Radioluminescence for time measurement instruments — Specifications

This international document establishes a set of technical specifications concerning radioluminescent indicators used in timekeeping instruments. Radioluminescence refers to the emission of light by a material that has been exposed to ionizing radiation. The content focuses on defining the necessary characteristics, performance criteria, and testing methods for these light-emitting components found within watches and clocks. It addresses the uniformity of glow, the duration of luminosity, and the stability of the light output under various environmental conditions. The text provides guidance on the composition and application of radioactive sources, such as tritium or promethium, integrated into the dial markers or hands to ensure visibility in low-light scenarios. It outlines procedures for measuring brightness levels and evaluating the consistency of illumination across different units. The specification aims to ensure that timepieces equipped with radioluminescent elements meet consistent quality standards, facilitating international trade and consumer confidence. By setting clear parameters for these components, the document supports the reliability of time measurement devices without requiring direct reference to specific manufacturers or regional regulations.