🏗️ Field measurement of airborne sound insulation of façade elements (e.g. windows) and façades — element method with loudspeaker (apparent sound reduction index R′45°, microphone on the element surface) or with road traffic noise (R′tr,s), and global method (level difference D2m with the microphone 2 m in front of the façade, standardized to a reverberation time of 0,5 s or normalized to an absorption area of 10 m²), PN-EN ISO 140-5 (withdrawn)

Construction PN-EN ISO 140-5

Overview

WHAT THE STANDARD COVERS. Scope from the PKN catalogue card of PN-EN ISO 140-5:1999 (Polish version), in full (our translation): “Two groups of methods for measuring airborne sound insulation (»global« methods and »element« methods) are specified for the façade and for its elements respectively. Definitions of 10 elements are given”. We read the text of the standard in two samples of ISO 140-5:1998 (second edition, 1998-08-15): the English one in SIST EN ISO 140-5:1999 (title page, foreword, beginning of Clause 1) and the French one (foreword, the rest of Clause 1, Clauses 2–5.6.2 with Figures 1 and 2). We do not have the rest of the element loudspeaker method (5.6.3 onwards), the global loudspeaker method, the road traffic methods (Clause 6), precision (7), expression of results (8), test report (9) or Annexes A–F (among others determination of the area S, checking transmission through the wall around the element, aircraft and railway noise methods); Table 1 (overview of methods) is not in the sample.

