Type : Motorized Smoke Damper
Leakage Rating :Class -III
Blade Type : 3V Single Skin; A : Parallel Operation
Construction : Galvanized Steel (GI)
MSD B-21 Series is a high performance UL 555S Classified smoke damper with Class-III leakage rating, installed vertically or horizontally (with blades running horizontally) and is rated for airflow and leakage in either direction.
Leakage Rating : Class -III
Max Velocity : 2000 fpm
Max Operating Pressure: 4 in. w.g (1000 pa)
Operating Temperature : 250°F (121°C) for ½ hr- Class-II
350°F (176°C) for ½ hr – Class-III
16 gauge (1.4 mm – 1.7 mm) thick galvanized steel.
Parallel operated 3 ‘V’ type blade made of 16 gauge (1.4 mm – 1.7 mm) thick galvanized steel.
Silicon rubber blade seals.
12 mm diameter Galvanized steel shaft.
Honeywell, Belimo, Seimens (24V AC, 120V AC, 230V AC).
Minimum 0.9 mm, single section is field or factory installed.
Multiple section is factory installed.
Sleeve thickness as per NFPA table 3-4.6.3.
For BMS open / close indication.
1½” x 1½” x 16 gauge (40 x 40 x 1.5 mm).
Externally mounted open, close visible Indicator.
For manual reset of damper.
Neck adapter for round duct connections.
Model : MSD-GB-21C3-A/R UL 555S Damper meets the required standards of SMACNA, NFPA, IBC, BOCA, ICBO, UL.
Actuator location standard: Left side from rear view
(Jack shaft view)
FC : Fail Close in the event of Fire
FO : Fail Open in the event of Fire
* The temperature ratings are for Honeywell 20 Nm actuators
with thermal enclosures.
Frame : Stainless Steel 16 gauge (304/316L)
Blade : Stainless Steel 16 gauge (304/316L)