Fully Open, Then One Quarter Turn Back ... Not!

Most of us have been taught in our SCUBA training to open a tank valve fully and then turn it back ¼ turn prior to diving. In recent years there’s been a lot of discussion about this practice, because occasionally it may be unclear to a user, or to the dive buddy, what position the tank valve is actually in. Unfortunately, SCUBA tank valves typically don’t have a position indicator that displays when it’s fully open, fully closed, or somewhere in between (more about that below).

I believe the current consensus in the diving industry is to fully open a valve or fully close a valve and not turn the valve ¼ turn back from the fully open position. This allows a user or a dive buddy to get immediate feedback when turning the valve on or off, or when checking the valve position. It is very important however to make sure you don’t over torque the valve in either direction.

Remember the age old rhyme: righty tighty, lefty loosey applies. This applies when the user is looking at a valve, and the valve stem or valve knob is pointed towards the operator. Another way to remember this is Clockwise-Close, Anticlockwise-Open.

At least 1 manufacturer is currently building tank valves with a color-coded ring between the valve handle and the valve body. These Vindicator Scuba Valves are available from many of your usual dive gear retailers. If the valve is closed, a red ring is displayed, and if the valve is open, a green ring is displayed. I understand a variation of this device is available (less than $20 each) for retrofit on an existing tank valve handle. These color-coded rings are not large, and they are not conspicuous from some viewing directions but may provide some level of added safety.

Enjoy the water and stay safe!

Dave Wills

Update: our September speaker, Tec Clark, created a video on this topic. Please watch.