00000nam 2200000za 4500 9.858205 CaOODSP 20221107155934 cr ||||||||||| 180627m20172018oncdo #ob f100 0 eng d CaOODSP eng n-cn--- D68-11/10-2018E-PDF Kessel, Ronald T., 1960- The safety of diver exposure to ultrasonic imaging sonars [electronic resource] / Ronald Kessel, Craig Hamm, Vincent Myers, DRDC - Atlantic Research Centre. [Ottawa?] : Defence Research and Development Canada, 2017, 2018. [12] p. : graphs, photographs External Literature (N) ; DRDC-RDDC-2018-N010 Title from cover. "Can unclassified." "February 2018." "Date of Publication from Ext Publisher: March 2017." Originally published in: UACE2017 – 4th Underwater Acoustics Conference and Exhibition, Conference Location: Skiathos Island, Greece, Pagination info: 847–854. Includes bibliographical references. "To achieve image-quality resolution, imaging sonars operate in the ultrasonic regime at frequencies on the order of 300 kHz up to 1.5 MHz. Although there are no known instances of harm or adverse effects caused by imaging sonars to divers, it is known from diagnostic ultrasound that human exposure to ultrasonic energy can be harmful. The risks identified in diagnostic ultrasound have apparently never been examined for imaging sonars. The risks posed by a diver hand-held imaging sonar are examined here in light of the metrics used in diagnostic ultrasound, especially the thermal and mechanical indices (TI and MI respectively). One imaging sonar in particular is assessed. Its ultrasonic field was characterized by direct measurement under anechoic conditions at the Defence R&D Canada Acoustic Calibration Facility and MI and TI were conservatively applied to assess the risk of harm to divers who may be exposed to the ultrasonic beam of the sonar during dive operations. This report reviews the exposure characteristics of ultrasonic fields and their connection to metrics commonly used by sonar engineers, the indices of diagnostic ultrasound, the experimental setup and results, and the implications for safe standoff and exposure time. The methodology can be applied to other ultrasonic sonar makes, models and technologies for imaging sonars and diver detection sonars"--Abstract, p. 847. gccst Occupational health Diver Handheld Sonar Diver Ultrasonic Safety Hamm, Craig A. Myers, Vincent. Defence R&D Canada. Atlantic Research Centre. External literature (N) (Defence R&D Canada) DRDC-RDDC-2018-N010. (CaOODSP)9.858173 PDF 907 KB https://publications.gc.ca/collections/collection_2018/rddc-drdc/D68-11-10-2018-eng.pdf