There are some scenarios, however, where coupling ITE directly to FWS can be advantageous. This is referred to as a "Non-CDU" water-cooling implementation. Figure 3 (Page 22) shows an example of a data center liquid-cooling system that couples the facility water supply (FWS) directly to the ITE. In this figure "FFU" references a facility filtration unit, and "RFU" references rack filtration unit. Some of the key advantages of a non-CDU implementation include: * Increased data center floor space or IT rack space; * Closer coupling of ITE heat sources with final heat dissipation medium (reduced thermal resistance); * Shared pumping redundancy; and * Improved liquid-cooling efficiency * Reduced number of fluid movers; * Typically, higher facilityside DT (lower flow rate) by removal of CDU approach temperature. While the benefits of a non-CDU implementation are attractive, they do require increased up-front design consideration, specifically in the realm of water quality, material selection and filtration. In both cases described above the water that is supplied to the rack or cabinet needs to be above the room dew point. ASHRAE Datacom Series book Thermal Guidelines for Data Processing Environments, Fourth Edition (ASHRAE 2015) specifies a maximum dew point of the room for a Class A1 environment of 17°C (63°F). Two techniques can be used to maintain TCS supply J U LY 2 0 19 ashrae.org ASHRAE JOURNAL 23http://www.servercool.com/contact-us/ https://www.ashrae.org/