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BS EN 1793-5:2025 Road traffic noise reducing devices. Test method for determining the acoustic performance - Intrinsic characteristics. Sound absorption under direct sound field conditions >
BS EN 1793-5:2025 Road traffic noise reducing devices. Test method for determining the acoustic performance - Intrinsic characteristics. Sound absorption under direct sound field conditions, 2026
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- European foreword
- Introduction
- Figure 1 — (not to scale) Sketch of the reverberant condition check in four cases
- 1 Scope
- 2 Normative references
- 3 Terms and definitions
- Figure 2 — (not to scale) Sketch of the sound source and the measurement grid in front of a vertical road traffic noise reducing device
- Figure 3 — (not to scale) Measurement grid for sound reflection index measurements in front of a vertical road traffic noise reducing device (sound source side)
- Figure 4 — (not to scale) Sketch of the set-up for the reference “free-field” sound measurement for the determination of the sound reflection index of a vertical road traffic noise reducing device
- 4 Symbols and abbreviations
- Table 1 — Symbols and abbreviations
- 5 Sound reflection index measurements [Go to Page]
- Table 2 — Distances di,k, dr,k and correction factors Cgeo,k for a plane reference surface
- Figure 5 (not to scale) — Sketch showing microphone positions and angles for the calculation of the correction factor Cdir,k [Go to Page]
- Figure 6 — Sketch of the minimum flat test specimen required for reflection index measurements in the 200 Hz – 5 kHz frequency range
- Figure 7 — (not to scale) Sketch of the set-up for sound reflection index measurement in front of a non-flat test specimen with a spatially periodic corrugation in the vertical direction [Go to Page]
- Figure 8 — (not to scale) Sketches of the set-up for the reflection index measurement in front of an inclined road traffic noise reducing device (side view)
- Figure 9 (not to scale) — Sketches of the set-up for the reflection index measurement in front of a curve road traffic noise reducing device (side view) [Go to Page]
- Figure 10 — Sketch representing the essential components of the measuring system [Go to Page]
- Figure 11 — Principle of the signal subtraction technique [Go to Page]
- Figure 12 — The Adrienne temporal window [Go to Page]
- Figure 13 — Example of an impulse response measure in front of a vertical, non-flat noise barrier. (a) before signal subtraction. (b) after signal subtraction [Go to Page]
- Figure 14 — Microphone grid reference positions (nR = 3) – indicated by the yellow circles - for a periodic flat non-homogeneous test specimen combining two different materials with a period in the horizontal direction [Go to Page]
- Figure 15 — Microphone grid reference positions (nR = 9) - indicated by yellow circles - for a non-flat homogeneous test specimen with two different periods in the horizontal and vertical directions (front view) [Go to Page]
- Table 3 — Nominal values of: Δdk5 and Δdk and associated tolerance εk [Go to Page]
- Figure 16 — Sketch illustrating the different reflections arriving at a microphone in the measurement grid (side view)
- Figure 17 — Sketch illustrating the positioning of the Adrienne window for the reflected component [Go to Page]
- 6 Measurement uncertainty
- 7 Measuring procedure
- 8 Test report
- Annex A (informative) Low-frequency limit and window width
- Figure A.1 — Fourier transform of the Adrienne window having a width of 7,9 ms
- Figure A.2 — Low-frequency limit of the Adrienne window as a function of the window width
- Table A.1 — Low-frequency limit, rounded to the nearest integer, of the Adrienne window as a function of the window width
- Annex B (normative) Measurement uncertainty
- B.1 General
- B.2 Measurement uncertainty based upon reproducibility data
- B.3 Standard deviation of repeatability and reproducibility of the sound reflection index
- Table B.1 — Standard deviation of repeatability and reproducibility of the sound reflection index, after the QUIESST project [19], [21], [22]
- Annex C (normative) Template of test report on sound reflection index of road traffic noise reducing devices
- C.1 General
- Table C.1 —Template of test report on sound reflection index of road traffic noise reducing devices For product xxxx produced by the firm yyyyy
- C.2 Test setup (example)
- Figure C.1 — (Example) General view of test barrier (from front (road) side) – White circles mark measurement positions based on the post spacing of 4 m
- Figure C.2 — (Example) Test arrangement showing loudspeaker and microphone array when measuring
- C.3 Test object and test situation (example)
- Figure C.3 — (Example) Plan view of the noise barrier (dimensions in millimetres)
- Figure C.4 — (Example) Cross-sections through noise barrier (dimensions in millimetres)
- C.4 Test results (example)
- C.4.1 Part 1 – Results in tabular form
- Table C.2 — Results in tabular form
- C.4.2 Part 2 – Results in graphic form
- Figure C.5 — Results in graphic form
- C.5 Uncertainty (example)
- Table C.3 — Estimation of the uncertainty of the declared values of RI
- Annex D (normative) Indoor measurements for product qualification
- D.1 General
- D.2 Parasitic reflections
- Figure D.1 — Clearance zone, shaded in light grey, around a device under test on the sound source side (side view)
- D.3 Reverberation time of the room
- Bibliography [Go to Page]