The Spanish industrial heritage is considered much worse than other heritage sectors in Spain and industrial heritage in other countries. The 2001 Industrial Heritage National Plan (PNPI) was a first step for changing this situation, but much remains to be done. One of the main needs is having an appropriate methodology for the categorization, classification and study of industrial heritage's assets. This work develops an own methodology and gives a clear criteria for its application to a large number of selected items from four sources with different approaches. This creates an own catalog which allows comparative analysis from different perspectives and classifies industrial assets by clear and easy criteria, favoring the extension of the catalog and whit it the interest of its analyses. (C) 2013 The Authors. Published by Elsevier Ltd.