🌿 Noise from the service equipment of a building — the engineering method: one-third-octave spectrum, class 1, background correction and standardisation to the reverberation time

Environment PN-EN ISO 16032

Overview

The document specifies the engineering method of measuring the sound pressure level in rooms, originating from service equipment installed in the building. The scope covers in particular sanitary installations, mechanical ventilation, heating and cooling equipment, lifts, refuse chutes, blowers, pumps and other auxiliary service equipment, and automatic garage doors. The 2024 edition extended the scope to sounds from other kinds of equipment or from activities carried out in the building — today the standard can be applied for example to noise from sports facilities or restaurants in the same building. The measurement of noise from external sound sources which generate in the building noise transmitted through the air or through the ground [so on the card; the card does not decide whether „podłoże" means here the ground or the structure of the building — in translations we render it literally] is excluded from the scope. The methods are suitable for rooms of about 300 m³ or less — dwellings, hotels, schools, offices, hospitals — and are not intended for large auditoria and concert halls.

What it is for: the introduction to the standard gives the reason plainly — many countries have building regulations protecting people against noise in dwellings and workplaces, and to demonstrate compliance with those regulations a standardised method of measuring the sound pressure level from service equipment or activities in a building is needed, carried out under defined operating conditions and cycles. In Poland the regulation in question is the technical conditions: § 326(1) of the regulation lays down that the level of noise and vibration penetrating into rooms in residential buildings, buildings of collective residence and public buildings must not exceed the permissible values specified in Polish Standards, determined in accordance with the Polish Standards concerning the method of measuring the A-weighted sound level in rooms. Annex 1 to the regulation, in the wording in force since 1 August 2024, links § 326(1) and (4) with two measuring standards at once: PN-EN ISO 10052 (the survey method) and PN-EN ISO 16032 (the engineering method), and takes the permissible sound levels in rooms from PN-B-02151-2:2018-01.

When the engineering method and when the survey method — this is the most important decision before setting out for the site. Both standards answer the same question ("how loud is it in the room when the building equipment is working"), but they differ in cost, time and resolution. The survey method according to PN-EN ISO 10052 is a screening method: a hand-held meter, sweeping with the microphone, a reverberation correction that may be taken from tables, the result at once as an A- or C-weighted sound level, and an uncertainty which — as the standard itself stipulates — is by assumption greater than in engineering-grade methods. The engineering method according to PN-EN ISO 16032 requires a one-third-octave analyser recording all bands simultaneously, an instrument and filters of class 1, a measurement of the reverberation time according to ISO 3382-2 and a calculation carried out on the spectrum, not on a reading from a meter. It is resorted to when the survey method does not suffice: in disputed and acceptance cases, when the result is to serve as evidence, when the difference between the noise and the background is small or the levels are very low, when the character of the noise has to be recognised (a tonal or low-frequency component) and the bands which decide the annoyance have to be identified, and when the room is larger than 150 m³ — because there the survey method simply does not apply. The Building Research Institute (ITB), assessing both methods even before they were introduced into the regulations, described the engineering method as very time-consuming, requiring real-time analysers with a low inherent noise level and a large memory buffer, and tests for a considerably larger number of measuring cycles, but at the same time as the only one which makes it possible to establish the occurrence of the noise and to determine its annoyance even at A-weighted sound levels of the order of 20–25 dB and with a small difference between the noise and the background.

Status of the standard and the trap of editions. The current edition is PN-EN ISO 16032:2024-09 (implementing EN ISO 16032:2024 and ISO 16032:2024), published on 2 September 2024 in the English version (34 pages), and on 23 January 2026 also in the Polish version (32 pages); it is managed by KT 253 for Architectural Acoustics. It superseded PN-EN ISO 16032:2006 — a standard published on 6 September 2006 and withdrawn on 2 September 2024. A practical note for the laboratory: Annex 1 to the technical conditions still cites PN-EN ISO 16032:2006, that is the withdrawn edition, as it does the withdrawn PN-EN ISO 10052:2007. The divergence between the regulation and the PKN catalogue has to be resolved consciously in the test report, stating which edition was used in the measurement. The second trap is purely catalogue-related: for the 2024 edition a corrigendum PN-EN ISO 16032:2024-09/Ap1:2025-05E was issued which — as the card notes — changes the title of the standard; the corrigendum appears on the card of the English version and no longer on the card of the Polish version, so checking the status from only one language version leads one astray.

