When it comes to the planning, construction and operation of liquid-cooled room cooling surfaces integrated into ceilings, walls and floors, or of systems with cooled massive building components, experts differ about the proper procedures. It is not only the cooling power output but also many other questions of detail that still want a harmonised procedure for planning and execution. For instance, how to deal with the result of a cooling-load calculation when using a room cooling surface? What is the state of the art regarding the selection of materials? What special requirements are to be taken into account in dimensioning the hydraulic system, the room temperature control and fire protection? This guideline is intended to provide more clarity on all these issues and to close a gap, with the aim of improving security in dimensioning the systems, promoting fair competition, and creating more transparency for all those involved in order processing.