<prompt> Maximum audible tolerance is:90 db for 6 hrs90 db for 8hrs85 db for 6 hrs85 db for 8 hrs  <response>: A noise of 90 db, 8hrs a day for 5 daysweek is maximum safe limit. No exposure in excess of 115 db is permitted. No impulse noise of intensity 140 lb is permitted. Persons working in area where noise exceeds 85 db should have pre employment and annual audiograms. Ear plugs offer protection up to 35db and to be used where noise exceeds 85 db. 