Control dampers

SNRD is a gravity damper: airflow pushes the blades open; when it stops or reverses, the blades fall closed.

W 200–1600 × H 200–1600 mm · calculated, not tested

SPRD is a free-blade damper with counterweight: blades open when the pressure difference exceeds the setting and close when it falls.

W 200–1200 × H 350–2000 mm · calculated, not tested

SVCD is a volume control damper for low-pressure HVAC systems. The blades are either locked at a set angle after balancing or driven by an actuator.

W 100–1000 × H 100–1200 mm · VIBM 10131/VLXD-TBMT, 10132/VLXD-TBMT (10/10/2017), BS EN 1751:1999 – casing Class A, closed blade Class 1

SVCD-MP and SVCD-HP share the sealed V-hook blade construction; they differ in casing and blade gauge.

W 200–5100 × H 200–2000 mm · Starduct in-house lab, ANSI/AMCA 500-D-18 method, 914x914 (P-06150), 2 runs 10/2026, report no. pending QA – closed-blade leakage 57–63 % of the AMCA 511 table Class 2 limit at 250–1500 Pa (not AMCA certified); casing leakage, Cd pending; pressure drop vs blade angle 0–80° calculated by CFD (damper@6, not tested)

SVCD-MP and SVCD-HP share the sealed V-hook blade construction; they differ in casing and blade gauge.

W 200–5100 × H 200–2000 mm · calculated, not tested – closed-blade leakage derived from the in-house SVCD-HP 914x914 test (seal-length scaling); pressure drop vs blade angle calculated by CFD (damper@6, not tested)

SVCD-T is a single-blade round VCD fitted directly in circular ducts or flexible-duct spigots.

Ø 100–500 mm · calculated, not tested