Acoustics is specialist science covering the generation, control, transmission and detection of sound and vibration. Acoustics relating to buildings is changing and moving from the suppression of noise to the design of environments which enhance health inparticular mental health.
What is a Dn,e,w sound reduction figure?
A Dn,e,w figure reflects testing at every frequency and it is the only result recommended by the BRE for products such as trickle vents.
As there is no industry standard for presenting acoustic test results, be wary of unspecified dB figures being quoted. The unspecified figure may be the highest dB achieved at a frequency and may not be relevant o your application or source of noise.
A Dn,e,w result reflects the true performance of the trickle vent.
Equivalent Area 2500mm2 EQA Free Area 2512mm2
Acoustic D n,e,w (+/-) – vent open – 38 (0:1) Acoustic D n,e,w (+/-) – vent closed – 51 (-1; -2))
Equivalent Area 5000mm2 EQA Free Area 5049mm2
Acoustic D n,e,w (+/-) – vent open – 35 (0:1)) Acoustic D n,e,w (+/-) – vent closed – 43 (0;0)
DB D n,e,w (+/-) rating – Air bourne sound insulation to BS EN ISO 10140-1:2016 Annex E and BS EN ISO 10140-
2:2010 and single number calculated in accordance with BS EN ISO 717-1:2013
Frequently used terms for acoustics
1Hz is one wave cycle per second, 20 Hz is 20 per second, where the cycles are 20 times shorter and closer.
A ‘frequency band’ is a continuous range of frequencies between an upper and lower limit.
An ‘octave band’ is a frequency band where the upper limit is twice the frequency of the lower limit.
A ‘one-third octave band’ is a frequency band where the upper limit 2 times the frequency of the lower limit.
Intensity of sound is measured in Decibels (dB). This is a logarithmic scale in which an increase of 10 dB doubling loudness.