ACCORDING TO THE TEXT OF ISO 140-5:1998 (foreword, Clauses 1–5.6.2). The standard was prepared by ISO/TC 43 “Acoustics”, subcommittee SC 2 “Building acoustics”; the second edition cancels and replaces the first (ISO 140-5:1978), which has been technically revised; Annexes A and B are normative, C–F informative. Scope (1): two series of methods — element methods and global methods — for measuring the airborne sound insulation of façade elements and whole façades respectively; the element methods estimate the sound reduction index of an element, e.g. a window — the most accurate uses a loudspeaker as an artificial source, others, less accurate, the available road traffic noise; the global methods estimate the outdoor/indoor sound level difference under actual traffic conditions — the most accurate use the actual traffic as source, a loudspeaker may also be used. The element loudspeaker method yields an apparent sound reduction index which under certain circumstances (taking account of measurement precision, 7.1) can be compared with the sound reduction index measured in laboratories according to ISO 140-3 or ISO 140-10 — it is preferred when the aim is to evaluate an element in relation to its laboratory performance; the element road traffic method serves the same purpose when the loudspeaker cannot be used — the two often give slightly different results, and the road traffic method tends to give lower values of the sound reduction index; in Annex D it is supplemented by aircraft and railway traffic methods. The global road traffic method yields the real reduction of a façade at a given place relative to a position 2 m in front of the façade — preferred for evaluating a whole façade including all flanking paths; the global loudspeaker method gives the reduction relative to a position 2 m in front of the façade when the real source cannot be used; the results of global methods cannot be compared with laboratory results. References (2): ISO 140-2, ISO 140-3, ISO 354 (measurement of sound absorption in a reverberation room), ISO 717-1, IEC 60651 and IEC 60804 (sound level meters), IEC 60942 (calibrators), IEC 61260 (filters). Definitions (3): average sound pressure level on the test surface L1,s (space-time average over the whole surface including reflections from the element and the façade); average sound pressure level in the room L2 (excluding zones of direct radiation of the source and the near field of the boundaries); equivalent level Leq; sound reduction index R = 10 lg(W1/W2); apparent sound reduction index R′ = 10 lg[W1/(W2 + W3)], with power W3 radiated by flanking elements; R′45° = L1,s − L2 + 10 lg(S/A) − 1,5 dB — with a loudspeaker and an angle of incidence of 45° (S — area of the element according to Annex A, A — equivalent sound absorption area of the receiving room; the equation assumes incidence at 45° only and a perfectly diffuse field); R′tr,s = Leq,1,s − Leq,2 + 10 lg(S/A) − 3 dB — with road traffic noise and the outdoor microphone on the surface; level difference D2m = L1,2m − L2 (notation Dtr,2m with road traffic, Dls,2m with loudspeaker); standardized level difference D2m,nT = D2m + 10 lg(T/T0) with T0 = 0,5 s; normalized level difference D2m,n = D2m − 10 lg(A/A0) with A0 = 10 m². Apparatus (4): microphone diameter at most 13 mm; instruments of class 0 or 1 according to IEC 60651 and IEC 60804, calibrator of at least class 1 according to IEC 60942; one-third-octave and octave filters according to IEC 61260; reverberation time equipment according to ISO 354; loudspeaker directivity in the free field such that local level differences on an imaginary surface of the size and orientation of the element are less than 5 dB in each band (for elements longer than 5 m up to 10 dB is accepted, recorded in the report). Loudspeaker methods (5): loudspeaker in one or more positions outside, at a distance d from the façade, angle of incidence (45 ± 5)° (Figure 1); the average level is determined on the element (element method) or 2 m in front of the façade (global method) and in the receiving room; the sound field shall be steady with a continuous spectrum; for one-third-octave measurements at least 100–3150 Hz (50–5000 Hz preferred), for octave measurements at least 125–2000 Hz (63–4000 Hz preferred); differences between one-third-octave power levels within an octave not more than 6 dB in the 125 Hz band, 5 dB in 250 Hz and 4 dB above; the level in the room at least 6 dB above background in all bands. Loudspeaker position (5.4): such that the level variation over the element is minimal — preferably on the ground, otherwise as high as possible; distance r from the source to the centre of the element at least 5 m (d > 3,5 m) for the element method and at least 7 m (d > 5 m) for the global method. Measurements in the receiving room (5.5): one moved microphone, an array of fixed microphones or a rotating microphone, energy averaging over all microphone and source positions; at least five microphone positions uniformly distributed; distances at least 0,7 m between positions, 0,5 m from boundaries and objects, 1,0 m from the source; rotating microphone — sweep radius at least 0,7 m, plane inclined at least 10° to the room surfaces, traverse period at least 15 s; background at least 6 dB (preferably more than 10 dB) below the level of signal plus background; with a difference of less than 10 dB, correction L = 10 lg(10^(Lsb/10) − 10^(Lb/10)) dB (the French text of the sample gives the limits here as “less than 10 dB, but greater than 16 dB” — as written the condition cannot be met; we leave it as it stands); with a difference of 6 dB or less in any band, the correction 1,3 dB is used and the values are marked in the report as the limit of measurement; absorption area A = 0,16 V/T from reverberation time measured according to ISO 354 — evaluation starts about 0,1 s after switching off the source or a few dB below the initial level, decay range at least 20 dB, end at least 10 dB above background; at least six decays per band, at least one loudspeaker position and three microphone positions; rotating microphone with a period of at least 30 s (with a reverberation time shorter than about 0,4 s it may be problematic). Element loudspeaker method (5.6): when results are to be comparable with laboratory results — check that the element corresponds to the specified construction and is correctly mounted according to the manufacturer, estimate the façade insulation so that transmission through the wall around the element does not contribute significantly to the room level; when comparing a window with a laboratory result — also that the opening area corresponds to the laboratory one and that the niche and window position do not differ from ISO 140-3 (examples of checks — Annex C; when transmission through the wall is suspected — procedure of Annex B); the level L1,s on the element surface is measured with the microphone fixed to the element with strong adhesive tape, with its axis parallel to the façade plane (pointing up or down) or perpendicular to the element — centre of the membrane at most 10 mm from the element with a parallel axis (depending on microphone diameter) or 3 mm with a perpendicular axis, with a hemispherical windscreen (Figure 2); for simultaneous measurements outside and inside, microphones and cables proven not to influence the insulation of the element are recommended.