What this description does not contain: we have not seen the full text of the standard — PKN and ISO supply it for a fee. The scope, the list of normative references, the definitions, the requirements for the apparatus and the general course of the method are given from the preview of ISO 16032:2024 (clauses 1–5), and not from the full edition. The details of clause 6 (the number and arrangement of microphone positions, the way of measuring the background in 6.6), of clause 7 (reverberation time), of clause 9 (precision) and of Annex B (the operating conditions and cycles of individual pieces of equipment) are not in the preview and we do not reproduce them here. Wherever figures from the edition PN-EN ISO 16032:2006 appear below — three measuring positions, octave bands 63–8000 Hz for the reverberation time (for the levels themselves the 2004 edition gives 31.5/63 Hz–8000 Hz), a threshold of 10 dB above the background, the operating cycle of a lift — this is expressly marked, because in the 2024 edition some of these provisions have changed (the measurement was moved to one-third-octave bands, and the procedure for detecting and averaging spatial and temporal variations of the sound was revised).

THE ENGINEERING METHOD IS NOT CHOSEN INSTEAD OF THE SURVEY METHOD, BUT ADDED TO IT — MEASUREMENT ON THE SCOPES (23.09.2026). The provision links both documents and leaves the laboratory a choice; the accreditation scopes show that in fact there is no choice. PN-EN ISO 10052 (the survey method) stands at 23 laboratories, PN-EN ISO 16032 (the engineering method) at 11 — and ALL ELEVEN have the survey method alongside. There is not a single laboratory accredited for the engineering method without the survey method; the other way round there are twelve.

THE UNIT OF ADJACENCY — THREE LEVELS, THREE DIFFERENT ANSWERS. The question "do laboratories have both standards at once" has three different answers depending on what we count as adjacency. In the same VALUE of the reference-document field: one case — AB 023 entered "PN-EN ISO 16032 PN-EN ISO 10052" as one string. In the same ENTRY of the scope (document): also this one. At the same LABORATORY, even in distant entries: eleven. The difference between the first and the third figure is elevenfold, and all three are true — which is why with every co-occurrence figure one has to say which level it refers to.

THE SAME MEASUREMENT SHOWS A MATCHING TRAP THAT NEARLY CHANGED THE CONCLUSION. Counting by the BEGINNING of the string, 22 laboratories have the survey method and ten have both; it would therefore follow that one laboratory (AB 023) has the engineering method without the survey method, i.e. that an exception exists. The exception is illusory: AB 023 has both, only in one value beginning with "PN-EN ISO 16032", so prefix matching does not see the second designation. After counting by the core — 23 and 11, without exceptions. The thesis therefore holds only with matching that is robust to the adjacency of two designations in one line.

Method principle

The sound pressure level from a piece of service equipment or from an activity in the building is measured at a fixed microphone position as a linear (unweighted) spectrum in one-third-octave bands, over a given interval of time or during a given operating cycle of the equipment under test. When determining the maximum level with the time weighting "S" or "F", the one-third-octave levels are recorded exactly at the moment when the instrument indicates the maximum of the A- or C-weighted sound level at the given microphone position; the equivalent level Leq is determined with an averaging time according to the guidance of Annex B of the standard or according to national requirements, if such exist. The levels measured at the different microphone positions serve to calculate the average sound pressure level in one-third-octave bands, and this in turn is corrected for the background noise. Only the corrected spectrum is then standardised to the reference reverberation time T₀ = 0.5 s (LnT = L − 10 lg T/T₀) or normalised to the reference absorption area A₀ = 10 m² (Ln = L − 10 lg [A₀T/(0.16 V)], where V is the volume of the room), unless a national regulation demands uncorrected levels only. At the end — and only at the end — the A-weighted and the C-weighted sound level are calculated from the bands thus prepared, by summing energetically the bands with the A and C weightings from Annex A of the standard. The order matters: in this method the A-weighted sound level is not a reading from a meter but the result of a calculation on the spectrum, and that is precisely where the differences from methods reading the A-weighted level directly come from.

