



Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Community
Ask the community for help and clear up your study doubts
Discover the best universities in your country according to Docsity users
Free resources
Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors
SDI Open Water Test Graded A+ 2024
Typology: Exams
1 / 7
This page cannot be seen from the preview
Don't miss anything!
Breathing 100% oxygen at 6 m/20 ft of sea water is the equivalent of breathing EAN at 40 m/132 ft of sea water in terms of oxygen partial pressure. - ANSWER-Facts Central Nervous System (CNS) Oxygen Toxicity - ANSWER-all a diver must do is violate the Maximum Operating Depth (MOD) for a particular mix causing the P02 to rise above 1.6 and the chances for a CNS hit increase exponentially Equipment risks associated with oxygen. - ANSWER-fire or explosion if not up to spec O2 clean Equivalent Air Depth(EAD) - ANSWER-a dive to depth on Nitrox is equivalent to a making a dive of a shallower depth on air (less nitrogen gets absorbed by body, less decompression obligation)(more oxygen available, dangerous to pass MOD) How can a dive computer help you avoid decompression sickness? - ANSWER-it will calculate approximately the amount of nitrogen absorbed by your body, and indicates when it is time to ascend and the rate at which it is safest to ascend How is nitrogen exposure similar to oxygen exposure? - ANSWER-exposure to higher levels of oxygen at depth causes your body to become more sensitive to increased levels of oxygen during subsequent dives How long, in a single dive, can one be exposed to a Nitrox mixture at its maximum operating depth(MOD) - ANSWER-the oxygen exposure time limit for a single dive is 45 minutes at a given maximum operating depth(MOD) How long, in any 24-hour period, you can be exposed to a Nitrox mixture at its maximum operating depth (MOD)? - ANSWER-you will have a cumulative time limit for oxygen exposure at the maximum operating depth(MOD) of 2:30 hours in any 24-hour period Nitrox compatible diving equipment and its preparation. - ANSWER-if a regulator, cylinder or valve will not be exposed to gas mixtures with an FO2 greater than 40 percent, at pressures greater than regulator intermediate pressure, they need not be O clean or service rated Nitrox primary benefits - ANSWER-extend your bottom times and to shorten your surface intervals significantly compared to your previous air-dives Normal Air that we breathe is comprised of what % oxygen and nitrogen - ANSWER- 21% oxygen and 79% nitrogen Pulmonary Oxygen Toxicity - ANSWER-can develop when you are exposed to elevated levels of oxygen over long periods of time.
Standard scuba air - ANSWER-although very clean and dry, still contains trace amounts of hydrocarbons and other contaminants. What are eight factors that may increase a divers susceptibility to oxygen toxicity? - ANSWER--If you overheat during a dive. -If you are an insulin dependent diabetic. -If you suffer from a deficiency of Vitamin E. -If you have an overactive thyroid (hyperthyroid) gland. -If you dive without proper thermal protection in cold water. -If you use drugs that may speed the onset of oxygen toxicity, such as adrenocortical hormones, dextroamphetamine, epinephrine, norepinephrine, and paraquat. -If you make a dive in which you are working or swimming hard underwater. -If you have scar tissue in your lungs you may be more susceptible to oxygen poisoning. What are five additional steps divers can take to help avoid oxygen toxicity while using Nitrox? - ANSWER--Get medical clearance for diving if you are an insulin dependent diabetic and if cleared to dive, restrict your diving to shallower depths. -Get medical clearance for diving if you are taking any of the other drugs listed in this chapter. If cleared to dive, restrict your diving to shallower depths. -Avoid overheating. -Wear adequate thermal protection while diving in cold water. -Never dive with Nitrox deeper than the MOD for the mix you are using. What are four things divers can do to help minimize the general risks associated with Nitrox and other forms of diving? - ANSWER--Analyze and label every cylinder prior to diving. -Set the appropriate mix in your dive computer and do not exceed the limitations it gives you during the dive. -Never exceed a PO2 of 1.6. -Avoid heavy exercise while diving with Nitrox.
What are the two gases that most Nitrox diving computers take into consideration when computing your allowable bottom time? - ANSWER-Oxygen and Nitrogen What are the two most important pieces of information that will appear on a Nitrox fill tag or label? - ANSWER-Nitrox mixture used in the tank (FO2) and its MOD What are the words represented by the acronym CONVENTID? - ANSWER-CON- stands for convulsions V- stands for visual disturbances, which may take the form of tunnel vision or the perception of bright flashes of light E- stands for ringing in the ears and other auditory hallucinations N- stands for nausea T- represents twitching of the muscles I- indicates irritability or apprehension D stands for dizziness What are three reasons why sport divers should avoid decompression diving? - ANSWER-decompression diving requires specialized training, additional equipment, and topside support. What are two equipment items that do not need to be cleaned for oxygen service? - ANSWER-BCDs and their low pressure inflators and dry suit inflation valves do not need to be cleaned or lubricated for oxygen service What are two reasons why EAN32 is a good choice for Nitrox diving? - ANSWER-good combination of extended bottom time and unrestricted depth within the sport diving range, using EAN32 poses less risk in terms of exposure to oxygen than other richer mixtures What does a Nitrox tank wrap used to identify Nitrox cylinders look like? - ANSWER- NITROX GREEN AND YELLOW What does the term blender mean, as it applies to Nitrox diving? - ANSWER-The certified person who calculates and mixes he nitrogen and oxygen mixture into your tanks, as long as the mix is within 1% of planned percentage What does the term decompression stop mean? - ANSWER-Your computer may require you to make one stop or a series of stops, commonly known as decompression stops.
What does the term oxygen toxicity mean? - ANSWER-physiological reaction of your body that occurs when you are exposed to breathing mixtures containing high partial pressures of oxygen, or mixtures containing lower partial pressures of oxygen for extended periods when the diver breathes a mixture of gas that allows the PO2 to exceed 1.6 by going too deep or exceeding the time limit at a lower PO What does the term technical diving refer to? - ANSWER-diving that requires additional specialized training, planning techniques, and equipment. It provides the diver with capabilities well beyond the limitations of sport diving What is Advanced Nitrox - ANSWER-Gas mixtures containing more than 40% oxygen are sometimes called Advanced Nitrox or Technical Nitrox. What is an oxygen analyzer? - ANSWER-electronic devices that are used to measure the percentage of oxygen in a gas mixture what is EAN32: - ANSWER-enriched air nitrox with 32% oxygen : 68% nitrogen FO2 is 32 (Fraction of Oxygen) what is EAN36: - ANSWER-enriched air nitrox with 36% oxygen : 64% nitrogen What is Nitrox - ANSWER-Nitrox contains a higher percentage of oxygen, unlike air which normally contains approximately 79 percent nitrogen and 21 percent oxygen. What is the FO2 setting most dive computers default to? - ANSWER-FO2 of 21% PO2 of 1. If you fail to adjust these you won't be able to get the most out of your mixture and it could potentially be dangerous What is the function of a fill station log? - ANSWER-To indicate that you accept responsibility for the Nitrox mixture you have recieved What is the key reason why, when available, technical divers generally prefer Trimix for dives past 40 m/132 ft? - ANSWER-by replacing most of the nitrogen in the breathing gas with helium, you will be affected less by nitrogen narcosis than you would be using regular air What is the maximum partial pressure of oxygen (PO2) we use in Nitrox diving? - ANSWER-a P02 of 1. What is the maximum percentage of oxygen that sport divers use in a Nitrox mixture? - ANSWER-40%
Why may you need additional thermal protection for Nitrox diving? - ANSWER-To protect from heat loss over longer dives