910.100 | General |
910.102 | Instrumentation |
910.103 | Definitions |
910.104 | Measurement Techniques for 35 Ill. Adm. Code 900 |
910.105 | Measurement Techniques for 35 Ill. Adm. Code 901 |
910.106 | Protocols for Determination of Sound Levels |
910.107 | Measurement Techniques for Highly-Impulsive Sound Under 35 Ill. Adm. Code 104 |
910.APPENDIX A | |
Tables of Long-Term Background Ambient Noise |
910. TABLE A | Daytime long-term background ambient Leq levels in decibels by land use categories and 1/3 octave-band level |
910. TABLE B | Nighttime long-term background ambient Leq levels in decibels by land use categories and 1/3- octave-band level |
910. TABLE C | Daytime long-term background ambient Leq levels in decibels by land use categories and octave-band level |
910. TABLE D | Nighttime long-term background ambient Leq levels in decibels by land use categories and octave-band level |
Section 910.100 | General |
1) | Use an integrating sound level meter alone or in conjunction with an octave-band or ⅓ octave-band filter set or a real-time sound analyzer (octave-band or ⅓ octave-band) that complies with the following standards incorporated by reference at 35 Ill. Adm. Code 900.106: |
A) | ANSI/ASA S1.4-2014/Part 1/IEC 61672:1-2013 "American National Standard Electroacoustics – Sound Level Meters – Part 1: Specifications (a nationally adopted international standard)". |
B) | ANSI/ASA S1.11-2014/Part1/IEC 61260:1-2014 Electroacoustics − Octave-Band and Fractional-Octave-Band Filters – Part 1: Specifications (a nationally adopted international standard)". |
C) | ANSI/ASA S1.6-2016 "Preferred Frequencies and Filter Band Center Frequencies, for Acoustical Measurements". |
D) | ANSI/ASA S1.8-2016 "Reference Values for Levels Used in Acoustics and Vibrations". |
E) | IEC 61672-1:2013 "Electroacoustics Sound Level Meters – Part 1: Specifications". |
2) | Use a magnetic tape recorder, graphic level recorder or other indicating device conforming with the SAE Recommended Practice J184 "Qualifying a Sound Data Acquisition System", August 2014, incorporated by reference at 35 Ill. Adm. Code 900.106. |
3) | Calibrate sound measuring equipment traceable to the National Bureau of Standards at least once every 12 months. |
4) | For outdoor measurement, use a microphone with an attached windscreen. |
1) | Us an anemometer and compass or other devices to measure wind speed and direction in compliance with the manufacturer's recommended procedures. |
2) | Use a thermometer, designed to measure ambient temperature, in compliance with the manufacturer's recommended procedures. |
3) | Use a hygrometer in compliance with the manufacturer's recommended procedures to measure the relative humidity. |
4) | Use a barometer in compliance with the manufacturer's recommended procedures to measure the barometric pressure. |
(Source: Amended at 42 Ill. Reg. ______, effective November 1, 2018) |
Section 910.103 | Definitions |
The definitions contained in 35 Ill. Adm. Code 900.101 apply to this Part. | |
Section 910.104 | Measurement Techniques for 35 Ill. Adm. Code 900 |
Section 910.105 | Measurement Techniques for 35 Ill. Adm. Code 901 |
1) | One or more outdoor microphone positions may be chosen within the boundaries of the receiving land, as long as the positions are at least 25 feet (7.6 meters (m)) from the property-line noise source. The 25-foot setback distance is from the noise source and not the property line unless the noise source is contiguous to the property line. |
2) | Other measurement locations may be used for investigatory purposes, including the following: |
A) | Determining the extent of noise pollution caused by the source of sound; |
C) | Analyzing those acoustical parameters that describe the sound source. |
3) | For measurements of sound sources with no audible discrete tones, set up the microphones at least 25 feet (7.6 m) from any reflective surface that may affect data. If microphones are within 25 feet, determine the effect, if any, of the reflective surface on the measured data. |
4) | For measurements of sound sources with audible discrete tones, set up the microphones at least 50 feet (15.2 m) from any reflective surface that may affect data. If microphones are within 50 feet, determine the effect, if any, of the reflective surface on the measured data. |
5) | Microphones need to be at least 5 feet (1.5 m) from small objects (trees, posts, bushes, etc.). If microphones are within 5 feet of small objects, determine the effect, if any, on the measured data. |
1) | Set up a microphone tripod at the chosen site, extended to a height between 3 feet 8 inches (1.12 m) and 4 feet 10 inches (1.47 m) above ground. |
2) | Attach the microphone at the top of the tripod and connect it to the measuring instrument with a 5-foot (1.5 m) or longer cable. |
3) | Adjust the angle of incidence of the microphone to yield the flattest frequency response compliant with the manufacturer's specifications. |
