –2016.......Fibrous Glass Duct Construc tion Standards

F. Underwriters Laboratories, Inc. (UL):

181-2013................Factory-Made Air Ducts and Air Connectors

555-2006 ...............Standard for Fire Dampers

555S-2014...............Standard for Smoke Dampers

PART 2 - PRODUCTS

2.1 DUCT MATERIALS AND SEALANTS

A. General: Except for systems specified otherwise, construct ducts, casings, and accessories of galvanized sheet steel, ASTM A653, coating

G90; or, aluminum sheet, ASTM B209, alloy 1100, 300 3 or 5052.

B. Joint Sealing: Refer to SMACNA HVAC Duct Constru ction Standards.

1. Sealant: Elastomeric compound, gun or brush grad e, maximum 25 flame spread, and 50 smoke developed (dry state) compound ed specifically for sealing ductwork as recommended by the manufact urer. Generally, provide liquid sealant, with or without compatible tape, for low clearance slip joints and heavy, permanently elasti c, mastic type where clearances are larger. Oil base caulking and glazing compounds are not acceptable because they do not retain elast icity and bond.

2. Tape: Use only tape specifically designated by t he sealant manufacturer and apply only over wet sealant. Press ure sensitive tape shall not be used on bare metal or on dry seal ant.

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 outli ned in the SMACNA

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

B. Duct Pressure Classification:

0 to 50 mm (2 inch)

> 50 mm to 75 mm (2 inch to 3 inch)

> 75 mm to 100 mm (3 inch to 4 inch)

Show pressure classifications on the floor plans.

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

D. Round and Flat Oval Ducts: Furnish duct and fitt ings made by the same manufacturer to insure good fit of slip joints. Whe n submitted and approved in advance, round and flat oval duct, with size converted on

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23 31 00 - 5 the basis of equal pressure drop, may be furnished in lieu of rectangular duct design shown on the drawings.

1. Elbows: Diameters 80 through 200 mm (3 through 8 inches) shall be two sections die stamped, all others shall be gored construction, maximum 18 degree angle, with all seams continuousl y welded or standing seam. Coat galvanized areas of fittings da maged by welding with corrosion resistant aluminum paint or galvaniz ed repair compound.

2. Provide bell mouth, conical tees or taps, latera ls, reducers, and other low loss fittings as shown in SMACNA HVAC Duc t Construction

Standards.

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

a. Ducts: Manufacturer's published standard gage, G 90 coating, spiral lock seam construction with an intermediate standing rib.

b. Fittings: May be manufacturer's standard as show n in published catalogs, fabricated by spot welding and bonding wi th neoprene base cement or machine formed seam in lieu of conti nuous welded seams.

4. Provide flat side reinforcement of oval ducts as recommended by the manufacturer and SMACNA HVAC Duct Construction Stan dard S3.13.

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

E. Casings and Plenums: Construct in accordance wit h SMACNA HVAC Duct

Construction Standards Section 6, including curbs, access doors, pipe penetrations, eliminators and drain pans. Access do ors shall be hollow metal, insulated, with latches and door pulls, 500 mm (20 inches) wide by 1200 - 1350 mm (48 - 54 inches) high. Provide vi ew port in the doors where shown. Provide drain for outside air louver p lenum. Outside air plenum shall have exterior insulation. Drain piping shall be routed to the nearest floor drain.

F. Volume Dampers: Single blade or opposed blade, m ulti-louver type as detailed in SMACNA Standards. Refer to SMACNA for S ingle Blade and

Figure 2.13 for Multi-blade Volume Dampers.

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G. Duct Hangers and Supports: Refer to SMACNA Stand ards Section IV. Avoid use of trapeze hangers for round duct.

2.3 DUCT ACCESS DOORS, PANELS AND SECTIONS

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

1. Each duct mounted coil and humidifier.

2. Each fire damper (for link service), smoke dampe r and automatic control damper.

3. Each duct mounted smoke detector.

4. Other locations called out on drawings.

B. Openings shall be as large as feasible in small ducts, 300 mm by 300 mm

(12 inch by 12 inch) minimum where possible. Access sections in insulated ducts shall be double-wall, insulated. Tr ansparent shatterproof covers are preferred for uninsulated d ucts.

1. For rectangular ducts: Refer to SMACNA HVAC Duct Construction

Standards (Figure 2-12).

2. For round and flat oval duct: Refer to SMACNA HV AC duct Construction

Standards (Figure 2-11).

2.4 FLEXIBLE DUCT CONNECTIONS

Where duct connections are made to fans, air termi nal units, and air handling units, install a non-combustible flexible connection of 822 g

(29 ounce) neoprene coated fiberglass fabric approx imately 150 mm (6 inches) wide. For connections exposed to sun and we ather provide hypalon coating in lieu of neoprene. Burning charac teristics shall conform to NFPA 90A. Securely fasten flexible conne ctions to round ducts with stainless steel or zinc-coated iron draw bands with worm gear fastener. For rectangular connections, crimp f abric to sheet metal and fasten sheet metal to ducts by screws 50 mm (2 inches) on center.

