Buildings need ventilation because they need to breathe. When you ventilate a building, you help to get rid of those things that are bad for occupants’ health, such as mould and disease.
There has been a general tendency to restrict ventilation by reducing air leakage in buildings. Part F of the building regulations has gone some way to solving that problem, but there are other issues associated with ventilation, such as poor acoustics.
If you put vents in your windows, you increase the chance of introducing outside noise. The more air you allow through a ventilator, the worse acoustic performance you will get.
Ventilation is there to improve the quality of life inside houses and offices. This is why our vents – either trickle vents, through-frame vents, over-frame vents, or glazed-in vents – are designed to keep outside noise to a minimum, while providing the optimum air flow for a healthy home.
The primary objective of a trickle ventilator is to provide background ventilation, whereas an acoustic trickle ventilator needs to provide background ventilation and acoustic performance. So, you must consider the acoustic performance in the open position, so that you’re getting both ventilation and acoustic benefits.
Our range of ventilators have different air intake sizes: the smaller the air intake, the better the acoustic value; the greater the air intake, the lower the acoustic value, because you’re letting air pass through a point in the building façade.
It’s very important that specifiers, fabricators and installers understand what it is they’re buying, what they’re trying to achieve, and how they’re going to achieve it interface-wise with their products. Also, if you don’t get the right ventilation strategy early on, you’re going to have a problem with cost. There is a big difference between an acoustic trickle slot vent and an over-frame vent, which provides more air and higher DNEW sound reduction. So, you’ve got to get the right product for the right application.
And it’s important that the ventilation specifications reflect the sound reduction in the open position, not the closed position, because you only get ventilation in the open position. The performance levels in the closed position are somewhat academic.
We can provide solutions to cope with most scenarios. For example, the SSH 2500EA acoustic trickle ventilator from AW Louvers has a slot height of just 11mm, and can provide a sound reduction of 46Dnew in one acoustic model in open position, and 48Dnew with two acoustic models in open position. This is market-leading performance in trickle slot ventilators.
Ventilation is there to improve the wellbeing of building occupants. While we focus on improving air flow within a building, it is vital that we don’t lose sight of a window’s acoustic properties.
Wayne Irvine
Managing director of AW Louvers, awlouvers.co.uk
