🏗️ Airborne sound insulation between rooms in a building — field measurements in one-third-octave bands 100–3150 Hz: level difference D, Dn, DnT and apparent sound reduction index R′, PN-EN ISO 140-4

Construction PN-EN ISO 140-4

Overview

WHAT THE STANDARD COVERS. We have a preview of ISO 140-4:1998 (second edition) — clauses 1–9 (without the annexes); the text is introduced unchanged (IDT) by PN-EN ISO 140-4:2000. Scope (Clause 1): field methods for measuring the airborne sound insulation of interior walls, floors and doors between two rooms under diffuse sound field conditions in both rooms, and for determining the protection this affords to the occupants of the building; the results are frequency-dependent and are converted into a single number according to ISO 717-1; they are used to compare the sound insulation between rooms and with requirements. Laboratory measurements — ISO 140-3, façades — ISO 140-5.

QUANTITIES (Clause 3). Average sound pressure level L in a room (energy average over n positions); level difference D = L1 − L2 (source − receiving); normalized level difference Dn = D − 10 lg (A/A0), A0 = 10 m² for dwellings; standardized level difference DnT = D + 10 lg (T/T0), T0 = 0.5 s for dwellings (this corresponds to a reference absorption area A0 = 0.32 V); apparent sound reduction index R′ = D + 10 lg (S/A), where S is the area of the partition (for doors — the area of the opening with the frame; for staggered rooms — the common part of the partition; when smaller than 10 m², max(S, V/7.5)); when there is no common partition, Dn is determined. Comparison with laboratory results is meaningful only when S is about 10 m².

APPARATUS AND PROCEDURE (clauses 4–8). Sound level meters of class 0 or 1 according to IEC 60651 and IEC 60804, a class 1 calibrator according to IEC 60942 before each measurement, filters according to IEC 61260, reverberation time measurement according to ISO 354. In empty rooms of the same shape and dimensions diffusers are recommended (at least 1.0 m², usually 3–4). Measurements in one-third-octave bands (octave bands — only by agreement, according to Annex B; the results are then not directly comparable). The sound in the source room steady, with a continuous spectrum, with no differences greater than 6 dB between adjacent one-third-octave bands; in the receiving room at least 10 dB above background in every band. One loudspeaker — in at least two positions; with different volumes the larger room is chosen as the source room (for DnT). Minimum distances: 0.7 m between microphone positions, 0.5 m from walls and diffusers, 1.0 m from the source; at least 5 fixed microphone positions (at least 10 measurements with one loudspeaker) or a moving microphone with a sweep radius of at least 0.7 m, a traverse period of at least 15 s and an averaging time of at least 30 s; with fixed positions averaging at least 6 s below 400 Hz and 4 s above. Mandatory bands: one-third octaves from 100 to 3150 Hz; additionally recommended 4000 and 5000 Hz, and for information 50, 63 and 80 Hz (Annex D). Absorption area of the receiving room from Sabine's formula A = 0.16 V/T; at least 6 decays per band (one loudspeaker, three microphone positions, two readings each), evaluation range of the decay at least 20 dB. Background at least 6 dB (preferably 10 dB) below the signal; with a difference of 6–10 dB a correction by formula, with ≤ 6 dB — a correction of 1.3 dB and a note that the result is a limit of measurement. The results Dn, DnT or R′ are given for all bands to 0.1 dB, in a table and a graph.

RESULTS AND TEST REPORT (clauses 8–9). Graph: logarithmic frequency axis, 5 mm per one-third-octave band and 20 mm per 10 dB; forms according to Annex E are preferred as a short version of the test report. Octave-band values are calculated from the three one-third-octave bands using equations (9)–(11): Dn,oct = −10 lg [Σ(j=1…3) 10^(−Dn,1/3 oct,j/10) / 3] dB, and likewise DnT,oct and R′oct. If the measurement of R′ is repeated in the same or the opposite direction, the arithmetic mean of all results in each band is given. The test report states: a reference to this part of ISO 140; the organization that performed the measurements; the name and address of the client; the date of the test; a description and identification of the building construction and test arrangement; the volumes of both rooms; Dn or DnT between the rooms or R′ of the separating element as a function of frequency; the area S used to evaluate R′; a brief description of the procedure and equipment; results that are measurement limits (written as "≥ … dB" when the level in a band cannot be measured because of acoustic or electrical background noise — 6.6); the flanking transmission, if measured (Annex C), stating which parts of the transmitted sound power it includes. Single-number ratings from the curves Dn(f), DnT(f) and R′(f) are evaluated according to ISO 717-1, stating clearly that they are based on a result obtained by a field method.

