This paper focuses on effects of reduced pressure on divers and equipment. The physical basis and operational procedures for altitude diving are presented and discussed. Other source material, discussion, and further development can be found in the References at the end.

This short paper touches on many aspects of geophysics impacting the technical diver, including gravitation, solar radiation, atmospheric environments, ocean and lake environments, and land environments. Global wind and water motion is also discussed from an oceanographic perspective.

Technical diving used to be the pervue of just commercial and military divers. Today, highly motivated and well trained recreational divers are pushing diving to new depths, on mixed gases, with sophisticated electronic sensors and dive computers, using modern rebreathers, wearing special exposure suits, in the oceans, lakes, and at high altitude. This new breed of diver receives training from any one of a number of new technical agencies, like Technical Diving International (TDI), International Association Of Nitrox And Technical Divers (IANTD), and Association Of Nitrox Diving Instructors (ANDI), as well as the established recreational agencies, NAUI, PADI, YMCA, SSI, and NASDS. For the technical diver and working commercial diver, this monograph is intentionally both a training tool and extended reference.

Diving has its own brand of medical complications, linked to ambient pressure changes. For brief consideration, a few of the common medical problems associated with compression-decompression and diving follow. The bubble problem has been long discussed, but we can start off by summarizing a few concensus opinions concerning decompression sickness. A cursory discussion of some drugs follows, and a discussion of bubble trouble and oxygen dose.

Topics are fundamental and chosen in their relevance to technical diving. Bibliographies do offer full blown treatments of all principles detailed for diving. For highlight, Figures include mathematical definitions for completeness, with the intended purpose of extending discourse. Problems (101) employ quantitative relationships detailed in the text, using data and information from Tables and Figures

RGBM explaination from a physilogical point of view.

Deep stops – what are they? Actually, just what the name suggests. Deep stops are decompression stops made at deeper depths than those traditionally dictated by classical (Haldane) dive tables or algorithms. They are fairly recent (last 15 years) protocols, suggested by modern decompression theory, but backed up by extensive diver practicum with success in the mixed gas and decompression arenas - so called technical diving.

Diving models address the coupled issues of gas uptake and elimination, bubbles, and pressure changes in different computational frameworks. Application of a computational model to staging divers is called a diving algorithm. The Reduced Gradient BubbleModel (RGBM) is a modern one, treating the many facets of gas dynamics in tissue and blood consistently. Though the systematics of gas exchange, nucleation, bubble growth or collapse, and decompression are so complicated that theories only reflect pieces of the decompression sickness (DCS) puzzle, the risk and DCS statistics of staging algorithms can be easily collected and analyzed. And the record of the RGBM, just over the past 5 years or so, has been spectacular, especially so far as safe staging coupled to deep stops with overall shorter decompression times. This is important. Models are one thing, even with all the correct biophysics, and actual diving and testing are something else.