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Over the past few years, the strategy for ventilating underground car parks has changed dramatically. Traditional ducted systems have been replaced by `jet´, `impulse´ and/or `induction´ systems. These use small fan units positioned around the car park to direct the smoke towards the extract point.
As a result, the need for distribution ductwork throughout the car park is eliminated. This may save car-parking spaces and make the car park a lighter, less cluttered environment.
Colt offer Jetstream and the Cyclone impulse fans specifically for this purpose.
Car Park fans at the Postbox Apartments, Birmingham
In 2004 Colt carried out comparative full-scale tests in an underground car park in Bristol. The purpose of the tests (3 MB PDF) was to demonstrate that the impulse and induction systems can provide an equivalent performance to traditional ducted systems.
The tests showed that there was infact a significant improvement in the time taken to clear the car park of smoke when using the new systems compared with traditional ducted systems.
In 2005 Colt and the Building Research Establishment (BRE) carried out a series of full-scale hot smoke tests (0.5 MB PDF), not only to demonstrate how well impulse systems can control the flow of smoke in a car park, but also to confirm the effectiveness of the computational fluid dynamics (CFD) modelling approach used by Colt. These tests included setting up a 35m x 30m x 3m test rig and setting light to a car shell containing a tray of diesel fuel to create a 1 MW fire size.
The results of the tests clearly indicated that impulse systems are capable of controlling the spread of smoke from a car fire and keeping significant areas of a car park effectively smoke free. BRE confirmed that: "The smoke movement during the fire with the impulse fans running was as predicted by the CFD modelling Colt had carried out before the tests." Read news story.
Please see our leaflet "Car Park Ventilation" (4 MB) for further details relating to:
- Legislation and standards
- Design approaches
- Features and benefits of impulse systems
- Extract systems
- Controls
- CFD
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