Undersea Applications

The Issues Facing Underwater Valves

Land, air, and sea, valves can be found just about anywhere we can imagine and in places that are hard to fathom.

Pressure relief valves and fittings have been sent to the far reaches of space and into the depths of the ocean. While trips to space happen occasionally, there is a lot of activity in the earth’s waters.

Offshore Drilling

The oil and gas industry has come a long way in the 121 years since H.L. Williams drilled the first offshore oil well from a pier near Summerland, California. According to IHS Markit, as of June 8, 2018, there are 778 offshore oil rigs worldwide.

There are not many environments on earth that are as harsh as the deep sea. And as oil and gas exploration takes us farther out into the deep, the setting will not become any more hospitable. On the surface, you have environmental conditions like extreme cold, gusty winds, permafrost, and ice.

At average seawater depths of around 3,000 meters, or 9,843 feet, equipment is subjected to freezing temperatures, corrosion, and an external pressure of 4,371 psi. Drilling also takes place in waters more than three times this and in shallow locations closer to shore.

On top of the physical conditions lies the fact that 10,000 feet under the ocean’s surface and hundreds of miles from land is not the most convenient location to service a valve. Last but not least, valve failure has the potential to cause an environmental catastrophe. That means valves and fittings used in offshore drilling operations need to be fail proof and remain leak free until their work is done.

Diving In

It’s not just about oil & gas. Pressure relief valves and fittings are a necessity when it comes to diving operations, which may or may not be associated with underwater drilling. It goes without saying that a diver’s air supply is critical to survival and valves control it. While humans may not have the physical ability to withstand the pressure of a thousand meters of seawater above their heads, the pressure faced by divers is still significant enough that specially-designed valves are required.

For every 10 meters below the surface, the pressure increases by one atmosphere, or 14.6 psi. Specially designed CPV valves have been used for diving applications withstanding up to 500 psi of external pressure.

Aside from the pressure, salt water is corrosive at any depth.

A Closer Look at Undersea Challenges

When outfitting piping systems above the surface, much of our attention is on internal pressure and corrosion. In undersea environments, we’ve got to look at the opposite. It’s the external forces that are the primary concern.

Without enough opposing internal pressure, the external pressure could crush the pipes and valves. On top of that, seawater is highly corrosive. As explained on the website Corrosionpedia, corrosion by seawater is caused by three primary factors:

1. It’s salinity (the concentration of chloride ions)
2. The dissolved oxygen (which can be influenced by the salinity)
3. The temperature (increasing temperature = increased corrosion)

These factors also vary based on depth or distance from the surface level.

This makes the selection of the right materials a top priority when it comes to the design of undersea valves and fittings.

Seaworthy Solutions

Because each use, location, and/or situation is unique, off-the-shelf valves are not an option for most underwater or undersea use. Designers and engineers must work with the manufacturer to ensure that they build the exact product needed for the application.

CPV Manufacturing proudly offers valves and fittings for even the harshest environments. O-SEAL®, Mark VIII®, and/or Direct Weld fittings are a good place to start for your underwater needs.

If you are an oil or gas producer and you need a pressure relief valve or fitting for undersea application, you need the one-on-one help and expertise of the manufacturer. Contact us and we’ll work with you to ensure you get exactly what you need for safe, reliable, and long-lasting operations.