【正文】 during normal operation and during startup and shutdown Procedures must be in place for response to an event that shuts down critical cooling systems while critical loads continue to operate, causing the space temperature to begin rising immediately. Procedures should also be in place governing how quickly elevated space temperatures can be returned to normal to avoid thermal shock damage. Data equipment usually tolerates a somewhat wider range of environmental conditions when not in use [sec Table in ASHRAE (2008)]. However, it may be desirable to provide uninterruptible cooling in the room to maintain operating limits and minimize thermal shock to the equipment.26日Humidity High relative humidity may cause conductive anodic failures (CAF), hygroscopic dust failures (HDF), tape media errors and excessive wear, and corrosion. In extreme casts, condensation can occur on cold surfaces of liquidcooled equipment. Low relative humidity may result in electrostatic discharge (ESD), which can destroy equipment or adversely affect operation. Tape products and media may HAVC excessive errors when exposed to low relative humidity. In general, facilities should be designed and operated to maintain the remended humidity range in Table 1, but excursions into the allowable range (more typically the equipment specification) should not significantly shorten equipment operating lift.Filtration and Contamination Before being introduced into the data and munications equipment room, outside air should be filtered and preconditioned to remove particulates and corrosive gases. Table 1 contains both remended and minimum filtration guidelines for recirculated air in a data center. Particulates can adversely affect data and munications equipment operation, so highquality filtration and proper filter maintenance are essential. Corrosive gases can quickly destroy the thin metal films and conductors used in printed circuit boards, and corrosion can cause high resistance at terminal connection points. In addition, the accumulation of particulates on surfaces needed for heat removal (., heat sink fins) can degrade heat removal device performance. Further information on filtration and contamination in data centers can be found in Chapter 8 of Design Considerations for Data Equipment Centers (ASHRAE 2005b) and Particulate and Gaseous Contamination in Data Environ meets (ASHRAE 2009)Ventilation Data and munications equipment room air conditioning must provide adequate outside air to achieve the following criteria:因此，當(dāng)設(shè)備長(zhǎng)期暴露在高溫環(huán)境下（溫度波動(dòng)頻率或幅度大），就會(huì)提高設(shè)備的故障率，降低設(shè)備使用壽命，硬件/軟件故障率提高，傳熱性能下降。圖 1A 數(shù)據(jù)中心Class Class 2和 NEBS推薦的環(huán)境參數(shù)表1 數(shù)據(jù)中心Class Class 2和 NEBS設(shè)計(jì)參數(shù)a. Inlet conditions remended in ASHRAE (2008). a. ASHRAE (2008)推薦送風(fēng)溫度；b. Percentage values per ASHRAE Standard 52. 1 dust spot efficiency test. MERV values per ASHRAE Standard b. ，MERV(Minimum Efficiency Reporting Value)c. Telcordia (2006).d. Telcordia (2001).e. Generally accepted telemunications practice. Telemunications central offices are not generally humidified, but personnel are often grounded to reduce electrostatic discharge (ESD)e. 通信行業(yè)常規(guī)做法。NEBS(網(wǎng)絡(luò)設(shè)備構(gòu)建系統(tǒng)):根據(jù)Telcordia(2001, 2006)規(guī)定，通常電信中心需要有環(huán)境控制裝置（露點(diǎn)，溫度和相對(duì)濕度）；交換機(jī)、傳輸設(shè)備和路由器一般按照此條規(guī)定的環(huán)境參數(shù)設(shè)計(jì)。第三類(lèi)：通常辦公室、家庭或者運(yùn)輸環(huán)境只需要控制環(huán)境溫度（溫度）；個(gè)人電腦、工作站、筆記本電腦和打印機(jī)一般按照此條規(guī)定的環(huán)境參數(shù)設(shè)計(jì)。 通信設(shè)備服務(wù)器和存儲(chǔ)設(shè)備一般按照此條規(guī)定的環(huán)境參數(shù)設(shè)計(jì)。雖然工作人員占用的數(shù)據(jù)通信機(jī)房較小，但對(duì)通風(fēng)設(shè)計(jì)也會(huì)有要求。磁帶存儲(chǔ)器tape storage新設(shè)備對(duì)電功和制冷量要求的會(huì)更大。CHAPTER 19 DATA PROCESSING AND TELECOMMUNICATION FACILITIES第19章 數(shù)據(jù)處理和電信設(shè)施Design CriteriaHVAC Load considerationsHVAC Systems and ComponentsAir Distribution Ancillary spaces Other Systems and considerations 設(shè)計(jì)標(biāo)準(zhǔn) 空調(diào)負(fù)荷注意事項(xiàng) 空調(diào)系統(tǒng)和組件 氣流組織 輔助空間 其它系統(tǒng)和注意事項(xiàng)DATACOM (data processing and telemunications) facilities are predominantly occupied by puters, networking equipment, electronic equipment, and peripherals. The most defining HVAC characteristic of data and munications equipment centers is the potential for exceptionally high sensible heat loads (often orders of magnitude greater than a typical office building). In addition, the equipment installed in these facilities typically:數(shù)據(jù)通信（數(shù)據(jù)處理和電信）設(shè)施主要由計(jì)算機(jī)、網(wǎng)絡(luò)設(shè)備、電子設(shè)備和其它輔助設(shè)備組成。在數(shù)據(jù)通信設(shè)備電源的發(fā)展過(guò)程和冷卻應(yīng)用中(ASHRAE 2005a)，典型的數(shù)據(jù)通訊設(shè)備產(chǎn)品壽命為1至5年，而空調(diào)設(shè)施和基礎(chǔ)設(shè)施的壽命為10年至25年。Communication (Extremedensity)通訊(超高密度)工作人員也占用數(shù)據(jù)通信中心，但其通常是暫時(shí)的，所以機(jī)房環(huán)境條件（如溫度，噪音）常由設(shè)備的需求決定，因此空調(diào)系統(tǒng)更多的是冷卻功能而不是舒適功能。第一類(lèi)：通常數(shù)據(jù)通信設(shè)施有嚴(yán)格控制環(huán)境參數(shù)（露點(diǎn)，溫度和相對(duì)濕度）和重要操作。 types of products typically designed for this environment are personal puters, workstations, laptops, and printers. types of products typically designed for this environment are switches, transport equipment, and routers.請(qǐng)注意，露點(diǎn)溫度和相對(duì)濕度也已給出。Temperature 溫度 The allowable temperature range is a statement of functionality, whereas the remended range is a statement of reliability. Thus, equipment exposed to prolonged high temperatures (and/or to steep temperature gradients) can experience increased failure rates, reduced service life, hardware and/or software failures, and/or thermal shutdown. Exceeding the remended limits for short periods of time should not be a problem, but running near the allowable limits for months could result in increased reliability issues. Facility designers and operators should strive for continuous operation in the remended range. ASHRAE (2008) and Telcordia (2001) remended range is 18 to 27℃.盡管建議的設(shè)備的允許溫度范圍是可靠的，但它只是一個(gè)功能說(shuō)明。The inlet air temperature in many data centers tends to be warmer near the top of racks, particularly if warm rack exhaust air dots not HAVC a direct return path to the CRACs. This warmer air also affects the relative humidity, resulting in lower values at the top of the rack. The air temperature generally follows a horizontal lint on the psychometric chart where absolute humidity remains constant but relative humidity decreases.Fig. 2 Class 1, Class 2, and NEBS Allowable Temperature Range Versus AltitudeTemperature Rate of Change Some data manufacturers HAVC established criteria for allowab