Flange shields are used to protect the faces, studs and gaskets on pipe flanges from atmospheric corrosion. Even with modern, highly resistant alloys, corrosion is still a problem – especially in refineries, gas plants and underground pipelines. To extend the life of modern pipe flanges, flange shields are therefore recommended. Designed to fit round raised face, full face and ring-joint flanges, they can cut maintenance costs considerably.

Many plant owners think it’s enough that they fit high-spec alloy flanges, such as those we supply at Chemipetro. However, environmental factors such as GICs (geomagnetically induced currents), UV radiation, dust and grime can play havoc with even the most up-to-date pipe fittings. Using shields can reduce these effects dramatically, leading to longer life and decreased chance of leakages and plant failure.

Flanges may be fitted with cloth or metal shields. The latter are available in a variety of alloys, including duplex. They are designed for high temperature, high pressure and highly corrosive environments. Shields fitted with spacing rods, which separate the shield from the flange, are especially useful where lateral and/or frontal sprayouts are a problem as they dampen the pressure.

Cloth shields are used in less extreme environments, or as extra “insurance” where high-spec flanges are already in use. They have the advantage of being cheap, and easy to fit. PTFE, polyethylene, PVC and polypropylene are the most common materials used.

Although the use of alloy shields can reduce running costs, especially on older plants, they should never be used over faulty flanges. Shields are not industry regulated the way pipe fittings are, and using them to “patch up” existing problems such as corrosion, cracking and leaking is both dangerous and illegal.