Thermal Considerations for Information Technology Equipment from Product Safety Perspective

Thermal consideration as one of the most significant factors from product safety discipline, it is related to cooling methods, ambient temperature, airflow, touch temperature for accessible parts, module power dissipation, and so on. This paper provides comprehensive perspectives to explores the thermal considerations which should be focused on the product safety compliance of information technology equipment, from theory analysis to practical implementations, from the design techniques to testing strategy. Some of the design techniques for thermal management are proposed, including DC fan and heatsink selections, some PCB (Printed Circuit Board) design tips, and the design considerations for a fan-less system. Regarding test strategy, this paper demonstrates that the maximum loading for a system at maximum ambient temperature maybe not be as the worst case to represent the test result for some safety-critical components, especially for temperature-dependent equipment with smart fan, since the fan speed will be variable with the monitor or sensing temperature or loading condition. Therefore, test engineers need to understand these related designs, including the key components to be monitored, the over-temperature protection mechanism, the algorithm of fan speed, and so on. This paper also discusses the requirements from existing product safety standards, including IEC 60950–1 and IEC 62368–1. At the end of this paper, liquid cooling solutions for information technology equipment has also been discussed from a product safety perspective; the considerations should be different for liquid filled heat-sink system and insulating liquid immersion cooling system.