4) | Separate the measuring instrument from the microphone to minimize any influence on the measurements, and minimize any cable movement during the measurement period. |
1) | Before taking sound pressure level measurements, measure and record (near the measurement site): |
2) | Turn the measuring instrument on and allow the instrument to stabilize. Monitor and record the battery condition of the calibrator and all measuring instruments. |
3) | Turn the calibrator on at its appropriate frequency. Allow the calibrator to stabilize and calibrate the measuring system according to the manufacturer's specifications. After the measuring system has been calibrated, remove the calibrator and attach a windscreen to the microphone. |
4) | Adjust the microphone to the angle of incidence that will yield the frequency response compliant with the manufacturer's specifications. |
5) | Measure the sound pressure level data within the limitations of subsection (d) and according to the manufacturer's recommended procedures. Other sound pressure levels may be used for investigatory purposes, including the following: |
A) | Determining the extent of noise pollution caused by the source of sound; |
C) | Analyzing those acoustical parameters that describe the sound source. |
6) | While sound measurements are being taken, maintain distance between the operator and the microphone to minimize any influence on the measurements. |
7) | While measurements are being taken, make visual and aural surveillance of extraneous sound sources and varying wind conditions to ensure that the conditions of measurement are accurately known. Record any variations in these parameters that may affect data. Record the number and basis for the affected data block. When using a tape recorder, record voice commentary concerning conditions on the cue track. |
8) | Minimize wind effects on the microphone by taking sound measurements when the wind velocity is less than 12 miles per hour (5.4 m/second) at the microphone position. |
9) | For the purposes of data correction, determine the ambient sound at the measurement site by means of measurement or analysis. |
10) | After taking sound pressure level measurements, remove the windscreen and attach the calibrator to the microphone. Turn the calibrator on at its appropriate frequency. After allowing the calibrator to stabilize, monitor and record the measuring system response. If the measuring system response varies by more than ± 0.5 dB from the most recent field calibration, the sound pressure level measurements obtained since such most recent field calibration cannot be used for enforcement purposes. |
11) | Before removing the calibrator from the microphone, turn the calibrator off. If the ambient sound has not been determined by means of measurement, determine the noise floor of the measuring system. If the noise floor is within 10 dB of the measured sound pressure level data, record the noise floor measurements. |
12) | At the end of the sound survey, monitor and record the battery condition of the calibrator and all measuring instruments. Near the measurement site, measure and record: |
13) | Record the physical and topographical description of the ground surface within the vicinity of the measurement site, survey site location, a description of the sound source, a diagram of the area, the location of reflective surfaces near the microphone, and the approximate location of the noise source relative to the microphone position. |
14) | A magnetic tape recorder may be used to preserve the raw data. Record calibration signals at the beginning and end of each tape as well as at intermediate times such as when relocating to a new measurement site. Record voice commentary concerning local conditions and affected data blocks on the cue track. Preserve the original tape recording for subsequent evaluation. |
15) | Any laboratory analyses of magnetic tape-recorded field data must include a description of the laboratory instrumentation and procedures, along with correlation of the laboratory analyses and field measurement techniques. |
1) | For measurements of non-impulsive sound with audible discrete tones, measure ⅓ octave-band sound pressure levels to determine if a noise source complies with 35 Ill. Adm. Code 901.106. |
2) | For measurements of non-impulsive sound with no audible discrete tones, measure octave-band sound pressure levels to determine if a noise source complies with 35 Ill. Adm. Code 901.102 and 901.103. |
a) | The raw data collection procedures to determine equivalent continuous sound pressure level (Leq) are described in this Section using as an example the determination of a 1-hour Leq corrected for ambient. The following procedures must be used: |
A) | Divide the 1-hour interval into many small blocks of time so that corruption of the data from short-term background, transient sound and loss of data can be limited to the corrupted or bad blocks. The block duration measured in seconds is fixed for any measurement hour. The duration must be neither less than 10 seconds nor greater than 100 seconds. For example, if the block duration is chosen to be 60 seconds (1 minute), then the data collection proceeds for 60, 1-minute periods of measurement. |
