As we continue to discuss the pros and cons of industry-acceptable products and practices we'll take a look at metal flange covers and challenge whether they are the best option.
Metal Flange Protector Types
There are two variations of metal flange protectors, one is known as a blind flange and a full face cover.
A blind flange is simply a flange that does not have a bored center and is used to cap or close off an open flange in a piping system. Also, blind flanges have the same face thickness as a flange, a matching face type, and mimic the bolting pattern.
Full Face Cover Flange
The other variation of metal flange protectors is a flat full-face cover (AKA Plate Protector). This version is much thinner than a blind flange and is easier to store, but does not offer all the same benefits that blind flanges offer.
Pros of Metal Flange Protection
Let's look at the pros of using metal protectors! Typically, these are made from stainless, carbon, or galvanized steel, which provides the strongest possible form of flange protection. These protectors are excellent in almost all applications such as storage, shipping, and fabrication.
Since the bore of the pipe is completely covered debris is kept out of the pipes while completely surrounding the face, keeping it protected.
A major pro of using blind flanges specifically is that they can remain on the pipe when testing the actual operating pressure of the piping system. And allow a nitrogen purge to be performed which pushes moisture out of the piping components before final bolting. This test also makes it easy to identify any leaks that the components may possess.
Cons of Metal Flange Protection
Now for the cons, a major con of metal protectors is that they are extremely heavy and difficult to handle, especially in larger sizes and typically they need additional equipment like a crane or lift. This adds to the time and labor needed to maneuver these.
Often when these covers are being removed from a component, it scrapes or slams against the flange face causing severe mechanical damage. Compared to most of the flange protectors on the market metal is also your most expensive option, due to its costly material and manufacturing time.
This material does not prevent rust and corrosion on its own, so you would need another form of prevention which would add to material cost. Another added cost is that these protectors require something between them and the flange face, such as a gasket or a piece of rubber. They also take up a lot of space in a warehouse if stored inside and must be properly protected from mechanical damage like a standard flange.
Here is a quick wrap-up of the pros & cons of using metal flange protection. Be sure to join us next week as we continue looking at the pros and cons of more industry-acceptable products and practices with different flange coatings.