🏗️ Determination of single-number quantities for impact sound insulation of floors and between rooms (Ln,w, L′n,w, L′nT,w), the spectrum adaptation term CI and the weighted reduction in impact sound pressure level by floor coverings (ΔLw, ΔLt,w) from measurements in one-third-octave bands (ISO 10140-3, ISO 16283-2) or octave bands (field only) — shifting the reference curve in 1 dB steps (0,1 dB for uncertainty) to the largest sum of unfavourable deviations not exceeding 32,0 dB or 10,0 dB, reading at 500 Hz, PN-EN ISO 717-2

Construction PN-EN ISO 717-2

Overview

WHAT THE STANDARD COVERS. Scope from the PKN catalogue card of PN-EN ISO 717-2:2021-06 (English version; scope in Polish on the card), in full (our translation of the Polish card text): “This document a) defines single-number quantities for the impact sound insulation between rooms and the impact sound insulation of floors, b) describes the rules for determining these quantities from the results of measurements carried out in one-third-octave bands in accordance with EN ISO 10140-3 and ISO 16283-2 and in octave bands in accordance with ISO 16283-2, c) defines single-number quantities for the impact sound reduction of floor coverings (floating floors, floor coverings, lightweight floor coverings), determined from the results of measurements carried out in one-third-octave bands in accordance with EN ISO 10140-3, and d) specifies a procedure for determining the impact sound reduction of floor coverings on lightweight floors. The single-number quantities determined in accordance with this document serve to rate airborne sound insulation and to simplify the formulation of acoustic requirements in building codes. In addition, where needed, a single-number evaluation to 0,1 dB has been introduced to express uncertainty (except for spectrum adaptation terms). The values of the single-number quantities are specified as needed. The rating of measurements in an extended frequency range is described in Annex A. The method for determining single-number quantities for heavy slab floors with floor coverings is given in Annex B. Examples of the calculation of the single-number rating are given in Annex C. The rating of measurements with a heavy and soft sound source (rubber ball) is given in Annex D.” (The sentence about “airborne sound” stands like this on the card; the ISO text speaks here of impact sound insulation.) We read the text of the standard in the preview of ISO 717-2:2020 from the cover to clause 4.5 (page 6); we do not have Clauses 5 and 6 (reduction by floor coverings on heavy and lightweight floors) or Annexes A–D.

