The Bench · N° 25

Who actually needs a helium escape valve

The valve addresses pressure that can build inside a watch during prolonged saturation diving. It has little role in ordinary scuba diving, swimming or daily wear.

Hen & Mills Editorial · 4 min read · 1 September 2026

A helium escape valve is designed for a specialised problem: a watch spending days inside a pressurised saturation-diving environment.

Helium atoms can enter the case while the diver lives and works under pressure. During decompression, the surrounding pressure may fall faster than the gas inside the watch can leave. A valve gives that internal pressure a controlled escape path.

Most watch owners, and most recreational divers, will never create those conditions.

Saturation diving

At significant depth, divers can work from a pressurised habitat or chamber and travel to the work site in a diving bell. Their bodies become saturated with inert breathing gas over time.

Instead of decompressing after every excursion, they remain under pressure for days or weeks and decompress once at the end.

Helium is commonly used in breathing mixtures because it reduces some problems associated with nitrogen at depth. It is also very good at finding its way through small seals.

How helium reaches the watch

The watch is not necessarily leaking in the ordinary sense. Under prolonged high external pressure, helium can slowly diffuse through sealing materials and tiny interfaces.

Inside the chamber, pressure outside and inside the case can approach balance over time.

The problem appears when chamber pressure is reduced during decompression. Trapped gas may leave the watch more slowly than the surrounding pressure falls.

What excess internal pressure can do

If the pressure difference becomes large enough, it can stress the crystal and its retaining system. Historical accounts often focus on crystals being forced from cases.

Modern constructions vary, and a failed seal or other component may respond differently.

The valve is meant to open before the pressure difference reaches a damaging level, then close again to maintain the case seal.

Automatic valves

An automatic helium valve uses a spring-loaded component calibrated to open when internal pressure exceeds external pressure by a set amount.

The owner does not operate it. It should remain sealed during normal use and release gas only when the pressure differential acts in the intended direction.

Its reliability depends on correct design, clean components and proper servicing like any other case penetration.

Manual valves

A manual valve usually has a screw-down crown or plug that the diver opens during decompression according to the manufacturer's instructions.

This gives the user control but creates a procedural requirement. Leaving it open in water or failing to secure it can compromise the case, depending on the design.

The watch's instructions are essential because appearance alone does not reveal every safety feature.

Why ordinary scuba diving is different

A recreational diver descends and returns over hours, not after living in a helium-rich chamber for an extended period. The watch is exposed to water pressure but does not have the same time to accumulate helium internally.

Normal diving water resistance is handled by the case, crystal, crown, back and gaskets.

A helium valve does not increase a modest depth rating and does not make poor seals safe.

It is not for releasing water

The valve should not be opened to drain moisture or equalise the watch during a flight. It is specifically intended to relieve excess internal gas pressure in the stated diving context.

If water has entered the case, the watch needs prompt professional attention. Operating a valve or crown can move contamination further into the movement.

Similarly, aircraft cabin pressure changes are far smaller than the conditions the feature is designed around.

Can a watch work without one?

Yes. Some saturation-diving watches use case construction that allows helium to escape through other paths or prevents a harmful pressure difference from developing.

A sufficiently robust crystal-retention system can also address the consequence rather than adding a dedicated valve.

The presence or absence of the feature does not by itself determine whether a watch is suitable for professional use. The complete tested specification matters.

Another opening in the case

A valve adds components, seals and a hole through the case. That can be engineered reliably, but it creates another area requiring inspection during service.

Threads can be damaged, gaskets can age and dirt can affect movement. A decorative-looking valve should still be treated as a functional case component.

After service, appropriate pressure testing should include the complete assembled watch.

Why brands include it

For a genuine saturation-diving model, the valve reflects a real occupational requirement. For a consumer dive watch, it also signals connection with professional equipment and adds visual character.

There is nothing wrong with enjoying the feature for that reason. Many watch functions are valued beyond their daily necessity.

The distinction is between having a legitimate technical origin and being personally necessary for every owner.

What a working diver should check

Professional users should follow employer, contractor and equipment requirements rather than choose a watch from marketing alone.

Confirm the applicable depth rating, valve procedure, service status, legibility and compatibility with the planned environment. A backup timing method and formal diving procedures remain essential.

The watch's last pressure test and service history matter more than a valve label on an unmaintained case.

What everyone else should know

Swimming, snorkelling and ordinary scuba diving do not require helium to escape from the watch. They require suitable water resistance, a secure crown and current testing.

A helium valve neither harms nor transforms daily use when it is correctly designed. It is simply a specialised pressure-relief device.

Its real audience is narrow: people whose watches remain in a helium-rich, pressurised habitat long enough to absorb gas and then experience controlled decompression.