This document compares data center standards between the United States' ANSI/TIA 942 standard and China's GB 50174-2008 standard. The US standard uses a tier system of 1 to 4, focusing on redundancy and fault tolerance, while the China standard uses an A to C class system. The document provides details on location, power, generator, UPS, and HVAC requirements according to the different tiers/classes of each standard.