🔊 Effectiveness of noise barriers at the installation site ("in situ") — PN-ISO 10847

Environment PN-ISO 10847

Overview

WHAT THIS TEST IS — SCOPE FROM THE PKN CARD, IN FULL: "Określono dwie metody (bezpośrednią i pośrednią) wyznaczania skuteczności ekranów akustycznych wszystkich rodzajów w środowisku zewnętrznym. Określono szczegółowe procedury pomiarowe skuteczności ekranu w miejscu jego zainstalowania, z uwzględnieniem usytuowania mikrofonów, warunków działania źródeł oraz środowisk akustycznych w obszarach objętych pomiarami przy uwzględnieniu istniejących warunków meteorologicznych. Podano definicje 10 terminów" [Two methods (direct and indirect) are specified for determining the effectiveness of noise barriers of all types in the outdoor environment. Detailed procedures are specified for measuring the effectiveness of a barrier at its installation site, taking into account the positioning of the microphones, the operating conditions of the sources and the acoustic environments in the areas covered by the measurements, with regard to the existing meteorological conditions. Definitions of 10 terms are given].

WHAT THE RESULT DOES NOT TELL (clause 1 of ISO 10847:1997). The standard measures the effectiveness of a given barrier at a given site and under given meteorological conditions. It does NOT allow the effectiveness of an identical barrier at another site to be compared; with the direct method it allows different barriers to be compared at the same site and under the same conditions. It does not cover the properties of the barrier itself — e.g. its sound insulation or sound absorption coefficient. Quantities describing the noise: A-weighted equivalent sound level, A-weighted sound exposure level, levels in octave or one-third-octave bands and/or the maximum level. Application: routine assessment of barriers, engineering and diagnostic assessment — before or after the barrier is installed.

EFFECTIVENESS OF THE BARRIER (definition 3.5): the difference in sound pressure levels at a specified receiver position before and after the barrier is installed — provided that the source, the terrain profile, the obstacles and reflecting surfaces, the ground and the meteorological conditions have not changed. The frequency weighting or bandwidth and the time constant are stated (e.g. effectiveness for A-weighted equivalent levels). The reference position (3.8) is a position where the barrier has a minimal effect on the sound of the source — it serves to track the source level; the receiver position (3.9) is chosen according to the purpose of the test.

TWO METHODS (clause 4): • DIRECT — only when the barrier is not there yet or can be removed for the "before" measurement; the levels are measured at the reference position and at the receiver position before and after, at the same positions, with an equivalent source, terrain, obstacles, ground and weather; • INDIRECT — when the barrier already stands and cannot be removed: the "before" level is estimated from a measurement at an equivalent site. The substitute site is equivalent when it has an equivalent terrain profile, obstacles and reflecting surfaces, and ground in a 60° sector on both sides of the line from the receiver positions to the source, and the surroundings within a radius of 30 m behind and beside the main receiver positions are similar (6.2). Ground equivalence is best described by the specific impedance; when it is not determined — by a description of the type of surface (e.g. paved, tall vegetation, loose or compacted ground).

THE WEATHER MUST BE EQUIVALENT "BEFORE" AND "AFTER" (6.3): • wind — the same class according to Table 1 (downwind: component from +1 m/s to +5 m/s; calm: from –1 m/s to +1 m/s, at all distances only under temperature inversion conditions; for short distances the "upwind" class is also permitted), and the components of the mean wind speed in the direction from the source to the receiver must not differ by more than 2 m/s; at a mean wind speed above 5 m/s no measurements are made at all. "Short distance": before — (Hs + Hr) / (d1 + d2) > 0.1; after — (Hs + H) / d1 > 0.1 and (H + Hr) / d2 > 0.1 (H — height of the barrier, Hs and Hr — of the source and the receiver, d1 and d2 — source–barrier and barrier–receiver distances); • temperature — the "before" and "after" means within 10 °C, similar temperature gradients with height; the results are not corrected for temperature; • humidity — important mainly for sources with a large share of frequencies above 3000 Hz; the results are not corrected for humidity; • cloud cover — the same class (Table 2): 1 — heavy cloud cover (at least 80 % throughout the measurement), 2 — moderate (50–80 % for at least 80 % of the time), 3 — light or sunny (below 50 % for at least 80 % of the time), 4 — clear night; • rain and snow are to be avoided, and for road barriers — a wet road surface.

BACKGROUND NOISE (6.4): the background level (including instrument noise) should be at least 10 dB below the measured level. For a difference of 4 dB to 9 dB, the correction from Table 3 is applied: for 4 and 5 dB — subtract 2 dB, for 6, 7, 8 and 9 dB — subtract 1 dB. For a difference below 4 dB the result is invalid.

INSTRUMENTS (clause 5): sound level meters of class (type) 1 or 2 according to IEC 651, integrating ones according to IEC 804 for equivalent and exposure levels; sound calibrator according to IEC 942 — check at the beginning and at the end of each session; octave and one-third-octave filters according to IEC 1260; windscreens; at least TWO measurement channels for simultaneous measurement at the reference and receiver positions. The measurement uncertainty must always be estimated. Meteorological instruments: anemometer (uncertainty ≤ ± 10 %), thermometer (≤ ± 1 °C), hygrometer (≤ ± 2 %).

