Code: There are a variety of methods for measuring noise levels.

Enforcement: Numerous municipalities and other agencies' codes stipulate noise level limits and require noise level measurements.

General Information: There are numerous ways to measure noise, depending on the code in which a noise level measurement is required. Included in the possible measurements are: dBA, Leq, Ldn and dB at various frequencies.

Strength: Gives a quantitative assessment of noise or potential annoyance verses vague standards, such as “you can’t disturb the peace,” which are left to subjective interpretation.

Weakness: It is common for the measurement required by a code and the measurement actually documented to vary. For instance, if a city’s code is specified in Ldn (an average over a full day) and the measurement is conducted in dBA, the result will be invalid. It is essential to have consistency between the required measurement and the recorded measurement. This measurement is further complicated by the fact that some municipalities do not understand their own code.