Exception permit for residential development in noise-affected area refused: review of measures and balancing of interests under Art. 31 para. 2 NAO insufficient

Facts

The investment foundation [A.] (appellant, building applicant) planned a residential development with 124 apartments and six retail units on the so-called 'Bürgli-Areal' in Zürich-Enge (Bederstrasse 67-83). The plot Cadastral No. EN1534 (7'610 m2) lies in the five-storey residential zone W5, is assigned to sensitivity level (ES) III and is subject to noise pollution.

On 2 October 2018 the Building Section of the City of Zürich granted the building permit. Together with it, the overall decision of the Cantonal Building Directorate of Zürich dated 20 June 2018 was notified, which concerned compliance with the noise limit values and the location within a perimeter of the cadastre of contaminated sites.

Neighbours (A. and B. [B.] , [C.] , [D.] , [E.] , [G. AG] , [F. AG] ) as well as [H.] lodged an appeal with the Building Appeals Court of the Canton of Zürich. The court joined the proceedings and partially upheld the developer's appeal on 10 May 2019, while dismissing the remaining appeals. The neighbours lodged an appeal with the Administrative Court of the Canton of Zürich, which on 27 February 2020 (VB.2019.00394) upheld the appeal and set aside the decision of the Building Appeals Court, the building permit and the overall decision.

The developer filed a public law appeal with the Federal Supreme Court, requesting the annulment of the lower court's judgment and remittal to the lower court, alternatively the granting of the building permit. The Cantonal Building Directorate and the Building Section requested that the appeal be upheld, and the Administrative Court requested that it be dismissed. The Federal Office for the Environment (FOEN), in its opinion of 20 October 2020, did not conclusively determine whether the project was compatible with federal noise protection law.

The noise exposure: during the day the immission limit values (65 dB(A)) at the façades between the ground floor and the 4th floor are exceeded by a maximum of 1 dB(A). At night (limit value 55 dB(A)) the exceedances in noise-sensitive rooms amount to up to 5 dB(A). Of the 124 residential units, 99 are affected at night in at least one room (approximately 80%).

The dispute concerned whether all proportionate measures under Art. 31 para. 1 NAO had been taken and whether an exception permit under Art. 31 para. 2 NAO could be granted.

Considerations

Admissibility: The public law appeal against a final cantonal decision on a building permit is admissible (Art. 82 let. a, Art. 86 para. 1 let. d, Art. 90 FSCA). The appellant, as the building applicant, has standing (Art. 89 para. 1 FSCA). The appeal is admissible.

Legal framework: Pursuant to Art. 22 EPA and Art. 31 NAO, a building permit for noise-sensitive buildings may only be granted if the immission limit values can be complied with, either by arranging the noise-sensitive rooms on the side away from the noise or by structural or design shielding measures. If this is not possible, Art. 31 para. 2 NAO permits an exception permit only where there is a predominant interest and the consent of the cantonal authority. An exception permit presupposes that all proportionate measures have been exhausted; the burden of proof lies with the building applicant. Where limit values are substantially exceeded, an in-depth examination of noise protection is required. Exceptions may not rely on general grounds that could practically always be invoked.

Review of measures: The Federal Supreme Court confirms the lower court's position that the developer must demonstrate which measures were examined, selected or rejected. Numerous variant studies are not required, but a comprehensible and thorough examination of noise protection relating to the specific plot and use is. The statements of the specialist authority and of the overall decision ('all measures under consideration were evaluated') are not sufficient. Equally insufficient are mere findings that no further reasonable measures are possible, or references to ineffective measures. The noise exposure is significant: sensitivity level III is intended for mixed zones, while pure residential zones are in principle assigned to ES II; the existing noise burden was already taken into account in assigning ES III and must not be weighted twice in the exception. The nighttime exceedance of up to 5 dB(A) weighs heavily given the logarithmic scale and the waking threshold of approximately 60 dB(A).

No violation of procedural rights: The lower court was not required to repeat or remit the review of measures of its own motion; this clarification is incumbent on the building applicant. There is no violation of the right to be heard (Art. 29 para. 2 Cst.), of the prohibition of arbitrariness (Art. 9 Cst.) or of the derogatory force of federal law (Art. 49 para. 1 Cst.).

Inadmissible novelties: The report of the architects and building physicists dated 18 May 2020 was submitted…