Noise Abatement Ordinance
(NAO)

¹ Noise ex­pos­ure levels are de­term­ined in the form of a rat­ing sound level, Lr, or a max­im­um sound level, Lmax, on the basis of cal­cu­la­tions or meas­ure­ments.⁴⁴

² Noise ex­pos­ure levels due to air­craft shall prin­cip­ally be de­term­ined by cal­cu­la­tion. The cal­cu­la­tions are car­ried out us­ing re­cog­nised state-of-the-art meth­ods. The FOEN shall re­com­mend suit­able cal­cu­la­tion pro­ced­ures.⁴⁵

³ The re­quire­ments for cal­cu­la­tion pro­ced­ures and meas­ur­ing in­stru­ments are giv­en in An­nex 2.⁴⁶