🌿 Environmental noise measurement

Environmental PN-ISO 1996

Overview

STATUS (as of 02.11.2026). PN-ISO 1996-1:2006 — Polish version, published on 13.12.2006, “Akustyka — Opis, pomiary i ocena hałasu środowiskowego — Część 1: Wielkości podstawowe i procedury oceny” (Acoustics — Description, measurement and assessment of environmental noise — Part 1: Basic quantities and assessment procedures), implements ISO 1996-1:2003 [IDT]; it replaced PN-ISO 1996-1:1999. PN-ISO 1996-2:1999 — Polish version, published on 12.03.1999, “Akustyka — Opis i pomiary hałasu środowiskowego — Zbieranie danych dotyczących sposobu zagospodarowania terenu” (Acoustics — Description and measurement of environmental noise — Acquisition of data pertinent to land use), implements ISO 1996-2:1987 [IDT], with an erratum and the amendment PN-ISO 1996-2:1999/A1:2002 (6.12.2002, implements ISO 1996-2:1987/Amd 1:1998 — corrections for impulsive sounds). Neither card has a withdrawal note; the PKN catalogue does not know the designation “PN-ISO 1996-2:2017”. The newer ISO editions have not been adopted as Polish Standards: ISO 1996-1:2016 (third edition, replaced ISO 1996-1:2003) and ISO 1996-2:2017 (third edition, replaced ISO 1996-2:2007, with the subject “determination of sound pressure levels”), both confirmed in ISO (stage 90.93). The content of both parts is described below according to these ISO editions.

PART 1 — QUANTITIES AND ASSESSMENT (ISO 1996-1:2016, clauses 1 and 3). It defines the basic quantities to be used for the description of noise in community environments and the basic assessment procedures, describes methods to assess environmental noise and gives guidance on predicting the potential annoyance response to long-term exposure. Sounds with different characteristics — impulsive, tonal, with a strong low-frequency content — receive adjustments, and the adjusted result is the “rating level”. Part 1 does not specify limits. The A-weighted equivalent continuous sound pressure level, LAeq,T, is ten times the logarithm to the base 10 of the ratio of the time-mean square of the A-weighted sound pressure over the time interval T to the square of the reference value p₀ = 20 µPa, in dB.

PART 2 — DETERMINATION OF LEVELS (ISO 1996-2:2017, clauses 1, 4, 6). It describes how sound pressure levels serving as a basis for assessing environmental noise limits or for comparing scenarios in spatial studies are determined — by direct measurement and by extrapolation of measurement results by means of calculation, primarily outdoors, with some guidance for indoor measurements, for all kinds of sources: road and rail traffic, aircraft and industry. The effort, and hence the uncertainty, is decided by the user; the uncertainty is determined according to GUM and stated in every case — the standard sets no upper limit for it. There are two strategies: a single measurement under well-defined meteorological conditions with careful control of source operation, or a long-term measurement, or many measurements spread over time, with the meteorological conditions recorded. A short-term measurement usually lasts from 10 min to a few hours, a long-term one from a month to a year.

INSTRUMENTS AND CALIBRATION (ISO 1996-2:2017, clause 5). The measuring chain, including the microphone, cables, windscreen and recorder, meets the class 1 requirements of IEC 61672-1, and the filters class 1 of IEC 61260; outdoors a windscreen is always used. At the beginning and at the end of every measurement the whole chain is checked with a class 1 sound calibrator according to IEC 60942: the difference between two consecutive checks, without adjustment, is at most 0.5 dB, otherwise the results obtained since the last correct check are discarded. Compliance of the meter, filters and calibrator is confirmed by a certificate of a laboratory meeting ISO/IEC 17025; the recommended interval between verifications is one year, the longest permissible 2 years. In the uncertainty budget the standard uncertainty of a class 1 meter is 0.5 dB, of a class 2 meter 1.5 dB (Table 1).

PERMISSIBLE NOISE LEVELS. Regulation of the Minister of the Environment of 14.06.2007 on permissible noise levels in the environment (consolidated text: Dz.U. 2014 item 112), Table 1, indicators LAeq D and LAeq N: for roads and railway lines the reference time interval is the 16 hours of the day and the 8 hours of the night, for other facilities and activities — the 8 least favourable consecutive hours of the day and the 1 least favourable hour of the night. E.g. single-family housing areas: roads and railways 61 / 56 dB, other facilities 50 / 40 dB; multi-family housing: 65 / 56 dB and 55 / 45 dB. Tables 3–4 (indicators LDWN and LN) serve long-term noise protection policy.

