Noise from Service Equipment in Residential Buildings and Hospitals – Regulations in selected countries in Europe

Abstract: Noise from service equipment can cause disturbances for both occupants and nearby residents. This paper describes the regulatory limits set by various European countries regarding noise from HVAC systems and other installations in residential buildings and hospital bedrooms. It is observed that the descriptors used are, in some cases, different from each other and therefore not always directly comparable. Very often the main differences are found in the verification procedures and descriptors rather than in the limit values. The regulations in each country define the necessary requirements and provide reference values for the design phase, while standards specify the measurement methods to be applied for field tests to ensure compliance with the requirements.

Keywords: Service equipment noise, HVAC systems, Acoustic comfort, Sound pressure level, Dwellings, Hospitals.

Introduction

Noise from building services can lead to annoyance and discomfort for the occupants and people in the surroundings and this is the reason why regulations in several European countries set noise limits for service equipment. Complying with regulations often involves a solid understanding of how noise from building services is generated and transmitted, enabling effective design choices that minimize noise. In an HVAC system, potential noise sources are fans, compressors, ducts, airflow noise, grilles, and terminal equipment.

Figure 1 shows an example of the layout of a typical mechanical ventilation with heat recovery (MVHR) installation in a dwelling and its potential sources of noise. Due to energy efficiency requirements, this type of units is becoming more common in dwellings around Europe and they work continuously, circulating air and affecting noise sensitive spaces such as bedrooms and living rooms. While the duct system consisting of ducts, branches, bends and grilles, provides some attenuation, it can also provide some flow generated noise.

In addition, noise may break out from the heat recovery unit enclosure to the room where it is located, and also through the duct walls. Structure-borne transmission from the fans can also be transmitted to the floors and walls if anti-vibration mounts are not used.

Figure 1. Typical layout of a MVHR system in a dwelling and its potential noise sources.

This paper reports and compares the regulatory limits and verification procedures in some European countries with a specific focus on residential buildings and hospitals. Regarding other buildings, very often the verification procedures are similar while the reference values change.

Understanding acoustic descriptors for service and equipment

Concerning service equipment noise, acoustic regulations distinguish between continuously and discontinuously operating systems.

Continuously operating systems are characterised by sound emission with an essentially stationary character, i.e. when the Sound Pressure Level, SPL, measured with Fast time weighting (F) fluctuates by no more than 5 dB throughout the entire operating time. For example, continuously operating systems are heating, cooling, air-conditioning, mechanical ventilation and central vacuum systems.

On the other hand, discontinuous operation systems are characterised by sound emissions with fluctuating or intermittent variations and short periods of operation; in these systems, the fast SPL varies randomly with oscillations greater than 5 dB. Therefore, sanitary installations, exhaust systems, lifts and automatic shutoffs are to be classified as discontinuous systems.

The main difference in the required limits for the two types of equipment concerns the measured quantity. For continuously operating systems, the limit refers to the equivalent SPL, LAeq,, which provides a representative noise value for a certain period of time, whereas for discontinuous operating installations, the limit refers to the maximum SPL, LAmax., which provides a representative value of the maximum noise level.

For both descriptors, LAeq, and LAmax., it is necessary to measure the background noise, i.e. the average ambient SPL when the equipment is switched off.

Measurement methods

When checking compliance with regulations or investigating noise complaints, measurements are usually performed. References to measurement methods are found in the building regulations or in the guidelines referred to in the regulations or in other national guidelines. The ISO standards for measuring noise from building services are typically ISO 10052 [1] and/or ISO 16032 [2]. As SPL can vary significantly from point to point in a room, these two standards include important aspects to ensure repeatable and accurate results, such as microphone positions, the number of measurements, the correction for background noise and the duration of each measurement.

The SPL of HVAC equipment will also vary with the operating conditions of the equipment, for example, for partial load or full load operation. Thus, the operating conditions must be specified in the reports. ISO 10052 [1] and ISO 16032 [2] provide a common framework defining some operating conditions for each kind of building services including ventilation, heating and cooling services, but in some countries, other conditions may apply in their own guidelines. However, for automatically controlled equipment, such as ventilation systems in dwellings, field tests require the adjustment of the operating conditions to comply with the building code requirements on air quality [3].