STATUS (state of the card on 29 September 2026). Card of PN-EN ISO 140-4:2000 (Polish version): "withdrawn and replaced by PN-EN ISO 16283-1:2014-05 - English version", published 08-02-2000, "Withdrawal date: 06-05-2014", 27 pages, price group N, Construction and Building Structures Sector, PKN technical committee KT 253 (Architectural Acoustics), ICS 91.120.20, "Introduces: EN ISO 140-4:1998 [IDT], ISO 140-4:1998 [IDT]", "Supersedes: PN-B-02154-04:1983 - Polish version", "Replaced by: PN-EN ISO 16283-1:2014-05 - English version, PN-EN ISO 16283-1:2014-05 - Polish version".

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17 September 2026, read on 28 September 2026). All records of number 140-4: 15 records of the copy at 12 laboratories (AB 023 — two entries; AB 838 and AB 1924 — two records each, because the copy also assigned this standard to the row of weighted ratings under the entry). "PN-EN ISO 140-4:2000" — 11 laboratories, without a year — AB 1241; exclusion of "Annex C" (informative; according to the text of the standard it explains the power transmitted along flanking paths) — AB 1413. In the same entry with PN-EN ISO 16283-1:2014-05 (usually with amendment A1:2018-02) — 10 laboratories (checked in the rows of the PCA documents); only this standard in the entry — AB 023 and AB 818 — AB 818 cites PN-EN ISO 16283-1 in a separate row, for airborne sound insulation between rooms. Exclusions in the 16283-1 part: "pkt 7.4" (clause 7.4 — mechanically moved microphone) — AB 796, AB 869, AB 1162, AB 1413, AB 1621 and AB 1924, "punktów 7.4 i 7.5" (clauses 7.4 and 7.5 — also the manually moved microphone) — AB 1391, "punktu 13" (clause 13 — uncertainty) — AB 838. PN-EN ISO 717-1 (single-number ratings) — in the row directly under the entry with this standard — at 9 laboratories: AB 796, AB 838, AB 869, AB 1162, AB 1271, AB 1391, AB 1413, AB 1621 and AB 1924; AB 1162 adds PN-EN ISO 140-14:2006. The "Laboratories" tab searches for records BEGINNING with "PN-EN ISO 140-4" and will show 11 laboratories — checked with the tab query on the labcoda.pl production server on 29 September 2026: 11; AB 1162 remains outside it (the record begins with PN-EN ISO 16283-1). Current scopes on the PCA website (read on 29 September 2026, issues from 7 February 2025 to 28 July 2026): all entries stand in the valid issues, every pair of range limits from the copy appears in the current document and no entry is suspended.

TEST ITEM AND RANGES. Buildings and building elements — most; floors, interior walls and interior doors — AB 023 and AB 818; interior walls and partitions — AB 1241. Determined: R′ and DnT (most), also Dn (AB 838, AB 1162); AB 1391 records "poziom ciśnienia akustycznego w pasmach 1/3 oktawowych" (sound pressure level in one-third-octave bands). In the rows with PN-EN ISO 717-1: the weighted index R′w with the spectrum adaptation terms C and Ctr — 8 laboratories (DnT,w — 7, without AB 1271; Dn,w — AB 838 and AB 1162), while AB 1391 records "izolacyjność akustyczna od dźwięków powietrznych między pomieszczeniami (z obliczeń)" (airborne sound insulation between rooms (from calculation)). Bands: (50 – 5000) Hz — 9 laboratories, (100 – 5000) Hz — AB 023 (with the option of 50, 63 and 80 Hz), AB 818 and AB 1924; octaves next to one-third octaves — AB 1413, AB 1621, AB 1924. Technique: "metoda terenowego pomiaru w warunkach pola rozproszonego" (field measurement method under diffuse field conditions; AB 796, AB 869), "metoda pomiaru terenowego" (field measurement method; AB 838, AB 1162), "in situ" (AB 023, AB 1241, AB 1271), "metoda pomiarowa bezpośrednia" (direct measurement method; AB 1391, AB 1413).

