2.

Interim computation methods for Lden and Lnight 2.1. Adaptation of existing national computation methods If a Member State has national methods for the determination of long-term indicators those methods may be applied, provided that they are adapted to the definitions of the indicators set out in Annex I. For most national methods this implies the introduction of the evening as a separate period and the introduction of the average over a year. Some existing methods will also have to be adapted as regards the exclusion of the façade reflection, the incorporation of the night and/or the assessment position. The establishment of the average over a year requires special attention. Variations in emission and transmission can contribute to fluctuations over a year. 2.2. Recommended interim computation methods For Member States that have no national computation methods or Member States that wish to change computation method, the following methods are recommended: For INDUSTRIAL NOISE: ISO 9613-2: "Acoustics - Abatement of sound propagation outdoors, Part 2: General method of calculation". Suitable noise-emission data (input data) for this method can be obtained from measurements carried out in accordance with one of the following methods: ISO 8297: 1994 "Acoustics - Determination of sound power levels of multisource industrial plants for evaluation of sound pressure levels in the environment - Engineering method", EN ISO 3744: 1995 "Acoustics - Determination of sound power levels of noise using sound pressure - Engineering method in an essentially free field over a reflecting plane", EN ISO 3746: 1995 "Acoustics - Determination of sound power levels of noise sources using an enveloping measurement surface over a reflecting plane". For AIRCRAFT NOISE: ECAC.CEAC Doc. 29 "Report on Standard Method of Computing Noise Contours around Civil Airports", 1997. Of the different approaches to the modelling of flight paths, the segmentation technique referred to in section 7.5 of ECAC.CEAC Doc. 29 will be used. For ROAD TRAFFIC NOISE: The French national computation method "NMPB-Routes-96 (SETRA-CERTU-LCPC-CSTB)", referred to in "Arrêté du 5 mai 1995 relatif au bruit des infrastructures routières, Journal Officiel du 10 mai 1995, Article 6" and in the French standard "XPS 31-133". For input data concerning emission, these documents refer to the "Guide du bruit des transports terrestres, fascicule prévision des niveaux sonores, CETUR 1980". For RAILWAY NOISE: The Netherlands national computation method published in "Reken- en Meetvoorschrift Railverkeerslawaai '96, Ministerie Volkshuisvesting, Ruimtelijke Ordening en Milieubeheer, 20 November 1996". Those methods must be adapted to the definitions of Lden and Lnight. No later than 1 July 2003 the Commission will publish guidelines in accordance with Article 13(2) on the revised methods and provide emission data for aircraft noise, road traffic noise and railway noise on the basis of existing data.

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Source: EUR-Lex (Cellar) · retrieved 2026-11-04 · Text as adopted (Official Journal); later amendments are not incorporated in this text.