![]() ![]() This program consists essentially of periodic surveys of noise-isolated equipment and their isolation devices. Step Four - Establish a monitoring program. These devices form a major part of the Noise Control Team's internal monitoring program.ĭ. In particular, all machinery and piping incorporating sound isolation devices should be identified and noted. ![]() The primary noise control features are Prairie/Masker and sound isolation devices. Step Three - Learn how the installed noise control features on your ship contribute to silencing. Step Two - Identify installed systems and equipment which contribute significantly to the amount of noise the ship generates.Ĭ. The team will be headed by the Chief Engineer and will consist of, as a minimum, the USW Officer, department/division representatives, and any technical ratings required to carry out the internal monitoring surveys.ī. Step One - Establish a Shipboard Noise Control Team. A ship's survival may depend on its ability to minimize shipborne radiated noise.Ī. The Ship Silencing Program is promulgated by the Fleet Commanders via references (a) and (b). The other goal is a maximum reduction in the ship's radiated noise to obtain the best possible counter-detection posture relative to enemy submarines. Reduction of sonar self noise over the frequency range of passive capable sonar is one goal of the Navy Ship Silencing Program. (a) CNSL/CNSPINST C9073.1A (Ship Silencing)ġ. A lack of understanding or inattention on the part of ship's personnel can negate the effect of installed quiet ship features and the efforts of your USW team to detect a submarine. Unwanted noise can severely limit a ship's overall USW capability, both active and passive. Our Navy has dedicated significant resources to build noise control features into USW capable ships (DD-963), as well as the new classes of destroyers and cruisers (DDG-51 & CG-47). Surface ship silencing, like damage control, is everyone's business. Results suggest noise levels in "effective quiet" areas frequented by aircraft carrier personnel during off-duty hours when at-sea may inhibit auditory recovery from occupational noise exposures that occur on-duty.Ģ4-hr noise exposure auditory rest berthing flight operations hearing loss leisure noise dosimetry.INFORMATION SHEET Division Officer Training The L eqs in leisure areas were significantly higher than berthing areas by approximately 21 dBA during non-flight operation periods (p = 0.001). Mean L eqs were 15 dBA higher during flight operations compared to non-flight operations in "effective quiet" areas (p = 0.001). All area measurements over the 24-hr period and during flight operations and 46.7% of the areas during the non-flight operation time period exceeded the "effective quiet" 70 dBA ACGIH TLV. Measured noise levels according to time period ranged as follows: (1) L eq (24-hr): 70.8-105.4 dBA (2) L eq (flt ops): 70-101.2 dBA and (3) L eq (non-flt ops): 39.4-104.6 dBA. The L eq measurements in decibels "A" weighted (dBA) were compared to determine significant differences between L eq (flt ops), L eq (non-flt ops), and L eq (24-hr) and were compared between leisure area and berthing area. Areas were classified by either (1) leisure areas that included mess (eating areas), gyms, lounges, an internet cafe, and the fantail social area or (2) berthing (sleeping) areas. The monitored areas were selected based on personnel occupancy/use during off-duty time periods. These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH ®) Threshold Limit Value (TLV ®) for "effective quiet" areas intended for temporary threshold shift recovery when personnel live and work in a potentially noise hazardous environment for periods greater than 24 hr. Equivalent sound level (L eq) measurements were collected during flight operations (L eq (flt ops)), non-flight operations (L eq (non-flt ops)), and over 24-hr periods (L eq (24-hr)). Noise dosimetry samples were collected in 15 designated spaces, representing 15 noise measurements, while at-sea during airwing carrier qualifications. The purpose of this investigation was to characterize noise levels in spaces designated as "effective quiet" areas on a U.S. ![]()
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