How to determine the insertion loss of a louvre?

[renson]

How can I determine the insertion loss of an acoustic louvre? I know how to calculate the specific Rw value, but I don't know to calculate the insertion loss. Can someone give me the explaination or the standard?

 

[okdb]

Hi,

2 ISO standards could help you: ISO 7235 for lab. measurements an ISO 11820 for in situ measurements.

In short, you get the insertion loss through calculating the sound power from the duct with and without louvers. To obtain the sound power levels, you have to perform sound pressure measurements using a boxe-shape or a half-sphere. If the air speed is low enough, you can also get the sound powers via "scanning" over the duct outlet with a sound meter or beter with a sound intensity probe.

Hope that this will help you!

OkdB