iso1996 -2:2017€¦ · iso 1996 -2:2017 acoustics—description, measurement and assessment of...

ISO1996-2:2017ACOUSTICS—DESCRIPTION, MEASUREMENT AND ASSESSMENT OF ENVIRONMENTAL NOISE—PART 2: DETERMINATION OF SOUND PRESSURE LEVELS

Copyright © Krittika Lertsawat

คาํเตอืน

เอกสารฉบบันี ทาํขึ นเพื�อการศึกษาใหค้วามรูแ้ก ่นิสิต นักศึกษา ผูเ้ขา้ฝึกอบรม ในชั นเรียน ซึ�งผูเ้ขียนทาํขึ นชว่ยให้การเรียนการสอนง่ายขึ น ตามความเขา้ใจและประสบการณ์ของผูเ้ขียนเอง และไมม่ีส่วนรบัผิดชอบในความถูกตอ้งหรือผิดพลาดของเอกสารนี แต่อยา่งใด หากจะมีประโยชน์ต่อผูท้ี�สนใจทั �วไป ก็นับเป็นประโยชน์อีกประการของเอกสารฉบบันี ผูใ้ดจะนําไปไปใชง้าน หรือคดัลอก ทั งหมดหรือบางส่วน โปรดอา้งอิงอยา่งที�พึ�งกระทาํอยา่งเชน่เอกสารทางวชิาการทั �วไป

ISO1996-2: 2017 สรุปความโดย กฤติกา เลิศสวัสดิ์



� Scope and Normative references� Terms and definitions� Measurement uncertainty� Instrumentation for acoustical measurement� Principles� Operation of the source: Industrial plants� Meteorological conditions� Measurement procedures: Long-term or Short-term,

indoor/outdoor� Evaluation of the measurement results: � Extrapolation to other locations� Calculation� Information to be recorded and reported



Annex A: (informative) Determination of radius of curvature

Annex B: (informative) Microphone locations relative to reflecting surfaces

Annex C: (informative) Selection of measurement/monitoring site

Annex D: (informative) Correction to reference condition (industrial plants)

Annex E: (informative) Elimination of unwanted sournd

Annex F: (informative) Measurement uncertainty

Annex G: (informative) Examples of uncertainty calculations

Annex H: (informative) Maximum sound pressure levels

Annex I: (informative) Measurement of residual sound

Annex J: (informative) Objective method for assessing the audibility of tones in noise—engineering method

Annex K: (informative) Objective method for assessing the audibility of tones in noise—survey method

Annex L: (informative) National and European source specific calculation models


Copyright © Krittika LertsawatCopyright © Krittika Lertsawat

Terms and definitions

Measurement time interval

• Time interval during which measurements are conducted (time periods of integration is measurement time interval for Leq,T and LE,T

• Time interval during which measurements are conducted (time periods of integration is measurement time interval for Leq,T and LE,T

Observation time interval

• Time interval during which a series of measurements is conducted

prediction time interval

• Time interval over which levels are predicted (i.e. transportation noise source), prediction time interval corresponds to the measurement time interval except, for the former, the levels are predicted and the latter, the levels are measured.

Long-term measurement

• Measurement sufficiently long to encompass all emission situations and meteorological conditions which are needed to obtain a representative average




Short-term measurement

• Measurement during measurement time intervals with well-defined emission and meteorological conditions

Receiver location

• Location at which the noise is assessed

Calculation method

• Set of algorithms to calculate the sound pressure level at a specified receiver location from measured or predicted sound power levels and sound attenuation data

Prediction method

• Subset of a calculation method, intended for the calculation of future noise levels




Meteorological window

• Set of weather conditions during which measurements can be performed with limited and known variation in measurement results due to weather variationEmission window

• Set of emission condtions during which measurements can be performed with limited variation in measurement results due to variations in operating condtions

Sound path radius of curvature (Rcur)

• Radius approximating the curvature of the sound paths due to atmospheric refraction in meters

Monitor

• Instrumentation used for a single automated continuous sound monitoring terminal which monitors the LpA, their spectra and all relevant meteorological quantities (wind speed and direction, rain, humidity, atmospheric, stability, etc.



