Section 15082, Commercial/Residential Duct Systems

PART 1.00 - GENERAL

1.01 Scope

A. Work covered by this specification consists of furnishing all labor, equipment, materials and accessories, and performing all operations required, for correct fabrication and installation of fibrous glass thermal insulation wrap on exterior surfaces of sheet metal commercial or residential air duct systems, in accordance with applicable project drawings and specifications, subject to terms and conditions of the contract:

1. All air duct systems operating at internal air temperatures not exceeding 250˚F (121˚C) or lower than 40˚F (4˚C).

B. Duct wrap insulation shall meet the requirements of ASTM C 1290, Type II, to maximum service temperature of 250oF (121oC). Facing material shall meet the requirements of ASTM C 1136, Type II, when surface burning characteristics are determined in accordance with ASTM E 84 with the foil surface or polymer surface of the material exposed to the flame as it is in the final composite.

C. Dimensions shown on the plans are finished inside dimensions.

D. Duct wrap shall be installed in accordance with manufacturer's instructions in such a manner that the insulation will provide the installed R-value as published for the product and printed on the facing, thus assuring specified in-place thermal performance.

1.02 Delivery and storage of materials

A. All insulation materials and fabricated duct sections and fittings shall be delivered to the job site in good condition and stored in a safe, dry place.

B. All means necessary shall be used at the job site to protect materials from dust, dirt, moisture, and physical abuse before and during installation.

PART 2.00 - PRODUCTS

2.01 Insulated duct system

A. All supply ducts, return ducts, and related fittings shall be insulated with faced duct wrap insulation meeting the R-value called for in project specifications or drawings.

The duct wrap insulation shall consist of a blanket of glass fibers factory-laminated to a scrim reinforced foil kraft vapor retarder facing with a 2 in. (50mm) (min.) stapling and taping flange on one edge.

PART 3.00 - EXECUTION

3.01 Receiving Inspection

A. The duct wrap shall be inspected to verify that it can be installed in accordance with project drawings and with operating performance parameters and limitations.

3.02 Insulation of straight duct and fittings

A. Before applying duct wrap, sheet metal ducts shall be inspected to ensure that they are clean, dry, and tightly sealed at all joints and seams.

B. All portions of duct designated to be externally insulated shall be completely covered with duct wrap.

C. To ensure installed thermal performance, duct wrap shall be cut to "stretch-out" dimensions in Table A below. Remove a 2 in. (50mm) (min.) piece of insulation from the facing at the end of the piece of duct wrap to form an overlapping stapling and taping flap.

D. Duct wrap insulation shall be installed with facing outside so that the tape flap overlaps the insulation and facing at the other end of the piece of duct wrap. Adjacent sections of duct wrap insulation shall be tightly butted with the 2 in. (50mm) (min.) stapling and taping flap overlapping. If ducts are rectangular or square, insulation shall be installed so it is not excessively compressed at corners. Seams shall be stapled approximately 6 in. (150mm) on center with 1/2 in. (13mm) (min.) steel outward clinching staples.

E. Where a vapor retarder is required, seams shall be sealed with pressure-sensitive tape matching the insulation facing, either plain foil or scrim-reinforced. All tears, punctures, and other penetrations of the duct wrap facing shall be sealed with tape or mastic to provide a vapor-tight system.

3.03 Final Inspection

A. Upon completion of installation of duct wrap and before operation is to commence, the system shall be visually inspected to verify that it has been correctly installed.

B. All system dampers shall be opened and fans turned on to blow all scraps and other loose pieces of material out of the duct system. Such material shall be removed.

C. The duct system shall be checked to ensure that there are no air leaks through joints.

3.04 Safety precautions

A. All job site operations shall be conducted in compliance with applicable provisions of the Occupational Safety and Health Act, NAIMA's Health and Safety Partnership Program, and all state and/or local safety and health codes and regulations that may apply to the work. Manufacturer's Material Safety Data Sheet (MSDS) shall be consulted when appropriate.