Noise Abatement Ordinance (NAO) (NAO)
Amended by No I of the O of 1 Sept. 2004, in force since 1 Oct. 2004 (AS 2004 4167).
English is not an official language of the Swiss Confederation. This translation is provided for information purposes only and has no legal force.
Section 1 Investigation
Art. 36 Obligation to investigate
1 The enforcement authorities shall investigate the exposure to exterior noise due to stationary installations, or order its investigation if they have grounds to believe that the relevant exposure limit values are being exceeded or that this is to be expected. 2 They shall take account of increases and reductions in noise exposure levels that are to be expected due to: the construction, alteration or improvement of stationary installations, in particular if the projects in question have already been approved or made available for public inspection at the time of the investigation; and the construction, alteration or demolition of other structures if the projects have been made available for public inspection at the time of the investigation. 3 …
Art. 36 — Amended by No I of the O of 1 Sept. 2004, in force since 1 Oct. 2004 (AS 2004 4167). Para. 3 — Repealed by Art. 15 of the O of 4 Dec. 2015 on Railway Noise Abatement Measures, with effect from 1 Jan. 2016 (AS 2015 5691).
Art. 37 Noise pollution register
1 In the case of roads, railway installations, aerodromes and military firing ranges and training grounds, the enforcement authorities shall record in specific registers (noise pollution registers) the noise exposure levels measured in accordance with Article 36. 2 The noise pollution registers specify: the noise pollution measured; the calculation procedure used; the input data for the calculation; the classification of the areas exposed to noise in the land use plan; the sensitivity levels applicable; the installations and their owners; the number of persons who are affected by noise exposure levels above the applicable exposure limit values. 3 The enforcement authorities are responsible for the supervision and revision of the registers. 4 On request, they submit the noise pollution registers to the FOEN. The Office may issue recommendations on the standardised recording and presentation of the data. 5 The Federal Office for Civil Aviation is responsible for measurement of noise expo
Art. 37 — Amended by No I of the O of 1 Sept. 2004, in force since 1 Oct. 2004 (AS 2004 4167). Para. 1 — Amended by No I of the O of 30 June 2010, in force since 1 Aug. 2010 (AS 2010 3223).
Art. 37a Determination and control of noise exposure levels
1 The enforcement authorities state the permitted noise exposure level in their decision on the construction, alteration or improvement of an installation. 2 If it is established or anticipated that the noise exposure levels due to an installation will deviate significantly and permanently from those quoted in the decision, the enforcement authorities shall take the necessary measures. 3 The FOEN may issue recommendations on the standardised recording and presentation of the noise exposure levels in these decisions.
Art. 37a — Inserted by No I of the O of 12 April 2000 (AS 2000 1388). Amended by No I of the O of 1 Sept. 2004, in force since 1 Oct. 2004 (AS 2004 4167).
Art. 38 Method of determination
1 Noise exposure levels are determined in the form of a rating sound level, Lr, or a maximum sound level, Lmax, on the basis of calculations or measurements. 2 Noise exposure levels due to aircraft shall principally be determined by calculation. The calculations are carried out using recognised state-of-the-art methods. The FOEN shall recommend suitable calculation procedures. 3 The requirements for calculation procedures and measuring instruments are given in Annex 2.
Para. 1 — Amended by No I of the O of 1 Sept. 2004, in force since 1 Oct. 2004 (AS 2004 4167 4313). Para. 2 — Inserted by No I of the O of 12 April 2000, in force since 1 May 2000 (AS 2000 1388). Para. 3 — Originally para. 2.
Art. 39 Point of determination
1 For buildings, noise exposure levels shall be determined at the centre of open windows in rooms sensitive to noise. Noise exposure levels due to aircraft may also be determined in the vicinity of the building. 2 In the non-developed sector of zones with higher noise abatement requirements, noise exposure levels shall be measured 1.5 m above the ground. 3 In building zones that have not yet been developed, noise exposure levels shall be measured at points where the building and planning legislation allows the building of rooms sensitive to noise. 4 For outdoor areas intended for private use, noise levels are measured 1.5 metres above the ground in the outdoor area.
Para. 1 — The correction of 7 May 2019 concerns the French text only (AS 2019 1337). Para. 4 — Inserted by No I of the O of 25 Feb. 2026, in force since 1 April 2026 (AS 2026 114).
Section 2 Rating
Art. 40 Exposure limit values
1 The enforcement authorities shall rate the exposure to exterior noise due to stationary installations on the basis of the exposure limit values specified in Annexes 3 ff. 2 The exposure limit value, it is also considered exceeded if it is less than the sum of the levels of exposure to similar types of noise generated by several installations. This does not apply to the planning values for new stationary installations (Art. 7 para. 1). 3 In the absence of exposure limit values, the enforcement authorities shall rate the noise exposure levels in accordance with Article 15 of the Act. They shall also take account of Articles 19 and 23 of the Act.
Art. 41 Validity of the exposure limit values
1 The exposure limit values apply to buildings with rooms sensitive to noise. 2 They also apply: in yet undeveloped building zones in areas where the construction of buildings with rooms sensitive to noise is allowed under the building and planning legislation; in the non-developed areas of zones with higher noise abatement requirements. 2bis The ambient limit values also apply if a building permit is granted to the entire area of the privately used outdoor space specified in Article 22 paragraph 2 letter a number 3 of the Act. 3 For areas and buildings in which, as a rule, people are present either only during the day or only at night, no exposure limit values apply at night or during the day.
Para. 2bis — Inserted by No I of the O of 25 Feb. 2026, in force since 1 April 2026 (AS 2026 114).
Art. 42 Special exposure limit values for rooms in industrial buildings
1 For rooms in industrial buildings (Art. 2 para. 6 let. b) lying in areas of sensitivity levels I, II or III, the planning and impact thresholds shall be increased by 5 dB(A). 2 Paragraph 1 does not apply to rooms in schools, institutions and homes. It applies to hotels and guesthouses only if these can be adequately ventilated when the windows are closed.
Art. 43 Sensitivity levels
1 In land use zones according to Articles 14 ff. of the Spatial Planning Act of 22 June 1979, the following sensitivity levels apply: sensitivity level I in zones with higher noise abatement requirements, notably in leisure zones; sensitivity level II in zones in which operations that emit noise are not permitted, notably in residential zones and zones for public buildings and installations; sensitivity level III in zones in which operations emitting a certain level of noise are permitted, notably in residential and industrial zones (mixed zones) and agricultural zones; sensitivity level IV in zones in which operations emitting a high level of noise are permitted, notably in industrial zones. 2 Parts of land use zones rated as sensitivity levels I or II may be assigned the next higher level if they are already exposed to noise.
Para. 1 — SR 700
Art. 44 Procedures
1 The cantons shall ensure that sensitivity levels are assigned to the land use zones in the building regulations or land use plans of the communes. 2 The sensitivity levels are assigned at the time of designation or modification of the land use zones, or at the time of modification of the building regulations. 3 Prior to assignment, the cantons shall determine the sensitivity levels on a case by case basis in accordance with Article 43. 4 …
Para. 2 — Amended by No IV 31 of the O of 22 Aug. 2007 on the Formal Revision of Federal Legislation, in force since 1 Jan. 2008 (AS 2007 4477). Para. 4 — Repealed by No 1 of the O of 27 June 1995, with effect from 1 Aug. 1995 (AS 1995 3694).
