This thesis was commissioned by Wärtsilä Catalyst Systems in Vaasa. The purpose of the thesis was to create instructions for the factory acceptance test of the NOR, which is Wärtsilä’s own NOX reducer. The system works according to the SCR-process which is a chemical process that reduces the amount of nitrogen oxides in exhaust gases by adding a reagent and a chemical catalyst that is used to speed up the chemical reaction. The factory acceptance test is a set of tests carried out at the factory, before the products are sent to the customers to ensure that everything is working as intended.

The key method used to achieve the goal was to take part in the testing. First to observe and learn what was being tested and when a high enough understanding of the process had been achieved some testing would be carried out individually to be able to get as much experience of the testing process as possible. The result is a test instruction that is easy to understand and navigate but at the same time very informative if needed. It suits both more experienced users and novices alike as there is both simpler and more detailed instructions included.