How to Switch Your Diving Gas Safely

The gas switch is one of the most hazardous parts of any extended range dive. It is a procedure conducted with a teammate and with a clearly defined sequence. In this blog, we teach you how to conduct a diving gas switch safely and with confidence.

What is a diving gas switch?

A diving gas switch is, as the name suggests, when a diver switches from one gas to another during their dive. Typical reasons for a gas switch include:
  • An open-circuit Extended Range Diver switching to a decompression gas in order to increase their off-gassing efficiency during a decompression dive.
  • An SCR Extended Range Diver bailing out of their decompression gas because their unit has malfunctioned.
The switch from one breathing gas to another is a critical procedure to master in order to prevent accidents due to breathing a gas at an unsafe depth.

How to conduct a safe diving gas switch.

The gas switch is one of the most hazardous parts of any extended range dive and is conducted in a specific way with your teammate. To make it easier for teammates to spot a potential mistake from happening, decompression regulators are often in a different color (such as green) which designates a higher oxygen decompression gas. CONTINUE YOUR TEC DIVING JOURNEY WITH SSI EXTENDED RANGE SPECIALTIES. We use the acronym SWITCH to help divers learn and master the correct sequence: S - SIGNAL to the teammate that your intention is to make a gas switch. W - Check on your personal dive computer to see at what WATER DEPTH you are currently at. I - IDENTIFY on the cylinder (via the markings), the maximum depth of the gas in the cylinder, and cross-check this against your dive computer to ensure that you are either equal to or shallower than that depth. T - TURN on the cylinder valve, pull out the second stage hose from its retainers, then purge the second stage to ensure the tank is open whilst looking at the SPG. C - Turn to your teammate and show them the maximum depth markings on the cylinder. Wait for them to CONFIRM that the current depth is either equal to or shallower than that depth. H - Make the gas switch. Confirm that the regulator is breathing ok, switch gases on the computer, and note when HANG TIME begins WATCH THE SSI XR GAS SWITCH PROCEDURE ON YOUTUBE. Gas Switch - How does it work? Gas switch - cylinders on the beach