在照明装置的使用寿命期间，可用光逐渐减少。还原率是环境、操作和年龄条件的函数。在照明设计中，我们必须通过使用维护系数来考虑这个秋天，并计划适当的维护计划来限制衰变。本指南提供了有关建议维护因素和选择合适设备的信息。它描述了影响折旧过程的参数，制定了估算室外电气照明装置经济维护周期的程序，并给出了维修技术建议。 报告用英文写成，并附有法文和德文的简短摘要。共21页，1图4表。

During the life of a lighting installation, the light available progressively decreases. The reduction rates are a function of environmental, operating and age conditions. In lighting design we must take account of this fall by the use of a maintenance factor and plan suitable maintenance schedules to limit the decay. This guide provides information on suggested maintenance factors and the selection of suitable equipment. It describes the parameters influencing the depreciation process and develops the procedure for estimating the economic maintenance cycles for outdoor electric lighting installations and gives advice on servicing techniques.The Report is written in English, with a short summary in French and German. It consists of 21 pages with 1 figure and 4 tables.