36C25622R0094 233100 HVAC DUCTS AND CASINGS.docx
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- Z2DA--Project #502-19-107 - Replace AHU-104 - Construction - 36C25622R0094 Federal contract opportunity
- Solicitation number
- 502-19-107
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This federal solicitation is for the replacement of Air Handling Unit 104 and associated ductwork at a Department of Veterans Affairs health care facility in Alexandria, Louisiana. Products and services required include the supply, return, outside, and exhaust air systems serving Building 7, with ductwork to be constructed of galvanized steel or aluminum sheet metal per SMACNA standards. Duct pressure classifications and seal class are specified, along with requirements for wet air exhaust ducts, negative pressure exhaust ducts, round and flat oval ducts, casings and plenums, volume dampers, access doors and panels, fire dampers, combination fire and smoke dampers, and instrumentation including thermometers and temperature sensors. Response date and award date are not provided.
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REPLACE AHU #104 AND DUCTWORK BLDG. 7
DEPARTMENT OF VETERANS AFFAIRS HEALTH CARE SYSTEM-ALEXANDRIA, LA
PROJECT NO.: 502-19-107
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, outside air, and exhaust air systems. |
| 2. | Exhaust duct for chemical fume hoods, kitchen hood exhaust (grease) and “wet exhaust” ducts. |
| B. | Definitions: |
| 1. | SMACNA Standards as used in this specification means 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 joints, to keep air leakage at duct joints, seams and connections to an acceptable minimum. |
| 3. | Duct Pressure Classification: SMACNA HVAC Duct Construction Standards, Metal and Flexible. |
| 4. | Exposed Duct: Exposed to view in a finished room or exposed to weather. |
1.2 RELATED WORK
| A. | Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, and SAMPLES. |
| B. | Section 07 84 00, FIRESTOPPING: Fire Stopping Material. |
C. Section 08 90 00, LOUVERS and VENTS: Outdoor and Exhaust Louvers.
| C. | Section 23 05 11, COMMON WORK RESULTS FOR HVAC: General Mechanical Requirements. D. Section 23 05 41, NOISE AND VIBRATION CONTROL FOR HVAC PIPING and EQUIPMENT: Noise Level Requirements. |
| E. | Section 23 05 93, TESTING, ADJUSTING, and BALANCING FOR HVAC: Testing and Balancing of Air Flows. |
F. Section 23 07 11, HVAC, and BOILER PLANT INSULATION: Duct Insulation.
| G. | Section 23 09 23, DIRECT-DIGITAL CONTROL SYSTEM FOR HVAC: Duct Mounted Instrumentation. |
| /H. | Section 23 36 00, AIR TERMINAL UNITS: Air Flow Control Valves and Terminal Units. |
| I. | Section 23 40 00, HVAC AIR CLEANING DEVICES: Air Filters and Filters' Efficiencies. |
| J. | Section 23 73 00, INDOOR CENTRAL-STATION AIR-HANDLING UNITS: Supply Air Fans. |
K. Section 28 31 00, FIRE DETECTION and ALARM: Smoke Detectors.
1.3 QUALITY ASSURANCE
| A. | Refer to article, QUALITY ASSURANCE, in Section 23 05 11, COMMON WORK RESULTS FOR HVAC. |
| B. | Fire Safety Code: Comply with NFPA 90A. |
| C. | Duct System Construction and Installation: Referenced SMACNA Standards are the minimum acceptable quality. |
| D. | 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 on the drawings. |
| E. | 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 the duct or provide at least the same level 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 selected 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. | Fire dampers, fire doors, and smoke dampers with installation instructions. |
| 6. | Flexible ducts and clamps, with manufacturer's installation instructions. |
| 7. | Flexible connections. |
| 8. | Instrument test fittings. |
| 9. | Details and design analysis of alternate or optional duct systems. |
C. Coordination Drawings: Refer to article, SUBMITTALS, 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 this 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 Buildings and Other Structures |
| C. | American Society for Testing and Materials (ASTM): |
| A1672009 | Standard Specification for Stainless and HeatResisting ChromiumNickel Steel Plate, Sheet, and Strip |
| A653-2019 | Standard Specification for Steel Sheet, ZincCoated (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 |
| B2092014 | Standard Specification for Aluminum and AluminumAlloy Sheet and Plate |
| C1071-2019 | Standard Specification for Fibrous Glass Duct Lining Insulation (Thermal and Sound Absorbing Material) |
| E84-2014 | Standard Test Method for Surface Burning Characteristics of Building Materials |
| D. | National Fire Protection Association (NFPA): |
| 90A-2018 | Standard for the Installation of Air Conditioning and Ventilating Systems |
| 96-2018 | Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations |
| E. | Sheet Metal and Air Conditioning Contractors National Association (SMACNA): |
| 3rd Edition –2006 | HVAC Duct Construction Standards, Metal and Flexible |
| 2nd Edition -2012 | HVAC Air Duct Leakage Test Manual |
| 6th Edition –2016 | Fibrous Glass Duct Construction Standards |
| F. | Underwriters Laboratories, Inc. (UL): |
| 1812013 | FactoryMade Air Ducts and Air Connectors |
