15841.doc

ADG 96-620 A

07-733 07-743

SECTION 15841 - DUCTWORK AND ACCESSORIES

PART 1 GENERAL

1.1 WORK INCLUDED

A Furnish and install all sheet metal duct systems as indicated on the plans or herein described.

B. Furnish and install all grilles, registers, diffusers, louvers, dampers and ductwork accessories as shown on the plan or herein described.

1.2

QUALITY ASSURANCE

A.

Duct construction shall be in accord with the requirements of the two following organizations and good industry practice.

1.

Various applicable manuals and standards of the Sheet Metal and Air Conditioning National Association (SMACNA).

2.

Material and duct construction standards of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).

1.3 CODES

A.

Materials, methods and installation shall also be in accord with the applicable requirements of the National Fire Protection Association (NFPA) Standards 90A and 90B.

B.

All duct work and piping shall be provided with seismic restraints in accordance with Seismic Hazard Level SHLB of the Seismic Restraint Manual: Guidelines for Mechanical Systems dated 1991, as published by the Sheet Metal and Air Conditioning Contractors National Association, Inc. and in accordance with the 2003 International Building Code.

1.4

SUBMITTAL DATA

A.

See Section 15000 for general submittal requirements.

B.

Submit manufacturer's literature and performance data for all dampers and duct accessories. Identify all materials of construction and the options and accessories which will be furnished with each unit. Performance data shall include throw, pressure drop and NC information. Performance data is not required for units supplied as specified.

C.

Submit a fabrication drawing for each hood to be installed. The drawing shall include complete dimensional data.

PART 2 PRODUCTS

2. 1

ENVIRONMENTAL AIR DUCT SYSTEMS

A.

Stainless Steel Duct

1. Stainless steel duct, as specified herein, refers to ductwork to be used for normal HVAC purposes where corrosion is a concern such as chemical or wet exhaust. All ductwork for this project shall be stainless steel as specified herein. Stainless steel duct shall be type 304 stainless steel with fully welded joints and seams.

2. Rectangular and round ducts shall be Type 304 stainless steel with full welded joints and seams.

3. Construction, welding and installation shall be in accord with appropriate SMACNA manuals. Lap welding of joints is approved. Laps to be run in the direction of air flow. Stainless steel thickness to be determined by SMACNA Duct Construction Manual for -6" w.g. static pressure with continuous external welded seams and joints all in accord with NFPA #96.

4.

Volume dampers and accessories used in stainless steel duct systems shall be constructed of stainless steel.

2.2

DUCT ACCESSORIES FOR ENVIRONMENTAL AIR DUCTS

A.

Duct turning vanes - single vane with trailing edge as per SMACNA Fig. 2‑3.

B.

Instrument Test Holes (I.T.H.): Unless otherwise detailed or noted on the plans, an instrument test hold shall consist of a 5/8" diameter hole drilled and deburred in the duct with plastic snap-in closure plug.

C.

Volume dampers - opposed blade type (rectangular) and double wall blade with solid-axle and blade seals (round) with locking quadrants, AMCA leakage rated less than 6 CFM/S.F. at 4" W.G.

PART 3 EXECUTION - ENVIRONMENTAL AIR DUCTS AND ACCESSORIES

3.1

INSTALLATION

A.

Install all ductwork and fittings generally in accord with the applicable SMACNA Manual or ASHRAE Guide. Adequately support with sheet metal strap, strap irons or rods as required, fastened securely to the duct and to building construction.

B. The Contractor shall build and install the associated duct for each system according to the

SMACNA standards as identified by the SMACNA manual “HVAC Duct System Design.”

C.

Joints shall be mechanically secure and airtight.

D.

All dampers shall operate smoothly through their entire range. Provide locking mechanisms to secure volume dampers in position.

E.

Instrument Test Holes

1.

Locate instrument test holes in all ducts downstream of each hood on each side of all coils, fans, filters and other duct-mounted equipment (e.g. humidifiers, etc.), at all locations specifically identified on the drawings and elsewhere as necessary to properly balance the system.

2.

Where used for testing and balancing procedures, provide I.T.H. in a traverse pattern on two accessible adjacent sides of the duct so instrument readings can be taken at 90 degrees. Do not place holes at the base of ducts where condensate can puddle.

3.

Where an I.T.H. is located in insulated duct, a plug of insulation shall be cut out over the I.T.H. or inserted and held in place with duct tape and the area identified 'I.T.H.'

F.

Slope ducts continuously back towards hoods with no depressions or low spots.

G.

Seismically brace all hood exhaust duct systems in accordance with SMACNA Seismic Restraint Guidelines, 2000 Edition.

H.

Clean all duct sections as they are installed and keep all openings sealed closed during construction.

I.

Inspect all joints, seams, connections to fans and equipment for leakage. Duct to prove airtight.

3.3

TESTING, BALANCING, CLEANING OF ENVIRONMENTAL AIR DUCT SYSTEMS

A.

Testing 1.

Each joint and seam shall be inspected.

2.

All dampers shall be checked for smoothness of operation. Repair unacceptable units to the satisfaction of the Contracting Officer.

3.

The Contractor shall operate all dampers after installation to ensure that operation is correct and that service access is adequate.

B.

Balancing

1.

See Section 15992: TESTING, ADJUSTING AND BALANCING.

2.

The systems serving each affected area shall be balanced to the airflows or pressure relationships indicated on the drawings and/or specified elsewhere.

3.

Balancing is to include adjusting existing terminal units to deliver the listed airflows. Set all dampers and make all necessary adjustments.

C.

Cleaning

1.

All equipment, plenums, ducts, grilles and registers, hoods and component parts of all duct systems shall be clean and free of dirt and debris on both the inside and outside of all components. Cleaning methods shall consist of sweeping, vacuuming, washing, etc., as necessary to establish clean conditions.

END OF SECTION 15841

PACKAGE M OUTBUILDING RENOVATION NIH-NIAID RML HAMILTON, MT

DUCTWORK AND ACCESSORIES 15841-4

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