How to Fill Scuba Tanks

How to Fill Scuba Tanks
At the core of any scuba dive is the humble air cylinder (tank) and its compressed air. However, working with any gas that has been compressed to very high pressures can be dangerous, and most scuba tanks are filled to pressures of around 3,000 psi (pounds per square inch). Filling a tank is a simple procedure, but it must be done with great care.

Instructions

Difficulty: Easy

Things You’ll Need:
  • Scuba air cylinder Cooling tank (filled with water) Scuba air compressor License and certification to fill scuba tanks
  • Scuba air cylinder
  • Cooling tank (filled with water)
  • Scuba air compressor
  • License and certification to fill scuba tanks
Step 1
Look at the hydrostatic testing date on the side of the tank. Do not fill a tank that is past its last test date. The risk of a rupture and explosion of compressed air is too great. Skip to another tank. Take note of the tank's pressure rating while you are at it. This will be engraved or stamped on the side of the tank.
Step 2
Look at the tank's valve for debris or a damaged o-ring. If there is any problem here, either take care of it, if possible, or skip to another tank.
Step 3
Open the tank's valve and bleed it of most or all of its remaining air. Then give it a good shaking and listen for water or debris inside. Close the valve. If there is any debris or water, do not fill the tank. Once again, skip to another tank.
Step 4
Put the air tank into the cooling tank. Pressurizing something creates a lot of heat. Heat means expansion, so a hot tank holds less air than a cool one. The cooling tank will help you get a good fill.
Step 5
Set the air compressor to the proper pressure. This assures it will automatically shut down when the tank reaches that pressure.
Step 6
Connect the filling hose valve from the air compressor to the tank's nozzle. This will be very similar to putting a scuba regulator on a tank. The filling valve formats are also much the same: the standard yoke valve and the DIN valve.
Step 7
Open the filling hose valve and the tank's valve to let the air into the tank. Once the air compressor stops, close all valves and disconnect the filling hose.

Tips & Warnings

 
A license from the Occupational Safety and Health Administration is required to legally operate a scuba air compressor. This guide should not be taken as a substitute for proper training and certification, and is for informational purposes only. If you are working with a new and unfamiliar compressor, remove and examine the air filters. Breathing even ordinary impurities in regular air under high pressure is dangerous and potentially toxic. Moisture tends to find its way in through the nozzles and valves of scuba tanks left in storage. To fend it off, leave such tanks with about 300 psi worth of air in them. That is too little to stress the tank, but enough to keep any water out.
 
A license from the Occupational Safety and Health Administration is required to legally operate a scuba air compressor. This guide should not be taken as a substitute for proper training and certification, and is for informational purposes only.
 
If you are working with a new and unfamiliar compressor, remove and examine the air filters. Breathing even ordinary impurities in regular air under high pressure is dangerous and potentially toxic.
 
Moisture tends to find its way in through the nozzles and valves of scuba tanks left in storage. To fend it off, leave such tanks with about 300 psi worth of air in them. That is too little to stress the tank, but enough to keep any water out.

Article Written By Edwin Thomas

Edwin Thomas has been writing since 1997. His work has appeared in various online publications, including The Black Table, Proboxing-Fans and others. A travel blogger, editor and writer, Thomas has traveled from Argentina to Vietnam in pursuit of stories. He holds a Master of Arts in international affairs from American University.

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