After a gaseous system has done its job, the extinguishing agent and the products of the fire remain in the room, and both need to be cleared before anyone can safely go back in. Post-discharge extraction is a mechanical ventilation system that purges the protected space once the fire is out, removing the agent and any smoke or decomposition products and venting them safely outside. MEP designs and installs post-discharge extract systems as part of a complete, safe gaseous suppression installation.
Some agents, such as chemical agents, are heavier than air and pool at low level where they remain a hazard long after discharge. Chemical agents can produce small amounts of decomposition products when exposed to fire, and every fire leaves smoke behind. Opening a door and hoping the room clears may not be reliable. A purpose-designed extract system removes the contaminated air in a controlled way and draws in fresh air, so the room can be safely re-entered and returned to service.
A post-discharge extract system uses fans and ductwork sized to change the air in the room a set number of times, discharging to a safe external location away from people and air intakes. It can be activated via external controls to begin extraction after system discharge, never during. We design the extract to suit the room, the agent and the building, and can integrate it with the detection and control system so re-entry is properly managed.
Get in touch with our team of fire suppression experts to discuss your requirements and receive a tailored solution.
It is a mechanical ventilation system that clears the extinguishing agent and fire products from a room after a gaseous system has discharged, so the space can be safely re-entered.
The agent and smoke remain in the room after the fire is out. Some agents pool at low level and stay hazardous, so the air must be purged before anyone goes back in.
No. That is neither safe nor reliable, particularly with heavier-than-air agents like CO2. A designed extract system clears the space in a controlled way.
No. It is interlocked to run only after the discharge and hold period are complete, so it never interferes with the system suppressing the fire.
It is ducted to a safe external point away from people, doors and fresh-air intakes, so the agent and smoke are released without creating a new hazard.
Some other offerings by MEP that you might be interested in.