Applications

• Acceptance testing of residential buildings, hotels, schools, offices and hospitals — demonstrating compliance with § 326 of the technical conditions as regards noise from service equipment
• Disputed and complaint cases in which the result of the survey method is contested or the difference from the permissible value is smaller than the uncertainty of the screening method
• Complaints about noise from ventilation, a heat substation, a heat pump, a pressure-booster set, a lift or a garage door penetrating into a dwelling
• Noise from activities in the building — a catering establishment, a club, a sports facility in the same structure (a scope added in the 2024 edition)
• Acoustic diagnosis of installations: identifying the bands which decide the annoyance, recognising a tonal or low-frequency component before designing a silencer or vibration isolation
• Comparative testing and calibration of the laboratory’s own procedures against the survey method PN-EN ISO 10052

Key parameters

Standard

Standard number

PN-EN ISO 16032:2024-09

Title (PL)

Akustyka — Pomiar poziomu ciśnienia akustycznego od urządzeń wyposażenia technicznego lub aktywności wykonywanych w budynkach — Metoda dokładna

Title (EN)

Acoustics — Measurement of sound pressure level from service equipment or activities in buildings — Engineering method

Step-by-step procedure

1. Establishing the subject of the test and the method

   Decide whether the case requires the engineering method or whether the survey method according to PN-EN ISO 10052 will suffice: the engineering method is chosen for disputed and acceptance cases, where the difference between the noise and the background is small, where the levels are very low, where the character of the spectrum has to be recognised, and in rooms larger than 150 m³. Check whether the source falls within the scope of the standard — noise from external sources transmitted through the air or through the ground is excluded from it (on the ambiguity of the word „podłoże" — see the proviso in the description).

2. Reconnaissance of the site

   Establish the volume of the room (the standard says that the methods are SUITABLE for rooms of about 300 m³ or less — this is an indication of the range, not a prohibition), make a sketch with the position of the equipment under test and of the planned microphone positions, and agree with the building manager on access to the equipment and on the possibility of making it run.

3. Preparing the measuring chain

   Set up a one-third-octave analyser recording all bands simultaneously; the chain with microphone and cable is to meet the requirements of class 1 according to IEC 61672-1, the filters those of class 1 according to IEC 61260-1. Assess the inherent noise of the chain so that it can be compared with the background levels. Mount the microphone on a stable stand of adjustable height.

4. Initial calibration

   Check the sensitivity of the chain with a class 1 calibrator according to IEC 60942. If the result deviates from previous calibrations by more than 0.5 dB, do not use the instrument until the cause has been explained and the correct sensitivity restored.

5. Operating conditions and cycle of the equipment

   Take the operating conditions and cycles of the equipment under test from Annex B of the standard or from national guidance, if such exists for the given kind of equipment (the standard names lifts expressly here). National guidance takes precedence. By way of example — according to the edition PN-EN ISO 16032:2006 the measuring cycle of a lift covered a journey with a stop at every floor together with the opening and closing of the doors, a return to the starting level and a further opening and closing of the doors, with the lift loaded to half its permissible load, and for sources with steady noise the level was determined over a working interval of the order of 30 seconds; before the measurement check the wording of Annex B in the edition being used.

