GB/T 3767-2016 in English

《GB/T 3767-2016声学 声压法测定噪声源声功率级和声能量级 反射面上方近似自由场的工程法》由TC17（全国声学标准化技术委员会）归口，主管部门为中国科学院。

Scope

This standard specifies a method for determining the sound power level or sound energy level of noise sources (machines or equipment) by measuring the sound pressure levels on surfaces that enclose the sound source in an approximately free-field environment near one or more reflective planes. These measurements can be used to calculate the octave band sound power levels or A-weighted sound power levels (or sound energy levels for impulse and transient noises).

**Note**: For specific noise sources, using different shaped measurement surfaces may yield different estimates of sound power level. The relevant noise testing procedures (see GB/T19052) provide detailed information on the selection of measurement surfaces.

### 1.2 Types of Noise Sources

The methods specified in this standard are applicable to various types of noise as defined by GB/T19052 (steady-state, non-steady-state, fluctuating, and random noises). Under conditions that meet the measurement requirements, this standard applies to sound sources of different types and sizes (e.g., stationary equipment, slowly moving equipment, apparatuses, machines, parts, components, etc.).

**Note**: This standard may not be applicable to extremely high or long noise sources such as chimneys, pipelines, conveying machinery, multi-source industrial equipment, etc. In these cases, alternative methods for measuring sound emission from specific noise sources are provided in the noise testing procedures GB/T19052.

### 1.3 Test Environment

The test environment suitable for measurements according to this standard can be either indoor or outdoor and should place the tested noise source on one or more reflective planes or near them. An ideal setting is a completely open space with no boundaries, except for the reflection plane(s) on which the noise source is mounted (for example, an acoustically treated semi-anechoic chamber). However, in less than ideal conditions, correction methods are specified within the designated range.

### 1.4 Measurement Uncertainty

This standard provides information on the uncertainty of sound power levels and sound energy levels measured according to specific frequency bands and A-weighted frequencies. The uncertainty meets the second-level accuracy requirements (engineering grade) as defined in GB/T19052.