1A-12 U.S. Navy Diving Manual—Volume 1 Table 1A-3.  Wet Suit Un-Hooded. Permissible Exposure Limit (PEL) within a 24-hour period for exposure to AN/SQS-23, -26, -53, -56, AN/BSY-1, -2 and AN/BQQ-5 sonars, including versions and upgrades. Exposure conditions shown above the double line should be avoided except in cases of compelling operational necessity. Estimated Ranges in yards for given SPL and PEL for sonar. All ranges and SPLs are nominal. *SPL is measured in dB/1 mPA at the dive site. To convert SPL for sound levels referenced to mbar, subtract 100 dB from tabled levels. (U) = upgrade SPL (dB) PEL (MIN) BSY-1 SQS-53C BQQ-5 BSY-2 SQS-26CX(U) SQS-53A, SQS-53B SQS-56(U) SQS-23 SQS-26AX SQS-26BX, SQS-26CX SQS-56 200 199 198 197 196 195 194 193 192 191 13 15 18 21 25 30 36 42 50 60 316 355 398 447 501 562 631 708 794 891 224 251 282 316 355 398 447 501 562 631 71 79 89 100 112 126 141 158 178 200 A V     E O    X I P D    O S T     U H    R I E S 190 189 188 187 186 185 184 183 182 181 180 179 178 177 176 175 71 85 101 120 143 170 202 240 285 339 404 480 571 679 807 960 1,000 1,122 1,259 1,413 1,585 1,778 1,995 2,239 2,512 2,818 3,162 3,548 3,981 4,467 5,012 5,623 708 794 891 1,000 1,122 1,259 1,413 1,585 1,778 1,995 2,239 2,512 2,818 3,162 3,548 3,981 224 251 282 316 355 398 447 501 562 631 708 794 891 1,000 1,122 1,259