SCD-LL-57 - NCA Manufacturing

MODEL SCD-LL-57
LOW LEAKAGE
STEEL CONTROL DAMPER
SCD-LL-57 - 02-05
Standard Construction:
Frame: Roll-formed galvanized steel
hat-section with staked corners
with integral bracing.
Blades: 16-18 ga. triple-vee profile
Roll-formed, galvanized steel
Minimum width: 4.250" (108 mm)
Maximum width: 7.250"
(184.2 mm)
Bearings: Nylon. Press-fit into frame.
Axles: Square, plated steel.
Seals: Pressure sensitive, 250°F dual
durometer blade edge seals
and flexible metal jamb seals.
Linkage: Concealed in frame. Linkage
bars are 12 ga. thick
galvanized steel.
Finish: Mill galvanized.
Extended Shaft: Removable, 6" long x 1/2” dia.
(152 mm x 12.7 mm) plated steel
coupled to square axle.
Max. Temperature: 250°F
Sizes: Minimum size: 5"w x 5"h
(127 mm x 127 mm)
Maximum size: Single section -
48"w x 72"h
(1219 mm x 1829 mm)
Multiple section - size unlimited
Options:
Bearings:
Notes:
Bronze Oilite.
Press fit into frame.
5"
(127 mm)
• Dampers fabricated 1/4" (6.4 mm) under
opening size unless otherwise noted
• All dimensions in ( ) indicate millimeters
Specify parallel or opposed blade action.
• All dampers 32" and over are supplied
with Jackshatfing. (See Jackshafting &
Enclosure submittal drawing for details).
Suggested Specification
Features
• The SCD-LL-57 series Control Dampers have been
designed and tested to provide an extremely tight
sealing damper which is cost effective for the majority
of HVAC applications. They are generally
recommended for face velocities up to 2000 fpm and
static pressures to 2.5" w.g. (Note: for systems in
excess of 2.5" w.g. contact the factory).
• The SCD-LL-57 series dampers have pressure
sensitive jamb and blade edge seals to provide the
ultimate in sealing characteristics without unduly
increasing torque requirements.
• The SCD-LL-57 series damper's rigid frame and
integrally braced corners provide true damper
alignment that greatly resists being installed out of
square or out of flat. This insures on site performance
equal to test results.
• The SCD-LL-57 dampers have been tested per
AMCA Standard 500-D with the following results:
LEAKAGE
cfm/SQ. FT.
AT
1.0" w.g.
3.5
AT
2.5" w.g.
5.0
AT
4.0" w.g.
7.0
• SCD-LL-57 is available in either parallel or opposed
blade models.
• SCD-LL-57 available as a face and by-pass mixing
damper.
• Dampers less than 12" (304.8 mm) in height are
furnished with a low profile flat top and bottom to
maximize free area.
• Factory installed electric or pneumatic operators
are available.
Low Leakage Control dampers shall be Model: SCD-LL-57 by NCA Manufacturing. Damper frames shall be of the steel, roll-formed hatsection
type with integrally braced corners to reduce racking. Damper blades shall be roll-formed 16-18 ga. galavanized steel for rigidity.
Bronze oilite or Nylon bearings shall be press-fit into frame to minimize wear. Linkage shall be of the concealed type to maximize free
area. Axles shall be square to prevent twisting. Both blade and jamb seals shall be of the pressure sensitive type for low leakage. Dampers
shall be rated for leakage per AMCA 500-D. Leakage shall not exceed 5 cfm/sq. ft. at 2.5" S.P.
Specifications are correct at time of printing. However, as part of our ‘continuous improvement program,’ we reserve the right to make further improvements without notice.
© 1999 NCA Manufacturing
Project:
Location:
Architect:
Engineer:
Contractor:
Address:
P.O. Number:
Date:
NCA MANUFACTURING, INC. 1036 SOUTH JUPITER ROAD GARLAND, TEXAS 75042 TEL. 972-276-5002 FAX 972-276-6747

MODEL SCD-LL-57
LOW LEAKAGE
STEEL CONTROL DAMPER
PRESSURE DROP - INCHES OF WATER (In. W.C.)
DAMPER SIZE 36 x 36
DAMPER SIZE 24 x 24
DAMPER SIZE 12 X 12
© 1999 NCA Manufacturing
Pressure drop testing was conducted by an independent laboratory in accordance with the AMCA Standard 500-D, Fig. 5.3
ductwork upstream & downstream
2.5
2
1.5
1.0 .9
.8
.7
.6
.5
.4
.3
.25
.2
.15
.1
.09
.08
.07
.06
.05
.04
.03
.025
.02
.015
2.5
2
1.5
1.0 .9
.8
.7
.6
.5
.4
.3
.25
.2
.15
.1
.09
.08
.07
.06
.05
.04
.03
.025
.02
.015
PRESSURE DROP
2.5
2
1.5
1.0 .9
.8
.7
.6
.5
.4
.3
.25
.2
.15
.1
.09
.08
.07
.06
.05
.04
.03
.025
.02
.015
SCD-LL-57 - 02-05
.01
100 150 200 300 400 500 700 900 1500 2000 3000 4000 6000
1000
VELOCITY THROUGH FACE AREA
Pressure (In. W.G.)
5
4
3
2
1
PRESSURE LIMITATIONS
0
0 12 24 36 48
Section Width (In.)
.01
100 150 200 300 400 500 700 900 1500 2000 3000 4000 6000
1000
VELOCITY THROUGH FACE AREA
Pressure & Velocity
Limitations presented in
the adjoining graphs are
conservative in order to
avoid mis-applications.
Please contact factory for
application guidance if
your requirements
exceed published
limitations.
Velocity (FPM)
.01
3000
2500
2000
1500
100 150 200 300 400 500 700 900 1500 2000 3000 4000 6000
1000
VELOCITY THROUGH FACE AREA
VELOCITY LIMITATIONS
1000
0 12 24 36 48
LEAKAGE
DAMPER SIZE 36 x 48
Section Width (In.)
10
98
7
Leakage Performance test was
conducted by an independent
laboratory in accordance with AMCA
Standard 500-D and is expressed as
CFM/SQ. FT. of damper face area.
STATIC PRESSURE
6
5
4
3
2.5
2
1.5
1.0
1 1.5 2 3 4 5 7 9 15 20 30 40 60
10
LEAKAGE IN CFM/SQ. FT.
NCA MANUFACTURING, INC. 1036 SOUTH JUPITER ROAD GARLAND, TEXAS 75042 TEL. 972-276-5002 FAX 972-276-6747