Equivalent Continuous Sound Level
The steady state dB(A) level which would produce the same A-weighted sound energy over a stated period of time as a specified time-varying sound.
Equivalent continuous A-weighted sound pressure level is widely used around the world as an index for noise. It is defined as "the A-weighted sound pressure level of a noise fluctuating over a period of time T, expressed as the amount of average energy." It is expressed as:
- where
- LAeq = equivalent continuous A-weighted sound pressure level [dB]
- p0 = reference pressure level = 20µPa
- pA= A-weighted pressure [Pa]
- t1 = start time for measurement [s]
- t2 = end time for measurement [s]
- p0 = reference pressure level = 20µPa
If we wanted to calculate the equivalent continuous A-weighted sound pressure level from the sound exposure level of a number of discrete events such as a train passing then we can use the follwing equation:
: Time (sec) targeted for LAeq. From 07:00 to 22:00 is 54,000 sec. From 22:00 to 07:00 is 32,400 sec.
See also: Community Noise Criteria, Weighted Equivalent Continuous Perceived Noise Level.
Subjects: Audio Noise & Vibration