ISO/TC 108/SC 2/WG 8 - Ground-borne noise and vibration from rail systems

This document specifies methods for measuring and analysing irregularities of running surfaces for use in the prediction and assessment of ground-borne noise and vibration arising from railway systems. This document a) defines the data that can be described as rail or wheel roughness and that can be used to quantify a source term for the generation of the dynamic forces that can lead to ground-borne vibration from railway vehicles, b) gives guidance regarding the types of equipment that can be used to measure roughness as a variation of height along the running direction of the rail surface or wheel parameter, c) gives guidance regarding the methods that can be used to obtain an estimate of the roughness wavelength spectrum from measurement records taken over a length of rail head or wheel perimeter, and d) gives guidance regarding the presentation of a roughness spectrum representing the condition of a length of rail or of a wheel related to its ability to generate vibration. This document does not e) give guidance regarding the characterization of localized geometrical features (e.g. switches, crossings, rail squats, occasional rail joints and localized geometrical defects of the running surface). These features are likely to produce dynamic forces that are not linear with their amplitude because of the change of geometry at the wheel-rail contact. Hence these features are not characterized by methods of analysis defined within this document. Annex A provides further information regarding the characterization of localized geometrical features, f) give guidance regarding the specification or testing of roughness measurement equipment that can be used. Annex B provides an overview of measuring equipment, g) give guidance regarding the measurement or analysis of track quality for any other purpose than the assessment of ground-borne vibration, h) present any example of roughness spectra intended to represent typical roughness. Roughness levels vary greatly between track sites and any examples used in this document have not been selected on any other basis than their usefulness for the purpose of demonstrating the principles of analysis, i) promote any particular make, model or manufacturer of measurement equipment, and j) recommend or promote software for the implementation of the analysis procedure.

ISO/TS 14837-31:2017 gives guidelines to encourage reporting of field measurements of ground-borne noise and vibration in a metric that allows international comparison and future development of empirical models. It also sets out the basic minimum requirements and good practice when taking measurements for the evaluation of human exposure in residential buildings to ensure they are reliable. While national standards or requirements based upon project-specific purposes would normally take priority, this guidance can be used where there are no particular requirements or to provide supplementary guidance. Thereby, this document provides a means of improving general quality and reporting of field measurements in a preferred format. There are a number of reasons for carrying out field measurements of ground-borne noise and vibration arising from rail operations, from complaint investigations to validation of prediction models, diagnostics and research as detailed in ISO 14837‑1:2005, 7.2. In the present document, two levels of evaluation are considered. - Scope 1 corresponds to basic measurements of floor vibration and noise in rooms in buildings to evaluate the human exposure to ground-borne vibration and ground-borne noise. Requirements are presented under two levels of accuracy: basic measurements with minimum accuracy; measurements with reduced uncertainty, also more reproducible and more appropriate for prediction. Ground-borne noise is noise generated by vibrating building elements (e.g. floors, walls and ceilings) in the room of interest and is therefore best expressed by both an acoustic and a vibrational quantity. Its identification as ground-borne noise (as opposed to airborne noise, potentially also present) requires simultaneous noise and vibration measurements. Nevertheless, there are also cases of very low frequency vibration (below 10 Hz to 16 Hz) where only vibration measurements are relevant. Rattle can also arise from vibration, which can be from building components or furniture. This document does not set out to characterize this phenomenon, but to note its presence when it occurs. NOTE In some cases, Scope 1 can relate to measurements on the ground outside a building (to resolve access issues or to comply with national regulations), although measurements at the building are generally preferred. - Scope 2 corresponds to measurements extended to evaluate the vibration immission to buildings, which includes vibration measurements at or near the building foundations and vibration measurements on ground next to the building so that the building coupling loss and building transmissibility can be estimated. Vibration measurements near the tracks (on ground surface or in tunnels) for a proper characterization of the source are outside the scope of this document. Certain requirements are specified in the interest of achieving a consistent minimum data set for each investigation, allowing data comparison between sites.

ISO/TS 14837-32:2015 provides guidance and defines methods for the measurement of dynamic properties of the ground through which ground-borne noise and vibration is transmitted, from the operation of rail systems and into foundations of neighbouring buildings. The purpose is to determine the parameters of the ground system which are necessary to reliably predict the noise and vibration transmission, to design railroads and foundations to meet noise and vibration requirements, to design countermeasures and to validate design methods.

ISO 14837-1:2005 provides general guidance on ground-borne vibration generated by the operation of rail systems, and the resultant ground-borne noise in buildings. It lists the factors and parameters that need to be taken into consideration and offers guidance on prediction methods appropriate for a range of circumstances (e.g. to support the assessment of effects on human occupants and sensitive equipment or operations inside the buildings in addition to the predictions required to assess the risk of damage to building structures). Attention is paid in ISO 14837-1:2005 to characteristics of the source: emission (e.g. train, wheel, rail, track, supporting infrastructure); propagation path: transmission (e.g. ground condition, distance); and receiving structures: immission: (e.g. foundations, form of building construction). The guidance covers all forms of wheel and rail systems, from light-rail to high-speed trains and freight. ISO 14837-1:2005 provides guidance for rail systems at-grade, on elevated structures and in tunnels. It does not deal with vibration arising from the construction and maintenance of the rail system. It does not deal with airborne noise. Structure-radiated noise from elevated structures, which can have a significant environmental impact, is also excluded.