NAUI Master Scuba Diver 170 Decompression and Recompression error, don’t compile the problem with rationalization or denial. Be helpful to yourself by letting others help you. Finally, understand and have compassion for chamber personnel and consultants. These people are trying to be helpful, often as volunteers, and they have stresses and tasks associated with their function that you may have little or no perception of during the course of the treatment itself. A Chamber Experience If you have the opportunity to take a “chamber ride,” do so. There is nothing that will impress you more than being inside a chamber during pressurization, venting, and ascent. Many chamber crews active in treating divers will organize orientation sessions for interested groups. Although chambers differ, there are elements most experiences will have in common. Chambers are noisy places. Most are steel “bells” which reverberate when struck by dropped objects and general activities. Gases hiss in and out through small orifices during pressurization and venting, and unless muffled, the noise can be too loud to talk over. In addition, as gas density increases with increasing pressure, voices become altered and sometimes difficult to understand. Other obvious sensations occur from the rapid change in temperature and humidity during pressure changes. During pressurization, the chamber gets warm and feels stuffy. During ascent, the chamber gets cool and “clouds” of humidity can form. If you are in a chamber for very long, the confinement and realization of loss of control over what is happening to you can impact you. However, if you’re in for treatment, these feelings will be outweighed by the feelings of concern and humanity which will surround the whole “caring” experience. A chamber ride is not a treatment, but it will yield an idea of what one would be like. ALTITUDE DIVING While you may believe that you will never dive at altitudes above sea level, the potential for underwater experiences using scuba at altitude is great. As access increases, we may all be able to travel to moderate or higher altitude dive sites. A high altitude dive may be defined as one conducted at an altitude greater than 300 m (1000 ft). At present, many high altitude freshwater lakes, ponds, mine shafts, caverns, caves, and rivers are regularly dived by recreational scuba divers. As a NAUI Master Scuba Diver, you should know how to dive at altitudes above sea level. Your safety is dependent upon your ability to use the dive tables correctly under such circumstances. Make sure you are trained for altitude diving before you use the information included here. Perhaps the most significant differences you will encounter when diving at higher altitudes are the variances in buoyancy control, in use and types of dive tables, and in depth gauge readings. In addition, you should be aware of the special techniques and potential hazards involved in diving at higher altitudes. This section will provide information for your use in diving at sites above sea level. Differences at Higher Altitudes What are the primary differences you face when participating in altitude diving and how can you safely deal with them? Altitude diving differs from ocean diving due to two important factors: 1. Fresh water (almost all altitude diving is fresh water) is less dense than sea water. 2. Atmospheric pressure at altitude is less than at sea level. As you have learned, the lower density of fresh water results in your being less buoyant, thus requiring less weight on your weight belt. Also, the lower density of fresh water causes your depth gauge to read differently than in sea water. The reduced atmospheric pressure at altitude adds to the variance in depth gauge readings (from readings taken at sea level). Finally, and most importantly, the lower atmospheric pressure at higher altitudes significantly increases your risk of decompression sickness should you not follow special altitude dive tables.
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