B) | The collected data for each block represents a block duration Leq (or sound exposure level (SEL)) in octave-bands (or ⅓ octave-bands if prominent discrete tones may be present). |
C) | Delete data for any block corrupted by one or more short-term background transient sounds. |
D) | After deleting corrupted data blocks, there will be a fixed number of "good" data blocks remaining. This number is designated as NPLNS, where PLNS stands for Property-Line Noise Source. These remaining "good" blocks are numbered consecutively. The subscript "i" is used to denote the numbering of the blocks in time order after corrupted data blocks have been deleted. |
E) | The data for the NPLNS remaining blocks are time averaged on an energy basis by octave (or ⅓ octave-band) using Equation 1 below. In this equation, two subscripts are used, i to designate time and j to designate the specific frequency, either an octave-band or ⅓ octave-band. The raw, 1-hour Leq in the jth frequency band is given by: |
[Equation 1] |
where Leq is the Leq in the jth frequency band for the ith non-deleted data block. |
F) | In terms of SEL, the raw SEL in the jth frequency band is given by: |
[Equation 2] |
G) | The raw, 1-hour Leq in the jth frequency band is given in terms of the corresponding SELj by: |
[Equation 3] |
A) | Adjust the measuring instrument to continuously measure sound pressure and accumulate Leq for each block of time. For convenience, the hour may be split into several smaller blocks such as 10, 6-minute blocks or 4, 15-minute blocks, etc. |
B) | A switch on the measuring instrument must be available to inhibit data collection whenever a short-term background transient sound occurs. Use this switch to prevent short-term background ambient sounds from corrupting the data. |
C) | Data collection must proceed for one hour. The energy average of the several measured Leqij each weighted by the number of seconds actually accumulated during the ith block results in the raw, 1-hour Leq in each frequency band given by: |
[Equation 4] |
[Equation 5] |
A) | Initial Measurement Duration. Measure the property-line noise source initially for one hour. Because of correction for short-term background transient sounds, actual reported data collection time T, in seconds, may be less than 3600 seconds (one hour). |
i) | If small blocks of data are used for data collection, then the total measurement duration in seconds, TPLNS, is given by NPLNS T, where T is the length of each block in seconds and NPLNS is the number of non-discarded blocks. If data inhibition is used for data collection, then TPLNS is the number of non-inhibited seconds during the measurement hour. In either case, TPLNS must be at least 900 seconds. |
ii) | If very few blocks were used for data collection, then the duration of each block, T, may be too long and must be reduced. |
iii) | For either data collection method, sounds considered to be short-term transient may actually be part of the long-term background ambient and must be so redefined. |
B) | Extended Measurement Duration. If TPLNS is less than 900 seconds during the first hour of measurements, modify the raw data collection procedures appropriately and take new measurements for an additional hour. If TPLNS after combining the first and the second hour of measurements is also less than 900 seconds, then collect additional raw data using the data inhibition method or method employed during the second hour until TPLNS is greater than or equal to 900 seconds. |
A) | The raw 1-hour Leq must be corrected for long-term background ambient sound. Subsection (b) describes methods to obtain the long-term background ambient sound level in the jth frequency band. The correction is dependent on the difference (in decibels) between the raw, 1-hour, jth band property-line noise source (Leqj) and corresponding jth band long-term background ambient sound level. The correction to be applied is as follows: |
i) | If the difference between the raw 1-hour Leq and the long-term background ambient sound is larger than 10 decibels, then the correction is set to 0. |
ii) | If the difference between the raw 1-hour Leq and the long-term background ambient sound difference is less than 3 decibels, then the jth frequency-band level, Leqj, is set to 0. |
iii) | If the difference between the raw 1-hour Leq and the long-term background ambient sound is between 3 and 10 decibels, then the correction given in Table 1 is subtracted from the raw, 1-hour property-line noise source Leqj. |
Difference
|
Correction
|
|
(dB)
|
(dB)
|
|
3
|
3
|
|
4
|
2.3
|
|
5
|
1.7
|
|
6
|
1.3
|
|
7
|
1.0
|
|
8
|
0.7
|
|
9
|
0.6
|
|
10
|
0.5
|
B) The duration of each block is held constant during the hour. This duration in seconds divides exactly into 900 and is neither greater than 100 seconds nor less than 10 seconds.
