GB/T 41311.1-2022Acoustics - Quantities and procedures for description and measurement of underwater sound from ships - Part 1: Requirements for precision measurements in deep water used for comparison purposes (English PDF)

GB/T 41311.1-2022 is the English-translated version of 声学 描述船舶水下噪声的量及其测量方法 第1部分：用于比对目的的深水精密测量要求.

GB/T 41311.1-2022 is the Chinese standard "Acoustics - Quantities and procedures for description and measurement of underwater sound from ships - Part 1: Requirements for precision measurements in deep water used for comparison purposes".

Its scope clause reads: This document specifies the general measurement system, measurement procedure and measurement method for the measurement of underwater radiated noise of ships under specified operating conditions.

Law. This document does not specify or provide guidance for underwater noise limits, nor does it address the potential effects of underwater noise on marine life.

The results of the measured quantities are given as root mean square sound pressure levels (SPL), therefore, the sound pressure levels measured in the far-field underwater of the ship or the equivalent can be used.

SPL, and normalized to a distance of 1 m, the measurement results given in 1/3 octave bandwidth (see 4.3). In this document, these measurements Expressed as "radiated noise level".

Sound pressure levels are measured in the geometric far field and then normalized to a distance of 1 m to match the corresponding Underwater noise limits are compared.

This document is applicable to the measurement of underwater radiated noise of various surface manned or unmanned ships during navigation, but not to submarines or aircraft.

The measurement method has no fixed limit on the size of the ship, but requires that the speed of the ship does not exceed 25.7m/s (ie 50kn). The measurement method smoothes the Lloyd's mirror interference effect, but does not eliminate the propagation of seabed reflection, seawater refraction and absorption effect.

For these effects, no specific calculation corrections are given in this document. This document does not require a fixed measurement location, but The selection of the measurement location puts forward specific requirements.

The intended uses of the method described in this document are. comparison with contract limit requirements, comparison of ships of the same type, evaluation of line spectrum characteristics, and research send.

Potential users include government agencies, research vessel operators and merchant ship owners.

Use data obtained from this measurement method to determine the source level of ships to carry out far-field noise forecasts, e.g. to meet most environmental impacts Required to study or create underwater noise contour maps, additional post-processing is required. Its clauses include terms and definitions.

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 39 pages — is available in the English PDF.

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