TS EN 12665

TS EN 12665 is the standard for the basic terms and criteria used when specifying lighting requirements. In practical lighting work, this kind of document provides a shared vocabulary for indoor and outdoor lighting design so that concepts such as illuminance, luminous flux, luminance, glare and related measures are understood consistently in specifications, design notes and technical discussions. Clear terminology matters because lighting is not only about producing light; it is also about defining visual conditions, user comfort and suitability for the task and space.

Why terminology matters in lighting specification

From a general technical perspective, lighting performance depends on more than lamp output. Surface reflectance, light distribution, the visual task, the geometry of the space and the intended environment all influence whether a scheme is appropriate. A terminology standard helps different professionals use the same concepts in the same way, reducing ambiguity between architects, electrical engineers, lighting designers and facility teams. It supports clearer communication when setting requirements, comparing solutions and documenting design intent.

What this standard provides as a framework

• A common set of basic terms used when describing lighting requirements.
• A basis for consistent interpretation of criteria in lighting specification and evaluation.
• Support for clearer technical documentation beyond the selection of luminaires or controls.
• Reduced terminology confusion in design, procurement and project coordination.