3.1Introduction

Cross ventilation is a highly effective method of ventilating a building 2. This type of ventiliation can also provide cost savings as cross ventilation requires a lower floor to ceiling height than single sided ventilation 1. The drawback of this type of ventilation is often a reduction in floor area as a result of using multiple chimneys 3 and the risk of compromising the acoustic separation across corridor walls.

When ventilating through corridor walls, cross talk attenuators 2 are required to maintain the acoustic performance of partitions, whilst allowing the flow of air into a circulation zone. In these instances, bulkheads accommodating attenuators (600mm to 1200m deep) are required to maintain the acoustic resistance of the partitions. These figures are based upon the NAT Vent Attenuator being used.

Ventilation chimneys are an alternative. As mentioned previously, the drawback of these schemes is reduced floor area such to accommodate multiple chimneys 3. Considerable care is often required when detailing and constructing these chimneys, such to ensure that these details do not compromise the acoustic performance of separating walls and floors.

When ventilating more than one floor, independent chimneys are often used such to maintain acoustic privacy between vertically stacked spaces. On the other hand, NAT Vent Attenuators can be placed within the ventilation stack, therefore removing the need for multiple chimneys 4.