GB/T 34388-2017 in English

GB/T 34388—2017 Interpretation of the standard for the measurement method of sound power level of foundry machinery noise

1. Background and significance of the standard

Foundry machinery is widely used in industrial production, and its noise problem directly affects the working environment and the health of operators. GB/T 34388—2017 specifies the measurement method of sound power level of foundry machinery noise, aiming to provide unified technical specifications for equipment manufacturers, testing agencies and users.

2. Scope of application of the standard

This standard applies to foundry machinery that radiates steady-state and non-steady-state noise, excluding pulse noise. Focus on the analysis of noise characteristics under the application of new energy technologies to ensure the validity and reliability of the measurement results.

3. Explanation of key terms

• Measurement surface: An imaginary geometric surface that envelops a sound source, used to determine the noise radiation area.
• Reference volume: The smallest rectangular parallelepiped imaginary surface that just envelops the sound source, ensuring the consistency of the test environment.
• Measurement distance: The vertical distance between the reference volume and the measurement surface, which affects the noise attenuation characteristics.

4. Measurement Requirements and Specifications

5. Measuring instruments and equipment

The measuring instruments shall meet the standards of GB/T3785.1 and GB/T3785.2, including: sound level meter, octave filter and piston sounder for calibration. The equipment shall be calibrated regularly to ensure the measurement accuracy.

6. Test environment requirements

The ideal test environment should be a free field on the reflecting surface. It is recommended to use an open field or an indoor space with good sound absorption treatment. The ratio of the sound absorption of the test room to the measurement surface area (A/S) shall meet the requirements of the engineering method or the simple method to ensure the validity of the measurement results.

7. Environmental correction and background noise processing

The environmental correction value K2 is calculated according to the test environment conditions and corrected in combination with the background noise level. Different correction methods are used for steady-state and non-steady-state noise to ensure the accuracy of the measurement results.

8. Calculation formula of noise sound power level

Calculation of surface average sound pressure level: $$ \overline{{L}}_{\mathrm{p}}=10~\mathrm{lg}\biggl(\frac{1}{N}\sum_{i=1}^{N}10^{0.1(L_{\mathrm{p}i}-K_{1i})}\biggr) $$ Calculation of sound power level: $$ L_{\mathrm{w}}=(\overline{{L}}_{\mathrm{p}}-K_{2}-K_{3})+10~\mathrm{lg}(S/S_{\mathrm{0}}) $$

9. Implementation suggestions

To ensure the accuracy of the measurement results, it is recommended in actual operation:

• Strictly follow the standard requirements to arrange the measurement points and perform background noise correction.
• Choose the appropriate measurement method (engineering method or simple method) according to the characteristics of the equipment.
• Regularly calibrate the measuring instruments to ensure that their accuracy meets the requirements.