Terms and definitionsAutomated sound monitoring system

• entire automated continuous sound monitoring system including all monitors, the base or central data collection position (host station) and all software and hardware involved in its operation

Reference condition

• Condition to which the measurement results are to be referred (corrected), i.e. atmospheric sound absorption at yearly average temperature and humidity and yearly average traffic flows for day, evening and night, respectively

Independent measurement

• Consecutive measurements carried out with a time space long enough to make both source operating conditions and sound propagation conditions statistically independent of the same conditions of other measurements in the series (meteorological conditions, a time space of several day)

Low-frequency sound• Sound containing frequency components of interest within the range covering the 1/3 octave

bands 16 Hz to 200 Hz



Measurement Uncertainty

� = �� + 10�� 1 − 10��.� �� + �� + �� + ��

The estimated value during the specified conditions for which a measured value is wanted In dB

The measured value including residual sound, Lres In dB

The residual sound in dB

An input quantity to allow for any uncertainty due to the selection of

receiver location in dB

An input quantity to allow for any uncertainty due to deviations

from the expected operating conditions of the source in dB

An input quantity to allow for any uncertainty due to meteorological conditions deviating from

the assumed meteorological conditions in dB



Measurement uncertainty:



Instrumentation for acoustical measurement

Valid certificate of verificationSound Level Meter• ISO/IEC 61672-1 class 1

• Temperature -10°C to +50°C Octave Band Pass Filter

• ISO/IEC 61260-1 class 1

• 1/1 octave or 1/3 octave band pass filterAcoustic Calibrator

• ISO/IEC 60942 class 1

• Twice measurement ∆L≤0.5 dBWind screen

• LpA 13mm microphone: Perpendicular -18+70 lg (v/1 m/s) dB, Horizon -32+83 lg (v/1 m/s) dB



• ตรวจวัดระดับเสียงของแหล่งกําเนิดเสียงที่กําลังส่งเสียงอยู่ ครั้งเดียว (Single measurement ) ภายใต้สภาวะทางอุตุนิยมวิทยาที่เหมาะสมตามเงื่อนไขที่กําหนด โดยจะต้องคํานึงถึง Lk ของเส้นทางผ่านของเสียงด้วย

Single measurement

• ตรวจวัดระดับเสียงเพื่อเก็บข้อมูลตัวอย่างหลายครั้ง (many sampled measurement ) ตลอดช่วงระยะเวลา หรือ ตรวจวัดระดับเสียงแบบระยะยาว (Long-term measurement)พร้อมกับตรวจวัดข้อมูลสภาวะทางอุตุนิยมวิทยาไว้ด้วย


Main strategies for environmental measurements:

Both types of measurements require post processing of measure data

�� = 10�� ∑ 10�.��!"#$%� dB

�$ = 10�� "#∑ 10�.��&"#

'%� dB



Meteorological conditions:Maximum permissible error: Long-term measurement

±0.5 K temperature of measuring device

±5 % RH of measuring device

±0.5 hPa for Barometer pressure

±0.5 m/s wind speed measuring device

±0.5 wind direction measuring device

ℎ� + ℎ)* ≥ 0.1

Transmission path condition: Hard ground + free-field conditions (long-term and short-term measurement)

ℎ� : Sound source height (m)ℎ) : Receiver height (m)* : distance between sound source and receiver

Long-term monitoring ISO1996-2:2017ACOUSTICS—DESCRIPTION, MEASUREMENT AND ASSESSMENT OF ENVIRONMENTAL NOISE—PART 2: DETERMINATION OF SOUND PRESSURE LEVELS


Wind speed and wind direction

Air temperature

Relative humidity

Occurrence of precipitation

Atmospheric stability

others

Measurement of meteorological conditions:


Copyright © Krittika LertsawatSource: B&K Sound and Vibration Measurement Booklet, 2000


Copyright © Krittika LertsawatSource: B&K Sound and Vibration Measurement Booklet, 2000



,��,./0 = 1 + 12��. dB

D≤400 m. D>400 m.