| 5552006 | Standard for Fire Dampers |
| 555S2014 | 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, 3003 or 5052. |
| B. | Specified Corrosion Resistant Systems: Stainless steel sheet, ASTM A167, Class 302 or 304, Condition A (annealed) Finish No. 4 for exposed ducts and Finish No. 2B for concealed duct or ducts located in mechanical rooms. |
| C. | Optional Duct Materials: |
| 1. | Grease Duct: Double wall factorybuilt grease duct, UL labeled and complying with NFPA 96 may be furnished in lieu of specified materials for kitchen and grill hood exhaust duct. Installation and accessories shall comply with the manufacturers catalog data. Outer jacket of exposed ductwork shall be stainless steel. Square and rectangular duct shown on the drawings will have to be converted to equivalent round size. |
| D. | Joint Sealing: Refer to SMACNA HVAC Duct Construction Standards. |
| 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 not acceptable 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. |
| E. | 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: |
| 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 Seal |
| D. | Wet Air Exhaust Ducts and Accessories: Ducts for dishwashers, scullery hood, cart washers, manual cart washers, cage washers, steam sterilizer hoods and orthotics hoods shall be 1.3 mm (18 gage) stainless steel made liquid tight with continuous external weld for all seams and joints. Provide neoprene gaskets at flanged connections. Where ducts are not self draining back to the equipment, provide low point drain pocket with copper drain pipe to sanitary sewer. Provide access door in side of duct at drain pockets. |
| E. | Duct for Negative Pressure Up to 750 Pa (3-inch W.G.): 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. |
| 2. | Rectangular Duct: Galvanized steel, minimum 1.0 mm (20 gage), Pittsburgh lock seam, companion angle joints 32 mm by 3.2 mm (11/4 by 1/8 inch) minimum at not more than 2.4 m (8 feet) spacing. Approved pre-manufactured joints are acceptable in lieu of companion angles. |
| F. | Round and Flat Oval Ducts: Furnish duct and fittings made by the same manufacturer to insure 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 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 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. |
| 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 ducts are submitted. |
| a. | Ducts: Manufacturer's published standard gage, 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 Standard S3.13. Because of high pressure loss, do not use internal tierod reinforcement unless approved by the Resident Engineer. |
| G. | Casings and Plenums: Construct in accordance with SMACNA HVAC Duct Construction Standards Section 6, including curbs, access doors, pipe penetrations, eliminators and drain pans. Access doors shall be hollow metal, insulated, with latches and door pulls, 500 mm (20 inches) wide by 1200 - 1350 mm (48 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. |
| H. | Volume Dampers: Single blade or opposed blade, multilouver type as detailed in SMACNA Standards. Refer to SMACNA for Single Blade and Figure 2.13 for Multi-blade Volume Dampers. |
| I. | Duct Hangers and Supports: Refer to SMACNA Standards 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 maintenance work, upstream, in the following locations: |
| 1. | Each duct mounted coil and humidifier. |
| 2. | Each fire damper (for link service), smoke damper and automatic control damper. |
| 3. | Each duct mounted smoke detector. |
| 4. | For cleaning operating room supply air duct and kitchen hood exhaust duct, locate access doors at 6 m (20 feet) intervals and at each change in duct direction. |
| 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 doublewall, insulated. Transparent shatterproof covers are preferred for uninsulated ducts. |
| 1. | For rectangular ducts: Refer to SMACNA HVAC Duct Construction Standards (Figure 212). |
| 2. | For round and flat oval duct: Refer to SMACNA HVAC duct Construction Standards (Figure 2-11). |
2.4 FIRE DAMPERS
| A. | Galvanized steel, interlocking blade type, UL listing and label, 11/2-hour rating, 70 degrees C (160 degrees F) fusible line, 100 percent free opening with no part of the blade stack or damper frame in the air stream. |
| B. | Fire dampers in wet air exhaust shall be of stainless-steel construction, all others may be galvanized steel. |
| C. | Minimum requirements for fire dampers: |
| 1. | The damper frame may be of design and length as to function as the mounting sleeve, thus eliminating the need for a separate sleeve, as allowed by UL 555. Otherwise provide sleeves and mounting angles, minimum 1.9 mm (14 gage), required to provide installation equivalent to the damper manufacturer's UL test installation. |
| 2. | Submit manufacturer's installation instructions conforming to UL rating test. |
2.5 COMBINATION FIRE AND SMOKE DAMPERS
Combination fire and smoke dampers: Multiblade type units meeting all requirements of both fire dampers and smoke dampers shall be used where shown and may be used at the Contractor's option where applicable.
