TDI Decompression Procedures ManualThe Decompression Procedures Manual is the text-book literary assistant to the TDI Decompression Procedures certification course. TDI has brought this course to the recreational diver in response to the demand and desire for more information. The Decompression Procedures course is available to two classes of divers. Recreational divers can take the course to develop new skills and understanding. Recreational-Technical divers can take the course during the series of courses available through TDI, usually between Advanced Nitrox and Extended Range and Trimix.