ACCORDING TO THE TEXT OF ISO 717-2:2020 (foreword, introduction, Clauses 1–4.5). The standard was prepared by ISO/TC 43/SC 2 together with CEN/TC 126 (Vienna Agreement). The fourth edition replaces the third (2013); main change — a new Annex D with a method for rating impact sound insulation with a heavy and soft source using the maximum A-weighted sound pressure level. Introduction: measurement methods according to ISO 10140-3 and ISO 16283-2 give frequency-dependent values; the standard converts them into a single number. Scope (Clause 1, as on the card): single-number quantities for buildings and floors; rules for determination from one-third-octave measurements (ISO 10140-3, ISO 16283-2) and octave measurements (option of ISO 16283-2, field measurements only); quantities for reduction by floor coverings and floating floors; procedure for floor coverings on lightweight floors; additional rating in 0,1 dB steps where uncertainty must be expressed (except spectrum adaptation terms). References: ISO 10140-1, ISO 10140-3:2010, ISO 10140-5, ISO 12999-1, ISO 16283-2:2018. Definitions (Clause 3): single-number quantity — value of the reference curve at 500 Hz after shifting according to 4.3.1, or at 500 Hz after shifting according to 4.3.2 reduced by 5 dB; CI — value added to the single-number quantity (e.g. Ln) to take account of the unweighted impact sound level and the spectrum of typical walking; weighted reduction in impact sound pressure level — ΔLw on a heavy reference floor, ΔLt,w (ΔLt1,w, ΔLt2,w, ΔLt3,w) on a lightweight one; Ln,eq,0,w — equivalent weighted normalized level of a bare heavy floor; L′iA,Fmax — maximum A-weighted sound pressure level with Fast time weighting for the rubber ball (averaged over all receiving points and source positions); L′iA,Fmax,V,T — with corrections for volume and reverberation time. Comparison (4.1): in the range 100–3150 Hz for one-third octaves or 125–2000 Hz for octaves; Table 1 — Ln,w from Ln (ISO 10140-3:2010, formula 1); Table 2 — L′n,w (ISO 16283-2:2018, formula 3) and L′nT,w (formula 1). Reference values (4.2, Table 3): one-third octaves 100–315 Hz — 62 dB; 400 — 61; 500 — 60; 630 — 59; 800 — 58; 1000 — 57; 1250 — 54; 1600 — 51; 2000 — 48; 2500 — 45; 3150 — 42 dB; octaves 125 — 67; 250 — 67; 500 — 65; 1000 — 62; 2000 — 49 dB; note: the energetic sum of the one-third octaves 800–1250 Hz is 61,41 dB, while the 1000 Hz octave value is 62 dB for consistency with older editions; the 2000 Hz value was reduced because of the 3150 Hz one-third octave, which for bare heavy floors can considerably increase unfavourable deviations. One-third octaves (4.3.1): data to one decimal place; the reference curve is shifted in 1 dB steps (0,1 dB for uncertainty) towards the measured curve until the sum of unfavourable deviations is as large as possible but not more than 32,0 dB; an unfavourable deviation — when the measured result exceeds the reference value, and only such deviations count; the value of the shifted curve at 500 Hz is Ln,w, L′n,w or L′nT,w; footnote 1: values with more decimal places are rounded to 0,1 dB before the calculation (multiply by 10, add 0,5, take the integer part, divide by 10) — this applies to the true values, not just the displayed ones. Octaves (4.3.2): sum of unfavourable deviations not more than 10,0 dB; the value at 500 Hz is reduced by 5 dB. Result (4.4): the single-number quantity with reference to the standard and the diagram according to ISO 10140-3 or ISO 16283-2; uncertainty may be stated according to ISO 12999-1 to one decimal place (example: Ln,w = 53,2 ± 1,0); adaptation terms have no uncertainty of their own; for field measurements it is stated whether the quantity was calculated from one-third octaves or octaves — differences of about ±1 dB, one-third-octave ratings are preferred. Rubber ball (4.5): the single-number quantity — maximum A-weighted level — is calculated according to Annex D.

STATUS (cards as of 02.10.2026). The card of PN-EN ISO 717-2:2021-06 (English version, published 11-06-2021, 36 pages, price group R) has no “Withdrawn” header: Construction and Building Structures Sector, KT 253 Architectural Acoustics, ICS 91.120.20, “Introduces: EN ISO 717-2:2020 [IDT], ISO 717-2:2020 [IDT]”, “Replaces: PN-EN ISO 717-2:2013-08 – English version”. The PKN search for “PN-EN ISO 717-2” (02.10.2026) also shows PN-EN ISO 717-2:1999 (Polish version), amendment A1 (English version 2006 and Polish 2008) and PN-EN ISO 717-2:2013-08 (English version).

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17.09.2026, read on 02.10.2026). The number 717-2 appears in 13 records at 7 laboratories: AB 796, AB 838, AB 869, AB 1162, AB 1271, AB 1391, AB 1924. In the current scopes on the PCA website (read on 02.10.2026, issues from 07.02.2025 to 28.07.2026) the number appears at all 7, almost always with several editions at once: only “2021-06” with the note “excluding Annex D” — AB 838; “1999” and “2021-06” — AB 796, AB 869, AB 1924; “1999”, “2013-08” and “2021-06” — AB 1162 and AB 1391; “2021-06” and “2013-08” — AB 1271, which for field measurement also lists “1999” and “1999/A1:2008”. No row is set in bold italics. The “Laboratories” tab searches for entries BEGINNING WITH “PN-EN ISO 717-2” and shows 5 laboratories (AB 796, AB 838, AB 869, AB 1271, AB 1924); at AB 1162 and AB 1391 the database entries begin with measurement standards (PN-EN ISO 10140-…, PN-EN ISO 140-7, PN-EN ISO 16283-2), so this tab does not show them — checked with a query of the tab on the production server labcoda.pl on 02.10.2026.

