STANDARD	1 Aug 1998	15812

UPDATES -

10 Mar 98	-	Modified restrictions on use of round duct.

SECTION 15812

LOW-PRESSURE STEEL DUCTS

PART 1 GENERAL

Edit Article '1.1' as necessary to give an accurate, but brief description of the work of this Section and accurate listing of related work, especially if the scope of the work is not shown graphically on the Drawings.

1.1	SUMMARY

A.	Includes But Not Limited To

1.	Furnish and install above-grade low-pressure steel ducts and related items as described in Contract Documents.

B.	Related Sections

1.	Division 13 - Smoke testing	13352opt.a 13352opt.b

2.	Section 15051 - General Mechanical Requirements	15051

3.	Section 15081 - Ductwork Insulation	15081

4.	Section 15761 - Furnishing of air coils	15761opt

5.	Section 15915 - Temperature control damper actuators and actuator linkages

15915 15915opt

1.2	REFERENCES

Delete or add references based on editing of other parts of this Section.

A.	American Society For Testing And Materials	ASTM

1.	ASTM A 653-96, 'Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process'

1.3	QUALITY ASSURANCE

A.	Pre-Installation Meeting - Schedule meeting immediately before installation of ductwork.

Pre-installation Meeting

PART 2 PRODUCTS

2.1	COMPONENTS

A.	Ducts

1.	Fabricate of zinc-coated lockforming quality steel sheets meeting requirements of ASTM A 653, with G 60 coating.

Use of round ductwork is allowed only where shown on standard plan drawings, or where specifically approved by Owner's Representative. Delete paragraph '2' if no round ducts used.

2.	Round Duct -

a.	Spiral Seam - 28 ga minimum for ducts up to and including 14 inches in diameter.

b.	Longitudinal Seam -

1)	28 ga minimum for ducts up to and including 8 inches in diameter.

2)	26 ga minimum for ducts over 8 and up to 14 inches in diameter.

Delete paragraph '3' if no ducts 36 inches and larger. Edit paragraph 'a' and delete paragraph 'b' if largest ducts are over 36 inches and less than 48 inches.

3.	Duct with height or width over 36 inches shall be fabricated using SMACNA T-
24 flange joints or of pre-fabricated systems as follows -

a.	Ducts with sides over 36 inches up to 48 inches - Transverse duct joint system by Ductmate / 25, Nexus, Ward, or WDCI (Lite) (SMACNA 'E' or 'G' Type connection).

b.	Ducts 48 Inches And Larger - Ductmate / 35, Nexus, or WDCI (Heavy) (SMACNA 'J' Type connection).

c.	Approved Manufacturers -	Approved Products

1)	Ductmate Industries Inc, 10760 Bay Meadows Drive, Sandy, UT 84092 (801) 571-5308

Stockton, CA (800) 344-3270

Pittsburgh, PA (800) 245-3188

2)	Nexus, Exanno Corp, P O Box 729, Buffalo, NY 14206 (716) 849-
0545

3)	Ward Industries Inc, 1661 Lebanon Church Road, Pittsburgh, PA 15236 (800) 466-9374

4)	WDCI, P O Box 10868, Pittsburgh, PA 15236 (800) 248-2355

B.	Duct Sealer

Edit the list of approved manufacturers to include only those with whom you are familiar and whose products are available in the Project area. Do not add or approve any other manufacturers or systems without written approval of Owner's Representative.

1.	Approved Manufacturers -	Approved Products

a.	Cain - Duct Butter or Butter Tak

b.	Design Polymerics - DP 1010

c.	DSC - Stretch Coat

d.	Duro Dyne - S2

e.	Hardcast - Versa Grip 102

f.	Kingco - 15-325

g.	Mon-Eco - 44-41

h.	Polymer Adhesive - Airseal #11

I.	Trans-Continental Equipment Co - Multipurpose Duct Sealant

j.	United - Water Base Duct Sealer

C.	Duct Hangers

1.	One inch by 18 gauge galvanized steel straps or steel rods as shown on Drawings, and spaced not more than 8 feet apart. Do not use wire hangers.

2.	Attaching screws at trusses shall be 2 inch No. 10 round head wood screws. Nails not allowed.

2.2	FABRICATION

A.	Ducts

1.	Straight and smooth on inside with joints neatly finished.

2.	Ducts shall be large enough to accommodate inside acoustic duct liner. Dimensions shown on Drawings are net clear inside dimensions after duct liner has been installed.

PART 3 EXECUTION

3.1	INSTALLATION	Installation

A.	Interface With Other Work - Reseal transverse joint duct leaks and seal longitudinal duct joint leaks discovered during air test and balance procedures specified in Section 13352, at no additional cost to Owner.

B.	Ducts

1.	Install internal ends of slip joints in direction of flow. Seal transverse joints air tight using specified duct sealer.

2.	Securely anchor ducts to building structure with specified duct hangers attached with screws. Do not hang more than one duct from a duct hanger.

3.	Brace and install ducts so they shall be free of vibration under all conditions of operation.

4.	Ducts shall not bear on top of structural members.

5.	Paint ductwork visible through registers, grilles, and diffusers flat black.

6.	Properly flash where ducts protrude above roof or through wall.

7.	Cover horizontal and longitudinal joints on exterior ducts with two layers of Hardcast tape installed with Hardcast RTA-50 adhesive according to Manufacturer's recommendations.

END OF SECTION