This white paper explains the sources of downtime in electric power systems and provides an explanation for site-to-site variations in power availability. The factors affecting power quality from generation to the utilization point are summarized. There is a qualitative description of a model, which can be combined with data to provide a method for estimating down time based on site-related factors.

从自然的发展规律来看，模块化设计是复杂系统赖以生存和繁荣的关键要素。这个成功模式的一个重要贡献就是容错能力在可靠性上极为关键和突出的优势，它可以确保模块化系统在故障模块维修期间改用其它性能完好的模块，以确保系统的正常运行。在数据中心，模块化设计已经植根于服务器和存储系统适用的全新容错架构中。随着数据中心不断演进以及受到大自然发展规律的启发，数据中心物理基础设施（DCPI）必须不断完善，以为企业新的生存、恢复和发展策略提供支持。

Lead-acid batteries are the most widely used method of energy reserve. Ventilation systems must address health and safety as well as performance of the battery and other equipment in a room. Valve regulated lead acid (VRLA) batteries and modular battery cartridges (MBC) do not require special battery rooms and are suitable for use in an office environment. Air changes designed for human occupancy normally exceed the requirements for VRLA and MBC ventilation. Vented (flooded) batteries, which release hydrogen gas continuously, require a dedicated battery room with ventilation separate from the rest of the building. This paper summarizes some of the factors and U.S. codes to consider when selecting and sizing a ventilation system for a facility in which stationary batteries are installed.

Fire safety regulations and their application to uninterrupted power supply (UPS) battery installations in the USA are reviewed. In some cases, fire codes do not clearly recognize improvements in battery safety resulting from changing battery technology. Valve regulated lead acid (VRLA) batteries are frequently deployed within data centers and network rooms without the need for the elaborate safety systems that are required for vented (flooded) lead acid batteries. Proper interpretation of the fire codes is essential in the design and implementation of data centers and network rooms.

燃料电池和微型燃气轮机是数据中心和网络机房可采用的新型发电技术。本文介绍了这些系统的多种工作模式，并分析了这些新技术相对于传统方案（如备用发电机）的优势及劣势。

This white paper explains the special power protection issues related to RS-232 cabling. First, the special vulnerabilities of RS-232 cabling are explained. Then appropriate protection and mitigation techniques are provided.

低于 5000VA 的 UPS 系统均采用下面两种基本设计方案：在线互动式和双转换在线式。本白皮书将介绍各种拓扑结构的优缺点，并着重陈述人们在实际应用需求方面的一些常见误区。

数据中心的规划和设计工作包括计算 IT 设备的电源和制冷需求，以符合电力基础设施的容量。本白皮书说明了计算功率和制冷需求的方法，并提供确定支持数据中心（包括 IT 设备、制冷系统、照明设施和备用电源）所需总电源功率容量的指导原则。

IT managers will be surprised to learn that some medium and high power UPS systems on the market today (rated 50 kW and higher) use undersized static bypass switches despite their negative implications. By using a contactor or a circuit breaker in parallel with SCRs, these static bypass switches are able use smaller, less expensive SCRs that are rated to carry less than full load current continuously. This paper shows that the availability of the UPS system is compromised when undersized static bypass switches are employed in the system. The advantages of fully rated static bypass switches are discussed.

现代封闭式热通道被用来应对数据中心功率密度的日益增长趋势，但同时这些热通道也为工作人员的工作环境带来问题。本白皮书将就这种高密度IT环境的额外热应力做基本的探讨。