传统的照明计算方法为房间内容的影响假设了一个净房间体积余量。位于光源和任务之间的物体将起到阻挡直射光的作用，并将导致一些光被物体吸收，一些光从物体表面反射。这可能会导致整个装置的局部和整体平面照度降低。本报告汇集了有关该主题的设计相关材料。本手册旨在作为专家参考，与相关设计指南一起使用。它包含关于不同类型建筑内部可能损失大小的信息，以及改善这些光损失影响的设计指南。该报告的一个主要部分涉及由一般照明系统照明的遮挡室内的计算方法。本文描述了对传统照明设计计算方法的修改，以确认工作平面上方和下方房间内容物的影响。 对如何应用计算机程序进行照明设计和分析，以解决室内障碍物问题提出了建议。报告用英文写成，并附有法文和德文的简短摘要。它由32页8图7表组成。

Traditional lighting calculation methods assume a clear room volume allowance for the influence of room contents. Objects located between light source and task will act to block direct light and will result in some light being absorbed by the object and some reflected from its surface. This may cause both local and general reductions in planar illuminance over a whole installation. This report draws together design related material on the subject. It is intended as specialist reference for use in conjunction with relevant design guidance. It contains information on the magnitudes of likely losses in different types of building interior and design guidance to ameliorate the effects of these light losses.A major part of the report is concerned with calculation methods for obstructed interior lit by general lighting systems. Modifications to traditional lighting design calculation methods to acknowledge the influence of room contents, above and below the working plane are described. Advice on the application of computer programs for lighting design and analysis to solution of problems involving obstructed interiors is given.The report is written in English, with a short summary in French and German. It consists of 32 pages with 8 figures and 7 tables.