What Are Nocturnal Emissions?

"Noise emission" refers to the noise source radiating noise to the surrounding living environment.

Noise emission

Right!

"

Scope of application

This standard specifies environmental noise emission limits and measurement methods for industrial enterprises and fixed equipment factories.

This standard applies to the management, evaluation and control of noise emissions from industrial enterprises. Institutions, institutions, and organizations that emit noise to the external environment shall also implement this standard.

2. Normative references

The content of this standard refers to the following documents or clauses therein. For undated references, the valid version is applicable to this standard.

GB 3096 Acoustic Environment Quality Standard

GB 3785 sound level meter electrical and acoustic performance and test methods

GB / T 3241 Octave and Fractional Octave Filters

GB / T 15173 Acoustic Calibrator

GB / T 15190 Technical Specifications for the Division of Environmental Noise in Urban Areas

GB / T 17181 integral average sound level meter

3. Terms and definitions

The following terms and definitions apply to this standard.

3.1 industrial enterprises plant boundary environmental noise

Refers to the sound that interferes with the surrounding living environment, which is produced by the use of fixed equipment in industrial production activities and is measured and controlled at the factory boundary.

3.2 A-weighted sound pressure level

Sound pressure level measured with A-weighted network, expressed in AL, in dB (A).

3.3 Equivalent continuous A-weighted sound pressure level Short for Equivalent Continuous A-weighted sound pressure level, which refers to the average energy value of A sound level within a specified measurement time T, expressed by LAeq, T (abbreviated Leq), unit dB (A). Unless otherwise specified, the noise values in this standard are equivalent sound levels.

By definition, the equivalent sound level is expressed as:

A

Where: instantaneous A sound level at time LA--t;

T--specified measurement period.

3.4 factory boundary

Places or building boundaries that are identified by legal instruments (such as land use permits, real estate permits, lease contracts, etc.) as the owner's right of use (or ownership). The boundary of various noise-producing fixed equipment is the boundary of its actual land occupation.

3.5 noise-sensitive buildings

Refers to buildings that need to be kept quiet, such as hospitals, schools, institutions, scientific research units, and dwellings.

3.6 day-time, night-time

According to the Law of the People's Republic of China on the Prevention and Control of Environmental Noise Pollution, "daytime" refers to the period between 6:00 and 22:00; "night" refers to the period between 22:00 and 6:00 the next day.

People's governments at or above the county level have other provisions for the division of daytime and nighttime for the needs of prevention and control of environmental noise pollution (such as taking into account time differences, differences in work and rest habits, etc.), and they shall be implemented in accordance with the provisions.

3.7 frequent noise

Refers to noise that occurs frequently, occurs at regular intervals and intervals, has a short duration, and has a high intensity, such as exhaust noise and cargo handling noise.

3.8 sporadic noise

Refers to noise that occurs by accident, occurs at irregular times and intervals, has a single duration, and has high intensity. Such as short whistle, engineering blasting noise, etc.

3.9 maximum sound level

The maximum value of A sound level measured for frequent or occasional noise events within a specified measurement time, expressed as Lmax, in dB (A).

3.10 sound pressure level in octave bands

The sound pressure level of the frequency band measured by an octave filter in accordance with the requirements of GB / T3241, and its measurement bandwidth is proportional to the center frequency. The center frequency of the octave band used for indoor noise spectrum analysis in this standard is 31.5HZ, 63HZ, 125HZ, 250HZ, 500HZ, and its coverage frequency ranges from 22HZ to 707HZ.

3.11 steady noise

During the measurement time, the noise level of the measured sound source is not more than 3dB.

3.12 non-steady noise

During the measurement time, the noise level of the measured sound source fluctuates more than 3dB.

3.13 background noise

Sum of ambient noise from sound sources other than the measured noise source.

4. Environmental noise emission limits

4.1 Limits of environmental noise emissions at the factory boundary

4.1.1 The environmental noise at the boundary of industrial enterprises shall not exceed the emission limit specified in Table 1.