C) Discard the data for any block corrupted by one or more short-term background ambient sounds.
2) Correction for the Long-Term Background Ambient Sound. Correct the raw 1-hour Leq for long-term ambient sound using the procedures of Sections 910.105 and 910.106 to determine an A-weighted, 1-hour, background-ambient-corrected Leq for the highly impulsive property-line noise source under study.
c) Controlled Test Method
1) General Measurement Description
A) The sound exposure per impulse from each separate individual impulsive source is measured.
B) The total sound exposure per hour from each source is the sound exposure per event multiplied by the number of events per hour.
C) The grand total sound exposure (SE) per hour is the sum of the sound exposures per hour from each of the separate individual sources.
D) The reported SEL is obtained from the grand total sound exposure (SE) per hour using the following:
SEL = 10 log (SE) + 94 [Equation 7]
E) The equivalent level, Leq, corresponding to a SEL measured or predicted for one hour (3600 seconds) is given by:
Leq = SEL - 10 log (3600) [Equation 8]
2) Determination of Sound Exposure Per Event
A) Determine the sound exposure per event from each, separate, individual source by measuring the total A-weighted sound exposure for about 10 repetitions of the source. This set of about 10 measurements may be performed continuously over a short period of time, or over a discontinuous set of measurement periods. In either case, the total measurement duration must be less than 100 seconds.
B) The separate, individual property-line noise source measurements collected under subsection (a) must be free of any short-term ambient sounds. If any short-term background transient sounds occur during these measurements, repeat the measurements until data, free of any corrupting short-term background ambient sounds, are obtained.
C) Correct the total measured A-weighted sound exposure for the group of about 10 repetitions for long-term background ambient by subtracting the A-weighted long-term background ambient sound exposure, which is the long-term A-weighted background ambient sound exposure per second multiplied by the number of seconds used to measure the several source repetitions.
D) A-weighted sound exposure per event is the total corrected sound exposure divided by the number of source repetitions measured.
E) Measure the long-term background ambient for a short time, at least 30 seconds, as near in time to the source measurements as possible, but within ½ hour. The total A-weighted long-term background ambient sound exposure per second is the total measured long-term background ambient sound exposure divided by the number of seconds of background ambient measurement.
F) There must be no short-term background ambient sounds present during the measurement of the long-term background ambient. If any short-term background transient sounds occur during these measurements, repeat the measurements until long-term background ambient measurement data, free of any corrupting short-term background ambient sound, are obtained.
