Acoustics

Question 1

What is STC

Ballast, Ch. 19

Answer 1

Sound transmision class
Measures the airpborn sound insulating properties of a building element

Ballast, Ch. 19

Question 2

What properties make higher STC numbers

Ballast, Ch. 19

Answer 2

Mass - density
air tight poperties
structurally discontinuous

Ballast, Ch. 19

Question 3

Is this statement True or False

Materials that absorb sound well do no maintain privacy between rooms, and building assemblies

Answer 3

True
Materials with a high sound absorption do no maintenance privacy between rooms and building assemblies that promote airborne noise privacy do not provide relief from impact noise

Ballast Ch.19

Question 4

What materials typically have high NRC

Answer 4

Soft and pourous material
Example fabric wrapped fiberglass acoustic wall/ceiling tile
Typical number 0.7

Question 5

What is NRC

Answer 5

Noise reduction coefficient
Single number between 0.0 - 1.0
average sound absorption of a material

Question 6

What materials have low NRC

Answer 6

Hard Smooth materials have low NRCs
Examples - marbles and concrete less than 0.2

Question 7

Fill in the blank

Reverb time in large spaces with low NRCs have______

Answer 7

long reverberation times

Question 8

Reverb time in small spaces with high NRCs have ___

Answer 8

Short reverberation times

Question 9

IIC

Answer 9

Impact Insulation Class for flooring and ceiling assemblies
the higher the rating the better it works at mitigating imapact noise

Question 10

What is the code mimum IIC for multiple family

Answer 10

50 IIC

Question 11

Fill in the blank

The most effective method of limiting plumbing noise in buildings is to _____.

Answer 11

Clamp against structure with resilient wrapping at clamp.

(AB 61)