An equation for estimating the maximum allowable surface temperatures of electronic equipment

Surface temperatures of electronic equipment and other machinery are an important design constraint since excessively high temperatures can be a safety hazard. Thus, government and industry standards have been established for maximum acceptable temperatures of hot surfaces that may be touched. Unfortunately, their recommendations are often limited to a few broad classes of materials, and appear to differ substantially from each other. They also do not adequately account for the unique properties of many advanced materials that have been developed recently. In order to address these issues, this paper presents explicit equations that can be used to set thermal safety criteria depending on the material and time of contact. They have been developed using data that are the basis for previous standards and are meant to supplement them in modeling, product design and testing.