3.5 The NAT Vent - Installation

The NAT Vent Attenuator is an attenuator specifically designed for low energy buildings. This product allows for cross ventilation through a partition without downgrading its acoustic performance. To meet the acoustic and ventilation requirements, MACH Acoustics designs and tests attenuator configurations using our in-house test facility, such to meet the individual needs of a building. Please see our website for further details: www.machproducts.co.uk

The NAT Vent Attenuator is constructed using foam blocks which tessellate together to form this product. A range of raw materials can be selected to acoustically adjust its performance. In addition, materials can be selected to the meet fire (Class O) requirements of recycled content. To control air flow and prevent the spread of fire, the NAT Vent Attenuator is often combined with volume control and fire dampers.

The installation of the NAT Vent Attenuator is exceptionally simple; the foam tiles are pushed into a bulkhead formed from timber or metal. Timber bulkheads can be lined with plasterboard. If the NAT Vent Attenuator is supplied in a metal duct, it can be simply supported on uni-struts to hold it in place.

2.6 Window Systems and Curtain Walling

The thermal damper is one of the main factors affecting the cost and depth of the NAT Vent Box. Replacing the damper with an openable or motorised vent/window, eliminates both the thermal damper and weather louvre from the box make up. This typically reduces costs by ≈50% and can reduce its depth by ≈225mm.
Facade and window manufacturers can easily accommodate openable vents in curtain walling or window frames. Placing the NAT Vent Attenuator directly behind an open vent, provides a simple, cost effective design solution for preventing noise break-in.

High level air inlet
In the case where noise levels are exceptionally high, for example due to motorway noise, flight paths or inner city noise, the depth of the attenuator is required to be increased. The additional depth of the NAT Vent Box can be accommodated by using a high level bulkhead 11.

2.8 Internal Sliding Doors and Windows

The presented illustrations show alternative arrangements 9 – 13. In this case, the NAT Vent Attenuator is placed on the outside of a thermally insulated door or sliding window. The key advantage of this scheme is that it again eliminates the need for a thermal damper. Additionally, it can often be easier to accommodate the NAT Vent Box outside of the thermal line.