Document BR56wwnZqkNwYwVvjD2NGayw4

w /) UJ ui CO Ot.i ui^Ei - * ZQ UJ 2 5Q tUcI <O UI 5m 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 DIFFERENCE IN DECIBELS BETWEEN TWO LEVELS BEING ADDED Figure 1910.95-2. Chart for combining noise levels value calculated in (4) as the highest value, and the next-highest-remamingvalue in (u) as the "next highest value " (6) Repeat step (5) progressively until all values determined in (u) of this subpara graph have been added The result is the overall A-weighted level at the ear drum while wearing the protectors Sample calculation 1-- Octave band 125 250 500 frequency (Hz) 2-- Measured sound 91 92 94 ievel (dB) 3-- A-weighbng --16 -9 -3 adjustments (dB) 4-- A-weighted 75 83 91 sound level (dB) 5-- Mean reduction --12 of hearing protector (dB) -18 -24 1000 2000 4000 8000 96 100 98 92 0 +1 +1 -1 96 101 99 91 -33 -34 -42 -25 6-- Adjust for two 4 6 8 standard deviations from Manufacturers data 7-- Net reduction --8 --12 --16 10 10 4 4 --23 --24 --38 --21 A-weighted 67 71 level at cardnun 9- -- Add A-weighted values 75 Step Pair 1 77 -75 2 79 15-73 3 80 10-71 4 80 60-70 5 81 00-67 6 81 20-61 Difference 2 615 910 10 60 1400 20 20 73 77 61 70 Incremerit from curve 215 095 050 040 020 Neg New "Highest Value" 7915 6010 80 60 81 00 81 20 81 20+ Round to nearest dB (81) 10-- Reduction factor "R" = 104 - 81 = 23 dB (3) Method 3--Approximate reduction fac tor "R" using A-weighted sound level If only an A-weighted sound level for the environment is available, an approximation of the hearing protector attenuation factor "R" may be ar rived at, using Method 2 ((2) of this para graph) and assuming a "pink" noise with a level of 100 dB m each octave band, and using the average attenuation without correction for 1491