sound level in the rooms

[thomasscj]

i want to know the stds of sound levels in residential buildings,
also, to know the differents in stds in dBA level and NC leval, how it related,

could u plz help me out?

[skippedover]

Noise in residential buildings is, to the best of my knowledge, not specified formally. db level is a logarithmic number with a specific vibration (noise) and frequency level referenced to a number scale. This allows for the comparison of one specific noise to another in relative terms. The NC number (Noise Crieteria) on the other hand is a simplified number that a manufacturer assigns to a specific grille, register or diffuser (GRD) based on a noise value at a specific air velocity (face velocity). It does not necessarily consider frequency, background noise or other potential contributors to the noise environment. The easiest way to diverge from the manufactures NC number is to change the velocity of the air flowing through the GRD. Other things that can change the NC would be the persence of dampers, position of dampers or louver angles. As a matter of good practice, most manufacturers would consider the NC to be excessive at face velocities exceeding 700 FPM. It is worthy of note that simply changing the style of GRD can often reduce excessive noise, at the sacrifice of introducing more air into the room for a supply.

[thomasscj]

i would like to know more details about noise level,
1, like if designed sound level is NC 35 that will be equills to how much dBA &
2, In case of normal residential area which frequency we can take as referrrence, (63 or higher)

[Carnak]

I keep meaning to look it up for you, basiocally from what fire alarm code says is a normal sound level. They want the alarm horns so many dB above a normal level

[dan sw fl]

i would like to know more details about noise level,
1, like if designed sound level is NC 35 that will be equills to how much dBA &
2, In case of normal residential area which frequency we can take as referrrence, (63 or higher)

NC versus db level
see ... http://www.sota.ca/nc_info.htm

[cem-bsee]

one can use fuzzy logic --

basically, if the level is annoying, it is too loud.

the human ear is good --

one can spend thousands for instruments & weeks of measurements --

what is your purpose? project?

[Carnak]

a day late and a dollar short.

Average ambient sound level in a residential occupancy is 35 dB.

This is from a table in the fire alarm code handbook, so I figure it is on the high side. They want the fire alarm horns to be so much louder than the ambient noise.

[skippedover]

Hearing is one of the five senses. What's noisy to one, is not to another. What tastes good to one, does not to another and so on. It just depends on who's hearing it.