6. Measuring the spectrum at the successive microphone positions

   At each fixed microphone position record the linear (unweighted) spectrum in one-third-octave bands over the given interval of time or over the whole operating cycle of the equipment. For the maximum level, read the one-third-octave bands exactly at the moment when the instrument indicates the maximum of the A- or C-weighted sound level — with the time weighting "S" or "F", in accordance with the requirement to which the test is to be referred. Determine the equivalent level with an integration time according to Annex B or to national requirements.

7. Measuring the background noise

   Measure the background with the source under test switched off, at the same microphone positions and in the same bands, and compare it with the assessed inherent noise of the chain. Note: the standard gives the procedure of background correction in clause 6.6, which we do not have from the preview; in the edition PN-EN ISO 16032:2006 the background was measured at three measuring positions as an equivalent level over intervals of about 30 s and averaged energetically, and where the difference between the noise and the background was less than 10 dB a corresponding correction was subtracted from the noise level — before the measurement check the wording of this clause in the edition being used.

8. Averaging over the positions and background correction

   From the levels measured at the individual microphone positions calculate the average sound pressure levels in one-third-octave bands and then correct them for the measured background.

9. Measuring the reverberation time and standardisation

   If the result is to be given as a standardised or normalised level, measure the reverberation time according to ISO 3382-2 in one-third octaves 50 Hz–5000 Hz (T20 or T30 with extrapolation are admissible) and convert the spectrum: LnT = L − 10 lg T/T₀ with T₀ = 0.5 s, or Ln = L − 10 lg [A₀T/(0.16 V)] with A₀ = 10 m². If a national regulation demands uncorrected levels — omit this step and state it in the test report.

10. Calculating the A- and C-weighted sound levels

    From the corrected (and, where applicable, standardised or normalised) spectrum calculate the A-weighted and the C-weighted sound level, by summing energetically the one-third-octave bands with the A and C weightings from Annex A of the standard. The range for the calculation may cover the one-third octaves 25 Hz–10 000 Hz, but must always cover 50 Hz–5000 Hz. Unweighted octave levels may additionally be measured or estimated from the one-third octaves and given in the test report, but the A- and C-weighted levels must not be calculated from them.

11. Test report and reference to the requirements

    Give the resulting quantity in the notation of Table 1 of the standard (maximum level "S" or "F", or equivalent level, in the uncorrected, standardised or normalised version, with A or C weighting), the operating conditions and cycle of the equipment, the background levels, the reverberation time if it was measured, and the edition of the standard used. The permissible values in buildings are given by PN-B-02151-2:2018-01; if the test is to serve to demonstrate compliance with § 326 of the technical conditions, note that Annex 1 to the regulation cites the edition PN-EN ISO 16032:2006, withdrawn on 2 September 2024.

Required equipment and apparatus

Health and safety (OHS)

• Making equipment run for the purposes of the measurement — a lift, a garage door, a heat substation, a pressure-booster set, air-handling units — is done only by a person authorised to operate it; do not interfere with the building installations yourself.
• The technical rooms in which the equipment under test stands (lift machine room, fan room, heat substation, boiler room) are sometimes zones of noise exceeding the permissible values at workplaces — wear hearing protectors while there.
• The testing is carried out in premises used by people, often at night: agree with the occupants the extent of entry, the time of presence and the switching off of equipment, and treat sketches, photographs and recordings as data covered by the privacy of the dwelling.
• The operating cycles of Annex B put a load on the equipment (lift journeys with half load, repeated opening of a garage door) — agree them with the service company, so that the measurement does not become the cause of a breakdown or of someone being trapped in the car.
• A stand with a microphone placed in passageways and on staircases is an obstacle — secure the position against being knocked over, also because floor vibrations transmitted to the microphone raise the background of the measurement.
• Do not confuse the engineering method (PN-EN ISO 16032) with the survey method (PN-EN ISO 10052) or with the withdrawn national PN-B-02156: giving the wrong number of the standard in the test report is a formal non-conformity, not an editorial trifle.

Frequently asked questions