🏗️ Impact sound insulation of floors in buildings — field measurement with a standard tapping machine in the source room and microphones in the receiving room, in one-third-octave bands 100–3 150 Hz: normalized impact sound pressure level L′n and standardized impact sound pressure level L′nT, PN-EN ISO 140-7

Construction PN-EN ISO 140-7

Overview

WHAT THE STANDARD COVERS. Scope from the PKN catalogue card of PN-EN ISO 140-7:2000 (Polish version), in full (our translation): “Field methods for measuring the impact sound insulation of floors using a standard tapping machine are specified. Definitions of the following terms are given: average sound pressure level in a room, impact sound pressure level, normalized impact sound pressure level, standardized impact sound pressure level, reduction of impact sound pressure level”. We read the text in the sample of ISO 140-7:1998 (introduced by PN-EN ISO 140-7:2000 without changes, IDT) from the cover to the end of Annex A (requirements for the tapping machine); we do not have Annexes B–E (among others B — octave band measurements, C — low frequencies, D — forms).

ACCORDING TO THE TEXT OF ISO 140-7:1998. The standard was prepared by ISO/TC 43 “Acoustics”, subcommittee SC 2 “Building acoustics”; the second edition replaced the first (ISO 140-7:1978) after a technical revision. Scope (1): field methods for measuring the impact sound insulation properties of floors using a standard tapping machine, for bare floors and floors with coverings; the results are used to compare floors and to compare the apparent insulation with requirements. Laboratory measurements of floors — ISO 140-6, reduction of impact sound by coverings on a heavyweight standard floor — ISO 140-8. Quantities (3): average sound pressure level in a room L — energy average over n positions, L = 10 lg[(1/n)·Σ10^(Lj/10)] dB, excluding the near field of the source and boundaries; impact sound pressure level Li — average level in a one-third-octave band in the receiving room when the floor is excited by the tapping machine; normalized impact sound pressure level L′n = Li + 10 lg(A/A0) dB, A0 = 10 m²; standardized impact sound pressure level L′nT = Li − 10 lg(T/T0) dB, for dwellings T0 = 0.5 s (equivalent to a reference absorption area A0 = 0.32 V); reduction of impact sound pressure level ΔL′ — difference of levels in the receiving room before and after installation of e.g. a floor covering. Equipment (4): tapping machine according to Annex A; sound level meters of class 0 or 1 according to IEC 60651 and IEC 60804; adjustment of the complete measuring chain with the microphone before each measurement using a class 1 calibrator according to IEC 60942 (unless the manufacturer states otherwise); diffuse-field correction for meters calibrated in plane progressive waves; filters according to IEC 61260; reverberation time measurement according to ISO 354. Procedure (5): measurements in one-third-octave bands, in octave bands only by agreement (Annex B; single-number results are then not directly comparable with one-third-octave results). Tapping machine in at least four randomly distributed positions, at least 0.5 m from the edges of the floor; for anisotropic floors (ribs, beams) more positions, with the hammer line at 45° to the beams or ribs; if the level changes after the tapping starts, measurement begins only once it is steady, and if it does not become steady within 5 min — over a defined period, stated in the report. Microphone: distances of at least 0.7 m between positions, 0.5 m from boundaries and diffusers, 1.0 m from the excited floor; at least 4 fixed positions, evenly distributed, or a moving microphone with a sweep radius of at least 0.7 m, a plane not within 10° of any room plane and a traverse period of at least 15 s. Number of measurements: with fixed microphones at least 6, combining at least 4 microphone positions and 4 tapping machine positions; with a moving microphone at least 4 (e.g. one per tapping machine position). Averaging time: at least 6 s in bands below 400 Hz, at least 4 s above; moving microphone — a whole number of traverses, not less than 30 s. Mandatory bands: one-third octaves from 100 to 3 150 Hz; additionally recommended 4 000 and 5 000 Hz (for comparison with ISO 140-6), and where low-frequency information is required 50, 63 and 80 Hz (Annex C). Absorption area from the reverberation time (ISO 354) using Sabine’s formula A = 0.16 V/T; decay evaluation from about 0.1 s after the source is switched off, over a range of at least 20 dB whose bottom is at least 10 dB above background; at least 6 decays per band (at least one loudspeaker, three microphone positions, two readings each). Background: at least 6 dB (preferably more than 10 dB) below the level of signal plus background; at a difference of 6–10 dB the correction L = 10 lg(10^(Lsb/10) − 10^(Lb/10)) dB; at a difference of 6 dB or less in any band the correction 1.3 dB is applied and the result is reported as a measurement limit (L′n ≤ … dB); electrical noise is checked with a dummy microphone; airborne sound from the tapping machine transmitted to the receiving room must not influence the result. Precision (6): repeatability according to ISO 140-2, verified from time to time, especially after a change in procedure or instrumentation. Results (7): L′n or L′nT in all bands, to one decimal place, in a table and as a graph (5 mm per one-third octave, 20 mm per 10 dB); conversion to octaves — energy sum of three one-third octaves; if the test is repeated — arithmetic mean. Test report (8): among others the volume of the receiving room, L′n or L′nT as a function of frequency, limit results, flanking transmission (if measured); single-number rating according to ISO 717-2, stating clearly that it is based on a field measurement. Tapping machine (Annex A): five hammers in a line, centre-line spacing (100 ± 3) mm, at least 100 mm from the centre of the supports (with vibration-isolating pads); momentum of each hammer as that of an effective mass of 500 g falling freely from 40 mm, momentum tolerance ±5 %; hammer mass (500 ± 12) g; falling direction perpendicular to the surface within ±0.5°; impact part cylindrical with a diameter of (30 ± 0.2) mm, surface of hardened steel, spherical with a radius of (500 ± 100) mm; mean time between impacts (100 ± 5) ms, time between successive impacts (100 ± 20) ms, time between impact and lift of the hammer less than 80 ms; for soft or uneven coverings the hammers must be able to fall at least 4 mm below the plane of the supports, and for very soft coverings pads under the supports are allowed to keep the 40 mm height; adjustment and verification on a flat hard surface (flatness ±0.1 mm, level ±0.1°), at regular intervals.

