This is the most important part of scuba diving. Scuba tank collects oxygen for breathe when diving under the water. A standard size of scuba tank is 11.5 liters that not means to a tank can collect oxygen 11 liters but it can collect oxygen as much as the air in your bedroom (3 X 3.5 meters). A tank bears a high pressure approximately 320 Bar or 4,700 pounds per sq. inch (320 multiple of a general pressure). In fact, the diver uses oxygen only 200 Bar. In case of non-deep level, one tank can use for 40-50 minutes. A tank provides head tank valve.
Generally Tec diver must select ingredients in air for diving. First of foundation for knowledge on Tec diver is diving by the air which has ingredients of oxygen but it differs from enriched air nitrox. A diver will select the air ingredient that is suitable for the depth, time and the decompression in each diving.
Enriched air nitrox is not gas for Tec diving, especially deco also is more difficult from nitrox diving such as it has to use more air and cannot bring air enough into under the sea. Tec diver uses air in the different ingredient for long diving and save time for deco processing.
First of all, Tec diver must have knowledge on Equivalent Air Depth (EAD) and Maximum Depth (MOD). Because of all Tec divers must learn in Enriched Air Nitrox Diver Course and Surface Air Consumption: SAC. SAC is different in each person. At the beginning Tec diver calculates in every detail as how much the air for each diving and must spare for an emergency situation, how is the dept for each tank can use?
Moreover, some Tec diver drunk on nitrogen so everyone has to plan before. Planning can protect from toxic oxygen. Important knowledge will teach in Enriched Air Diver Specialty and Deep Diver Specialty.
Thought and attitude of Tech diver and Rec diver are different. To dive by planning on a computer with using all of air then manages the next happing during the diving is really dangerous for a diver. For Tec diver has to plan and do it by a plan. Such as plan for gas to breathe, plan for the depth and time, Deep Stop and Deco Stop level throughout running time record at any level of under water.
As above information shows a combination of strong and healthy body, advanced dive skill, calculation, planning, positive thinking in diving and concentrate in diving practice.
All qualifications mostly the beginners feel boredom but other thinks that is challenge. Tec divers always receive an exotic experience which anyone hardly finds.
Can you find Surface Air Consumption: SAC?
Firstly, we must know where I can found SAC. Easy way is to dive into any level such as 5 meters, 10 meters, 20 meters and so on then you swim with comfortable manner, don’t be hurry and not too slowly as your plan. So, you should to check air in a tank before you started and after that calculates the left air in a tank. After the test, a diver uses all details to calculate with a result of a tank capacity (Liter) the depth (Meter) time (Minute) and used air (Bar). For this time, SAC is known for general diving. We can find SAC during Deco processing by calm dive, dive by against the water current or dive with speed.
Calculates above result; SAC = (used air (Bar) X air tank capacity (Liter) / pressure (Ata))/Time (Minute)
Result after calculation, you can plan for air management with safety using for diving from an equation by SAC x pressure (Ata) x time = air for using. Bring air for using + spare air as you plan. A diver will know the air which prepare to dive, is it enough?
For this case, a diver must have another tank for Deco processing and dive up from the deep level. A diver can use tank pairs but has to reduce time during Deco processing to collect the air when dive up to the high level for Deco processing to find the air using for dive up and Deco by calculate before.
One third of spared air has to be full quantity, don’t use during Deco processing. Because of danger for Tec diving is to use spared thing for an emergency situation and there’s nothing to use for a real situation even your life.
From the experience, SAC at 10 meters depth level with 5 meters depth level are a bit different because of factors in pressure, worry, drunk on nitrogen. So should calculate SAC at the different depth level that is better.
In fact, SAC for Rec diver is not necessary. During diving and a diver often observes SPG, he will know the air is nearly left and should to dive up to surface level. In Deco processing if a diver hasn’t the air left, he still dives up with safety.
As well, before a diver is going to dive, has to record air quantity in roaster as same as to check in & check out. A roaster tells in each group, how much did each person hold SAC? But they calculate in Bar unit or psi, if every diving used the same tank. It cannot use with Tec diving because Tec diving uses the different types of tank. How does Tec diver use SAC on the below diving planning?
- 30 meters / 50 minutes will use air totally 4,000 liters
- Dive up for Deepstop at 24 meters / 2 minutes with air using 136 liters
- Deco processing at 19 meters / 1 minutes with air using 58 liters
- Deco processing at 9 meters / 4 minutes with air using 152 liters
- Deco processing at 6 meters / 16 minutes with air using 512 liters
- Deco processing at 3 meters / 32 minutes with air using 832 liters
Totally air that a diver has to use per diving is 5,690 liters. A diver should to add spared air for an emergency situation to be 8,535 liters. A diver must bring for 4 air tanks and each tank can collect 2,400 liters.
Each diving of Tec diver uses the different air for breathing such as Nitrox that suits for the deep level or use concentrated Nitrox for Deco processing. Time for Deco processing is less than an above diving planning and might be less than 4 tanks.