Noise Control Standards

Article 1 ^{[正體中文]}

These Standards are determined pursuant to Article 9, Paragraph 2 of the Noise Control Act.

Article 2 ^{[正體中文]}

The terms used in these Standards are defined as follows.

1. Control zone: Refers to Class 1-4 noise control zones as specified in the Noise Control Zone Delineation Operating Standards.

2. Noise level: Use of decibels adjusted (dB (A)) means the A-weighted value of the noise level.

3. Background noise level: Refers to the noise level apart from the noise source to be measured.

4. Peripheral boundary: Refers to the boundary lines managed or used by premises or facilities. When a premise or facility is isolated by an obvious surrounding wall, the wall shall serve as the boundary; when there is no physical separation, the property scope or scope within which the members of the public do not commonly enter shall be the boundary.

5. Time periods

   1. Daytime: Refers to from 6:00 a.m. to 8:00 p.m. in Class 1 and 2 control zones, and from 7:00 a.m. to 8:00 p.m. in Class 3 and 4 control zones.

   2. Evening: Refers to from 8:00 p.m. to 10:00 p.m. in Class 1 and 2 control zones, and from 8:00 p.m. to 11:00 p.m. in Class 3 and 4 control zones.

   3. Nighttime: Refers to from 10:00 p.m. to 6:00 a.m. on the following day in Class 1 and 2 control zones, and from 11:00 p.m. to 7:00 a.m. on the following day in Class 3 and 4 control zones.

6. Equivalent sound level: Refers to the average energy value of the measured noise level during a specific time period. Equivalent sound level of from 20 Hz up to 20 kHz is expressed as L_eq, and from 20 Hz up to 200 Hz is expressed as L_eq,LF; the following calculation formula is used:

   1. $L_{\mathrm{eq}}=10\lg (\frac{1}{T}\int_0^T \left(\frac{P_t}{P_0}\right)^2\,d t)$^{[Formula description]}

      • T: Measurement time, expressed in seconds.

      • P₁: Measured sound pressure, in units of Pascals (㎩) .

      • P₀: Baseline sound pressure of 20 μ㎩.

   2. $L_{\mathrm{eq}, \mathrm{LF}}=10\lg \sum_{n=20\; Hz}^{200\; Hz} \mathrm{10}^{(\mathrm{0.1}L_{\mathrm{eq}, n})}$^{[Formula description]}

      • L_eq,n: 1/3 octave band filters are used to measure the equivalent sound level of each 1/3 octave band.

      • n: Center frequency of the 1/3 octave band from 20 Hz up to 200 Hz.

7. Maximum noise level （L_max）: The maximum noise level value measured during the measurement period.

8. The combined sound level: Means the sound level of a measured location in which the sound level is created and by two or more facilities.

Article 3 ^{[正體中文]}

Noise noise level measurements must comply with the following regulations:

1. Measurement instruments:

   Measurement of noise from 20 Hz up to 20 kHz shall be conducted with any type of sound meter complying with CNS No. No.7129 specifications; measurement of noise from 20 Hz up to 200 Hz shall be conducted with any type of sound meter complying with CNS No.7129 specifications ; the said meter shall also comply with the IEC 61260 (1995) Class 1 standard. IEC 61260（1995）Class 1.

2. Measurement height:

   1. When the measurement location is outdoors, the sound sensor should be from 1.2 m to 1.5 m above the ground or an extension of the floor slab of the floor on which measurements are performed.

   2. When the measurement location is indoors, the sound sensor should be from 1.2 m to 1.5 m above the ground or floor slab.

3. Dynamic response:

   In general, a noise meter with fast dynamic response should be used. However, a noise meter with slow dynamic response may be employed when the noise from a noise source has little variation, such as the noise from a motor.

4. Correction for the background noise level:

   1. The background noise level in a premise where measurements are being performed should differ from the noise level of the noise source being measured by at least 10 dB(A). If the difference is less than 10 dB(A), the background must be corrected on the basis of the following table.

   2. Correction of background noise level:

      1. L1: measured value including background noise level.

      2. L2: measured value of background noise level.

      L1-L2	3	4	5	6	7	8	9
      Corrected value	-3	-2		-1

   3. The statutory responsible persons or on-site personnel at premises and facilities must cooperate with the measurement of the background noise level, and their influence on the background noise level should be corrected for. When background noise level measurements are performed, and the statutory responsible person or on-site personnel cannot cooperate, then there is no need to correct for the background noise level, and the situation should be noted.

   4. When it is desired to measure the overall noise level of a premise, but the difference from the background noise level is less than 3dB(A), the measurement should be discontinued, and either another suitable measurement location found or the noise from other sources eliminated or reduced before measurements are performed.

   5. When a premise to be measured is a factory (facility) with equipment operating 24 hours a day, and the equipment cannot be stopped to accommodate measurement of background noise level at any time apart from annual maintenance, an annual maintenance background noise level monitoring plan may be submitted to the special municipality, county, or city competent authority; after the special municipality, county, or city competent authority has granted its approval, measurement of the noise level at a location outside the premise's peripheral boundary approved by the special municipality, county, or city competent authority should be performed for a continuous period of from 24 hours to 72 hours during annual maintenance. The results should be reported to the special municipality, county, or city competent authority for approval, and shall provide a basis for correction for the background noise level when measurements of noise within a frequency range of from 20 Hz up to 20 kHz are performed at any place outside the peripheral boundary of the factory (facility) within two years of the date of approval.

5. Testing time period:

   Perform measurements at times when the emission of noise is most representative or that have been designated by the complainant.

