Previously, we discussed what a flange face is and why it is important. In this article, we go further by discussing how to identify the gasket seat of different flange types.
Preserving flange faces, mechanical piping and equipment is a vital but challenging task you face in today’s oil and gas industry. To ensure your preserving your project assets contact us today for more information and pricing.
Identifying the Gasket Seat for Different Flange Types
RF flanges are the most common type in process plant applications. They are easy to identify as the gasket seat is raised above the bolt circle face. The height of the gasket seat on a 150 - 300lb flange is 1/16” and on a 400 - 2500lb the height is ¼”. The area that needs protection is the critical machined surface on top of the raised section.
RTJ or Ring Type Joint Flanges are typically used in high pressure or high-temperature applications and a steel ring gasket is compressed and deformed into a grove in the flange face creating a metal-to-metal seal. Many RTJ flanges have a raised face but it is not a part of the sealing process. On an RTJ flange, the critical machine's surface that needs protecting is the groove itself.
GrayLoc or CofferLok style flanges are also metal to metal high pressure flange sealing systems. Protecting the sealing surface during all phases of fabrication, welding, blasting, and painting is extremely important. On these flanges, the critical machined surface is the beveled or angled surface where the compression takes place.
Flat Face flanges are just that, flat. No raised face & no ring grove to help with the sealing process. The bolt holes are within the seating area requiring a full-face gasket. The entire flange face is the critical machined surface and should be protected.
Next week we'll look at types of flange face mechanical damage that can kill your production or project schedule and cost you a ton of money.