SECTION 15891 HVAC SHEET METAL DUCTWORK PART 1 - GENERAL 1.01 by yurtgc548

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									SECTION 15891

HVAC SHEET METAL DUCTWORK


PART 1 - GENERAL

1.01   RELATED DOCUMENTS

       A.    Drawings and general provisions of Contract including General and
             Supplementary Conditions, Division 1 Specification Sections, and the
             Mechanical General Requirements Section 15050 apply to work of this
             Section, as if repeated herein.

1.02   DEFINITIONS

       A.    Ductwork sizes on Drawings state inside clear dimensions. For
             acoustically lined and internally insulated ductwork, maintain ductwork
             sizes inside lining or insulation.

1.03   REFERENCES

       A.    Fabricate ductwork in accordance with latest edition of SMACNA HVAC
             Duct Construction Standards and ASHRAE handbooks unless more
             stringently detailed.

       B.    Construct ductwork to conform to NFPA 90 A, Air Conditioning and
             Ventilating Systems and NFPA 96, Standard for the Installation of
             Equipment for the Removal of Smoke and Grease-Laden Vapors from
             Commercial Cooking Equipment, latest edition.

       [C.   Ductwork shall be seismically supported and braced per the SMACNA
             "Guidelines for Seismic Restraints of Mechanical Systems and Plumbing
             Piping Systems."

1.04   SUBMITTALS

       A.    Submit in accordance with Division 1 and Section 15050.

       B.    Submit typical shop standards and/or SMACNA details for each class of
             duct specified, including particulates such as gauge sizes, welds, joint
             details, and fitting configurations prior to start of work.
       C.   Submit written report confirming ductwork has been fabricated and
            installed in accordance with SMACNA standards.

       D.   Submit shop drawings of ductwork only when it is necessary to deviate
            from the design drawings.

1.05   FLOW DIAGRAMS

       A.   Predicated upon Project magnitude, Construction Documents may include
            flow diagrams as a part of the working Drawings. These flow diagrams are
            not for the purpose of giving physical dimensions or locations but rather to
            make clear the interconnections, by the duct systems, of the various units
            of the process. If an item is shown on either the flow diagram or the
            Drawings, but not on both, it will be assumed that the contractor has
            included such item in his estimate of the cost of the work and that he shall
            provide same.


PART 2 - PRODUCTS

2.01   ACCEPTABLE MANUFACTURERS

       A.   Manufactured Round and Oval Ductwork:

            1.     Buckley
            2.     Spiral Metal Corporation
            3.     United Sheet Metal
            4.     Metal Manufacturing
            5.     PAR, Inc.
            6.     Spiro-Fab, Inc.

2.02   MATERIALS

       A.   Galvanized Ductwork: Fabricated using galvanized steel sheet of lock
            forming quality, having zinc coating of 1.25 ounces per square foot for
            each side per ASTM A 525, G 90. All ductwork, supports, and
            reinforcement to be galvanized unless otherwise noted.

       B.   Steel ductwork (kitchen grease removal): 16 gauge, welded steel.

       C.   Support Materials: Provide galvanized angle iron, channels, stays, and
            rods. Do not use raw steel.

       D.   Fasteners: Use galvanized rivets and bolts throughout; sheet metal screws
            are acceptable on low pressure ducts only.
       E.    Proprietary Duct Joint Systems: "Ductmate 35" consisting entirely of metal
             components. PVC components will not be acceptable.

       F.    Sealant Material: Water and fire resistant, compatible with mating
materials.

2.03   DUCT CONSTRUCTION CLASSIFICATIONS

       A.    General: Construct and seal ductwork in accordance with SMACNA
             pressure classifications and seal classes listed for ductwork systems
             involved.

       B.    Rectangular Ductwork:

             1.     +1" WG Class with Seal Class C: Supply air ductwork downstream
                    of fan coils.

