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Colt International has developed a new Extended Corridor System for means-of-escape corridors
in residential buildings. Compared with conventional Automated Opening Vent (AOV) corridors,
this system offers developers substantial space and cost saving benefits, while providing a safe
evacuation route, with increased smoke extraction. Colt's Extended Corridor System also aids fire
fighters by rapidly clearing smoke during the later stages of a fire.
With local authority approval, the first Extended Corridor System is currently being installed
in a residential building at the Angel Meadows development in Manchester. By extending the escape
distance in the corridor from 7.5m to 18.0m in one direction, the system has made it possible to
omit one staircase, gaining useable space and saving building costs. Read an article reproduced
with permission from Fire Safety Engineering (October 2007).
Computational Fluid Dynamic (CFD) models show Colt's Extended Corridor System will out perform
the smoke clearing capabilities of conventional dead-end corridors that are compliant with Approved
Document B. This document refers to corridors limited to an escape distance of 7.5 metres or less,
relying on Automated Opening Vents (AOV) of 1.5m2 free area for smoke evacuation.
Colt has achieved this exceptional smoke extraction performance by offering both a corridor
extraction system at one end of the corridor and a dedicated air inlet system at the other.
Inlet air prevents the corridor from becoming excessively depressurised, which could make it
difficult for evacuees and fire fighters to open doors, as well as causing extract fans to stall,
resulting in total system failure.
Simon O'Hea, marketing director of Colt International, commented: "We expect plenty of interest
in the Extended Corridor System, principally because of the great space and cost savings it provides
developers.
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However, this does not mean a compromise in safety; its excellent smoke-extraction
technology will also save lives."
Colt's engineers first conceived the Extended Corridor System's mechanical ventilation system when
developing and testing the Colt Shaft - a ventilating fire-fighting shaft that reduces spatial
requirements by 80 percent, compared to other systems. As with the Colt Shaft, the Extended Corridor
System enables developers of apartments, hotels and office buildings to increase saleable space
while maximising safety, potentially saving lives.
CFD test results
The CFD model showed AOV maintained corridors removed an acceptable layer of smoke when the
occupants evacuated the building in the early stages of the fire and shut the door after them,
but was very slow at clearing the residual smoke, even in zero-wind conditions. With positive-wind
conditions, smoke in the AOV-dependent corridor would be much worse, whereas the Extended Corridor
System is unaffected by wind.
When the apartment door was opened with a fire that had grown much larger (in excess of 4.5MW),
the conventional corridor was almost completely smoke-logged in approximately ten seconds with
the AOV systems overwhelmed and incapable of providing appreciable benefits to fire fighters at
the scene. With the Extended Corridor System, however, the corridor was almost completely cleared
of smoke within 45 seconds of the apartment door closing, despite the fact that the extended
corridor was more than twice as long. At earlier stages of the computer-simulated fire, the
Extended Corridor System cleared the extended corridor of smoke completely in even less time.
For more information on the Colt Extended Corridor System, click here.
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