ISO 11690-1:2020 音響学—機械を含む低騒音の職場の設計に推奨される方法—パート1：騒音制御戦略 | ページ 6

3.1.1

音圧レベル

L_p

注記1:音圧レベルは、特定の点での騒音を表す主要な量です。これはデシベルで表され、標準化された騒音計で測定する必要があります (IEC 61672-1 を参照)

注記2 使用した周波数重み付け（AまたはC）または周波数帯域幅と時間重み付け（S［遅い］、F［速い］、I［インパルス］またはピーク）を示す必要があります。

注記3例えば，時間加重ピークを有する C 特性音圧レベルはL _{pC,peak で}ある。

注記4音圧レベルがエミッション（3.2参照），イミミッション，エクスポージャー（3.3参照）のいずれを指すかにかかわらず， L _pという表記が使用される。

3.1.2

等価連続音圧レベル

L _p式、T

注記1等価連続音圧レベルはデシベルで表される。

注記 2:等価連続音圧レベルは、ワークステーションでのイミミッションと人の暴露を評価するための主要な量です。

注記 3:イミッションまたはエクスポージャーが考慮される場合、インパルスおよびトーンの調整、デシベル単位のDL_IおよびDL_Tを使用して、インパルス成分およびトーン成分の影響を考慮することができます ( L _pA,eq,T + DL_I + DL_T ) (ISO 1996-1, ISO 1996-2, および ISO 1999 を参照)

注記4:この文書で考慮されるすべての場合において、音圧は特定の測定時間間隔で決定されるため、下付き文字「eq, T 」はしばしば省略されます(IEC 61672-1を参照)

3.1.3

ワークステーション

オペレータが占めることができる機械の近くの位置、またはタスクが実行される位置

3.2.1

noise emission

airborne sound radiated into the environment from a defined source (machine or equipment) [see Figure 1 a)]

3.2.2

sound power level

L_W

ten times the logarithm to the base 10 of the ratio of the sound power P, in watts, radiated by the sound source under test to the reference sound power P₀ = 1 pW

Note 1 to entry: Sound power level is expressed in decibels and is a descriptor of the emission of a sound source (see the ISO 3740 and ISO 9614 series). The frequency weighting or the width of the frequency band used should be indicated.

Note 2 to entry: For example, the A-weighted sound power level is L_WA.

3.2.3

emission sound pressure level

L_p

sound pressure level caused by a sound source under test at its work station or at any other specified position

Note 1 to entry: Emission sound pressure level is expressed in decibels (dB) and is an additional descriptor of the emission of a sound source (see ISO 11200 to ISO 11204).

Note 2 to entry: The frequency weighting and/or the time weighting or the width of the frequency band used shall be indicated.

Note 3 to entry: For example, the C-weighted peak emission sound pressure level is L_pC,peak.

Note 4 to entry: The A-weighted emission sound pressure level is often averaged over an operational period of a sound source; it is denoted L_pA.

3.2.4

surface sound pressure level

L_pA,d

A-weighted sound pressure level averaged on an energy basis over a measurement surface at a distance d from the sound source

Note 1 to entry: When d = 1 m, it is usually noted L_pA,1m.

3.2.5

measured noise emission value

L

any of the A-weighted sound power level, the A-weighted time-averaged emission sound pressure level, or the C-weighted peak emission sound pressure level, determined from measurements

Note 1 to entry: Measured values may be determined either for a single machine or from the average of a number of machines.

Note 2 to entry: Measured noise emission value is expressed in decibels and is not rounded.

3.2.6

noise emission declaration

information on the noise emitted by the machine, given by the manufacturer or the supplier in technical documents or other literature, concerning noise emission values

Note 1 to entry: The noise emission declaration may take the form of either the declared single-number noise emission value or the declared dual-number noise emission value.

3.2.7

uncertainty

K

value of the measurement uncertainty associated with a measured noise emission value

Note 1 to entry: Uncertainty is expressed in decibels and is not rounded.

