Andy Moorhouse

Annoyance due to railway vibration at different times of the day

The time of day when vibration occurs is considered as a factor influencing the human response to vibration. The aim of the present paper is to identify the times of day during which railway vibration causes the greatest annoyance, to measure the differences between annoyance responses for different time periods and to obtain estimates of the time of day penalties. This was achieved using data from case studies comprised of face-to-face interviews and internal vibration measurements (N=755). Results indicate that vibration annoyance differs with time of day and that separate time of day weights can be applied when considering exposure-response relationships from railway vibration in residential environments.

Human response to vibration in residential environments

This paper presents the main findings of a field survey conducted in the United Kingdom into the human response to vibration in residential environments. The main aim of this study was to derive exposure-response relationships for annoyance due to vibration from environmental sources. The sources of vibration considered in this paper are railway and construction activity. Annoyance data were collected using questionnaires conducted face-to-face with residents in their own homes. Questionnaires were completed with residents exposed to railway induced vibration (N = 931) and vibration from the construction of a light rail system (N = 350). Measurements of vibration were conducted at internal and external positions from which estimates of 24-h vibration exposure were derived for 1073 of the case studies. Sixty different vibration exposure descriptors along with 6 different frequency weightings were assessed as potential predictors of annoyance. Of the exposure descriptors considered, none were found to be a better predictor of annoyance than any other. However, use of relevant frequency weightings was found to improve correlation between vibration exposure and annoyance. A unified exposure-response relationship could not be derived due to differences in response to the two sources so separate relationships are presented for each source.

Exposure-response relationships for annoyance due to freight and passenger railway vibration exposure in residential environments

In this work, exposure-response relationships for annoyance due to freight and passenger railway vibration exposure in residential environments are developed, so as to better understand the differences in human response to these two sources of environmental vibration. Data for this research come from a field study comprising interviews with respondents and measurements of their vibration exposure (N = 752). A logistic regression model is able to accurately classify 96% of these measured railway vibration signals as freight or passenger based on two signal properties that quantify the duration and low frequency content of each signal. Exposure-response relationships are then determined using ordinal probit modeling with fixed thresholds. The results indicate that people are able to distinguish between freight and passenger railway vibration, and that the annoyance response due to freight railway vibration is significantly higher than that due to passenger railway vibration, even for equal levels of exposure. In terms of a community tolerance level, the population studied is 15 dB (re 10(-6) m s(-2)) more tolerant to passenger railway vibration than freight railway vibration. These results have implications for the expansion of freight traffic on rail, or for policies to promote passenger railway.

Design of measurement methodology for the evaluation of human exposure to vibration in residential environments

Exposure-response relationships are important tools for policy makers to assess the impact of an environmental stressor on the populace. Their validity lies partly in their statistical strength which is greatly influenced by the size of the sample from which the relationship is derived. As such, the derivation of meaningful exposure-response relationships requires estimates of vibration exposure at a large number of receiver locations. In the United Kingdom a socio-vibrational survey has been conducted with the aim of deriving exposure-response relationships for annoyance due to vibration from (a) railway traffic and (b) the construction of a new light rail system. Response to vibration was measured via a questionnaire conducted face-to-face with residents in their own homes and vibration exposure was estimated using data from a novel measurement methodology. In total, 1281 questionnaires were conducted: 931 for vibration from railway traffic and 350 for vibration from construction sources. Considering the interdisciplinary nature of this work along with the volume of experimental data required, a number of significant technical and logistical challenges needed to be overcome through the planning and implementation of the fieldwork. Four of these challenges are considered in this paper: the site identification for providing a robust sample of the residents affected, the strategies used for measuring both exposure and response and the coordination between the teams carrying out the social survey and the vibration measurements.

