A Critique of the IPC-9591 Standard: Performance Parameters for Air Moving Devices

This paper presents a critique of the IPC standard (IPC-9591) on air-moving devices for the electronics industry, published in 2006. We investigate the applicability of the methods specified by IPC-9591. A fatigue life and a grease life of ball bearings in the fans were calculated using the stress-life method and grease life equation, respectively. The calculated life was compared to the experimental results of the fans. In addition, the mean time to failure of fan electronics was calculated using multiple methods specified by IPC-9591 and validated with experimental results of the fans. Through these exercises, the reliability prediction methods for air-moving devices were shown to be flawed. We make recommendations for IPC and the industry on appropriate methods of reliability assessment for air-moving devices.