This paper is divided into two parts: the first seeks to compare the results of two surveys made with a time of flight scanner, Riegl z420i, and a phase based scanner, the Faro Focus 3D . These surveys were conducted inside an industrial heritage building, the Fabra i Coats boiler room (built between 1910 and 1920). T he c omplexity of t his c onstruction a llowed us t o m ake a c omparison be tween t echnical characteristics of the instruments, settings, data collection and lighting conditions. The second part develops a classification workflow for this information . A rchitectur al parts and installations were separated in relation to three topics: historical construction , function and architectural program. A high density point cloud model was generated, over 1.300 million points in a building volume of 7.000m³. Finally, advantages of this process in relation to the diffusion of heritage, conservation documentation for the proper understanding of the current state are discussed as well as the representation of its historical evolution in an interactive real - time point viewer