Moreover, in several countries additional methods apply for low-frequency noise, pure tones, impulses and intermittent noise. It should be noted that usually (Vienna agreement) the ISO standards are implemented as EN standards and subsequently as national standards in CEN member countries.

The following issues are relevant to ensure the quality of measurements of service and equipment noise:

·         The confirmation that the instrumentation complies with IEC standards.

·         The calibration of test instruments.

·         The Instrumentation details, which must be capable of measuring low sound pressure levels at relevant frequency bands with sufficient accuracy.

·         The operator expertise in both the test method and systems.

·         The quality of tests reports according to the test standard including the test conditions.

Limit values in some European countries

In this paragraph, the regulatory limits for equipment noise in dwellings and in hospitals in selected European countries, are reported together with the reference standard for the verification and other specific information. For a better understanding, the limit values, the reference standards and detailed comments have been collected in table format. More information can be found in some previous studies by the authors [4, 5].

The selected countries and related regulations are Denmark, England, France, Italy, Norway, Portugal, Spain and Turkey.

Limit values for service equipment noise in dwellings are found in Table 1 [5] and in Table 2 for hospitals bedrooms [4].

The data are generally divided into those for continuously operating equipment whose descriptor is generally LAeq and discontinuously operating equipment with the descriptor LASmax or LAFmax. In almost all cases, there is either a correction for reverberation time or a correction depending on the presence or absence of furniture.

Please note that all data presented in tables 1and2 have been extracted from regulations and laws which were in force in November 2022. Links to the regulations of each of the selected countries can be consulted in the reference section.

It should also be noted that the limit values included in this paper should not be applied directly as legislation, but the original documents or updates consulted, as they include more details and conditions than in the present paper.

Table 1. Service equipment noise limits for dwellings (habitable rooms) (1). November 2022.

(1) Overview information only. Detailed criteria and conditions are found in references.

(*) Limits in (brackets) = Recommendation.

Table 2. Service equipment noise limits for hospital bedrooms(1). November 2022.

(1) Overview information only. Detailed criteria and conditions are found in references.
(*) Limits in (brackets) = Recommendation. (**) +: Requirements apply to furnished rooms. Not specified: Regulations do not specify if requirements apply to furnished rooms.

The values given are mandatory or recommended according to the requirements of the various countries. It can be seen that the requirements for continuously operating systems generally vary between 25 and 30 dB(A), while for discontinuous noise, they vary between 30 and 35 dB(A).

To get an idea of the extent of these requirements, a comparison can be made with the limit values defined by the ISO/TS 19488 [26] for the acoustic classification of dwellings. The scope of this standard is to specify a classified level of acoustic quality for a dwelling and help users and builders to be informed about the acoustic conditions and define increased acoustic quality. It does not have a legal status in a country, unless decided by its own authorities. At present, none of the countries surveyed refer to ISO/TS 19488 for the acoustic performances of buildings.

ISO/TS 19488 provides six classes from A to F. For service equipment producing continuous noise, the values range from a value of less than 22 dB(A) for Class A to a value of less than 42 dB(A) for Class F. For service equipment producing intermittent or irregular sound, from neighbouring spaces, the values range from a value below 26 dB(A) for Class A to a value below 46 dB(A) for Class F. Therefore, the limit values are approximately Class C for both types of noise.

As a reference, EN 16798-1 [27] specifies levels for the characteristic parameters of indoor environmental quality to be used in building system design for the purpose of calculating energy performance. Regarding the noise from installations and HVAC systems, the standard considers three levels of expectation for the equivalent noise level normalized to reverberation time, LAeq,nT, according to the building’s intended use and the type of environment considered. These reference values are suggested for design purposes, but only in few cases become part of the requirements for the enforced legislation in European countries studied in this paper.

Conclusion

In the paper, the regulatory limits and related test methods were described. An initial analysis of the requirements showed that the descriptors applied seemed different among the various European countries. However, from a detailed analysis, it was seen that the meaning is essentially equivalent. In fact, for verification of noise emitted by continuously operating equipment LAeq is generally used and LAmax with slow or fast time constant is used for discontinuously operating equipment. In both cases, a correction for reverberation time is generally applied. A comparison of the limit values shows that for LAeq the limits vary between 25 and 30 dB(A) while for LAmax values vary between 30 and 35 dB(A).

