Internally fitted industrial fire suppression systems
October 2013, System Integration & Control Systems Design
Until recently, the traditional method of fire detection and suppression for buildings and rooms was confined to smoke detection and flooding by a fire suppression medium. These mediums were mostly in a gaseous form, usually having disadvantageous effects on equipment and humans, and environmentally undesirable results like ozone depletion.
The introduction of fire extinguishing aerosol generators has expanded the choices of fire suppression mediums through both the sensing and actuation methods. The Pyrogen ranges of fire extinguishing aerosol generators have advantages in general room flooding applications. One of these is the ability to be situated internally in the volume to be protected, ranging from engine compartments in vehicles, aircraft, and marine vessels, to electrical and electronic equipment.
This ability for internal fitment is achieved by the various methods of activation, plus the nature and composition of the post-activation residue. Activation methods include electrical, thermal cord and self-activation:
* Electrical, from a conventional fire alarm panel.
• Thermal cord attached to the aerosol generator, initiated when a pre-set temperature is reached.
• Self-activation in the event of the two previously described methods having failed, due to extraneous reasons.
The post-activation residue has 24 kV insulation properties, enabling immediate re-use of electrical equipment following replacement of the components which created the fire.
These design and construction features enhance the normal ‘failure to safety’ required in fire suppression systems. This autonomous system has no external power supply and is on standby 24/7 for the ten years installed life of the Pyrogen unit – all with zero maintenance.
There is an advantage to fire detection and suppression systems fitted internally to electrical equipment, compared to sub-station flooding by fire suppression media.
Electrical equipment by requirement and construction is to a minimum IP55 protection i.e. gasketed doors, covers and fitments. This inhibits the egress of smoke from the compartment until the fire is of major proportions i.e. before the smoke detectors in the sub-station would activate and initiate the release of the fire suppression medium, gas or aerosol.
When activated, the sub-station is flooded with the suppression medium but it has no means of ingress into the switchgear compartments. The result could be a complete burn out and destruction of the electrical switchgear panel in which the fire started.
With Pyrogen aerosol generators, correctly selected for the volume to be protected, the fire source can be localised to minimise collateral damage.