Fabric shall not be stressed other than by air pres sure. Allow at least

25 mm (one inch) slack to ensure that no vibration is transmitted.

2.5 SOUND ATTENUATING UNITS

Refer to Section 23 33 19 DUCT SILENCERS.

2.6 FIRESTOPPING MATERIAL

Refer to Section 07 84 00, FIRESTOPPING.

2.7 SEISMIC RESTRAINT FOR DUCTWORK

Refer to Section 13 05 41, SEISMIC RESTRAINT REQUI REMENTS FOR NON-

STRUCTURAL COMPONENTS.

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2.8 DUCT MOUNTEDTEMPERATURE SENSOR (AIR)

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

2.9 INSTRUMENT TEST FITTINGS

A. Manufactured type with a minimum 50 mm (two inch ) length for insulated duct, and a minimum 25 mm (one inch) length for duc t not insulated.

Test hole shall have a flat gasket for rectangular ducts and a concave gasket for round ducts at the base, and a screw cap to prevent air leakage.

B. Provide instrument test holes at each duct or ca sing mounted temperature sensor or transmitter, and at entering and leaving side of each heating coil, cooling coil, and heat recovery unit.

PART 3 - EXECUTION

3.1 INSTALLATION

A. Comply with provisions of Section 23 05 11, COMM ON WORK RESULTS FOR

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

B. Fabricate and install ductwork and accessories i n accordance with referenced SMACNA Standards:

1. Drawings 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, grill es, etc., and to coordinate with other trades. Fabricate ductwork ba sed on field measurements. Provide all necessary fittings and of fsets at no additional cost to the government. Coordinate with other trades for space available and relative location of HVAC equip ment and accessories on ceiling grid. Duct sizes on the draw ings are inside dimensions which shall be altered by Contractor to other dimensions with the same air handling characteristics where ne cessary to avoid interferences and clearance difficulties.

2. Provide duct transitions, offsets and connection s to dampers, coils, and other equipment in accordance with SMACNA Stand ards. Provide streamliner, when an obstruction cannot be avoided and must be taken in by a duct. Repair galvanized areas with galvaniz ing repair compound.

3. Provide bolted construction and tie-rod reinforc ement in accordance with SMACNA Standards.

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4. Construct casings, eliminators, and pipe penetra tions in accordance with SMACNA Standards, Chapter 6. Design casing acc ess doors to swing against air pressure so that pressure helps t o maintain a tight seal.

C. Install duct hangers and supports in accordance with SMACNA Standards.

D. Install fire dampers, smoke dampers and combinat ion fire/smoke dampers in accordance with the manufacturer's instructions to conform to the installation used for the rating test. Install fire dampers, smoke dampers and combination fire/smoke dampers at locat ions indicated and where ducts penetrate fire rated and/or smoke rated walls, shafts and where required by the COR. Install with required p erimeter mounting angles, sleeves, breakaway duct connections, corros ion resistant springs, bearings, bushings and hinges per UL and N FPA. Demonstrate re-setting of fire dampers and operation of smoke d ampers to the COR.

E. Seal openings around duct penetrations of floors and fire rated partitions with fire stop material as required by N FPA 90A.

F. Control Damper Installation:

1. Provide necessary blank-off plates required to i nstall dampers that are smaller than duct size. Provide necessary trans itions required to install dampers larger than duct size.

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

G. Protection and Cleaning: Adequately protect equi pment and materials against physical damage. Place equipment in first c lass operating condition or return to source of supply for repair or replacement, as determined by COR. Protect equipment and ducts duri ng construction against entry of foreign matter to the inside and c lean both inside and outside before operation and painting. When new duc ts are connected to existing ductwork, clean both new and existing duct work by mopping and vacuum cleaning inside and outside before operation .

3.2 DUCT LEAKAGE TESTS AND REPAIR

A. Ductwork leakage testing shall be performed by t he Testing and

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

B. Ductwork leakage testing shall be performed for the entire air distribution system (including all supply, return, exhaust and relief

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23 31 00 - 9 ductwork), section by section, including fans, coil s and filter sections.

C. Test procedure, apparatus and report shall confo rm to SMACNA Leakage

Test manual. The maximum leakage rate allowed is 4 percent of the design air flow rate.

D. All ductwork shall be leak tested first before e nclosed in a shaft or covered in other inaccessible areas.

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

F. If any portion of the duct system tested fails t o 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 complet ed 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 DUCTWORK EXPOSED TO WIND VELOCITY

Provide additional support and bracing to all expo sed ductwork installed on the roof or outside the building to wi thstand wind velocity of 145 km/h (90 mph).

3.4 TESTING, ADJUSTING AND BALANCING (TAB)

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

3.5 OPERATING AND PERFORMANCE TESTS

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

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