This document may not be reproduced in full or in part without the written consent of Marshall Day Acoustics Limited Rp 001 R0 20210601 SJP (Waihi North Noise Assessment) ISSUE 12 of 79 2.3 General Noise Guidance 2.3.1 NZS 6801 and 6802 The Hauraki District Plan refers to, and requires assessment in accordance with, NZS 6801:2008 and NZS 6802:2008. These Standards represent current industry best practice. NZS 6802:2008 is commonly used in New Zealand to inform assessments of environmental effects. The Standard provides the following guidance on desirable upper limits of sound exposure at or within the boundary of any residential land use: • Daytime – 55 dB LAeq (15 min) • Evening – 50 dB LAeq (15 min) • Night-time – 45 dB LAeq (15 min) and 75 dB LAFmax The noise levels provided in the Standard are intended to provide territorial authorities with appropriate guidance for the development of local noise criteria. (It notes that the inclusion of an evening period and its hours of application are a matter for the relevant local authority.) Clause C8.6.2 of the Standard provides further discussion on these guidelines: ‘The recommended daytime limit of 55 dB LAeq (15 min) is consistent with the guideline values for community noise in specific environments published by the World Health Organization. The World Health Organization identifies that during the daytime, few people are seriously annoyed by activities with levels below 55 dB LAeq. The night-time limit recommended should not exceed 45 dB LAeq (15 min) outside dwellings so that people can sleep with windows open for ventilation and achieve the desirable indoor 30 to 35 dB LAeq (15 min) level as a design level to protect against sleep disturbance.’ 2.3.2 Resource Management Act 1991 Regardless of any noise performance standards provided in local legislation or specific land-use consents, the RMA imposes overarching obligations on all generators of noise. Section 16 of the Act concerns one’s duty to avoid unreasonable noise and states that: ‘Every occupier of land (including any premises and any coastal marine area), and every person carrying out an activity in, on, or under a water body or the coastal marine area, shall adopt the best practicable option to ensure that the emission of noise from that land or water does not exceed a reasonable level.’ Section 17 also states that every person has a duty to avoid, remedy, or mitigate any adverse effect on the environment arising from an activity carried out by or on behalf of the person. 2.3.3 International Guidance The key international guidance is that provided by the World Health Organization’s (WHO) Guidelines for Community Noise4. For community or environmental noise, the critical health effects (those effects which occur at the lower exposure levels) are: • Sleep disturbance; • Annoyance (slight, moderate, high); and • Speech interference/communication disturbance. The Guideline Values for these three critical health effects for community or environmental noise are presented in Table 3. These guidelines, based on extensive international research, are the exposure levels that 4 Berglund, B. et al, Guidelines for Community Noise. World Health Organisation (1999). represent the onset of the effect for the general population. That is, at these noise levels, critical health effects only begin to appear in a small number of vulnerable or sensitive groups. The WHO regards these as ‘ideal’ objectives that are not often reached in practice. Table 3: WHO Guideline Values for the critical health effects of community or environmental noise Specific Environment Critical health effect(s) dB LAeq Time base (hours) dB LAmax Outdoor living area Serious annoyance, daytime & evening Moderate annoyance, daytime & evening 55 50 16 16 - - Dwellings, indoors Inside bedrooms Speech Intelligibility and moderate annoyance, daytime & evening Sleep disturbance, night-time 35 30 16 8 - 45 Outside bedrooms Sleep disturbance, window open (outdoor values) night-time 45 8 60 2.3.4 Parks, Conservation Areas and Open Spaces Although specific health impacts from noise are not an issue for conservation areas, due to the limited exposure time of people in these areas and their general discretionary choice in being present, it is expected that there could be a degree of impact in terms of people’s expectations of high amenity. If this is perceived as being impacted there can be subsequent annoyance effects. Included in the WHO Guidelines is advice relating to Parkland and conservation areas, which is as follows; “Existing large quiet outdoor areas should be preserved and the signal-to-noise ratio kept low”. This essentially deems it desirable to ensure that little change to the noise environment occurs in these areas, to ensure that amenity remains high. The WHO Guidelines are supported by numerous studies on the effects of noise on users of parks, open spaces and wilderness areas. Horonjeff5 (2005) attempts to define methods quantifying the natural soundscape of wilderness environments in terms of duration of ‘quiet time’ and the time a visitor has to wait to experience quiet times of certain durations. This ‘wait time’ can then be used to evaluate the impact of anthropogenic noise sources on areas mainly devoid of human made sounds. The study was based on the effects of aviation noise intrusion. The author concludes “… sources relatively low in level, by urban and suburban standards, are distinctly audible in low-ambient environments. And their presence is readily obvious at long distances. During low wind conditions, it was not unusual for the ambient sound level to drop near or below the human threshold of hearing. Under such conditions, motorized sources can be audible for long periods of time”. Other studies concur and have found that ‘back-country’ visitors consistently show greater sensitivity to sounds than do ‘front-country’ visitors (i.e. those who may use easily accessible lookouts etc.). Therefore, because the ventilation raises associated with WUG are proposed in what amounts to conservation/open space areas, it is recommended that operational noise emissions should be minimised as much as is practicable, and they should not exceed the background noise level at any nearby walkways or campsites. This approach reflects the intent of the WHO Guidelines and is considered an appropriate method to adopt for this project. We consider that construction noise, as temporary in nature, does not need to meet this goal. 5 Horonjeff, R, D; “Queuing for Quiet-The Natural Soundscape from a Visitor Perspective”, Presented at the Acoustical Society of America Noise Conference meeting 2005, Minneapolis, October 19, 2005
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