substitution request - Alliance Construction Solutions

B. Low Pressure Round Dampers (less than 1500 FPM and under 1” W.C. S.P. differential):
1. Dampers 4” diameter through 18” diameter shall have 18 ga. galvanized steel
frame and the following blade construction:
4”-12” diameter, 22 ga. galvanized steel; 13”-18” diameter, 20 ga. galvanized
steel.
Project No.: 10145
550 15 th Street Dual Brand Hotel
03/16/2012
Axle shaft shall be carbon steel with retainers mounted on nylon bearings with
notched end shaft indicating damper position, locking quadrant and handle.
C. Medium/High Pressure Rectangular Dampers (less than 4000 FPM and under 6” W.C. S.P.
(48” wide or less) or 8” W.C. S.P. (36” wide or less)):
1. Dampers shall be opposed blade for volume control and parallel blade for
isolation/shut-off service.
2. Frame shall be 16 ga. galvanized steel with welded corners / 1/8 inch thick 6063-
T5 alloy aluminum frame. Blades shall be double skin galvanized steel with
single-lock seam / .081" thick 6060-T5 extruded aluminum, airfoil shape. Blade
edge seals shall be double durometer vinyl and metallic compression seals at the
jambs. Axles shall be solid carbon steel mounted on bronze oilite bearings.
Linkage shall be in-jamb type located outside the airstream. Maximum damper
size shall be 48” wide and 60” high. For fixed position balancing damper, delete
blades to maintain 30% free area with all other damper blades 100% closed. For
isolation or shut-off duty, damper leakage shall not exceed 9.5 CFM/sq.ft. at 4”
W.C. S.P. differential. Provide extended shaft with notched end indicating damper
position, locking quadrant, and handle.
Air Balance Model AC-S15/AC-S16 (steel)
OR
Air Balance Model AC-52S/AC-S26 (aluminum)
D. Medium/High Pressure Round and Flat Oval Dampers (less than 3000 FPM and under 4”
W.C. S.P. differential):
1. Damper frame construction shall be galvanized steel as follows:
ROUND
Under 6” diameter 12 gauge
6” to 18” diameter 14 gauge
20” to 30” diameter 2 x 1/2 x 1/8 channel
32” to 42” diameter 2 x 1 x 1/8 channel
FLAT OVAL
6” to 18” wide 2 x 1/2 x 14 gauge channel
19” to 48” wide 2 x 1/2 x 1/8 channel
49” to 72 wide ( 6” to 18” high) 2 x 1/2 x 1/8 channel
(19” to 26” high) 2 x 1/2 x 1/8 channel
2. Amper blades shall be galvanized steel as follows:
23 3300 - 4 AIR DUCT ACCESSORIES