Scope 1.1
This Standard describes procedures for the determination of the occupational
noise exposure level (L ex,T) using sampling techniques. L ex,T represents the
long-term noise exposure of employees. It is calculated from measurements of
the equivalent sound level (L eq,t) in the workplace. The procedures in this Standard normally form part of any occupational hearing
conservation program. The user of this Standard should be proficient in noise
measurement. 1.2
This Standard provides procedures for measuring the occupational noise exposure
from all types of noise, eg, continuous noise, pure tones, and impulse noise.
All types of noise (including impulse noise) are measured in terms of equal
energy. 1.3
This Standard can be used for determination of the nosie exposure level of
individuals (L ex,T) or extended to groups (L TRADE) with similar noise
exposures. It can also be used to measure the noise exposure (L eq,t) from a
given job or activity (eg, operating a particular machine). 1.4
This Standard provides for measurements in terms of L eq,t (3 dB exchange rate)
and calculation of (L ex,T). Procedures for calculating related quantities,
such as Pa2h, are provided. This Standard may also be used for the measurement of L OSHA (5 dB exchange
rate) and calculation of associated indices as shown in Appendix D. In this
case, the results may not be a good representation of exposure to impulsive
noise. Note: Measurements taken in L eq cannot be converted to L OSHA, or vice versa,
unless the time distribution of sound levels is known. 1.5
This Standard provides procedures to determine the noise exposure level of
employees with a given precision. In certain cases, the user is only
interested in determining that an employee's exposure is above or below the
criterion level. The procedures in this Standard can be relaxed in this case
when the noise exposure level is either far above or far below the criterion
level.