M26 Cylinder Valves
When students are looking to buy twinsets, stages and regulators they often ask my advice about whether they should buy the standard DIN fitting or the new M26 fitting.There has been a lot of concern that the introduction of M26 valves will force all UK divers to change their cylinder valves and regulators.
As there is a lot of debate about this I thought it would be useful to cover this subject.
All this discussion of changing to M26 arises due to a European standard that will come into force in August 2008. BS EN144-3 states that cylinders and valves used for mixtures including over 22% Oxygen must use an M26 Valve.
It is this new standard that is suggesting that for Nitrox we need to change from the existing DIN valves to M26 valves.
So the question is does the UK diving community have to follow this standard?
Well is there a safety reason why we need to do this? The HSE did not support the drafting or introduction of this standard on the basis that it would not increase safety. So it appears there is no safety reason for doing this.
Is there a legal reason why we need to do this? Well European standards are not laws, there is no reason why you must legally obey a standard. For example there are European standards on cylinder colouring with Nitrox cylinders having to have black and white coloured shoulders with a black N on the white quarters. The vast majority of divers and dive shops find it convenient to ignore this standard so why not any other standard. So there is no legal reason why we have to adopt M26 valves.
The only reason why we would have to adopt this is if all dive shops started on insisting on only putting Nitrox into cylinders that use M26 valves. This may happen as shops may mistakenly believe that they have to enforce this standard. They may cite HSE regulations – but remember the HSE did not support the introduction of this standard as their view was that it would not improve safety.
Your shop may cite meeting the standard as part of their risk assessment. BS EN144-3 is a standard but standards are not mandatory. Whilst they are one way to show that appropriate risk controls have been taken they are not the only way. The UK diving industry and the diver training agencies have followed a de-facto standard for avoiding the inadvertent breathing of the wrong mixture since the introduction of Nitrox in the 1990s. This de-facto standard has proved highly effective and so we take the view that a tried and tested de-facto standard has just as much, if not more, merit than an inconsistent EN standard.
So if a dive shop can show that they have suitable risk controls in place then there is no need to enforce M26 valves.
At Dive-Tech we use a lot of cylinders and regulators; we train people on the use of air, Nitrox and Trimix as well as teaching them how to blend various gasses. We will not be adopting M26 valves but need to show that we have suitable risk controls in place.
In order to justify this we have carried out a risk assessment which is included below.
In order to avoid the inadvertent breathing of the wrong mix Dive-Tech will continue to mitigate this risk by;
Ensuring that only cylinders in Oxygen service are used for Nitrox/Trimix
Ensuring that that 100% Oxygen is not put into cylinders marked as Breathing Air
Ensuring all breathing mixes are analysed before use
Marking all breathing mixes with contents and MOD
Recommending that Nitrox/Trimix cylinders are not loaned to those unqualified for their use.
Teaching the above procedures on all Nitrox and Trimix courses
The risk assessment was shown to my local HSE inspectors recently and they provided a number of minor comments which were incorporated into the statements above. They had no further comments to add to it – which is as close to agreement as I would ever expect to get.
If some shops start to insist on M26 valves and others do not then divers will start to vote with their feet.
So my view is that no, we don’t need to switch to M26 valves.
Have fun and dive safe
Mark
http://www.dive-tech.co.uk
http://www.divingniknaks.com