M26 Valve Differences – Be Aware!

In many countries outside of the EU, it is difficult or impossible to find M26 valves, cylinders, or adaptors. Don't let the introduction of the M26 valve catch you out when you travel. Read on to find out more. Egypt has a history of divers from Europe arriving to go diving in Egypt only to find that, in many locations, the rebreather oxygen cylinders being supplied were not fitting their oxygen regulators on their rebreather unit. Whilst instances of this have declined in Egypt, it is worthwhile providing a reminder of what to be aware of, especially for new rebreather divers who might travel outside of Europe.

What is the M26 valve?

In 2008, it was decided in Brussels that some new regulations were needed regarding the transport of breathing gases under pressure. They decided that each gas should have its own individual tank valve fitting, so that the wrong gas could never be put into the wrong cylinder. The DIN fitting for use with air cylinders was already being used, so they decided to stipulate an entirely different fitting for use with gas mixes with a higher content of oxygen than normal – nitrox or oxygen. The M26 valve thread and its corresponding regulator first stage was born. With a slightly larger diameter than the familiar DIN fitting this is the type of cylinder valve that must be fitted to any new cylinder that is going to be used with any gas greater than 22% oxygen. This is a European directive that came into force in August 2008. These valves will match any regulator supplied in the European Union (EU) which has been designated for use with gas containing an oxygen content greater than 22%. DISCOVER 7 LIVEABOARD DIVE TRIPS FOR EXPERIENCED DIVERS.

How will the M26 valve affect my diving?

In simple terms, if you buy a rebreather in the EU it will come with an M26 fitting on the oxygen regulator. If you buy a new rebreather cylinder for oxygen use then it will also come fitted with a M26 valve. Both the regulator and the valve look similar to the DIN type of valve, just slightly bigger. The cylinder valve should have the information stamped or etched on the valve itself. READ MORE: 6 XR DIVING HAND SIGNALS YOU SHOULD KNOW.

What about when I travel?

It is important for extended range divers and rebreather divers travelling outside of the EU who have these M26 regulators to recognize that this directive is purely within the EU. In many countries outside of the EU, it is very difficult and sometimes not possible to purchase the specific M26 cylinders or adaptors you will need. When you travel to other continents, such as to go diving in Africa or diving in Asia, make sure you check with the diving operator to ensure that either:
  • There are cylinders available with M26 threads.
  • Or, they can supply an adaptor.
If they cannot provide either, you will need to remember to take your own adaptor with you. So, if you have an M26 regulator, remember to check with your diving operator what the options are before you travel! GO BEYOND - BECOME A CERTIFIED REBREATHER DIVER WITH SSI.