The Effect of Fluctuations on the Perception of Low Frequency Sound

Results of laboratory tests are presented in which 18 subjects, including some low frequency noise sufferers, were presented with low frequency sounds with varying degrees of fluctuation. Thresholds of acceptability were obtained for each sound and each subject, using the method of adjustment. These thresholds were then normalised to individual low frequency hearing threshold. It was found that sufferers tend to set thresholds of acceptability closer to their hearing threshold than other subject groups. Also, acceptability thresholds were set on average 5dB lower for fluctuating sounds. It is proposed that a sound should be considered fluctuating when the difference between L10 and L90 exceeds 5dB, and when the rate of change of the ‘Fast’ response sound pressure level exceeds 10dB/s

Field Measurements in the Development of Methods for the Assessment of Low Frequency Noise

A procedure for the assessment of Low Frequency Noise (LFN) by Environmental Health officers has recently been developed in the UK. The development of the assessment method included laboratory test, interview-based questionnaires and field measurements. The results of the field measurements are presented in the form of frequency analyses and time histories. The examples are likely to be of particular interest to Environmental Health officers involved in the assessment of low frequency noise complaints.

Quantification of the effects of audible rattle and source type on the human response to environmental vibration

The present research quantifies the influence of source type and the presence of audible vibration-induced rattle on annoyance caused by vibration in residential environments. The sources of vibration considered are railway and the construction of a light rail system. Data were measured in the United Kingdom using a socio-vibration survey (N = 1281). These data are analyzed using ordinal logit models to produce exposure-response relationships describing community annoyance as a function of vibration exposure. The influence of source type and the presence of audible vibration-induced rattle on annoyance are investigated using dummy variable analysis, and quantified using odds-ratios and community tolerance levels. It is concluded that the sample population is more likely to express higher levels of annoyance if the vibration source is construction compared to railway, and if vibration-induced rattle is audible.

Research into the human response to vibration from railways in residential environments.

This paper describes progress in research being carried out at the University of Salford to develop a method by which human annoyance to vibration in residential environments can be assessed. The objective of this study is to yield a robust relationship between vibration exposure and human response, therefore providing a reliable basis for the development of standards and guidance for the assessment of vibration in residential buildings. The vibration sources to be considered are those affecting residents that are outside their control, such as construction, road, and rail activities. Noise is also a consideration. The protocol involves the measurement of vibration outside and inside individual residences and a social study questionnaire based on face‐to‐face interviews with householders. Work so far has concentrated on the response of people in their own homes to railway noise and vibration. Approximately 1000 case studies have been obtained, and examples of early field measurements and results are prese...

Measurement of force and moment mobilities using a finite difference technique

Measuring only force mobilities it is possible to derive a moment mobility without the need for an externally applied moment. The method uses finite differences of both forces and velocities about a central point. In this way pure forces and moments can be extracted as can pure velocities and angular velocities. There are, however, errors associated with finite difference techniques. In this case the purity of the extracted quantities depends on the area over which they are measured and its significance in terms of wavelength. Meanwhile experimental errors such as noise dictate that the area is sufficiently large to provide differences which are incorruptible. The paper aims to quantify the finite difference error in a general way free of situation specifics.

Human annoyance, acceptability and concern as responses to vibration from the construction of Light Rapid Transit lines in residential environments.

The aim of this paper is to investigate the use of different self-reported measures for assessing the human response to environmental vibration from the construction of an urban LRT (Light Rapid Transit) system. The human response to environmental stressors such as vibration and noise is often expressed in terms of exposure-response relationships that describe annoyance as a function of the magnitude of the vibration. These relationships are often the basis of noise and vibration policy and the setting of limit values. This paper examines measures other than annoyance by expressing exposure-response relationships for vibration in terms of self-reported concern about property damage and acceptability. The exposure-response relationships for concern about property damage and for acceptability are then compared with those for annoyance. It is shown that concern about property damage occurs at vibration levels well below those where there is any risk of damage. Earlier research indicated that concern for damage is an important moderator of the annoyance induced. Acceptability, on the other hand, might be influenced by both annoyance and concern, as well as by other considerations. It is concluded that exposure-response relationships expressing acceptability as a function of vibration exposure could usefully complement existing relationships for annoyance in future policy decisions regarding environmental vibration. The results presented in this paper are derived from data collected through a socio-vibration survey (N=321) conducted for the construction of an urban LRT in the United Kingdom.