I submitted this question online to the NFPA but there has been no response. I am thinking about self-installing (myself with friends) a 13D system in a single home I am building in PA. The township tells me they require I use a "certified" installer. I am exploring the possibility of paying for a friend to become trained and certified. He could then start a business and install systems for others. I only need certification for 13D home systems. I don't see an option for training and certification for only 13D systems. Would I have to get the full training and certification for 13 systems (including commercial systems) if I only want 13D? What are the minimal training and certification needed for only 13D systems.