FläktGroup car park ventilation Design input critical to car park ventilation

Whether for simple pollution control, smoke clearance and purging, or complete smoke control, almost every car park needs ventilation. Understanding why – and the different purposes ventilation can fulfil – is key to designing and specifying the right system for each car park.

Given the myriad of regulations and the huge variety of car park designs, understanding the issues involved in ventilating car parks is key to being able to offer the best solutions for each individual case, writes Gavin Power, Sales Director, FläktGroup Ireland.

“There are many different types of car park and each has its own ventilation needs. For example, an above ground car park, which will typically have open sides, will require less mechanical ventilation, as they are generally subject to natural ventilation (although this makes them susceptible to high winds).

Below ground car parks will require mechanical ventilation, consisting of extract fans, jet fans or induction fans, with levels below the first basement ideally being fitted with a fresh air mechanical ventilation airflow supply.

Some below ground car parks take the form of complex tunnels, but often these are either too short or have too many joins and bends to be applicable to tunnel theory. So, a combination of car park design philosophies and tunnel-specific requirements may be needed when designing the solution. Standards compliance is also critical and it is essential that all applicable local and national regulations are factored in to the proposed solution. Standards can vary fundamentally and a case in point is the basis of calculating the specific pollution control ventilation rate. Some regulations require this to be worked out based on the overall car park volume or area, the number of car parking spaces, or even just the floor area. Others require that the ventilation rate is calculated based on the amount of pollution generated by vehicles moving around within the car park. However, during an actual fire, most regulations require an emergency smoke extraction rate to be based on a specific number of air changes per hour.

Unlike traditional ducted systems, FläktGroup’s thrust fan system (JTv) removes the need for costly and space-consuming ductwork, with strategically-placed arrays of compact jet thrust fans precisely directing supply air (from inlet points) towards each extract point, so that a good level of ventilation is provided throughout the car park.

Supply air for such a system can be delivered in a number of ways, including via vehicle entrance or exit ramps, fresh air openings (grilles), or by using mechanical means such as air supply fans.

These systems are more effective than traditional ducted systems for providing pollution control, smoke clearance or purging, and smoke control in all but the smallest car parks. In addition, they deliver energy efficiencies, save space and, in the event of a fire, can ensure less smoke damage and better smoke containment. They also allow the car park to be brought back into use more quickly.

The benefits of enhanced design

Providing an enhanced design includes computer modelling of the project, embracing computational fluid dynamics (CFD) and advanced controls.

There are significant benefits to this approach, including a higher system performance with improved smoke control, lower installation and running costs, as well as lower installation costs for other services (because they don’t need to be routed around ducts, for example).

In addition, using enhanced design optimises car park space, potentially increasing the capacity of the car park, as well as giving a cleaner appearance and producing lower external noise levels due to being able to use lower powered extract fans.

Contact: Gavin Power, Sales Director, FläktGroup Ireland. T: 01 463 4600; E: gavin.power@flaktgroup.com

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