Study On The Light Environment Of Stairway At Night In Old Communities Of Mountainous Cities Under The Background Of Aging

This paper relies on Chongqing University Innovation Team Building Project(Team Name: Health Lighting Innovation Team,No.CXTDX201601005).At present,China’s aging rate continues to rise,and the growing number of old people’s material life and other issues are the current and future focus point of the whole society.Due to the deterioration of physical functions and other aspects,the elderly are fall more easily than young people,while falling from the stairway is more serious.The lack of night lighting aggravates the risk of the event.There are many old communities which have high aging rate,dangerous stairway,and lack of night lighting in Chongqing.So,it is urgent to create a safe,comfortable and beautiful stairway light environment for the elderly.Therefore,this study from the perspective of the elderly,through the means of literature research,field investigation,simulation experiment and field experiment,focuses on the light environment of the old community.This paper consists of five parts:theoretical research,investigation research,evaluation system construction,simulation experiment research and field experiment.(1):Theoretical research: In this part,through a large number of domestic and foreign literature,starting with the lighting needs and lighting psychology of the elderly,the paper analysis the stairway lighting in detail.Firstly,it summarizes the four lighting forms of the stairway,their respective characteristics and sphere of application,then analysis the influencing factors of the stairway lighting,such as the number of steps and enclosure forms.Finally,summarizing the four basic principles of the stairway lighting design: safety,comfort,energy conservation and environmental protection,and aesthetics.This part providing theoretical support for the follow-up research.(2):Investigation research: This part carries on the field investigation to 5 old communities in Yuzhong District of Chongqing,analysing the core problems of the existing stairway lighting through the measured data,and obtains the main factors that affect the elderly residents’ cognition of the stairway lighting safety combined with the questionnaire.(3):Construction of evaluation system: In this part,based on the criteria of safety,comfort and energy-saving,the evaluation system of night light environment of old community stairway covering 11 indexes is constructed,and the weight of each index is given by Delphi method and AHP,and the weight vector of each evaluation index to the target layer is finally determined.(4):Simulation experiment: in this part,the number of steps,color temperature and lighting form are used as variables,Simulating the lighting scene through Dialux,the following conclusions are obtained: when the number of steps is less than or equal to level2,it is better to use the side lighting form of steps,when the number of steps is 11-18 or greater than level 18,the street lighting form should be used as much as possible,and the color temperature should be controlled around 4000 K,avoiding use of low color temperature light source;(5):Field experiment: In this part,according to the most widely used street lamp lighting form in the current stairway lighting,the field standing lamp experiment is carried out,and the following conclusions are drawn:(1):The installation position and angle of the light source shall ensure that a small shadow is formed on the tread of the stairway,and the shadow ratio is preferably between0.25-0.5,not more than 0.56 and not less than 0.22.(2):When the horizontal illuminance of stairway tread exceeds the inflexion illuminance,the total expected value and overall satisfaction of the lighting scheme tend to be gentle.Therefore,the inflexion can be taken as the reference lower limit of the average illuminance of the tread,that is,10 lx can be taken as the reference lower limit of the average illuminance of ≤ 2 and ≥ 19 stairway tread,7.5lx can be taken as the reference lower limit of the average illuminance of > 10 and ≤ 18 stairway tread.(3):When the riser illuminance of the stairway is 1 / 2 of the tread illuminance,the total expected value and overall satisfaction of the stairway lighting reach the peak,so the riser illuminance of the step can be set as 1 / 2 of the tread illuminance.Finally,the above four parts of the research results are summarized and analyzed,and the future research work is prospected,in order to provide reasonable suggestions for the follow-up study of the old community stairway lighting light environment,and to play a positive role in promoting the design of more humanized old community lighting.