This report describes the work of developing a specification of requirements for Waste Heat Recovery Units. The main part of the paper describes how the work with the specification of requirements has been performed. One specific question to be answered is:What are the customer?s demands in case of properties for the Waste Heat Recovery Units and how is that information collected as an order documentation to suit the business area Oil & Gas?The report begins with a description of the assignment and continues with the aim and background. A theoretical part describes the different areas and methods that have been important during the process.