What do the measurement parameters of the noise meter (sound level meter) mean?
Lp instantaneous sound level
Leq equivalent continuous sound level
Le is the exposure sound pressure level.
Lmax Maximum sound level.
Lmin . Minimum sound level
Lpk peak sound pressure level
LN time rate sound pressure level (LHI, L5, L10, L50, L90, L95, LLO, LAV)
Lx. X% of the measurement time is greater than this sound level
Waveform peak hold Lpeak .Lcpeak . Lceq .
Ltm5 Maximum sound level within 5 seconds
Equivalent Continuous Sound Level
The A-weighted sound level can better reflect the human ear's subjective perception of the intensity and frequency of the noise, so it is a better evaluation method for a continuous steady-state noise, but for a fluctuating or discontinuous noise Noise, the A-weighted sound level is not appropriate. For example, traffic noise varies with the flow and type of vehicles; another example is that the sound level of a machine is stable when it is working, but because it works intermittently, it will have the same sound level as another machine that works continuously. The impact is different. Therefore, a problem is proposed to evaluate the impact of noise on people by means of time-averaged noise energy, that is, the equivalent continuous sound level, symbol "Leq" or "Laeq·T". It uses a continuous and stable A sound level equal to the sound energy in the same time period to represent the size of the noise in this period of time. For example, if there are two machines with a sound level of 85dB, the maximum workbench works continuously for 8 hours, and the workbench works intermittently, the sum of the effective working hours is 4 hours.
Obviously, the average energy acting on the operator is twice as large as the former, that is, 3dB larger. Therefore, the equivalent continuous sound level reflects the amount of noise energy that people actually accept when the sound level is unstable, and it is an equivalent amount used to express the noise that changes with time.
