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Helium Escape Valve

For most of us, our adventures beneath the waves go as far as we can hold our breath. Going further down, you enter the realm of saturation diving. This far below the surface exists a world teaming with life and biodiversity, but one which is fundamentally hostile to us. At this depth, the pressure of water above takes a heavy toll on unprepared equipment, and unprepared people for that matter. But why is this the case? Today we are taking a deep dive (pun intended) into an often misunderstood part of the professional divers’ watch, the humble helium escape valve and the role of helium in deep sea diving...


When we think of a deep sea diving watch, your Rolex Sea Dwellers and Omega Seamaster Planet Oceans of the world, we are quite familiar with the small, circular cut out usually found at the 9 o’clock position. But what does this actually do? It seems that the key prerequisite for a deep sea capable watch is to be, well, waterproof. This is usually achieved by rubber o-rings and pressure testing. Helium however behaves differently to H2O and can subvert even the most sophisticated of waterproofness systems. This is due to the helium molecule being amongst the smallest of all molecules. Even when the waterproof seals of a watch are working fine to keep water out, the helium molecules can still get through this and enter the watch even though other gases and water cannot.

So why is this a problem? The primary users of such watches are saturation divers. These divers can operate at great depths for extended periods of time by living in dry environments pressurised with an oxygen & helium mix. This is due to helium being an inert gas that has no negative effects on the diver, unlike nitrogen which causes nitrogen narcosis and the loss of consciousness. Additionally, when decompressing, nitrogen facilitates a potentially lethal state called ‘the bends’. Consequently, helium is far safer and is used to replace nitrogen in most deep sea mixed-gas diving applications.

Herein lies the requirement for a helium escape valve. Whilst living and working in this environment, helium molecules can enter the watch and build up inside creating a high pressure differential to the outside world. This build-up of gaseous pressure within the case can inflict serious damage on the watch and even blow out the crystal or crown when it’s unscrewed or the pressure changes. For the diver, this can be extremely dangerous when simply checking the time or handling the watch can potentially write it off. Losing the ability to tell the time at this depth can be catastrophic.


To prevent this from happening, the helium escape valve automatically allows helium molecules to escape using a one-way valve. This lets the helium out whilst preventing anything external from entering. This enables correct performance, pressurisation and decompression of the watch as it moves between differing sea level pressures over the course of its service.

In reality, most divers will not be living or working in a pressurised environment for days or weeks on end. For many of us, our adventures are a little closer to shore meaning we have no direct need for a watch equipped with a helium escape valve. Regardless of how deep you dive, the Enoksen Deep Dive family is safe up to 100ATM and comes fitted with a helium escape valve just in case it’s needed. In our opinion, the E01 family would not be fit for purpose without it.