STATUS (PKN catalogue cards as of 02.10.2026). The card of PN-EN ISO 140-7:2000 (Polish version, published 11-01-2000, 22 pages, price group L) has the header “Withdrawn and replaced by PN-EN ISO 16283-1:2014-05”: Building and Construction Sector, KT 253 Architectural Acoustics, ICS 91.120.20, “Introduces: EN ISO 140-7:1998 [IDT], ISO 140-7:1998 [IDT]”, “Replaces: PN-B-02154-07:1983”, withdrawal date 18-06-2019; in the additional information: “Standard withdrawn on 2014-05-06 and then restored to current status on 2015-09-09 by the President of the Polish Committee for Standardization in accordance with Communication No. 1/2015 of 9 September 2015”. The card of PN-EN ISO 16283-1:2014-05 (Polish version, published 18-06-2019, 52 pages, no “Withdrawn” header) has the title “Part 1: Airborne sound insulation”, lists PN-EN ISO 140-5, 140-14, 140-4 and 140-7 in “Replaces”, and amendment A1:2018-02 in “Additional elements”. Impact sound is covered by Part 2: the card of PN-EN ISO 16283-2:2021-02 (Polish version, published 07-02-2025, 56 pages, no “Withdrawn” header, EN ISO 16283-2:2020 [IDT]) has the scope “procedures for determining the impact sound insulation using sound pressure measurements with an impact source operating on a floor or stairs”, for rooms from 10 m³ to 250 m³ and frequencies from 50 Hz to 5 000 Hz; earlier editions of this part: 2016-02 (withdrawn 04-09-2018) and 2018-09 (withdrawn 04-02-2021), none of which lists PN-EN ISO 140-7 under “Replaces”. The PKN search engine (query “PN-EN ISO 140-7”, 02.10.2026) shows only the 2000 (p) edition. EVS: ISO 140-7:1998 “Withdrawn”, with ISO 140-7:1978, ISO 16283-1:2014 and ISO 16283-2:2015 in its history.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17.09.2026, read 02.10.2026). The number 140-7 appears in 11 records of 9 laboratories: AB 023, AB 796, AB 818, AB 838, AB 869, AB 1162, AB 1271, AB 1391, AB 1924. In the current scopes on the PCA website (read 02.10.2026, issues from 07.02.2025 to 28.07.2026) all 9 cite PN-EN ISO 140-7:2000. In 8 of them the same entry also cites PN-EN ISO 16283-2 — 7 the 2021-02 edition (AB 818 without exclusions, AB 1271 excluding clause 7.2.3, AB 796, AB 869, AB 1162 and AB 1924 excluding clauses 7.2.3 and 7.4, AB 838 — 7.2.3, 7.4 and 13), AB 1391 the 2016-02 edition, withdrawn on 04-09-2018, excluding clauses 7.4 and 7.5; AB 023 has PN-EN ISO 16283-2 in a separate entry. The “Laboratories” tab: “PN-EN ISO 140-7” — 8 laboratories (all except AB 1162) — checked with a query of the tab on the labcoda.pl production server on 02.10.2026.

