substitution request - Alliance Construction Solutions

C. Clean and dry ductwork prior to insulating. Butt insulation joints firmly together to ensure
complete and tight fit over surfaces to be covered.
D. Maintain integrity of vapor barrier on ductwork insulation, and protect to prevent puncture
and other damage.
1. Avoid the use of staples on vapor barrier jackets.
2. Seal vapor barrier penetrations with vapor barrier tape recommended by the
manufacturer.
E. Extend ductwork insulation without interruption through walls, floors and similar ductwork
penetrations, except where otherwise indicated.
F. Flexible Fiberglass Insulation: Cut back insulation to provide a 2” facing overlap at all
seams. Seams shall be stapled at approximately 6” on centers with outward clinching
staples, then sealed with pressure-sensitive tape matching the facing and designed for use
with duct insulation. Insulation on the underside of ductwork 24” and wider shall be
secured with mechanical fasteners and speed clips spaced approximately 18” on centers.
The protruding ends of the fasteners shall be cut off flush after the speed clips are
installed, and then sealed with the same tape as specified above.
G. Corner Angles: Except for oven and kitchen hood exhaust duct insulation, install corner
angles on all external corners of insulation on ductwork in exposed finished spaces before
covering with jacketing.
H. Calcium Silicate Insulation:
1. Secure 3/4" high rib lath by wire on 16” centers with ribs turned to create 3/4” air
space. Secure metal lath to outstanding ribs by welding or wire on 16” centers to
serve as insulation base. Secure insulation to metal lath with 14-gauge
galvanized wire ties on 16” centers. Stretch 1” hexagonal, 20-gauge mesh
smoothly and securely over insulation. Apply 1/2” thick coat of insulating and
finishing cement to exterior surface, and finish smooth. Allow cement to dry, and
cover with 8-oz. canvas applied with lagging adhesive. Brush with one final coat
of lagging adhesive.
I. Installation of external insulation for ductwork exposed to weather:
1. All insulation shall be applied with edges tightly butted and fastened to the duct
with mechanical fasteners spaced on 12” to 18” centers or as required to hold
insulation firmly against the duct surface. Insulation shall be tightly secured in
place with washers firmly embedded in the insulation.
2. Apply a heavy brush or trowel coat of weatherproof, fire-retardant, vapor barrier
mastic to completely seal all joints and extend over adjacent insulation. Embed
glass cloth into wet mastic to ensure complete and uniform contact, smoothing out
all wrinkles. Immediately apply a second coat of weatherproof fire-retardant
vapor barrier mastic over entire membrane surface, leaving a large bead over all
joints.
3.07 INSTALLATION OF EQUIPMENT INSULATION:
Project No.: 10145
550 15 th Street Dual Brand Hotel
03/16/2012
23 0713 - 10 MECHANICAL INSULATION