Various types of decompression tables are available for divers. Two of these decompression stations are the Hempleman and Air Table. Both tables have both their benefits and drawbacks. These tables should be handled with care. Always use a dive guide in conjunction with the decompression Table.
Air Table decompression tables
Decompression tables were developed in the 1930's by the Navy's Naval Experimental Diving Unit. They created the first standardised tables based upon a theory. This theory stated that the human body is able to eliminate nitrogen in a linear fashion, rather than at an exponential rate. This theory was reflected in decompression tables, which were designed to aid divers staying safe underwater.
Divers used to use 'per container' accounting in the beginning. This is a more conservative way of determining nitrogen content. This compares the different compartment gases to an M-values matrix. These values are sometimes called "half-times" by diving practitioners. However, it is important that these numbers are not real entities and only mathematical expressions. These air tables are conservative for short-term dives and can be inaccurate for shallower, longer dives.
Hempleman's despression tables
Val Hempleman's decompression table helped save many lives by keeping the Royal Navy at the cutting edge in deep diving technology. Hempleman, who was Royal Naval Physiological Laboratory chief from 1968 to 1982 worked to overcome the "bends." His research on decompression tables helped a man survive for ten hours at a depth equivalent to 1,535 feet.
Hempleman modified his tables and added a variable proportion of tissue nitrogen tension to ambient. This was done in 1968. After initially being unable to convince the Navy to adopt the tables, Hempleman made modifications based in his diving experiences. The updated tables were finally adopted by the Navy in 1972.
Hempleman's revised despression tables
Hempleman revised the decompression tables for diving in 1968. These tables allow for a variable ratio of tissue tension to ambient pressure. These results were initially not liked by the Navy. However, Hempleman modified them for practical purposes. The Navy adopted the new tables in 1972.
In 1908, Haldane's first table model was published. Haldane was an ambitious self-experimenter who published the first recognised diving tables in 1908. His experiments included animal experiments as well as the creation of the first British Admiralty decompression table. Haldane’s recommendations were widely accepted as a clinical indicator for decompression illness.
Hempleman's modified depression tables
Hempleman changed the decompression tables in 1968 so that they included a variable ratio between tissue nitrogen tension and ambient pressure. However, the Navy refused to approve the changes and refused the tables' implementation. This led Hempleman to change the tables for practical purposes. In 1972, the U.S. Navy adopted these tables in metric units.
The British Royal Navy adopted the tables in 1908 and continued using them until the 1950s, when they were revised because of concerns that they were too conservative. In the same decade, the U.S. Navy began using what are now known as C and R tables, and this practice became common in the 1980s.