1 Scope
2 Normative references
3 Definitions
3.1 Speech communication
3.2 Speech intelligibility
3.3 Vocal effort
3.4 Speech interference level
3.5 Lombard effect
4 Symbols
5 Determination of noise parameters
5.1 General
5.2 Equipment for measurement
5.3 Microphone positions
5.4 Time-averaging
5.5 A-weighted sound pressure level at the speaker's
position
5.6 Speech interference level
6 Criteria for direct speech communication
6.1 Vocal effort of the speaker
6.2 Speech level at the listener's position
6.3 Relation between speech interference level and
communication distance (SIL method) for
satisfactory speech intelligibility
6.4 Additional assessments of the quality of speech
communication
6.5 Use of hearing protectors
Annexes
A Selected values of median hearing threshold deviations
for males up to 70 years of age (octologically
normal persons) in accordance with ISO 7029
B examples of the use of figures 1 and 2
C Bibliography