From a comparison with the values in ISO/TS 19488 Table 4, it is observed that the noise Class of the regulatory limits generally are approx. Class C for both types of noise on a range between A and F.

Concerning the three performance levels in EN 16798-1, where different values are suggested depending on the type of environment, it is vital to compare them with the requirements in the Building Codes before applying them, as the suggested values in EN 16798-1 for some environments are much noisier than the regulatory limits.

References

[1]     ISO 10052:2021. Acoustics — Field measurements of airborne and impact sound insulation and of service equipment sound — Survey method, Geneva, Switzerland. [Online]. Available: https://www.iso.org/standard/76560.html.

[2]     ISO 16032:2024. Acoustics — Measurement of sound pressure level from service equipment or activities in buildings — Engineering method, Geneva, Switzerland. [Online]. Available: https://www.iso.org/es/contents/data/standard/08/38/83874.html.

[3]     B. Rassmusen, L. Sell, and L. S. Søndergaard, ‘Field tests of low noise levels from MVHR ventilation systems – Overview obstacles and pilot test of test procedure improvement’, in Proceedings of the Baltic-Nordic Acoustics Meeting 2024, T. Lokki, 2025 2024, pp. 203-209. Article 55.[Online].Available: https://vbn.aau.dk/ws/portalfiles/portal/715662658/BNAM2024_FieldTestsLowNoiseLevelsMVHR-VentilationSystems_Rasmussen_Sell_S_ndergaard.pdf.

[4]     B. Rasmussen, T. Carrascal, and S. Secchi, ‘A Comparative Study of Acoustic Regulations for Hospital Bedrooms in Selected Countries in Europe’, Buildings, vol. 13, no. 3, Art. no. 3, Mar. 2023, doi: 10.3390/buildings13030578.

[5]     B. Rasmussen and T. Carrascal García, ‘Noise from ventilation systems in dwellings - Regulations and field test procedures in selected countries in Europe’, INTER-NOISE NOISE-CON Congr. Conf. Proc., vol. 265, no. 1, pp. 6221–6229, Feb. 2023, doi: 10.3397/IN_2022_0926.

[6]     Danish Transport, Construction and Housing Authority, 2017, Bygningsreglement 2018 (Danish building regulations 2018). [Online]. Available: http://bygningsreglementet.dk  (with link to English version)

[7]     B. Rasmussen, D. Hoffmeyer, and H. S. Olesen, Udførelse af bygningsakustiske målinger (Performing building acoustic field measurements). in SBi-anvisning. København: SBi Forlag, 2017. [Online]. Available: http://sbi.dk/byggeteknik/bygningsfysik/lydisolering/udforelse-af-bygningsakustiske-malinger/udforelse-af-bygningsakustiske-malinger.

[8]     Danish Standards, DS 490:2018, Lydklassifikation af boliger (Sound classification of dwellings).

[9]     Ministry of Housing, Communities & Local Government, Building regulation in England. Resistance to sound: Approved Document E. [Online]. Available: https://www.gov.uk/government/publications/resistance-to-sound-approved-document-e.

[10]   Ministry of Housing, Communities and Local Government, Building regulation in England. Ventilation: Approved Document F. 2018. [Online]. Available: https://www.gov.uk/government/publications/ventilation-approved-document-f.

[11]   Association of Noise Consultants ANC, Measurement of Sound Levels in Buildings. ANC Guidelines, June 2020. Northallerton, 2020.

[12]   BSI, BS 8233:2014 - Guidance on sound insulation and noise reduction for buildings – BSI British Standards. The British Standards Institution, 2014. [Online]. Available: http://shop.bsigroup.com/ProductDetail/?pid=000000000030241579.

[13]   Conseil National du Bruit (French Noise Council), Guide du CNB. no 6. Réglementations acoustiques des bâtiments. (Acoustic building regulations). 2017. [Online]. Available: http://www.bruit.fr/images/stories/pdf/guide-cnb-6-reglementations-acoustiques-batiments-novembre%202017.pdf.

[14]   Guide de Mesures Acoustiques (Acoustic Measurement Guide). France: Ministêre de l’Ecologie, du Developpement durable et de l’Energie. Ministêre du Logement et de l’Égalité des Territoires, 2014. [Online]. Available: http://www.ecologique-solidaire.gouv.fr/sites/default/files/Guide%20de%20mesures%20acoustiques%20-%20ao%C3%BBt%202014.pdf.