REFERENCE METHODOLOGY FOR INSTALLATIONS. Regulation of the Minister of Climate and Environment on the requirements for emission measurements (consolidated text: Dz.U. 2023 item 1706), § 8 and Annex 7: periodic measurements of noise from installations and equipment for which a decision on the permissible noise level or an integrated permit has been issued are carried out once every two years. Accuracy class 1 meters, reference sound sources of at least class 1, calibration certificates not older than 24 months, windscreens regardless of the weather. Points: in undeveloped areas 1.5 m above the ground, at protected buildings 0.5–2 m from the façade in front of a window opening or 4 m ± 0.2 m above the ground. Meteorological conditions, measured at least 3.5 m above the ground: temperature from −10 °C to 50 °C, humidity 25–90 %, mean wind speed up to 5 m/s, pressure 900–1100 hPa. A-weighting, time constant F; continuous recording over the reference time T (8 h in the daytime 6.00–22.00, 1 h at night 22.00–6.00) or the sampling method. Background noise is subtracted energetically; when the difference between the level and the background is less than 3 dB, the level is determined by calculation according to PN ISO 9613-2. For a point 0.5–2 m from a closed or tilted window the result is reduced by 3 dB; the result is valid when the expanded uncertainty U95 does not exceed 2.7 dB.

WHAT WE DO NOT GIVE HERE. We have not read the texts of PN-ISO 1996-1:2006 and PN-ISO 1996-2:1999 with A1:2002 — we do not describe differences from the ISO editions of 2016 and 2017; Part 2 adopted as a Polish Standard has a different subject (acquisition of data on land use). Of ISO 1996-2:2017 clauses 1–6 and the beginning of clause 7 (operation of the source: road and rail traffic) are available; operation of air traffic and industrial plants (7.4–7.5), meteorological conditions (clause 8), microphone location and measurement procedures (clause 9), processing of results with the residual sound correction (clause 10), extrapolation and calculation (clauses 11–12) are outside this text — microphone heights, weather conditions and the handling of background noise are given according to the Polish reference methodology for installations, not according to the standard.

Method principle

A sound level meter measures the sound pressure with frequency weighting A and averages it over the time interval T: the A-weighted equivalent continuous sound pressure level, LAeq,T, is ten times the logarithm to the base 10 of the ratio of the mean square of that pressure to the square of the reference pressure of 20 µPa (ISO 1996-1:2016, clause 3).

Levels are determined by direct measurement or by extrapolation of measurements by calculation; every result requires data processing and a statement of the uncertainty, determined according to GUM (ISO 1996-2:2017, clauses 1, 4, 6).

Applications

• Determination of sound pressure levels as a basis for assessing permissible noise levels — road and rail traffic, aircraft, industry (ISO 1996-2:2017, clause 1)
• Control of permissible noise levels in the environment — indicators LAeq D and LAeq N (Regulation of the Minister of the Environment of 14.06.2007, consolidated text Dz.U. 2014 item 112)
• Periodic measurements of noise from installations and equipment with a decision on the permissible noise level or an integrated permit — once every two years (consolidated text Dz.U. 2023 item 1706, § 8 and Annex 7)
• Long-term noise protection policy — indicators LDWN and LN (Tables 3–4 of the 2007 regulation)
• Noise assessment with adjustments for impulsiveness, tonality and low frequencies — rating level (ISO 1996-1:2016, clause 1)

Key parameters

Standard

Standard number

PN-ISO 1996-1:2006, PN-ISO 1996-2:1999 + A1:2002

Title (PL)

Akustyka — Opis, pomiary i ocena hałasu środowiskowego

Title (EN)

Acoustics — Description, measurement and assessment of environmental noise

Step-by-step procedure

1. Strategy and reference time

   A single measurement under defined meteorological conditions with control of source operation or a long-term measurement with weather recording (ISO 1996-2:2017, clause 6); reference time according to the regulation on permissible noise levels (Table 1).

2. Measurement point (installations)

   Undeveloped area — 1.5 m above the ground; at protected buildings — 0.5–2 m from the façade in front of a window opening or 4 m ± 0.2 m above the ground (reference methodology, Annex 7 part B).

3. Check of the chain before measurement

   With a class 1 calibrator according to IEC 60942 (ISO 1996-2:2017, 5.2).

4. Measurement

   A-weighting, time constant F; continuous recording over the reference time T or the sampling method; temperature from −10 °C to 50 °C, humidity 25–90 %, mean wind speed up to 5 m/s, pressure 900–1100 hPa (Annex 7 parts D–E).

5. Background noise

   At the same points after the source has been switched off or during breaks in its operation, possibly at a comparable location, on the same day, at the same time of day and in similar weather; the background is subtracted energetically, and for a difference of less than 3 dB — the calculation method (Annex 7 part E).

6. Check of the chain after measurement

   Difference between two consecutive checks at most 0.5 dB, otherwise the results obtained since the last correct check are discarded (ISO 1996-2:2017, 5.2).

7. Result and uncertainty

   LAeq D or LAeq N with the expanded uncertainty U95 (valid at U95 not exceeding 2.7 dB); for a point 0.5–2 m from a closed or tilted window the result is reduced by 3 dB; comparison with the permissible level for the type of area (Annex 7 parts A and E; 2007 regulation, Table 1).

Required equipment and apparatus

Health and safety (OHS)

• In the available text the standard gives no safety warnings

Frequently asked questions