STATUS (catalogue cards as of 03.10.2026). The card of PN-EN ISO 140-5:1999 (Polish version, published 22-12-1999, 29 pages, price group N) has the header “Withdrawn”: withdrawal date 18-06-2019, Construction Sector, KT 253 Architectural Acoustics, ICS 91.120.20, “Introduces: EN ISO 140-5:1998 [IDT], ISO 140-5:1998 [IDT]”, “Replaces: PN-B-02154-05:1983”, “Replaced by: PN-EN ISO 16283-1:2014-05 — Polish version, PN-EN ISO 16283-3:2016-04 — Polish and English version”; additional information: standard withdrawn 2014-05-06 and then restored to current status on 2015-09-09 by the President of PKN (Announcement No. 1/2015). The card of PN-EN ISO 16283-3:2016-04 (Polish version, published 29-09-2023, 48 pages, KT 253) has no “Withdrawn” header: “Part 3: Façade sound insulation”, “Introduces: EN ISO 16283-3:2016 [IDT], ISO 16283-3:2016 [IDT]”, “Replaces: PN-EN ISO 140-5:1999, PN-EN ISO 140-14:2006”; according to its scope the procedures apply to rooms of 10–250 m³ and bands of 50–5000 Hz, also to rooms where the sound field may not approximate a diffuse field. What changed for the result: according to the scope on the successor’s card it covers non-diffuse fields, whereas R′45° in ISO 140-5 assumes a perfectly diffuse field in the receiving room (note to 3.6); we have not read the text of ISO 16283-3, so we do not give differences in the procedure.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17.09.2026, read 03.10.2026). The number 140-5 appears in 9 records at 7 laboratories: AB 023, AB 818, AB 838, AB 1162, AB 1391, AB 1621, AB 1924. In the current scopes on the PCA website (read 03.10.2026, issues from 07.02.2025 to 21.07.2026) all give “PN-EN ISO 140-5:1999”; five of them (AB 838, AB 1162, AB 1391, AB 1621, AB 1924) cite PN-EN ISO 16283-3:2016-04 in the same item — AB 838 “excluding clause 13”, AB 1391 “excluding clauses 7.2.2 and 7.2.3”; AB 023 and AB 818 — only the withdrawn 140-5. The “Laboratories” tab (“PN-EN ISO 140-5”) shows 6 laboratories — all except AB 1162, where the designation stands after PN-EN ISO 16283-3; checked with the tab query on the production server labcoda.pl on 03.10.2026.

WHAT THE LABORATORIES TEST (items in PCA scopes). Buildings and building elements, façades and their elements, roofs, gates (industrial, garage), external doors: normalized level difference Dls,2m,n, standardized level difference Dls,2m,nT and apparent sound reduction index R′45° in one-third-octave bands, at AB 1621 and AB 1924 also in octave bands, frequency ranges (50–5000) Hz or (100–5000) Hz with measurement possible at 50, 63 and 80 Hz (AB 023); weighted indices and spectrum adaptation terms C and Ctr “from calculation” according to PN-EN ISO 717-1 (AB 838, AB 1924). The notations Dls and R′45° in the scopes indicate loudspeaker methods.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. Choice of method: the result of the global method (D2m) is not comparable with the laboratory sound reduction index of the element, and the element road traffic method tends to give lower R′ than the loudspeaker method (1) — comparing two results obtained by different methods may suggest a difference between products. Comparison with the laboratory: without checking the mounting, transmission through the wall around the element and — for windows — the dimensions of the opening and niche, the R′45° result does not correspond to the laboratory R (5.6.1). Geometry: the angle of (45 ± 5)° and the distance of at least 5 m (element) or 7 m (global) are conditions of the formula with the −1,5 dB correction; outside them the correction does not correspond to the actual incidence (3.6, 5.4). Microphone on the element: distance from the surface at most 10 mm or 3 mm depending on the axis (5.6.2) — a microphone further away measures a different L1,s. Background: with a difference of 6 dB or less the result is only a limit of measurement and must be marked as such (5.5.3). Calculation: R′45° and D2m,nT are level differences measured by this method, corrected by a term from absorption area or reverberation time — A comes from reverberation time measurement according to ISO 354 in the same room, and S — the area of the element determined according to Annex A (which we do not have); a reverberation time overestimated k times shifts the result by 10 lg k dB. Standard: PN-EN ISO 140-5 has been withdrawn since 18-06-2019 (previously withdrawn and restored in 2014–2015), and two laboratories cite only it.

