The SIL method simply evaluates verbal intelligibility in cases of direct communication in a noisy environment. It can be used for fixed or mobile workplaces, indoors or outdoors, as long as direct communication is involved.
The UNE EN ISO 9921-2004 standard provides in its annex E a description of this method, considered an objective evaluation method.
This application allows you to obtain two different results:
- Evaluate intelligibility in verbal communication, based on the value of the SIL parameter.
- Calculate maximum distance between speaker and listener to maintain satisfactorily intelligible communication, based on the tables set forth in NTP 794.
NTP 794, referring to the SIL method, proposes three summary tables (depending on whether the sender and receiver are native speakers and listeners without hearing problems, or if it is the case of non-native speakers and listeners, but who handle the language with ease. fluency, or if the people communicating have mild hearing disorders) that allow obtaining the maximum distance between the speaker and the listener at which a communication is considered to be satisfactorily intelligible, based on the previously calculated LSIL.
The SIL method considers environmental noise, the application allows you to enter this value in two ways:
-The measurement carried out with a sound level meter, integrating sound level meter or dosimeter, of the sound pressure levels in the octave bands (500 Hz, 1000 Hz, 2000 Hz and 4000 Hz), in the position of the listener.
-The A-weighted sound pressure level, measured using a “SLOW” response time at the listener's position.
Other values ​​that need to be entered are the speaker's vocal effort and the distance between speaker and listener. The speaker's vocal effort can be the verbal sound pressure level measured one meter in front of the mouth, or determined according to a vocal effort table.