db of voice

[khompifoo]

Hi
I want to make a silencer which will be placed instead of a part of pipe that carry gas at the speed of 308.6 (m/s).
in my desgne I made a progous surface to dissipate the kinetic energy of the gas.and I have achived a speed of 90(m/s).(the outflow pipe diameter is 30 cm)
I want to know :
1)Is there any standard in designing a silencer?
2)what is the relation between the gas speed and the acceptable db(decibel) range for industrial enviroments?

 

[BigInch]

dBa = 10*LOG((Q_kg/sec)^2*(PD_kPa/P0_kPa)^3.6 * (T_K/MW)^1.2)+126

dBa decibels
Flow Q_kg/sec
Pressure drop =PD_kPa
Upstream pressure =P0_kPa
Temperature ºK = T_K/MW

Check with your health and safety officer for allowed time exposures to various dBa levels, or try searching OSHA for some guidelines.

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[BigInch]

Typ values dBa
Diesel truck (10 m) 100
Lawn mower (1 m) 107
Pneumatic riveter (1 m) 115
Chainsaw (1 m) 117
Amplified Hard Rock (2 m) 120
Jet plane (30 m) 130


BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com