WHAT THE LABORATORIES TEST (items in the PCA scopes). Structures and building elements, ceilings and floors as construction products (AB 1271) — “weighted normalized impact sound pressure level L′n,w and weighted standardized impact sound pressure level L′nT,w and spectrum adaptation term CI (calculated)” after field measurement in one-third-octave bands 50–5000 Hz (AB 796, AB 838, AB 869, AB 1162, AB 1271, AB 1924 — the last 100–5000 Hz), in the laboratory Ln,w and CI and “weighted reduction in impact sound pressure level ΔLW and spectrum adaptation terms CIΔ and CIr” for floor coverings on a reference floor (AB 1162, AB 1271), “impact sound insulation of floors (calculated)” (AB 1391). Neighbouring standards in the same items: PN-EN ISO 16283-2, PN-EN ISO 140-7, PN-EN ISO 10140-1 and -3.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. Shifting: the sum of unfavourable deviations must be the LARGEST, but not more than 32,0 dB (one-third octaves) — stopping earlier gives a quantity 1 dB or more too low or too high. Sign: only bands in which the MEASURED level exceeds the reference count (in impact sound insulation a lower level is a better result). Octaves: limit 10,0 dB and subtraction of 5 dB from the value at 500 Hz; octaves may be used only in field measurements and this must be stated in the report. Rounding: input data are rounded to 0,1 dB before the calculation, not only on the screen. Uncertainty: CI has no uncertainty of its own. Edition: AB 838 excludes Annex D — rating with the rubber ball is not covered by accreditation there; laboratories listing the 1999 or 2013-08 edition next to 2021-06 calculate with the same curve principle, but the 2020 edition has the additional Annex D.

WHAT WE DO NOT GIVE. We do not have Clauses 5 and 6 (reference floors and calculation of ΔLw, ΔLt,w) or Annexes A–D, including the CI formulae and the method for the rubber ball — so we do not give formulae for the adaptation terms, reference floor curves or the way L′iA,Fmax,V,T is determined.

Method principle

Impact sound pressure level results in one-third-octave bands (100–3150 Hz) or octave bands (125–2000 Hz) are compared with a reference curve shifted in 1 dB steps until the sum of unfavourable deviations is the largest, but not more than 32,0 dB or 10,0 dB; the single-number quantity is the value of the shifted curve at 500 Hz (for octaves minus 5 dB).

Applications

• Field measurements of floors in buildings (L′n,w, L′nT,w) — 7 laboratories in the PCA scopes
• Laboratory measurements of floors and floor coverings (Ln,w, ΔLw) on a reference floor
• Acoustic requirements in building regulations — comparison with the permissible value

Key parameters

Standard

Standard number

PN-EN ISO 717-2:2021-06 (wersja angielska; EN ISO 717-2:2020 IDT, ISO 717-2:2020 IDT)

Title (PL)

Akustyka — Ocena izolacyjności akustycznej w budynkach i izolacyjności akustycznej elementów budowlanych — Część 2: Izolacyjność od dźwięków uderzeniowych

Title (EN)

Acoustics — Rating of sound insulation in buildings and of building elements — Part 2: Impact sound insulation

Step-by-step procedure

1. Input data

   Impact sound levels in one-third-octave bands 100–3150 Hz (or octave bands 125–2000 Hz in the field), rounded to 0,1 dB. PN-EN ISO 717-2:2021-06 current (cards as of 02.10.2026).

2. Reference curve

   Values from Table 3 (one-third octaves 62…42 dB, octaves 67…49 dB).

3. Shifting

   Shift the curve in 1 dB steps towards the results, counting only bands in which the result exceeds the reference, until the sum is the largest but ≤ 32,0 dB (one-third octaves) or ≤ 10,0 dB (octaves).

4. Reading

   Quantity = value of the shifted curve at 500 Hz (for octaves minus 5 dB); if uncertainty is needed — 0,1 dB step and uncertainty according to ISO 12999-1.

5. Result

   Quantity with reference to the standard, diagram according to the measurement standard; in the field — whether from one-third octaves or octaves; rubber ball — according to Annex D.

Required equipment and apparatus

Health and safety (OHS)

• The standard is a calculation standard — it contains no safety warnings itself; hazards arise from the measurement (tapping machine, work in buildings) according to the measurement standards
• TECHNICAL NOTE: the sum of unfavourable deviations must be as large as possible, but not more than 32,0 dB; for octaves 10,0 dB and subtraction of 5 dB; octaves only in field measurements

Frequently asked questions