(Source: Amended at 42 Ill. Reg. ______, effective November 1, 2018)
910.APPENDIX A Tables of Long-Term Background Ambient Noise
Background Category
|
Octave-Band Center Frequency (Hz)
|
1
|
2
|
3
|
4
|
5
|
20
|
63
|
56
|
48
|
42
|
36
|
25
|
64
|
57
|
49
|
43
|
37
|
31
|
65
|
58
|
50
|
44
|
38
|
40
|
65
|
58
|
51
|
44
|
38
|
50
|
66
|
59
|
51
|
45
|
39
|
63
|
66
|
59
|
52
|
46
|
40
|
80
|
67
|
60
|
52
|
46
|
40
|
100
|
68
|
60
|
53
|
47
|
41
|
125
|
67
|
59
|
52
|
46
|
40
|
160
|
66
|
59
|
52
|
46
|
40
|
200
|
66
|
58
|
51
|
45
|
39
|
250
|
65
|
58
|
50
|
44
|
38
|
315
|
64
|
57
|
49
|
43
|
37
|
400
|
63
|
55
|
48
|
42
|
36
|
500
|
62
|
54
|
46
|
40
|
34
|
630
|
61
|
53
|
44
|
38
|
32
|
800
|
60
|
51
|
42
|
36
|
30
|
1000
|
58
|
49
|
40
|
34
|
28
|
1250
|
56
|
47
|
38
|
32
|
26
|
1600
|
54
|
45
|
36
|
30
|
24
|
2000
|
52
|
43
|
33
|
28
|
21
|
2500
|
50
|
41
|
30
|
25
|
19
|
3150
|
49
|
39
|
28
|
23
|
17
|
4000
|
48
|
37
|
25
|
20
|
15
|
5000
|
46
|
35
|
23
|
18
|
13
|
6300
|
44
|
33
|
21
|
16
|
10
|
8000
|
43
|
31
|
19
|
14
|
8
|
10,000
|
41
|
29
|
17
|
12
|
6
|
12,500
|
39
|
27
|
15
|
10
|
4
|
Background Category
|
Octave-Band Center Frequency (Hz)
|
1
|
2
|
3
|
4
|
5
|
20
|
53
|
48
|
43
|
37
|
31
|
25
|
54
|
49
|
44
|
38
|
32
|
31
|
55
|
50
|
45
|
39
|
33
|
40
|
55
|
50
|
46
|
39
|
33
|
50
|
56
|
51
|
46
|
40
|
34
|
63
|
56
|
51
|
47
|
41
|
35
|
80
|
57
|
52
|
47
|
41
|
35
|
100
|
58
|
52
|
48
|
42
|
36
|
125
|
57
|
51
|
47
|
41
|
35
|
160
|
56
|
51
|
47
|
41
|
35
|
200
|
56
|
50
|
46
|
40
|
34
|
250
|
55
|
50
|
45
|
39
|
33
|
315
|
54
|
49
|
44
|
38
|
32
|
400
|
53
|
47
|
43
|
37
|
31
|
500
|
52
|
46
|
41
|
35
|
29
|
630
|
51
|
45
|
39
|
33
|
27
|
800
|
50
|
43
|
37
|
31
|
25
|
1000
|
48
|
41
|
35
|
29
|
23
|
1250
|
46
|
39
|
33
|
27
|
21
|
1600
|
44
|
37
|
31
|
25
|
19
|
2000
|
42
|
35
|
28
|
23
|
16
|
2500
|
40
|
33
|
25
|
20
|
14
|
3150
|
39
|
31
|
23
|
18
|
12
|
4000
|
38
|
29
|
20
|
15
|
10
|
5000
|
36
|
27
|
18
|
13
|
8
|
6300
|
34
|
25
|
16
|
11
|
5
|
8000
|
33
|
23
|
14
|
9
|
3
|
10,000
|
31
|
21
|
12
|
7
|
1
|
12,500
|
29
|
19
|
10
|
2
|
|
Background Category
|
Octave-Band Center Frequency (Hz)
|
1
|
2
|
3
|
4
|
5
|
31
|
70
|
63
|
55
|
49
|
43
|
63
|
71
|
64
|
57
|
51
|
45
|
125
|
72
|
64
|
57
|
51
|
45
|
250
|
70
|
63
|
55
|
49
|
43
|
500
|
67
|
59
|
51
|
45
|
39
|
1000
|
63
|
54
|
45
|
39
|
33
|
2000
|
57
|
48
|
38
|
33
|
26
|
4000
|
53
|
42
|
30
|
25
|
20
|
8000
|
48
|
36
|
24
|
19
|
13
|
Background Category
|
Octave-Band Center Frequency (Hz)
|
1
|
2
|
3
|
4
|
5
|
31
|
60
|
55
|
50
|
44
|
38
|
63
|
61
|
56
|
52
|
46
|
40
|
125
|
62
|
56
|
52
|
46
|
40
|
250
|
60
|
55
|
50
|
44
|
38
|
500
|
57
|
51
|
46
|
40
|
34
|
1000
|
53
|
46
|
40
|
34
|
28
|
2000
|
47
|
40
|
33
|
28
|
21
|
4000
|
43
|
34
|
25
|
20
|
15
|
8000
|
38
|
28
|
19
|
14
|
8
|