Fire and gas dampers prevent the spread of fire, smoke and gas between ventilation ductwork, where people must have the maximum amount of time to react to possible fire. The dampers are type- approved according to A-0 (A-60).
The dampers have a flanged steel casing with opposed blades with thermal expanding gasket. The fail-safe is made by a thermal release device which operates if the temperature inside the duct increases above 72 °C (optionally 90 °C). If the power supply is interrupted, a spring return actuator closes the blade. The actual position of the blade is marked on the casing.
ALCT SHUT-OFF DAMPERS
ALCT shut-off dampers shut off the airflow in ductwork. The dampers can be used as functional isolating dampers or as fire closure of main external ventilation openings as required by SOLAS. The dampers have a mild-steel frame and rotary blades actuated electrically, pneumatically or manually. The voltage or the working pressure of the control air must be specified at order.
ALSD SMOKE DAMPERS
ALSD smoke dampers prevent the spread of smoke and gases through the pipework in case of fire. The dampers have a steel casing with spiro pipe connections on both ends and with a manually operated rotary flap, peripherally sealed with a rubber gasket. The actual open/closed position is secured with a fixing spring and labeled on the casing.
ALNV NON-RETURN VALVES
ALNV non-return valves are installed in ventilation ductwork of ships and off-shore objects to prevent the backflow of air through the ventilation ducts.