Top 5 Tips For Choosing Acoustic Ventilation
January 9, 2020 | HVAC
The importance of acoustic ventilation is easy to underestimate. In situations like recording studios or concert venues, it’s vital to bring clean air into the room. But in doing so, you need to ensure that you don’t at the same time introduce unwanted noise elements. As soon as you make a hole in a wall or ceiling to allow air in, you’re almost certainly allowing noise in as well. Acoustic air vents are fitted with a sound absorbent lining in order to mitigate this problem and allow airflow while cutting noise. So what do you need to take into account when selecting products to provide ventilation and cut noise?
1. Performance ratings
Products used to provide ventilation are rated according to their Dn,e,w performance. This is a weighted normalised measure that allows differences in noise levels to be accurately measured. By using this, it’s possible to compare the relative performance of acoustic ventilator equipment from different suppliers.
2. Beware decibels
Many acoustic ventilation suppliers quote decibel (Db) levels from test results. However, there is no accepted standard for measuring acoustic test results in this way. The appearance of a high Db rating therefore may simply be down to the results achieved at a particular frequency. It may have no bearing on the particular noise that you’re trying to deal with.
3. Ask for a report
If the manufacturer’s sales material doesn’t make clear the Dn,e,w performance of its product, then ask to see the results of a full acoustic test. Most companies should make this data readily available to potential customers. Look too to see if products comply with the appropriate British Standards, BS EN 20140-10:1992 and BS EN ISO 717-1:1997 for extra reassurance that you’re choosing a quality product.
4. Frequencies matter
The acoustic performance of ventilation can vary according to the frequency of the sound in question. This is why the Dn,e,w measure is so important, as it gives a measure of the acoustic performance of vents across the full frequency spectrum.
5. Airflow
Another key measure to take into account in selecting vents is the airflow – or equivalent area. Because ventilation is a balancing act between ventilation performance and noise transmission, a vent that’s good at suppressing noise may be less good at delivering the required airflow. You may therefore need to offset this by installing a greater number of vents to get the required air throughput. You also need to consider any baffles or grilles that are fitted to manage the airflow.
There’s a lot to think about when installing acoustic ventilation, but by following the guidance above, you should be able to find the product you need to keep your room comfortable without harming its acoustic properties.