ISO 1996-2:2017 音響学—環境騒音の説明、測定、評価—パート2：音圧レベルの決定 | ページ 6

3.1

measurement time interval

time interval during which measurements are conducted

Note 1 to entry: For measurements of sound exposure level or equivalent-continuous sound pressure level, the measurement time interval is the time period of integration.

Note 2 to entry: For measurements of maximum sound pressure level or percent exceedance level, etc., the measurement time interval is the observation time interval (3.2) .

3.2

observation time interval

time interval during which a series of measurements is conducted

3.3

prediction time interval

time interval over which levels are predicted

Note 1 to entry: It is now perhaps more common to predict sound levels using computers than to measure them for some sources such as transportation noise sources. The prediction time interval corresponds to the measurement time interval (3.1) except, for the former, the levels are predicted, and for the latter, the levels are measured.

3.4

long-term measurement

measurement sufficiently long to encompass all emission situations and meteorological conditions which are needed to obtain a representative average

3.5

short-term measurement

measurement during measurement time intervals (3.1) with well-defined emission and meteorological conditions

3.6

receiver location

location at which the noise is assessed

3.7

calculation method

set of algorithms to calculate the sound pressure level at a specified receiver location (3.6) from measured or predicted sound power levels and sound attenuation data

3.8

prediction method

subset of a calculation method (3.7) , intended for the calculation of future noise levels

3.9

meteorological window

set of weather conditions during which measurements can be performed with limited and known variation in measurement results due to weather variation

3.10

emission window

set of emission conditions during which measurements can be performed with limited variation in measurement results due to variations in operating conditions

3.11

sound path radius of curvature

R_cur

radius approximating the curvature of the sound paths due to atmospheric refraction

Note 1 to entry:R_cur is given in metres.

Note 2 to entry: Often, the parameter used is 1/R_cur to avoid infinitely large values during straight ray propagation.

3.12

monitor

instrumentation used for a single automated continuous sound monitoring terminal which monitors the A-weighted sound pressure levels, their spectra and all relevant meteorological quantities such as wind speed, wind direction, rain, humidity, atmospheric stability, etc.

Note 1 to entry: Meteorological measurements need not be taken at each monitor provided such measurements are taken within an appropriate distance from the monitors and such distance is given in the report.

3.13

automated sound monitoring system

entire automated continuous sound monitoring system including all monitors (3.12) , the base or central data collection position (host station) and all software and hardware involved in its operation

3.14

reference condition

condition to which the measurement results are to be referred (corrected)

Note 1 to entry: Examples of reference conditions are atmospheric sound absorption at yearly average temperature and humidity and yearly average traffic flows for day, evening and night, respectively.

3.15

independent measurement

consecutive measurements carried out with a time space long enough to make both source operating conditions and sound propagation conditions statistically independent of the same conditions of other measurements in the series

Note 1 to entry: In order to achieve independent conditions for meteorological conditions, a time space of several days is normally required.

3.16

low-frequency sound

sound containing frequency components of interest within the range covering the one-third octave bands 16 Hz to 200 Hz

Note 1 to entry: This definition is specific for this document. Other definitions can apply in different national regulations.