,��,./0 = 2��



Window is a combination of emission (e.g. day, evening, night) + meteorological conditions, as shown in the table. Preferably, a window should include constant emission and propagation conditions. In many cases, the emission conditions are independent of the meteorological conditions and in other cases. (strong relationship as aircraft noise)

Meteorological window1 2 3 4

Emission window

1

2

N

Industrial sound source:



Distance< 100 m. 100 to 300 m. > 300 m.

day night day night day night

Industry source source 48h 48h 72h 72h

Minimum time (in hours) between two measurements to be independent

Industrial sound source: ISO1996-2:2017ACOUSTICS—DESCRIPTION, MEASUREMENT AND ASSESSMENT OF ENVIRONMENTAL NOISE—PART 2: DETERMINATION OF SOUND PRESSURE LEVELS


Varia

tion

of in

depe

nden

t mea

sure

men

t: รายฤดูกาล (seasonal)

รายวัน (diurnal)

รายสัปดาห์ (weekly)

อื่นๆ (others) Depe

nden

t fac

tors:

เสียงนั้นเป็นตัวแทนของเสียงจากแหล่งกําเนิดที่ต้องการ

เลือก noise descriptor (Leq,T, Lmax)

ช่วงระยะเวลาตรวจวัดที่ครอบคลุมเหตุการณ์ของเสียงนั้น

ประเภทของเสียง (ในที่นี้มุ่งที่ Industrial source)




Operation of source: Source operating conditions

Leq measurement Lmax measurement

� ตรวจวัดระดับเสียงจากแหล่งกําเนิดเสียงอุตสาหกรรม เป็นแหล่งกําเนิดเสียงแบบไม่เคลื่อนที่ (stationary sound source) โดยวิธีการสุ่มเก็บตัวอย่างของระดับเสียง

� ตรวจวัดเสียง ต้องครอบคลุมการเปลี่ยนแปลงตามปัจจัยต่างๆ ของแหล่งกําเนิดเสียงในแนวทางเส้นทางผ่านของเสียง (transmission path)

� ตรวจวัดระดับเสียงสูงสุดจากแหล่งกําเนิดเสียงอุตสาหกรรม ที่เป็นตัวแทนของเสียงที่แหล่งกําเนิดนั้นทํางานตามปกติ (plant operating condition)

� ตรวจวัดระดับเสียงสูงสุดในบริเวณที่ใกล้กับสภาวะของผู้รับเสียงมากที่สุด (nearest proximity to receiver condition)

� ตรวจวัดเสียงสูงสุด ต้องครอบคลุมรอบของการทํางานของแหล่งกําเนิดเสียงและตรวจวัดจํานวนของรอบซ้ําตามหลักสถิติด้วย

Industrial sound source: ISO1996-2:2017ACOUSTICS—DESCRIPTION, MEASUREMENT AND ASSESSMENT OF ENVIRONMENTAL NOISE—PART 2: DETERMINATION OF SOUND PRESSURE LEVELS


Operation of source: Source operating conditions

Leq measurement Lmax measurement


,�� = 5 ��' − �6� 78 − 1 ��

�

'%�

Standard uncertainty

Leq,5min or Leq,10min ที่

ระยะห่าง d เมตร

ระยะห่างนั้นครอบคลุมเสียงของแหล่งกําเนิดที่ต้องการตรวจวัดทั้งหมด

ในกรณีที่มีการเปลี่ยนแปลงสภาวะการทํางานของแหล่งกําเนิด ให้ตรวจวัด Leq,t ไปตามความถี่ และ

ช่วงระยะเวลาที่แหล่งกําเนิดเสียงทํางาน Key: X: standard deviation, s in dBY: different, in dB

�� − �6 = 0.05 ln 10 · =7 dB



Quantities of measurement: LAeq,t or

Leq,t, LpA or Lp + time series + Time stamp

+ Met.conditions+Event detection LE,T

Attended measurement

Unattended measurement

Indoor/outdoor conditions

Long-term/Short-term measurement

Tonal noise, Impulsive noiseLow-frequency noise

Leq,T 10 minLE,T single events, -10 dB downLN,T based on Leq,1secor LAeq,T

LFMaxor LSMax




Industrial sound source: microphone location

Indoors:Outdoors:

Floor

Wall

ceiling

0.5 m.

0.5 m.

0.5 m.