6. Testing location:

   1. When measuring noise in a frequency range of from 20 Hz up to 20 kHz at sources that are not public address facilities, apart from measurements at locations designated by a complainant as his or her living place, the measurements should be performed at any place specified by the competent authority outside the peripheral boundary of a factory (facility), entertainment premise, business premise, construction project, or other premises or facilities announced by the competent authority; measurements shall be taken at points at least one meter from the wall of the nearest building.

   2. When measuring noise in a frequency range of from 20 Hz up to 200 Hz at sources that are not public address facilities, if measurements are performed at indoor points within a complainant's designated living place the measurements shall be conducted at points at least one meter from the nearest indoor wall line; however, this restriction shall not apply if it is desired to perform measurements with no obstructions between the noise source and sound sensor. Indoor doors and windows should be kept shut; other noise sources that will influence measurement results should be temporarily turned off.

   3. When measuring noise at a public address facility, if the noise source at the public address facility has a horizontal projection distance of three meters or more, the measurements should be performed at a location designated by the competent authority. If a mobile public address facility is moving at the time, the measurements should be performed at a location designated by the competent authority and no less than three meters from the mobile noise source at its closest approach.

7. Assessment method:

   1. When a noise source is not a public address facility, the equivalent sound level (L_eq or L_eq,LF) or maximum noise level (L_max) shall be calculated on the basis of the following noise source emission characteristics, and the results may not exceed the values in the noise control standards table:

      1. If the needle of a noise meter exhibits regular variation of a periodic or intermittent nature, but the maximum value is generally constant, the maximum value (L_max) should be taken as the average of readings over the course of five consecutive changes. For example, Diagram 1 shows a regularly changing sound, with a constant period of variation. In addition, Diagram 2 shows an intermittent, regularly changing sound with a constant maximum value. In these examples, the average of five maximum values is taken.

      2. Other situations are expressed using equivalent sound level. Continuous measurement sampling time must be at least two minutes, and sampling intervals may not be greater than two seconds. For instance, in Diagram 3, when the noise meter's reading is constant, or the needle only changes by 1-2dB(A), the results are expressed using equivalent sound level. In Diagram 4, when the sound volume and interval of occurrence are irregular, the results are also expressed using equivalent sound level.

      

      Diagram 1

      

      Diagram 2

      

      Diagram 3

      

      Diagram 4

   2. With regard to assessment methods for noise from public address facilities, the equivalent sound level (L_eq) or maximum noise level (L_max) shall be calculated on the basis of the following noise source emission characteristics, and the results may not exceed the noise control standard value:

      1. In the case of mobile public address facilities, the maximum value (L_max) at the time the facility passes shall determine noise level.

      2. In the case of stationary or currently stopped public address facilities, the noise level shall be expressed as equivalent sound level (L_eq) . Continuous measurement sampling time must be at least two minutes, and sampling intervals may not be greater than two seconds.

Article 4 ^{[正體中文]}

Noise control standards for factory plants or sites are as follows:

Control zones		20 Hz up to 200 Hz,			20 Hz up to 20 kHz
		Daytime	Evening	Nighttime	Daytime	Evening	Nighttime
Equivalent sound level (Leq)	Category 1	42	42	39	50	45	40
	Category 2	42	42	39	60	55	50
	Category 3	47	47	44	70	60	55
	Category 4	47	47	44	80	70	65

Article 5 ^{[正體中文]}

The following are noise control standard values for entertainment and business premises:

Control zones	20 Hz up to 200 Hz			20 Hz up to 20 kHz
	Daytime	Evening	Nighttime	Daytime	Evening	Nighttime
Category 1	35	35	30	55	50	40
Category 2	40	35	30	60	55	50
Category 3	40	40	35	70	60	55
Category 4	40	40	35	80	70	65

Article 6 ^{[正體中文]}

Noise control standards for construction sites are as follows:

Control zones		20 Hz up to 200 Hz			20 Hz up to 20 kHz
		Daytime	Evening	Nighttime	Daytime	Evening	Nighttime
Equivalent sound level (Leq)	Category 1	47	47	42	70	50	50
	Category 2	47	47	42	70	60	50
	Category 3	49	49	44	75	70	65
	Category 4	49	49	44	80	70	65
Maximum noise level (Lmax)	Categories 1 and 2	-			100	80	70
	Categories 3 and 4				100	85	75

Article 7 ^{[正體中文]}

Noise control standards for amplifying facilities are as follows:

Control zones	Daytime	Evening	Nighttime
Category 1	60	50	40
Category 2	75	60	50
Category 3	80	65	55
Category 4	85	75	65

Article 8

　

The following are noise control standard values for premises and facilities announced by the competent authority:

Control zones	20 Hz up to 200 Hz			20 Hz up to 20 kHz
	Daytime	Evening	Nighttime	Daytime	Evening	Nighttime
Category 1	35	35	30	55	50	35
Category 2	40	35	30	60	55	45
Category 3	40	40	35	70	60	50
Category 4	40	40	35	80	70	60

Article 9

　

When the combined sound level created by facilities not belonging to one person, juridical person or non-juridical person that exceed the values for noise control standards of the foregoing articles, all such facilities shall equally comply with the values for post-correction noise control standards in the following table:

Value of sound source not belonging to one person, juridical person, or non-juridical person.	Corrected value for noise control standards with which all facilities shall comply
2	-3
3	-4
4	-6
5	-7
Over 6	-8

Article 10 ^{[正體中文]}

Special municipality, county, and city competent authorities shall announce specific noise control zones on the basis of the noise control zone types in the Noise Control Zone Delineation Operating Standards; the noise control standard values in such noise control zones shall be five decibels lower than the noise control standard values prescribed Articles 4 through 8.

When a measurement location has two or more noise control zone boundaries, the noise level may not exceed the noise control standard value for any internal area.

Article 11 ^{[正體中文]}

These Standards shall take effect from the date of promulgation.