Touch Temperature Safety Standards and their Impact on Server Design

High server heat loads result in excessive exhaust air and surface temperatures for given server airflows. Increasing surface temperatures are restricted by safety standards that govern how hot surfaces can be such that they can be safely handled. Handling of hot surfaces and components must be considered as part of the server design process as parts in the rear of the server, facing into the hot aisle, often need to be serviced during operation. This paper will focus on reviewing trends in server and data center temperature and air flow as well as the International Electrotechnical Commission (IEC) touch safety standards and requirements. This paper will also discuss a server design that highlights how caloric analyses of air heating through the server can lead to a significant under-prediction of surface temperatures on touch points and surfaces due to non-uniform airflow and heating within the server. This paper also seeks to help educate the community on the importance of touch safety standards and how such standards can significantly impact server design and potentially limit the ability to lower fan speeds to improve energy and air usage in servers and data centers.