At least 1 m. from significant sound transmission (window, door, air intakeThe distance between neighbouring microphone locations shall be at least 0.7 m.Room volume: <300 m3

at least 3 discrete locations or continuous moving microphone

National regulations can prescribe different rules to determine measurement positions.

� Selection of measurement site� Minimize the effect of residual sound

from non-relevant sound sources� Selection of microphone location

� To assess the situation at a specific location

� For other purposes o Incident sound fieldo Location with the microphone flush-

mounted on the reflecting surface o Location with the microphone 0.5 m.

to 2 m. in front of the reflecting surface

� For general mapping: a microphone height of 4.0±0.2 m. in multi-storey residential areas.



Short-term attended measurements:Long-term unattended measurements:

Quantities to measure

Time stamp

Event detection

Leq,T (T at

least 30 min)

LE,T

LN,T Ls,max/LF,max

Tonal sound

Impulsive sound

Low-frequency sound



Residual sound กรณี ตรวจวัดเสียง

อุตสาหกรรม

(Industrial noise)• กรณีที่มีเสียงจากการจราจร (traffic noise) จะยากในการตรวจวัดเสียงจากอุตสาหกรรม

• Octave band pass filter

• Weighting network

Outdoor conditions

• Wind induced noise

• Transmission path attenuation

uncertainty

• Measurement uncertainty

• Standard uncertainty

Residual sound measurement:




To obtain accurate sound information in

specific sound-sensitive community areas

To obtain accurate sound information on the Lp

produced by different types of noise sources at the particular location

To obtain sound information to monitor

noise events

To meet monitoring system technical considerations,

particularly from more than one station under

important noise events

To monitor compliance with periodical sound

exposure level requirements

Guide of selection of measurement/monitoring site: Process of site selection

Interference from other sound sources

(i.e. traffic noise, leisure, wildlife, etc.)

Ease of access to utilities (telephone,

electric power)

Terrain and building obstruction

Ease and costs of obtaining site access and

approvals (location on private property,

costs to use the land, operation cost of access)

Monitor station security considerations (theft,

vandalism)

Likely uncertainty of the measurement

Stage 1:

Stage 2:



Leq,T

LE,T

LN,T

LFmax, LSmax

Tonal sound

Impulsive sound

Low-frequency sound

Short-term measurement :




Evaluation of measurement results:Assign each sample to a specific window

(meteorological/operating conditions)

Correct for residual sound

Correct each sample to reference condtions (atmospheric conditions, reference traffic conditions, time of day)

Calculate Leq,T over each window

Base on frequency of occurrence during the relevant time period

Determine the measurement uncertainty

��>,? = 10 log∑ ∆C'10�.��D,&"'

∑ ∆C''��

Duration of each measurement

� = 10 log 10�� ⁄ − 10�� ⁄ dB

Residual sound pressure level in dB

Measured sound pressure level in dB

Corrected sound pressure level in dB



Standard uncertainty of measurement :�$ = 10 log

1F�510�.��&

"G

'��

H$7 = �"G��∑ 10�.��& − 10�.��!"G

' dB

Measured value representing on independent measurement in dB

Energy averaged measured sound pressure level of Nm independent measurement within meteorological and emission window k in dB

Standard uncertainty of the measurement within window k

,$ = 10 log 10�.��! + H$ dB − �$

,$ = ∑ �&��! K�!��

�!'%� dB

If the different Li is small



Evaluation of measurement results: Determination of Lden

�L/M,$ = 10 log 5F)�.,' × 10�.��O,&,!'

�� − 10 log PL/M × 3600 ��

Statistical yearly day average of number of single events of source category i

Numerical value of the duration of the day in hours

Seconds in an hour

Average sound exposure level of each meteorological window k of each source categories i

Average sound exposure level of each meteorological window k of each source categories i

��0��'��,$��'�S�,$

P�0��'��P�'�S�



Measurement procedures: Industrial plants

Operation of the source

Leq

measurement

Lmax

measurement

Meteorological conditions (favorable)

Correction to reference

condition (Annex D)

Measurement procedures

Selection of time interval

Microphone location

Measurements

Evaluation of the measurement

results

Leq measurement

Lmax measurement

Level of residual

uncertainty

iso1996 -2:2017€¦ · iso 1996 -2:2017 acoustics—description, measurement and assessment of...

Documents