照明系统外文翻译.docx

1、照明系统外文翻译英文翻译原文：ABSTRACT This paper discusses the implementation of semi-permanent, high-mast pole-mounted lighting for nighttime road work construction and maintenance based on an installation along Interstate 90 in Albany, New York. The high-mast lighting system met state lighting performance speci

2、fications. There were no recorded accidents at the site during the construction period. Although this is largely attributable to roadway closures allowed during part of the project, the consensus of the contractor and transportation agency is that the lighting contributed at least in part to an incr

3、ease in safety. The cost of the high-mast lighting system was approximately 16% higher than the estimated cost of the portable light towers. Despite the higher estimated cost of the high-mast lighting system, the economic and societal benefits appear considerable in this particular location, namely

4、an urban, heavily traveled throughway. In particular, this lighting approach probably allowed the duration of the construction period to be shortened, leading to a reduction in worker and driver risk exposures and to a reduction in traffic delays for motorists. An approach to identifying projects wh

5、ere this lighting technique might be warranted is presented.INTRODUCTION Semi-permanent, high-mast (70 ft.) pole-mounted fixtures were used by a construction contractor hired by the New York State Department of Transportation (NYSDOT) to illuminate nighttime road work construction and maintenance al

6、ong a three-mile stretch of Interstate 90 (I-90) in Albany, N.Y., as an alternative to the more common portable light towers (1). The high-mast lighting was installed prior to construction work and removed after the construction project was completed, about seven months later. Freyssinier et al. (2)

7、 documented the high-mast lighting system and its performance in terms of photometric performance, visibility and glare. The high-mast lighting system was found to have performed well and as intended. The installation provided a level of illumination sufficient for performing the maintenance and con

8、struction activities at the site (3), with less pronounced shadows and relatively low glare. The purpose of the present paper is to discuss approaches to identifying if and when this lighting approach can be appropriate for a highway construction project. Issues regarding safety, economics and envir

9、onmental impacts are discussed, and an approach to warranting semi-permanent, high-mast nighttime construction lighting is offered. To decide if and when semi-permanent high-mast lighting is feasible for highway construction work, one must consider safety, economics and environmental impacts. These

10、issues are discussed, in turn, in the following sections. SAFETY Crash Risk Factor When the contractor hired by NYSDOT to perform road work along I-90 proposed using semi-permanent, high-maslighting for nighttime construction work, safety engineers analyzed the proposal against the concern that most

11、 (aboutwo-thirds) of the proposed high masts would be located within the 30 ft clear zone desired for this highway. The clear zone is defined (4) as the area outside the paved roadway area where a vehicle could safely travel if it left the road. Acknowledging that portable lighting for nighttime roa

12、dway construction work is nearly always located withinthe clear zone and in fact often closer to drivers, NYSDOT engineers concluded that high-mast lighting probably had a lower risk factor than portable light towers, and authorized the contractor to proceed with the installation and roadwork, based

13、 on the following reasons: While in use, portable light plants are almost always located inside the clear zone. About one third of the 108 high-mast poles proposed could be located outside the clear zone without compromising lighting quality. The lower number of poles in the clear zone, compared to

14、the number of conventional, portable units needed to illuminate a portion of the highway, was thought to weigh against the added risk of drivers! constant exposure to semi-permanent poles during both daytime and nighttime. Howeveradditional safety features were recommended, such as traffic barriers,

15、 guards and crash cushions. High-mast poles avoid the high-risk exposure of workers every night during setup and removal of the conventional portable light units. In the I-90 project, it was estimated that at least 8250 worker-hours of high-exposure would be eliminated. Time savings in the mobilizat

16、ion of portable lights meant night construction could be completed in 222 days rather than 275, reducing the work to one construction season. NYSDOT!s authorization was conditioned on tremoval of the high-mast poles by winter shutdown, regardless of the contractor!s work accomplishments.Worker Safet

17、y Implications While the conventional light towers are extremely useful because of their portable nature, there are a number of known issues regarding the difficulty of their installation, operation, and maintenance. First, there are a large number of warnings associated with most products (during s