3.2.8

declared single-number noise emission value

L_d

3.2.9

declared dual-number noise emission value

L and K

measured noise emission value, L, and its associated uncertainty, K, both rounded to the nearest decibel

3.3.1

noise immission at a work station

all noises that arrive, whether or not a worker is present, over a specific time period T, at a measuring point (work station) in the actual situation; i.e. noise coming from the machine, noise coming from the other sound sources and noise reflected by the ceiling, the walls and any fittings [see Figure 1 b)]

Note 1 to entry:T can be the duration of a measurement, an operating cycle of a machine, a process, the duration a worker is usually present at or near the measurement point, or the duration of the workshift.

3.3.2

noise exposure of a person

all noises that arrive, over a specific time period T, at a person’s ear in the actual situation [see Figure 1 c) and Figure 2]

3.3.3

noise immission and noise exposure descriptors

Note 1 to entry: Immission is measured at the work station. Exposure is measured at the ear of the person.

Note 2 to entry: can result from the energetic summation of immission or exposure values, , measured over individual time periods T_i , with .

3.4.1

sound reduction index

R

descriptor of transmission loss defined as ten times the logarithm to the base 10 of the ratio of the sound power incident on a test specimen to the sound transmitted through the test specimen (see Figure 3.)

Note 1 to entry: It is expressed in decibels and is frequency dependent.

3.4.2

sound absorption coefficient

α

fraction of the acoustic energy absorbed when sound waves strike a surface

Note 1 to entry: The sound absorption coefficient is frequency dependent.

Note 2 to entry: A single number rating is given in ISO 11654.

3.4.3

equivalent absorption area

A

3.4.4

insertion loss

D_i

difference in sound power level or emission sound pressure level with and without a noise control device applied to a sound source

Note 1 to entry: Insertion loss is frequency dependent and is expressed in decibels.

Note 2 to entry: The A-weighted insertion loss is always related to a given source.

Note 3 to entry: The insertion loss is used to assess the acoustical performance of enclosures (see ISO 11546-1 and ISO 11546-2), screens (see ISO 10053 and ISO 11821) and silencers (see ISO 7235, ISO 11691 and ISO 11820).

3.4.5

reduction of sound pressure level at a work station

result of a set of noise reduction measures described by the difference in noise immission levels

Note 1 to entry: For example, L_pA,eq,8h,1 – L_pA,eq,8h,2, where numeral 1 means before and numeral 2 means after technical measures for reduction have been taken.

3.4.6

direct sound

sound which propagates directly from the source to the point of observation

Note 1 to entry: No reflection of sound is involved so it is not affected by the characteristics of the room in which the source is located.

3.4.7

reflected sound

sound at any point in a room, resulting from reflections from room surfaces and fittings, and excluding the direct sound

3.4.8

diffuse-field conditions

sound propagation in rooms or regions of rooms where the sound is reflected so often and uniformly from all surfaces of the room and the fittings that the sound pressure level of the reflected sound is the same at any point inside the region

3.4.9

non-diffuse-field conditions

sound propagation in rooms or regions of rooms where sound does not propagate uniformly in all directions

3.4.10

reverberation time

T₆₀

time, in seconds, it takes for the sound pressure level in a room (originally in a steady state) to decrease 60 dB after the source is turned off (See Figure 4)

Note 1 to entry: The reverberation time is frequency dependent.

Note 2 to entry: It is useful for describing the acoustic properties of rooms with a diffuse sound field; room volume must be taken into account.

3.4.11

spatial sound distribution curve

curve which shows how the sound pressure level from a reference sound source decreases when the distance to the source increases

Note 1 to entry: Spatial sound distribution curves are frequency dependent and characterize the acoustic properties of rooms. In some cases, several spatial sound distribution curves are necessary to characterize a room.

3.4.12

rate of spatial decay of sound pressure levels per distance doubling

DL₂

amount, in decibels, by which the sound pressure level decreases over a given range of distances, when the distance from the source is doubled (see Figure 5)

3.4.13

excess of sound pressure level

DL_f