I was just rereading this how-to manual published in January 2006 by Pacific Gas & Electric of Northern California. Gosh it is good. With minimal editing it is still on-target today - and considering how rapidly the "state of the art" is changing, it is a compliment that it is still on the edge. If rewritten today, authors would perhaps place added emphasis on a wider range of semi-approved temperatures for data center operations, and describe in more detail the fragility of systems within turbulent temperature changes (rapid heat-up and rapid cool-down).
If you are not a mechanical engineer, it is not easy reading, and I still need some explanations on the terms used. But an iterative approach, reading some and then returning to it 3-4 months later, helps to bring the concepts into focus and enable you to ask simple questions from the engineers around you. Have a Green Day!