WHAT WE DO NOT GIVE. We do not have Table 1, 5.6.3 onwards, Clauses 6–9 or Annexes A–F: the way of determining the area S, the microphone position 2 m in front of the façade in the global method, the course of the road, aircraft and railway traffic methods, precision data or report requirements — so we give none of these values.

Method principle

Outside the building a sound field is generated by a loudspeaker placed at 45° to the façade (or the actual road traffic noise is used) and the average sound pressure level is measured on the surface of the element under test (element method) or 2 m in front of the façade (global method) and in the receiving room; from the level difference, the element area and the equivalent absorption area determined from reverberation time, the apparent sound reduction index of the element R′45° or the level difference D2m standardized to a reverberation time of 0,5 s or normalized to an absorption area of 10 m² is calculated.

Applications

• Façade elements (windows, external doors, gates) — checking in the building an insulation comparable with the laboratory result (element loudspeaker method)
• Whole façades and roofs — reduction of outdoor noise relative to a point 2 m in front of the façade, including flanking paths (global methods)
• Buildings and building elements in PCA scopes — 7 laboratories, some together with PN-EN ISO 16283-3 and PN-EN ISO 717-1

Key parameters

Standard

Standard number

PN-EN ISO 140-5:1999

Title (PL)

Akustyka — Pomiar izolacyjności akustycznej w budynkach i izolacyjności akustycznej elementów budowlanych — Pomiary terenowe izolacyjności akustycznej od dźwięków powietrznych ściany zewnętrznej i jej elementów

Title (EN)

Acoustics — Measurement of sound insulation in buildings and of building elements — Part 5: Field measurements of airborne sound insulation of façade elements and façades

Step-by-step procedure

1. Choice of method

   Element with loudspeaker — evaluation of the element against the laboratory; element with road traffic — when a loudspeaker is impossible; global — evaluation of the whole façade at the site. PN-EN ISO 140-5:1999 withdrawn 18-06-2019, successor PN-EN ISO 16283-3:2016-04 (PKN catalogue cards as of 03.10.2026).

2. Checks before measurement

   When comparing with the laboratory: conformity of construction and mounting, influence of transmission through the wall around the element, for windows — opening and niche as in ISO 140-3 (5.6.1, Annexes B and C).

3. Field outside

   Loudspeaker on the ground or as high as possible, angle (45 ± 5)°, r ≥ 5 m (element) or ≥ 7 m (global); continuous spectrum, level ≥ 6 dB above background in the room; L1,s with the microphone on the element or L1,2m 2 m in front of the façade.

4. Receiving room

   L2 from ≥ 5 microphone positions (energy averaging), background and correction; reverberation time according to ISO 354 (≥ 6 decays per band) and A = 0,16 V/T.

5. Result

   R′45° = L1,s − L2 + 10 lg(S/A) − 1,5 dB or D2m, D2m,nT, D2m,n in bands; single-number ratings according to ISO 717-1; further requirements (Clauses 7–9) — we do not have the text.

Required equipment and apparatus

Health and safety (OHS)

• A high-power loudspeaker outside the building — define a zone in which the sound level does not endanger bystanders; the part of the standard we read contains no safety requirements
• Fixing the microphone on façade elements above ground floor — work at height requires fall protection

Frequently asked questions