Dwelling STC Requirements

[AVare]

I find various gems browsing NRC-IRC documents. The latest gem is nrcc 44774 dealing with atached dwelling STC criteria for party walls. We know that STC is a poor metric for music isolation, but the use of ALD50 and RW(sub 50-3150) is not widespread yet. The document does not call it such, but clearly it uses STC to mean FSTC.

What I found particularly interesting was fig 4 on pdf page 3. Interpolating equivalent annoyance, or better, non-annoyance levels, music isolation has to be at least 59 STC to match the nominal annoyance levels for any of the partitions tested. That is not for satisfaction, just the same annoyance as typical wall construction. Add 5 dB for a construction factor, and a 64 STC for music partitions for minimal annoyance is quite realistic. This is in good agreement with the recommendation often made for an STC of around 65. Of course we add the proviso of TL analysis to be certain of any specific construction.

It's nice to see independent verification of our practices. Particularly when doing it professionally.

Quietly pleased,
Andre

[Soundman2020]

Don't know I missed this post, but thanks, André! Interesting stuff in there....

- Stuart -

[xSpace]

It is my understanding that for a party wall the goal has been 55stc for many years. What would be interesting , to me, if the class evaluation of the peoples measured where included. To include the building type, age and specific things that could be a teller of how far in the past this paper reaches as an examination of how buildings, builders and materials have either exceeded, remained the same or failed in this troublesome area.

Not that I have to deal with it