Article 5.2.2.4bis.9. The provisions of section 4.5.5 apply to the establishments meant in this subsection. By way of derogation from this subsection, by day the specific noise in the open air from the establishment during mechanical treatment at the measuring points specified in Article 1, 3 and 4 of appendix 4.5.1 to this order is limited such that the background value in appendix 4.5.4 to this order, increased by 20 dB(A), is not exceeded. This provision does not apply in establishments that require silence, to which section 4.5.5 continues to apply.