2.6 FIRESTOPPING MATERIAL
Refer to Section 07 84 00, FIRESTOPPING.
2.7 DUCT MOUNTED Thermometer (air)
| A. | Stem Type Thermometers: ASTM E1, 7-inch scale, red appearing mercury, lens front tube, cast aluminum case with enamel finish and clear glass or polycarbonate window, brass stem, 2 percent of scale accuracy to ASTM E77 scale calibrated in degrees Fahrenheit. |
| B. | Thermometer Supports: |
| 1. | Socket: Brass separable sockets for thermometer stems with or without extensions as required, and with cap and chain. |
| 2. | Flange: 3 inch outside diameter reversible flange, designed to fasten to sheet metal air ducts, with brass perforated stem. |
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 duct 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 casing 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, COMMON WORK RESULTS FOR HVAC, particularly regarding coordination with other trades and work in existing buildings. |
| B. | Fabricate and install ductwork and accessories in 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, 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 on the drawings 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. |
| 2. | Provide duct transitions, offsets and connections to dampers, coils, and other equipment in accordance with SMACNA Standards. Provide streamliner, when an obstruction cannot be avoided and must be taken in by a duct. Repair galvanized areas with galvanizing repair compound. |
| 3. | Provide bolted construction and tierod reinforcement in accordance with SMACNA Standards. |
| 4. | Construct casings, eliminators, and pipe penetrations in accordance with SMACNA Standards, Chapter 6. Design casing access doors to swing against air pressure so that pressure helps to maintain a tight seal. |
| C. | Install duct hangers and supports in accordance with SMACNA Standards. |
| D. | Install fire 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 locations indicated and where ducts penetrate fire rated and/or smoke rated walls, shafts and where required by the Resident Engineer. Install with required perimeter mounting angles, sleeves, breakaway duct connections, corrosion resistant springs, bearings, bushings and hinges per UL and NFPA. Demonstrate resetting of fire dampers and operation of smoke dampers to the Resident Engineer. |
| E. | Seal openings around duct penetrations of floors and fire rated partitions with fire stop material as required by NFPA 90A. |
| F. | Flexible duct installation: Refer to SMACNA Standards, Chapter 3. Ducts shall be continuous, single pieces not over 1.5 m (5 feet) long (NFPA 90A), as straight and short as feasible, adequately supported. Centerline radius of bends shall be not less than two duct diameters. Make connections with clamps as recommended by SMACNA. Clamp per SMACNA with one clamp on the core duct and one on the insulation jacket. Flexible ducts shall not penetrate floors, or any chase or partition designated as a fire or smoke barrier, including corridor partitions fire rated one hour or two hours. Support ducts SMACNA Standards. |
| G. | Where diffusers, registers and grilles cannot be installed to avoid seeing inside the duct, paint the inside of the duct with flat black paint to reduce visibility. |
| H. | Control Damper Installation: |
| 1. | Provide necessary blankoff 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. |
| 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. |
| I. | Air Flow Measuring Devices (AFMD): Install units with minimum straight run distances, upstream and downstream as recommended by the manufacturer. |
| J. | 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 Resident Engineer. 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. | 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. |
| B. | Ductwork leakage testing shall be performed for the entire air distribution system (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 Resident Engineer on ductwork constructed to the 500 Pa (2" WG) duct pressure classification. In no case shall the leakage testing of ductwork constructed above the 500 Pa (2" WG) duct pressure classification or ductwork located in shafts or other inaccessible areas be eliminated. |
| C. | Test procedure, apparatus and report shall conform 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 enclosed in a shaft or covered in other inaccessible areas. |
| E. | All tests shall be performed in the presence of the Resident Engineer and the Test and Balance agency. The Test and Balance agency shall measure and record duct leakage and report to the Resident Engineer 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 Resident Engineer. |
| 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) Refer to Section 23 05 93, TESTING, ADJUSTING, and BALANCING FOR HVAC.
3.4 operating and performance tests Refer to Section 23 05 11, COMMON WORK RESULTS FOR HVAC.
E N D 23 31 00 - 1
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