Flame dampers stop flames advancing in the piping (in-line) or inhibit, for example, the spread of fire from outside the tank into the tank (end-of-line).
Flame dampers can be divided into two groups depending on the nature of the flame. In the first phase of a fire, the pressure wave and the flame wave advance separately (deflagration). If the pipe goes on and the flame continues to spread, an explosive fire (detonation) occurs when the flame wave meets the pressure wave.
Selection criteria are process-dependent
It is said that a flame damper cannot eliminate fires, but a properly selected and installed damper can inhibit the spread of fire to critical locations.
In selecting the type of a flame damper and considering an installation site, it is important that the process is known and that the potential ignition risks and locations can be assessed.
Flame dampers are always selected based on the explosibility class of the media. Since the functionality of flame dampers is based on extinguishing of a flame wave passing through it by absorbing its energy, proper dimensioning of the damper is of utmost importance. If the flame damper is too tight, this results in an excessive pressure drop for the normal gas flow, whereas if the flame damper is too loose, it cannot stop the flame wave from advancing and is thus altogether useless in the piping and renders a false feeling of security.
We carried out this demonstration at the Protego test facility in Braunschweig, Germany.
The explosion classes used by PROTEGO are IIA, IIB3 and IIC (highest).