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Street Lighting: A Metric for Specifying White Light

街道照明：指定白光的指标

基本信息

批准号：
EP/F035624/1
负责人：
Stephen Fotios
金额：
$ 22.04万
依托单位：
University of Sheffield
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2008
资助国家：
英国
起止时间：
2008 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FF035624%2F1
关键词：
Street Lighting Metric Specifying White

项目摘要

This project will investigate lighting in subsidiary (residential) streets. In recent decades this has been provided mainly using low pressure sodium (LPS) and high pressure sodium (HPS) lamps. These lamps have high luminous efficacy (light output) and a long working life, and these characteristics were considered sufficient to outweigh their poor colour properties / the orange appearance and poor colour rendering. Brightness is an important consideration when lighting pedestrian environments because it is linked to the perception of safety / brighter streets are considered to be safer. Street lighting engineers suggested that using whiter light sources, such as metal halide (MH) and compact fluorescent (CFL) lamps, would create a clearer and brighter environment, and furthermore that street lighting using these whiter light sources could adopt a reduced illuminance (light level) whilst maintaining the same level of brightness and clarity. This illuminance reduction would offset the efficacy of MH and CFL lamps, which tends to be lower than HPS and LPS lamps, and may even lead to a reduction in energy consumption. This anecdotal evidence has been supported through a series of experiments carried out by the applicant (EPSRC grant ref. GR/25074/01) demonstrating savings of approximately 30% in capital and energy costs. A primary reason for this interaction between lamp type and illuminance is that the human eye responds differently at the low levels of light found at night-time than it does in the higher levels typical of daytime, but illuminance specification is calibrated only to the daytime response. The BSI road lighting committee (CPL/34/8) took account of the white light effect in the 2003 revision of BS5489-1. This document interprets the S-series of lighting classes for subsidiary streets specified in BS EN 13201-2:2003 according to the rates of crime and traffic flow. The metric by which BS5489-1:2003 identifies whiter lighting is the General Colour Rendering Index (CRI) and this is because it provides an obvious distinction between the white lamps and the standard HPS and LPS lamps. Thus, BS5489-1:2003 permits a reduction of one class of the S-series, a reduced illuminance, when using lamps having CRI >60. Unfortunately, CRI, by definition and in practice, cannot reliably be used to predict anything except perhaps the naturalness of colour appearance. This is exacerbated at night-time because CRI is based on the visual response under daytime light levels. Even at daytime levels CRI fails to predict the visual appearance of an environment under different types of lamp, and colour appearance under LED lamps, for example, is not well predicted. Although the CRI specification may work with lamps now commonly used for street lighting there will be occasions when it gives inappropriate guidance, for example when extrapolated to distinguish between some other types of lamp.A better method of specification is needed to avoid misapplication. Of equal importance is the need to provide research evidence that can be translated into guidance that is readily accessible to practising lighting engineers. Otherwise it may be ignored, wasting the opportunity for improvements in the visual environment and energy consumption.This project will carry out further tests, supplementing the evidence from recent studies, to generate a dataset against which to test tools for predicting whether an illuminance reduction is appropriate. These tests include brightness matching and visual acuity, using an extended range of lamps. Consultations with lighting engineers will be used to determine how the findings should be presented to ensure an appropriate balance between accuracy and ease of application.

本项目将调查附属（住宅）街道的照明。近几十年来，这主要使用低压钠 (LPS) 和高压钠 (HPS) 灯来提供。这些灯具有高发光效率（光输出）和长工作寿命，并且这些特性被认为足以抵消它们较差的颜色特性/橙色外观和较差的显色性。照明步行环境时，亮度是一个重要的考虑因素，因为它与安全感相关/更明亮的街道被认为更安全。街道照明工程师建议，使用更白的光源，例如金属卤化物（MH）和紧凑型荧光灯（CFL）灯，将创造更清晰、更明亮的环境，此外，使用这些更白的光源的街道照明可以采用降低的照度（光级），同时保持相同水平的亮度和清晰度。这种照度的降低将抵消 MH 和 CFL 灯的功效，而 MH 和 CFL 灯的功效往往低于 HPS 和 LPS 灯，甚至可能导致能源消耗的减少。这一轶事证据已通过申请人进行的一系列实验（EPSRC 拨款编号 GR/25074/01）得到支持，证明资本和能源成本节省了约 30%。灯类型和照度之间存在这种相互作用的主要原因是，人眼在夜间的低光水平下的反应与在白天典型的较高光水平下的反应不同，但照度规格仅针对白天响应进行校准。 BSI 道路照明委员会 (CPL/34/8) 在 2003 年修订 BS5489-1 时考虑了白光效应。本文件根据犯罪率和交通流量解释了 BS EN 13201-2:2003 中规定的辅助街道的 S 系列照明等级。 BS5489-1:2003 识别更白照明的指标是一般显色指数 (CRI)，这是因为它在白灯与标准 HPS 和 LPS 灯之间提供了明显的区别。因此，当使用 CRI >60 的灯时，BS5489-1:2003 允许降低 S 系列的一类，即降低的照度。不幸的是，根据定义和实践，CRI 不能可靠地用于预测任何东西，除了颜色外观的自然度之外。这种情况在夜间会加剧，因为 CRI 基于白天光照水平下的视觉反应。即使在白天，CRI 也无法预测不同类型灯下环境的视觉外观，例如，无法很好地预测 LED 灯下的颜色外观。尽管 CRI 规范可能适用于现在常用的街道照明灯，但有时它会给出不适当的指导，例如，在推断以区分某些其他类型的灯时。需要更好的规范方法来避免误用。同样重要的是需要提供研究证据，这些证据可以转化为执业照明工程师可以轻松获得的指导。否则可能会被忽略，浪费改善视觉环境和能源消耗的机会。该项目将进行进一步的测试，补充最近研究的证据，以生成一个数据集，用于测试预测照度降低是否合适的工具。这些测试包括使用范围广泛的灯的亮度匹配和视敏度。将与照明工程师协商来确定如何呈现研究结果，以确保准确性和易于应用之间的适当平衡。