[15]   DPCM 5-12-1997– Requisiti acustici passivi degli edifici (Determination of passive acoustic requirements for buildings). 1997. (Italian Prime Minister Decree). 1997.

[16]   D.M. 22-6-2022 - Criteri ambientali minimi per l’affidamento del servizio di progettazione di interventi edilizi, per l’affidamento dei lavori per interventi edilizi e per l’affidamento congiunto di progettazione e lavori per interventi edilizi. (Minimum environmental criteria for the commissioning of design services for building construction, for the commissioning of works for building construction and for the joint commissioning of design and works for building construction). (Italian Decree of the Ministry of Ecological Transition). [Online]. Available: https://www.gazzettaufficiale.it/eli/id/2022/08/06/22A04307/sg.

[17]   UNI (Italian Standardization Body), UNI 11367:2010. Acustica in edilizia - Classificazione acustica delle unità immobiliari - Procedura di valutazione e verifica in opera. (Building Acoustics - Acoustic classification of building units - Evaluation procedure and in-situ measurements). Italy, 2010.

[18]   Direktoratet for byggkvalitet, Oslo. (Norwegian Building Authority), Byggteknisk Forskrift (TEK17). Veiledning om tekniske krav til byggverk. (Regulations on technical requirements for building works). [Online]. Available: https://dibk.no/byggereglene/byggteknisk-forskrift-tek17/.

[19]   Standards Norway, NS 8175:2019. Lydforhold i bygninger - Lydklasser for ulike bygningstyper. (Acoustic conditions in buildings - Sound classification of various types of buildings), Jul. 2019. [Online]. Available: https://online.standard.no/nb/ns-8175-2019.

[20]   Ministério do Ambiente, do Ordenamento do Território e do Desenvolvimento Regional, Decreto-Lei n.o 96/2008, de 9 de junho. Regulamento dos Requisitos Acústicos dos Edifícios. (Portuguese Building Acoustics Code). 2008. [Online]. Available: https://diariodarepublica.pt/dr/detalhe/decreto-lei/96-2008-449682.

[21]   Ministério do Ambiente, do Ordenamento do Território e do Desenvolvimento Regional, Decreto-Lei n. 9/2007. Regulamento geral do ruído. (Regulations on general noise), vol. Diário da República n.o 12/2007, Série I. 2007, pp. 389–398. [Online]. Available: https://data.dre.pt/eli/dec-lei/9/2007/01/17/p/dre/pt/html.

[22]   Ministerio de Transportes, Movilidad y Agenda Urbana, Documento Básico DB HR Protección frente al Ruido. Código Técnico de la Edificación. (DB HR Protection against noise. Spanish Building Code). 2019. [Online]. Available: http://www.codigotecnico.org/cte/export/sites/default/web/galerias/archivos/DB_HR_sept_2009.pdf.

[23]   Ministerio de la Presidencia, Real Decreto 1367/2007, de 19 de octubre, por el que se desarrolla la Ley 37/2003, de 17 de noviembre, del Ruido, en lo referente a zonificación acústica, objetivos de calidad y emisiones acústicas. (RD 1367, which develops Law 37/2003, in terms of acoustic zoning, quality objectives and acoustic emissions). [Online]. Available: https://www.boe.es/eli/es/rd/2007/10/19/1367/con.

[24]   Turkish Ministry of Environment and Urbanization (2017), Binalarin Gürültüye Karşi Korunmasi Hakkinda Yönetmelik (Regulation on Protection of Buildings against Noise). [Online]. Available: Republic of Turkey Official Gazette. www.resmigazete.gov.tr/eskiler/2017/05/20170531-7.htm.

[25]   Department of Health, HTM 08-01 Health sector buildings: acoustic design requirements. The Stationery Office, 2013. [Online]. Available: https://www.england.nhs.uk/publication/health-sector-buildings-acoustic-design-requirements-htm-08-01/.

[26]   ISO/TS 19488:2021. Acoustics - Acoustic classification of dwellings. [Online]. Available: https://www.iso.org/standard/77742.html.

[27]   EN 16798–1:2019. Energy performance of buildings — Ventilation of buildings — Part 1: Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics (Module M1–6).