For most noise at work applications an integrating sound level meter is essential. It provides the Leq measurement that is used in assessing the worker's exposure and for calculating the LEP,d. An integrating meter may also provide you with the sound exposure level (A weighted SEL or LAE).
This is the most important parameter that is provided by an integrating sound level meter. It is the average energy over a period of time (the measurement period) and so is ideal when the noise levels are not very steady, which is usually the case.
For noise at work we are interested in the A weighted (similar response to the human ear) Leq. This is called the LAeq and expressed in dB(A).
Using an integrating sound level meter, or Leq meter, is actually easier than trying to estimate the average level with a non-integrating sound level meter. An Leq meter will usually have a Start and Stop button (or just a reset button). When you want to start measuring you press the Start button. You then wait for the Leq level on the display to settle. If the noise level you are measuring is fairly steady then the Leq will settle within a few seconds. If you are measuring a production cycle that takes a few minutes, with different noise levels throughout that time, it is worth measuring for a few production cycles to ensure you get a good average.
When you press the Stop button you should have the Leq value that is so important to us. On a meter with just a Reset button, you will have to read the display manually once it has settled down.