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ASHRAE psychrometric chart showing the IT equipment manufacturer recommended and the allowable ranges: recommended range: temperature-18 C to 27 C, RH-60%; allowable range: A1: 15 C to 32 C, RH-8% to 80%; allowable range: A2: 10 C to 35 C, RH-8% to 80%; allowable range: A3: 5 C to 40 C, RH-8% to 85%; and allowable range: A4: 5 C to 45 C, RH-8% to 90%

ASHRAE psychrometric chart showing the IT equipment manufacturer recommended and the allowable ranges: recommended range: temperature-18 C to 27 C, RH-60%; allowable range: A1: 15 C to 32 C, RH-8% to 80%; allowable range: A2: 10 C to 35 C, RH-8% to 80%; allowable range: A3: 5 C to 40 C, RH-8% to 85%; and allowable range: A4: 5 C to 45 C, RH-8% to 90%

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Airside economizers lower the operating cost of data centers by reducing or eliminating mechanical cooling. It, however, increases the risk of reliability degradation of IT equipment due to contaminants. IT Equipment manufacturers have tested equipment performance and guarantee the reliability of their equipment in environments within ISA 71.04-201...

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Context 1
... psychrometric chart in Fig. 1 illustrates the recommended and allowable ranges for temperature and humidity, respectively [2][3][4][5][6]. Air entering the data center through airside economizers operating outside ASHRAE's recommended temperaturehumidity envelope is a potential risk to IT equipment within the data center [6]. Environmental factors such as ...
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... psychrometric chart with dry and wet bulb temperatures, are mostly in the A3 allowable region from ASHRAE TC 9.9 guidelines. It is an indication that our IT equipment was exposed during this period to conditions well outside the recommended zone. In allowable A3, you have an upper dry bulb temperature of 40 C. For the month of May, as shown in Fig. 10, there is some distribution of inlet conditions across A2-A3. Here, some data points are in the A1 region, but none are in the recommended envelope. There are slight excursions into A4 zone as ...
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... the month of June, as shown in Fig. 11 along with the distribution across A1-A4, there were excursions well outside both the recommended and the allowable zones. Although the percentage excursions outside the allowable zone are less than 10% in this In the month of July, as shown in Fig. 12, the excursions outside the recommended/allowable envelope are almost the same as ...
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... the month of June, as shown in Fig. 11 along with the distribution across A1-A4, there were excursions well outside both the recommended and the allowable zones. Although the percentage excursions outside the allowable zone are less than 10% in this In the month of July, as shown in Fig. 12, the excursions outside the recommended/allowable envelope are almost the same as the month of June and they have similar distributions. Discussion on a Power Distribution Unit Failure. The research data center was under operation until a failure was recorded on two PDUs in the hot aisle adjacent to the racks. Figures 13(a) and 13(b) ...
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... research data center was under operation until a failure was recorded on two PDUs in the hot aisle adjacent to the racks. Figures 13(a) and 13(b) show failed PDUs in the hot aisle. Copper connectors as seen appear to have been exposed directly to the surrounding air with the right temperature and moisture and certain levels of contaminants. ...
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... Observation of Servers. In addition, the following hardware components shown in Figs. 14(a)-14(c), respectively, are of the server under operation in the research data center, visually inspected for possible gaseous/particulate ...

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... In this subsequent research, a few servers were randomly removed from the racks and a qualitative study of cumulative corrosion damage was carried out [149,150]. The particulate matter was characterized using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and Fourier transform infrared spectroscopy (FTIR) as shown in Fig. 20. The figure at the top depicts the particle sizes measured at random locations using image analysis in MATLAB. ...
... As for the facility water, the linear graph showed that the experimental value of DRH is 80%. Based on this series of studies [148][149][150][151][152], it can be concluded that for the data center site studied in these investigations the DRH value of the particulate matter lies between 70 and 80%. Therefore, the operating relative humidity inside the IT pod of this site should be maintained below this range. ...
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Over the last decade, several hyper-scale data center companies such as Google, Facebook, and Microsoft have demonstrated the cost-saving capabilities of airside economization with direct/indirect heat exchangers by moving to chiller-less air-cooled data centers. Under pressure from data center owners, IT equipment OEMs like Dell and IBM are developing IT equipment that can withstand peak excursion temperature ratings of up to 45°C, clearly outside the recommended envelope, and into ASHRAE's A4 allowable envelope. As popular and widespread as these cooling technologies are becoming, airside economization comes with its challenges. There is a risk of pre-mature hardware failures or reliability degradation posed by uncontrolled fine particulate and gaseous contaminants in presence of temperature and humidity transients. This paper presents an in-depth review of the particulate and gaseous contamination-related challenges faced by the modern-day data center facilities that use airside economization. This review summarizes specific experimental and computational studies to characterize the airborne contaminants and associated failure modes and mechanisms. In addition, standard lab-based and in-situ test methods for measuring the corrosive effects of the particles and the corrosive gases, as the means of testing the robustness of the equipment against these contaminants, under different temperature and relative humidity conditions are also reviewed. It also outlines the cost-sensitive mitigation techniques like improved filtration strategies and methods that can be utilized for efficient implementation of airside economization.
... From the studies of Refs. [8], [16], and [20][21][22] and this paper, it was noted that there had been no server failures in the test site due to gaseous and particulate contaminants. It is then recommended that this data center can be operated outside of the ASHRAE recommended envelope for an extended period taking advantage of free cooling. ...
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A remarkable amount of energy in data centers is consumed in eliminating the heat generated by the IT equipment to maintain and ensure safe operating conditions and optimum performance. The installation of Airside Economizers, while very energy efficient, bears the risk of particulate contamination in data centers, hence, deteriorating the reliability of IT equipment. When RH in data centers exceeds the deliquescent relative humidity (DRH) of salts or accumulated particulate matter, it absorbs moisture, becomes wet and subsequently leads to electrical short circuiting because of degraded surface insulation resistance between the closely spaced features on printed circuit boards. Another concern with this type of failure is the absence of evidence that hinders the process of evaluation and rectification. Therefore, it is imperative to develop a practical test method to determine the DRH value of the accumulated particulate matter found on PCBs (Printed Circuit Boards). This research is a first attempt to develop an experimental technique to measure DRH of dust particles by logging the leakage current versus RH% (Relative Humidity percentage) for the particulate matter dispensed on an interdigitated comb coupon. To validate this methodology, the DRH of pure salts like MgCl2, NH4NO3 and NaCl is determined and their results are then compared with their published values. This methodology was therefore implemented to help lay a modus operandi of establishing the limiting value or an effective relative humidity envelope to be maintained at a real-world data center facility situated in Dallas industrial area for its continuous and reliable operation.