             2.     +2" WG Class with Seal Class B: Return air ductwork, general
                    exhaust ductwork.

       C.    Round or Oval Ductwork: Same as rectangular ductwork except do not use
             round ductwork in negative static pressure greater than -2" WG or oval
             ductwork in any negative static pressure applications whatsoever.

       D.    Materials: Use galvanized steel sheet for all applications listed except use
             steel in constructing ductwork for kitchen hood exhaust systems. Provide
             kitchen hood exhaust system per NFPA 96.

2.04   SHEET METAL PLENUMS

       A.    Construct plenums and equipment casings in accordance with Section 6 of
             SMACNA standards except that sheet metal shall be 16 gauge minimum
             throughout.


PART 3 - EXECUTION

3.01   FABRICATION

       A.    No variation of duct configuration or sizes permitted except by written
             permission of the Architect.

       B.    Complete metal ducts within themselves with no single partition between
             ducts. Open corners are not acceptable.
       C.   Lap metal ducts in direction of air flow. Hammer down edges and slips to
            leave smooth duct interior.

       D.   Fabricate tees, bends, and elbows with radius of not less than 1-1/2 times
            width of duct on center line. Where rectangular elbows are used, provide
            turning vanes. All mitered elbows shall have single thickness turning
            vanes; dual wall airfoil type blades are not acceptable.

       E.   Increase duct sizes gradually, not exceeding 15" divergence wherever
            possible. Maximum divergence upstream of equipment to be 30" and 45"
            convergence downstream.

       F.   Rigidly construct metal ducts with joints mechanically tight, substantially
            airtight, braced and stiffened so as not to breathe, rattle, vibrate, or sag.
            Seal duct joints and connections with sealant as ducts are being assembled.

       G.   Provide necessary baffling in mixed air plenums to ensure good mixed air
            temperature.

       H.   Fabricate round and oval duct fittings with spiral or continuously welded
            seams. Joints shall be 4" slip type, cemented, brazed, or electric welded.
            Prime coat welded joints. Fabricate elbows of 5-piece construction.
            Provide standard 45 degree takeoffs unless otherwise indicated.

       I.   Reinforce plenum or casing door frames with galvanized steel angles tied
            to horizontal and vertical plenum supporting angles. Install hinged access
            doors for access to equipment, for cleaning, and inspection.

       J.   Fabricate seams and joints in kitchen hood exhaust and dishwasher
            exhaust ductwork liquid tight with continuous external welds.

3.02   INSTALLATION

       A.   Provide openings in ductwork to accommodate thermometers and
            controllers. Provide pitot tube openings for testing of systems, complete
            with metal cam with spring device or screw to ensure against air leakage.
            Where openings are provided in insulated ductwork, install insulation
            material inside a metal ring.
B.   Mount duct-type smoke detectors on the ductwork under this Section of
     the Specifications. All mounting arrangements, holes cut into ductwork,
     sealing of openings along with ceiling and access doors for each duct-type
     detector shall be provided under this Section of the Specifications. Duct
     detectors along with all sampling tubes and accessories shall be furnished
     under Division 16.

C.   Clean ductwork as it is installed to remove dirt and dust. During
     installation, close duct openings and open ends with temporary covers to
     keep construction duct out of the duct systems.

D.   Construct ductwork with sufficient clearance around equipment to allow
     normal operating and maintenance activities of equipment.

E.   At each point where ducts pass through partitions, seal joints around duct
     with noncombustible material.

F.   Where manufactured duct joint systems such as "Ductmate" are employed,
     install components in strict accordance with the manufacturer's
     recommendations. Bolt metal corner pieces except where bolting access is
     restricted, in which case metal corner clips shall be used.

G.   Install ducts and supports in accordance with SMACNA standards.
     Adequately attach hangers to the building structure. Refer to Section
     15090.

H.   Prior to operation or test and balance, clean duct systems with high power
     vacuum machines. Protect equipment which may 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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