How does a cold smoke air transfer grille system work?

In everyday use, intumescent grilles allow air to circulate freely throughout a building; but in a fire, the intumescent expands to form a solid block that stops the fire from spreading. However, these grilles will not prevent the passage of cold smoke which can be equally dangerous.

The capability to maintain a smoke barrier prior to the need for fire containment is becoming an increasingly critical area for intumescent products.

  • In doors, the thickness of the door core makes it very difficult to introduce mechanical dampers. So here the inclusion of shutter plates with a thinner intumescent fire block on both sides allows fitment in standard 44mm FD30S fire doors, as well as thicker FD60S doors. Lorient offers a range of combined intumescent fire and smoke air transfer grilles that allow the passage of air during normal operation.
  • Wall mounted fire and smoke resistant air transfer grilles consist of an intumescent air transfer grille, with the addition of shutter plates that are contained in a non-combustible housing, allowing for ease of installation into rigid and flexible walls.

Our Cassette Type Damper (LVHCTD) allows for simple and rapid duct installation in small spaces, when used with an LVH44 or LVH54 air transfer grille it can provide up to 240 minutes fire resistance.

These are connected via a control panel (Lorient’s Talkback System DCM) to a standard fire alarm system. In the event of an alarm condition, the dampers shut in order to maintain the smoke leakage rate for the door assembly, as defined in the relevant building controls guidance.

Talkback Damper Control System

Most large buildings, such as in healthcare settings, can require a significant number of fire and cold smoke resistant air transfer grilles within any one fire zone. These air transfer grilles may be a considerable distance apart, but are usually controlled according to the buildings fire compartmentation strategy.

The Talkback system has been designed to control up to sixteen individually addressed air transfer grille assemblies from one centralised status monitoring unit. A 2-way communication system operates between the Damper Control and Monitor Unit (DCM) and the air transfer grille actuators. This facilitates a continuous assessment of the status of the shutter plates and immediately identifies and provides an alarm condition in case of any defective shutters.

Talkback is designed to give peace of mind to a building’s occupants in that it:

  • it fails-safe – the smoke shutters will automatically close in the event of an alarm, power failure or loss of communication;
  • resets automatically – when the alarm is cancelled or power restored;
  • is self-testing – every 24 hours the dampers are automatically closed and opened to check they are working and to dislodge any dust and debris between the moving parts;
  • continuously monitors the status of each damper and displays this on the DCM;
  • is easy and quick to install – simple loop wiring is used and the damper units are supplied ready assembled and tested;
  • uses a safe 12V DC supply to open and close the dampers;
  • has been successfully tested in accordance with the requirements of the Electro Magnetic Compatibility and Low Voltage Directive and therefore bears the CE mark (copies of the relevant test reports are available on request).