Seawater is a highly corrosive material. Water and air react with iron to cause rust through redox reactions, and the high content of salt in seawater only accelerates the process by increasing water’s conductivity and speeding up the chemical reaction.
Seawater does not just affect submerged metal, either. Even salt carried by the air can attract moisture and create an especially conducive environment for rust to form. The consequences of marine corrosion on valve performance can be severe: dramatic reductions in efficiency, premature system failures leading to costly downtime and emergency repairs, and even safety hazards for shipboard personnel.
Shipboard infrastructure requires especially reliable protection from marine corrosion. In this article, we will explore what seawater can do to shipboard valves and how military-spec valves for seawater applications resist corrosion to ensure reliable performance in high-stakes operations.
The Effects of Marine Corrosion on Valve Performance
Your average valve is not built for marine environments. The high content of salt and moisture in the air surrounding your valve, let alone direct exposure to seawater, wears away at valves far more quickly than corrosive elements in industrial environments on dry land can.
Shipboard valves can suffer myriad problems caused by marine corrosion if left unchecked, such as:
Material Degradation
The bronze used in marine environments is actually very good at corrosion management. It will actually patina. We could change this to “The steel, bronze, and brass bodies of commercial and industrial valves” and I think it would get the point across better.
Every material used in valve construction has a different rate of corrosion. If a valve is built from multiple different materials that corrode at different rates, a process known as galvanic corrosion can occur. Where the two different metals are in contact with each other, the more active metal—the most vulnerable to seawater—corrodes even faster than it would on its own.
Reduced Operational Efficiency
In mission-critical shipboard systems, precision performance is essential. As seawater causes valves to corrode, the buildup of corrosion products such as rust or copper salts can subtly or not-so-subtly affect the alignment of valve components. As a result, corroded valves may not open or close properly, leading to improper flow rates and impairing the overall functionality of the system.
Saltwater corrosion products can not only clog precision components, but also increase friction between moving parts—accelerating wear and dramatically raising risks of premature failure.
Potential for Leaks and Safety Hazards
The effects of marine corrosion on valve performance can be dangerous. Pitting and crevice corrosion dramatically increase the risk of leaks. Leaks in shipboard systems can have serious consequences—the release of essential fluids such as hydraulic fluids into the environment, for example, or flooding in shipboard areas.
Marine corrosion-related valve malfunctions can lead to even more catastrophic outcomes. Valve failures in critical fuel, cooling, steam, or fire suppression systems can cause fires and explosions or severely damage essential downstream equipment. These safety hazards can cause severe harm to the ship’s crew or exacerbate harm in the event of an onboard emergency.
How to Protect Shipboard Valves From Seawater
Your typical industrial valve can wear out far faster at sea than it will on land, but a valve’s lifespan in seawater conditions can be on the scale of decades, as long as the valve is appropriately designed for the environment and properly cared for.
A sturdy valve with a body produced from highly corrosion-resistant materials such as stainless steel, titanium, or nickel-aluminum bronze is especially well-protected from marine corrosion. Valves intended for marine use can also be coated with materials that inhibit corrosion from forming or protect the valve body from the moisture and salts that cause corrosion. For example, certain protective coatings like epoxy, paint, or cathodic protection systems provide a barrier layer that prevents chemical reactions between the metal surface and the water, oxygen, and salt in the environment. Valve materials can also be anodized to prevent corrosion.
Shipboard valves also require regular, proactive maintenance and inspection, more so than valves on land. The spread of corrosion can be slowed or halted by regular cleaning. Preventive maintenance actions such as replacing seals and reapplying protective coatings can also dramatically reduce the risks of potential failure and extend a valve’s lifespan in seawater conditions.
Reducing the Risks of Marine Corrosion With Mil-Spec Valves
Mil-spec valves for seawater applications are particularly well-suited to resist corrosion and ensure optimal performance in maritime environments, thanks to the rigorous military specifications that naval valves are expected to adhere to.
Danco mil-spec pressure relief valves, for example, are built using ASTM-rated bronze, steel, and stainless steel selected to resist saltwater corrosion far more effectively than standard commercial materials. Seals and gaskets are also selected from materials that resist degradation from saltwater exposure to reduce the risk of leaks and wear.
Mil-spec valves are also designed with features that minimize corrosion risks and maintain optimal performance conditions and durability in shipboard systems. For example, the design of mil-spec valves will prioritize the use of smooth surfaces and other design elements that reduce risks of crevice corrosion or galvanic corrosion.
Mil-spec requirements also demand stringent quality control and testing procedures to ensure valve materials meet high standards of performance in corrosive environments. Naval valves also usually come with detailed maintenance protocols to ensure they are inspected, cleaned, and serviced regularly to extend their service life.
Dante Valve: Your Choice for Mil-Spec Pressure Relief Valves
Since the 1980s, Dante Valve’s Danco line of pressure relief valves for seawater applications—in particular, naval vessels—has provided US Navy shipbuilders with the ideal choice for reliable pressure relief in maritime environments.
Our commitment to our customers as both a manufacturer and a distributor of top-quality valves sets ever-higher standards for more than just product quality and performance in the most demanding maritime conditions. We deliver quick quotes, quick response times, and immediate delivery to keep our customers’ work on track.
For more information about Danco valve products, contact us today, or request a quote if you are ready to make a purchase.