WHAT THE LABORATORIES TEST (PCA entries). “Normalized impact sound pressure level L’n and standardized impact sound pressure level L’nT in 1/3 octave bands” (AB 838, AB 869, AB 1162, AB 1271), “Apparent normalized impact sound pressure level L’n and standardized impact sound pressure level L’nT” (AB 796; AB 1924 — in octave and/or one-third-octave bands), “Impact sound insulation of floors” (AB 023, AB 818), “Sound pressure level in 1/3 octave bands” (AB 1391), weighted ratings L’n,w and L’nT,w and the spectrum adaptation term CI (from calculation); frequency ranges (100–5 000) Hz (AB 023 and AB 818 with the option of 50, 63 and 80 Hz; AB 1924) or (50–5 000) Hz; “Field measurement method under diffuse field conditions” (AB 796, AB 869), “Field measurement method” (AB 838, AB 1162), “In situ method” (AB 1271).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. With the successor: the PKN card names PN-EN ISO 16283-1 as the successor, i.e. the part on airborne sound — field measurements of impact sound are in PN-EN ISO 16283-2 (title and scope of the card), whose cards do not mention 140-7. With the quantity: L′n (to an absorption area of 10 m²) and L′nT (to a reverberation time of 0.5 s) are different numbers for the same floor; the report gives whichever is appropriate (Clause 8 g). With background noise: at a difference of 6 dB or less the result is only a measurement limit and must be given as L′n ≤ … dB (5.6, 8 i). With beamed floors: four positions may not be enough, and the hammer line is to be at 45° to the beams (5.2). With soft coverings: the tapping machine must meet the additional requirements of Annex A (hammers falling 4 mm below the plane of the supports). With octave bands: single-number results from octaves are not directly comparable with one-third-octave results (5.1). With the rating: the evaluation according to ISO 717-2 must clearly state that it is based on a field measurement (8).

WHAT WE DO NOT GIVE. We do not have Annexes B–E (octave procedure, low-frequency measurements, forms) or the text of PN-EN ISO 16283-2 — so we give neither the octave procedure nor the differences between ISO 140-7 and ISO 16283-2, nor the content of clauses 7.2.3, 7.4, 7.5 and 13 of that standard, which are excluded in the scopes. The standard contains no floor sound insulation requirements (limit values).

Method principle

A standard tapping machine operates on the floor under test — five hammers of 500 g with hardened-steel heads, falling freely from a height of 40 mm, on average every 100 ms. In the room below the floor, the average sound pressure level in one-third-octave bands (impact sound pressure level Li) is measured for several tapping machine and microphone positions, together with the reverberation time. The impact sound pressure level is normalized to a reference absorption area of 10 m² (L′n) or standardized to a reverberation time of 0.5 s (L′nT).

Applications

• Floors in buildings — field measurement in one-third-octave bands; 9 laboratories in PCA scopes
• Bare floors and floors with floor coverings, including soft ones — comparison of floors and comparison of apparent insulation with requirements
• Determination of the weighted ratings L′n,w and L′nT,w according to ISO 717-2 from field results

Key parameters

Standard

Standard number

PN-EN ISO 140-7:2000 (wersja polska; EN ISO 140-7:1998 IDT, ISO 140-7:1998 IDT) — wycofana 18-06-2019

Title (PL)

Akustyka — Pomiar izolacyjności akustycznej w budynkach i izolacyjności akustycznej elementów budowlanych — Pomiary terenowe izolacyjności od dźwięków uderzeniowych stropów

Title (EN)

Acoustics — Measurement of sound insulation in buildings and of building elements — Part 7: Field measurements of impact sound insulation of floors

Step-by-step procedure

1. Preparation

   Check of the tapping machine according to Annex A and calibration of the measuring chain with a class 1 calibrator; determination of the receiving room volume. PN-EN ISO 140-7:2000 withdrawn on 18-06-2019 (PKN cards as of 02.10.2026).

2. Excitation of the floor

   Tapping machine in at least 4 random positions, ≥ 0.5 m from the edges; with beams, hammer line at 45° and more positions; measurement after the level has become steady.

3. Measurement of the impact sound pressure level

   At least 4 microphone positions (0.7 m / 0.5 m / 1.0 m) and at least 6 measurements, or a moving microphone; one-third octaves 100–3 150 Hz; averaging ≥ 6 s below 400 Hz, ≥ 4 s above; energy average.

4. Reverberation time and background

   Reverberation time according to ISO 354 (≥ 6 decays per band, range ≥ 20 dB), absorption area A = 0.16 V/T; background measurement and correction according to Formula (5) or 1.3 dB with a limit result.

5. Result

   L′n or L′nT in each band to one decimal place, table and graph; single-number rating according to ISO 717-2 with a statement that it is based on a field measurement.

Required equipment and apparatus

Health and safety (OHS)

• The standard contains no safety warnings; long tapping can alter the surface of the covering — the standard then recommends a moving microphone with parallel measurement in all bands (5.3.4)
• TECHNICAL NOTE: the standard is withdrawn — for new tests check which standard the order or regulation specifies; in accreditation scopes PN-EN ISO 16283-2 is cited alongside it

Frequently asked questions