THE DOW CHEMICAL COMPANY
MECHANICAL
GLOBAL
ENGINEERING SPECIFICATION
G5S-5051-01
12-JUL-1996
Page 3 of 7
3.8. External insulation for rectangular and round duct
3.8.1. Duct insulation for indoor applications
3.8.1.1. Unless otherwise specified, external insulation
shall be a minimum of .024 grams/cubic cm (1.5 lbs./cubic
ft.), 40 mm (1 1/2 inches) thickness of flexible fiberglass
duct wrap insulation with aluminum foil scrim kraft (FSK)
facing.
3.8.1.2. All joints and punctures in the vapor seal will be
sealed with aluminum foil vapor seal tape. Minimum width of
tape shall be 75 mm (3 inches).
3.8.1.3. All portions of ducts designated to be insulated
shall be completely covered. Transverse joints shall overlap
at least 50 mm (2 inches) and be secured with staples.
3.8.1.4. External wrap insulation shall have weld pin
fasteners on the underside of duct work for duct widths in
excess of 630 mm (24 inches) to prevent insulation from
sagging.
3.8.2. Duct insulation for equipment rooms
3.8.2.1. All duct specified to be insulated and exposed in
equipment room shall be insulated with 0.032 grams/cubic cm,
(2.0 lbs./cubic ft.), 25 mm (1 inch) fiberglass rigid board.
3.9. Paint/coatings
3.9.1. Unless otherwise specified, carbon steel materials used
in ductwork construction that is not galvanized shall be coated
in accordance with paint/coating specifications indicated on
drawings.
3.9.2. Weld spots on galvanized sheet steel shall be coated with
cold galvanized coating, ZRC preferred. Coating to be applied in
accordance with Dow Engineering Specification G16S-0205-01.
3.10. Caulking/sealant
3.10.1. Unless otherwise specified on the drawings or job
specifications caulking/sealant shall be "Dow Corning 795"
manufactured by Dow Corning Corporation, Midland, Michigan
48686-0994.
4 INSTALLATION
4.1. Field verify duct routing prior to fabrication of ductwork.
Coordinate routing with other disciplines. Provide all minor
DOW RESTRICTED - For internal use only