NBN ISO 13472-2:2025

< p class=" MsoBodyText" > < span lang=" EN-GB" > This document specifies a test method for measuring in situ the sound absorption coefficient of road surfaces for the one-third octave band frequencies ranging from 250 Hz to 1 600 Hz under normal incidence conditions. If necessary for practical applications the diameter of the tube can be reduced to 80 mm. This will increase the upper boundary of the frequency range to 2 000 Hz one-third octave band (see < a href=" #Section_sec_5.4" > < !-- [if supportFields]> < span
style=' color:#0070C0' > < span style=' mso-element:field-begin' > < / span> < span
style=' mso-spacerun:yes' >  < / span> REF Section_sec_5.4 \r \h < span
style=' mso-element:field-separator' > < / span> < / span> < ![endif]--> < span style=" color: #0070c0 " > 5.4< !-- [if gte mso 9]> < xml>
< w:data> 08D0C9EA79F9BACE118C8200AA004BA90B020000000800000010000000530065006300740069006F006E005F007300650063005F0035002E0034000000< / w:data>
< / xml> < ![endif]--> < / span> < !-- [if supportFields]> < span style=' color:#0070C0' > < span
style=' mso-element:field-end' > < / span> < / span> < ![endif]--> < / a> ) but reduces the area under test.< / span>

< p class=" MsoBodyText" > < span lang=" EN-GB" > The test method is intended for the following applications:< / span>

< p class=" ListContinue1" style=" mso-list: l0 level1 lfo1 " > < !-- [if !supportLists]--> < span lang=" EN-GB" style=" mso-fareast-font-family: Cambria mso-bidi-font-family: Cambria " > < span style=" mso-list: Ignore " > —< span style=" font: 7.0pt ' Times New Roman' " >      < / span> < / span> < / span> < !--[endif]--> < span lang=" EN-GB" > determination of the sound absorption coefficient (and, if of interest, also the complex acoustical impedance) of semi-dense to dense road surfaces < / span>

< p class=" ListContinue1" style=" mso-list: l0 level1 lfo1 " > < !-- [if !supportLists]--> < span lang=" EN-GB" style=" mso-fareast-font-family: Cambria mso-bidi-font-family: Cambria " > < span style=" mso-list: Ignore " > —< span style=" font: 7.0pt ' Times New Roman' " >      < / span> < / span> < / span> < !--[endif]--> < span lang=" EN-GB" > determination of the sound absorption properties of test tracks according to ISO 10844^[< a href=" #Reference_ref_4" > < !-- [if supportFields]> ^{< span style=' color:#0070C0' > < span
style=' mso-element:field-begin' > < / span> < / span>} < span style=' color:#0070C0' >
REF Reference_ref_4 \r \h ^{< span style=' mso-element:field-separator' > < / span>} < / span> < ![endif]--> ^{< span style=" color: #0070c0 " > 2< !-- [if gte mso 9]> < xml>
< w:data> 08D0C9EA79F9BACE118C8200AA004BA90B0200000008000000100000005200650066006500720065006E00630065005F007200650066005F0034000000< / w:data>
< / xml> < ![endif]--> < / span>} < !-- [if supportFields]> ^{< span
style=' color:#0070C0' > < span style=' mso-element:field-end' > < / span> < / span>} < ![endif]--> < / a> ^] or other similar standards and test surfaces defined in national and international type approval regulations for road vehicles and their tyres < / span>

< p class=" ListContinue1" style=" mso-list: l0 level1 lfo1 " > < !-- [if !supportLists]--> < span lang=" EN-GB" style=" mso-fareast-font-family: Cambria mso-bidi-font-family: Cambria " > < span style=" mso-list: Ignore " > —< span style=" font: 7.0pt ' Times New Roman' " >      < / span> < / span> < / span> < !--[endif]--> < span lang=" EN-GB" > verification of the compliance of the sound absorption coefficient of a road surface with design-specifications or other requirements.< / span>