ALONGSIDE THIS STANDARD. The successor — PN-EN ISO 16283-1 — according to the introduction of ISO 16283-1:2014 replaced ISO 140-4, 140-5 and 140-7 (and ISO 140-14) and differs in that it also covers rooms in which the sound field is not diffuse, explains how an operator can measure with a hand-held microphone or sound level meter, and incorporates the guidance of the former ISO 140-14; it applies to rooms with volumes from 10 to 250 m³ and to bands from 50 to 5000 Hz. The card of PN-EN ISO 16283-1:2014-05 (Polish version) has no "Wycofana" (withdrawn) header — the successor is CURRENT (state of the card on 29 September 2026): Polish version published 18-06-2019, 52 pages, KT 253 (Architectural Acoustics), "Introduces: EN ISO 16283-1:2014 [IDT], ISO 16283-1:2014 [IDT]", "Supersedes: PN-EN ISO 140-5:1999, PN-EN ISO 140-14:2006, PN-EN ISO 140-4:2000, PN-EN ISO 140-7:2000"; amendment PN-EN ISO 16283-1:2014-05/A1:2018-02 (EN ISO 16283-1:2014/A1:2017) according to its card supplements clause 3.14 and changes, among others, 4.1, 4.2, 8.2.1, 8.5 and 9.2. Measurement of noise from service equipment in buildings (PN-EN ISO 16032, PN-EN ISO 10052) has separate Knowledge Base entries.

WHAT WE DO NOT GIVE. The preview ends before the annexes, so we do not give the content of the annexes (A — requirements for the sound source, B — measurements in octave bands, C–F — informative, including the forms of Annex E) or the precision requirements according to ISO 140-2 beyond the principle in Clause 7.

Method principle

In the source room a loudspeaker generates steady noise with a continuous spectrum; in the source and receiving rooms the energy-averaged sound pressure levels L1 and L2 are measured in one-third-octave bands (at least 100–3150 Hz), and in the receiving room the reverberation time T, from which the absorption area A = 0.16 V/T is obtained. From the level difference D = L1 − L2 the normalized difference Dn (A0 = 10 m²), the standardized DnT (T0 = 0.5 s) or the apparent sound reduction index R′ = D + 10 lg (S/A) is calculated, after background correction; single-number ratings — according to ISO 717-1 (ISO 140-4:1998, clauses 1–9).

Applications

• Interior walls, floors and doors between rooms in buildings — checking sound insulation against requirements (12 laboratories)
• Comparison of sound insulation between rooms; comparison with laboratory results — with a common partition of about 10 m²

Key parameters

Standard

Standard number

PN-EN ISO 140-4:2000 (wersja polska; EN ISO 140-4:1998, ISO 140-4:1998 IDT)

Title (PL)

Akustyka — Pomiar izolacyjności akustycznej w budynkach i izolacyjności akustycznej elementów budowlanych — Pomiary terenowe izolacyjności od dźwięków powietrznych między pomieszczeniami

Title (EN)

Acoustics — Measurement of sound insulation in buildings and of building elements — Part 4: Field measurements of airborne sound insulation between rooms

Step-by-step procedure

1. Preparation

   Choice of the source room (the larger one when DnT is required), diffusers in empty rooms of identical shape; calibration of the measuring chain.

2. Levels in the rooms

   Noise in the source room (differences between adjacent one-third octaves ≤ 6 dB); measurement of L1 and L2 at ≥ 5 fixed microphone positions or with a moving microphone; one loudspeaker — at least two positions.

3. Background

   Measurement of background noise in the receiving room; correction for a difference of 6–10 dB, with ≤ 6 dB — 1.3 dB and a note on the limit of measurement.

4. Reverberation time

   In the receiving room according to ISO 354; absorption area A = 0.16 V/T.

5. Results

   Dn, DnT or R′ in one-third-octave bands to 0.1 dB, in a table and a graph; octave bands — from three one-third octaves using equations (9)–(11); for a repeated measurement of R′ — the arithmetic mean; report according to Clause 9; single-number ratings according to ISO 717-1, noting that the result comes from a field method.

Required equipment and apparatus

Health and safety (OHS)

• Measurements with a high-power loudspeaker — hearing protection for persons in the source room and advance notice to building occupants
• SUBSTANTIVE NOTE: the standard is withdrawn and replaced by PN-EN ISO 16283-1 — 10 of 12 laboratories cite both in the same entry; when asking for the test, establish under which standard the result will be expressed

Frequently asked questions