ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ This paper will be published at Ashrae journal. For any questions please contact davidjp@mst.edu. Dependence of ESD Charge Voltage on Humidity in Data Centers (Part2 - Data Analysis) Atieh Talebzadeh Abhishek Patnaik Xu Gao Mahdi Moradian Yunan Han David E. Swenson David Pommerenke ABSTRACT This is Part2 of a three-part paper investigating the dependence of charge voltage generated by human activity on humidity in data centers. The first paper described the experimental methods, while this paper is devoted to the analysis of the electrostatic charge voltage levels along the following parameters: relative humidity, absolute humidity, footwear, flooring, and type of activity. The human activities studied included well-defined walking, random walking, taking off and dropping a sweater, and standing up from a chair. This study confirms the importance of footwear and flooring and quantifies their effectiveness. The results indicate that lower absolute humidity may not always lead to higher voltages, while reducing the relative humidity will cause the average voltages to increase. The high voltages created by removing and dropping a sweater and by standing up from a chair indicate that these types of user activities might pose a higher risk of generating voltages greater than 6 kV much larger than the walking activities. The analyses are based on the definition of walking, standing, chair event and sweater event voltages, as presented in Part1. INTRODUCTION Typically, triboelectric charging caused by friction between non-conducting objects or between one conducting and one insulating object creates the charges that may cause an electrostatic discharge (ESD). Various researchers have studied the effect of the relative humidity (RH) on tribo-charge generation. Simonic (1981) investigated ESD discharges in different carpeted rooms, confirming the known strong correlation between the RH and the peak discharge current. For a range of 15% to 55% RH, a relationship has been derived between the probability of an ESD event occurring at a given current level and the RH; this relationship states that the probability of an ESD event occurring at a