18、etup, operation, maintenance, stowing, and transportation). Second, the two main risks associated with the use of portable light towers are the interaction of workers with traffic during setup and removal when both conditions represent a high risk of collision between workers and drivers, and the se

19、tup of light towers near power lines. Although there are no published statistics, it is reasonable to believe that crews are at increased risk of injury or fatality when raising a mast near power lines. It follows that by having a semi-permanent lighting installation, much of the risk mentioned woul

20、d not be present. TABLE 1 Estimated Operational Cost of Portable Light Tower InstallationEstimated number of portable light towers required 120*Daily setup and removal costNumber of crew members in charge of setup and removal 10Estimated number of hours to setup and remove light towers, per night 3T

21、otal worker hours per night 30Estimated cost per hour (base rate + benefits + overhead & profit) $40 Total setup and removal cost per night $1,200 Daily operational cost Hourly operational cost per light tower (fuel, oil, regular maintenance, etc.) $3.60 Estimated daily cost per light tower ( 6 hour

22、s per night) $21.60 Daily rental cost ( $990 per month rent) $33 Total operational cost per night (assuming contractor owns 100 towers and rents 20) $3,252 Total cost per night (setup, removal, and operation) $4,452Estimated duration of project in days 275*Total cost to provide lighting with 120 por

23、table light towers $ 1,224,300120 towers is estimated to be required to illuminate a sufficient portion of the work zone at one time. The duration was estimated to be 40 days shorter using the high-mast system. Another potential safety benefit of high-mast lighting that could not be quantified preci

24、sely was the fact that warning signs, signals, and other materials for guiding traffic through the work zone could be set up each night under lighted conditions. In comparison, such warnings are typically set up by workers in advance of having the conventional light towers operational. The Environme

25、ntal Protection Agency recommends a maximum noise level of 75 dBA in work environments for hearing conservation (5). Though the generators that power most of the commercial light towers typically have a noise level rating of 71 dBA, the large number of light towers (each with its own generator) and

26、their relatively close spacing (typically about 100 ft between units) can cause noise to add up to levels that could be more than the maximum recommended. During this project, five large generators powered the entire high-mast lighting installation; each generator was located as far from the work ar

27、ea as possible. Each of these generators was rated at 71 dBA, dramatically reducing noise levels throughout the site. Workers of this project commented that the noise reduction enabled them to hear vehicles approaching, again greatly decreasing their risk of injury by a moving vehicle or machine. Fi

28、nally, by using high-mast lighting with remotely located generators, workers were not as exposed to the fumes and harmful pollutants that result from the generators adjacent to each portable light tower and that might cause headaches, fatigue, and potential heart problems (6). ECONOMIC ANALYSIS Tabl

29、es 1 and 2 summarize the economics of a lighting system using the portable towers and the high-mast system. Despite the higher estimated cost (approximately 16% higher) of the high-mast system as outlined in these two tables, there were several positive economic implications that resulted from the u

30、se of high-mast lighting. One significant benefit was the time saved every day from not having to setup and remove the portable light towers. This time could be used performing the contracted construction work rather than setting up lighting equipment, probably contributing to the ahead of schedule

31、completion of the project. In this project, the estimated cost of setup and removal of portable light tower added up to $330,000 (30 worker-hours per night at $40 per hour, for 275 days). For larger jobs this cost would increase considerably. TABLE 2 Estimated Operational Cost of Semi-Permanent High

32、-Mast Lighting InstallationNumber of high-mast poles installed 108Number of 250-kW generators installed 5Installation costsEstimated installation cost per pole $2,844 Estimated installation cost per kW of generator capacity $24.50 Total estimated installation costs (poles and generators) $337,777Lighting equipment rentalEstimated rental cost per pole with four luminaires $5,500 Total lighting equipment rental (for the duration of the project) $594,000Generation costsEstimated purchase cost per kW of generator capacity $200 Estimated total generators purchas