BS EN ISO 4869-2:1995

Foreword
Introduction
1 Scope
2 Normative references
3 Definitions
4 Measurement of sound attenuation of hearing protectors
5 Calculation of the assumed protection value APV[fx] of a
  hearing protector for a selected protection performance
6 Octave-band method
7 HML method
8 SNR method
Annex A (informative) Example of the calculation of the
        assumed protection values, APV[fx]
Annex B (informative) Example of the calculation of L'[Ax]
        according to the octave-band method
Annex C (informative) Example of calculation and use of H,
        M and L values
Annex D (informative) Example of the calculation and use
        of SNR values
Annex E (informative) Bibliography
Annex ZA (normative) Normative references to international
         publications with their relevant European publications

Describes three methods of estimating the A weighted sound pressure levels effective when hearing protectors are worn. Coverage includes: Octave-band method, HML method, and SNR method. Also gives detailed tables.