EDITIONS (state on 25.09.2026). PKN: PN-ISO 10847:2002 — Polish version, publication 10-10-2002, 18 pages, KT 115 Environmental Noise, introduces ISO 10847:1997 [IDT], without the "Wycofana" [Withdrawn] header. ISO: ISO 10847:1997, edition 1 of August 1997, 13 pages, ISO/TC 43/SC 1, stage 90.93 — confirmed; the last review in 2024 confirmed the edition, which remains current (ISO website, read on 25.09.2026).

HOW ACCREDITATION SCOPES CITE THE STANDARD. Measurement of 25.09.2026 on the database of PL accreditation scopes (1310 laboratories with entries): 26 entries at 18 laboratories; notations "PN-ISO 10847:2002" (23), "PN ISO 10847:2002" without a hyphen (2) and "PN-ISO 10847" without a year (1). Subject of the test: "Środowisko ogólne — ekrany akustyczne «in situ»" [General environment — noise barriers in situ] in various notations or "Ekrany akustyczne / Acoustic screens" [Noise barriers]. Methodology: "Równoważny poziom dźwięku A" [A-weighted equivalent sound level] (most often) and "Skuteczność ekranów (z obliczeń)" [Effectiveness of barriers (calculated)]; some entries add levels in one-third-octave bands. Declared level ranges: lower limits from 22 dB to 30 dB, upper ones from 100 dB to 137 dB; bands — e.g. from 50 Hz to 12 500 Hz or from 20 Hz to 20 000 Hz. MIND THE WORDS: the term "bezpośrednia" [direct] ("Metoda pomiarowa bezpośrednia" [Direct measurement method], "pomiar bezpośredni" [direct measurement]) stands in the scopes of 17 of the 18 laboratories — in the technique field or in the text of the methodology, next to "Równoważny poziom dźwięku A" [A-weighted equivalent sound level]. In the standard, the "direct method" is the measurement before and after the barrier is installed at the same site — the notation in the scope alone does not show whether this method of the standard is meant or the way the sound level is measured. Only one entry explicitly names "pomiary bezpośrednie i pośrednie" [direct and indirect measurements].

THE KEY OF THE "LABORATORIES" TAB: "PN-ISO 10847" — 17 laboratories and 24 entries, without foreign entries. The tab will not show 1 laboratory (AB 1241), which wrote the standard without a hyphen ("PN ISO 10847:2002").

WHAT WE DO NOT GIVE. We had a fragment of the text of ISO 10847:1997 made available by the publisher: the foreword and clauses 1–6.4. We do not have the requirements for the sound sources, the positioning of the microphones (including the heights and distances of the positions), the measurement time, the calculation of the effectiveness or the content of the test report. We do not give these data.

Method principle

The effectiveness of a barrier is the difference in sound pressure levels at the receiver position before and after the barrier is installed, with the source, terrain, ground and weather unchanged. The "before" level is measured at the same site (direct method) or at an equivalent site without a barrier (indirect method); at the same time, measurements are made at the reference position to track the source level.

Applications

• Noise barriers along roads and railway lines — assessment of effectiveness after construction (acceptance, control)
• Assessment before and after the barrier is installed (direct method) or for an existing barrier (indirect method)
• Comparison of different barriers at the same site and under the same conditions (only with the direct method)
• NOT for the properties of the barrier itself (insulation, absorption) or for transferring the result to another site

Key parameters

Standard

Standard number

PN-ISO 10847:2002 (wersja polska; wprowadza ISO 10847:1997 [IDT])

Title (PL)

Akustyka — Wyznaczanie „in situ" skuteczności zewnętrznych ekranów akustycznych wszystkich rodzajów

Title (EN)

Acoustics — In-situ determination of insertion loss of outdoor noise barriers of all types

Step-by-step procedure

1. Choice of method

   The barrier is not there or can be removed — direct method; the barrier stands — indirect method with an equivalent site (±60° sector, surroundings 30 m).

2. Measurement positions

   Reference position (minimal effect of the barrier) and receiver positions according to the purpose of the test; the same positions "before" and "after". WE DO NOT GIVE the details of the positioning.

3. Weather conditions

   Check and record the wind class, temperature, humidity and cloud cover; no measurements in wind > 5 m/s, avoid precipitation and a wet road surface.

4. Calibration

   Calibrator at the beginning (after the instruments have warmed up) and at the end of the session.

5. "Before" and "after" measurements

   Simultaneous measurements at the reference and receiver positions; background noise check (≥ 10 dB, corrections from Table 3).

6. Result

   Effectiveness as the level difference; the test report documents the equivalence of the "before" and "after" conditions. WE DO NOT GIVE the formulae or the content of the test report.

Required equipment and apparatus

Health and safety (OHS)

• Measurements next to roads and railway tracks in operation — high-visibility vests, agreement with the operator, safe placement of the tripods
• Meteorological masts — stable fixing, not near power lines

Frequently asked questions