Do non-metallic flanges have an RF face?
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As the title suggests, for non-metallic flanges such as PE pipes and PVC pipes, do the flanges made of the same material and used in pairing with them also have RF faces, M faces, and FM faces, just like metal flanges? ?
Flange connections for non-metallic pipes such as PE and PVC pipes also typically require sealing surfaces to ensure the integrity of the connection. The RF face (Raised Face) is a common type of sealing surface found in metal flanges. Its characteristic is that the sealing surface is slightly higher than the bolt holes of the flange, which helps to achieve a good sealing effect. Non-metallic flanges, although made of different materials, can also have various types of sealing surface designs such as RF surfaces and FF surfaces (Flat Face) to meet different connection and sealing requirements. In practical applications, the sealing surfaces of non-metallic flanges may be designed and selected based on factors such as the pressure rating of the piping system, the type of fluid, and the connection requirements. For example, some PE and PVC flanges may feature a raised design similar to the RF face, while others may use a flat seal (FF face); there may even be other specially designed sealing surfaces to meet the requirements. However, the plasticity and strength of non-metallic materials are usually different from those of metals, so their sealing surface design and processing techniques also vary. When selecting and using non-metallic flanges, it is necessary to follow the manufacturer’s product specifications and recommendations, as well as relevant industry standards. For more accurate information, please consult the specific pipe or flange manufacturer for detailed product specifications and installation guidelines. .
I heard that the stiffness is too poor, so a full-plane safety point is used. Some should also be able to use an RF surface, but the tightening force must be controlled when installing the bolts.
But the loose-flange has only an RF face, no FF face
For the loop flange, RF can only be used; its flange is made of steel, while the part that holds it in place is non-metallic. GB 51160-2016 Technical Code for Fiber-Reinforced Plastic Equipment and Piping – Appendix D; HG-T 20696-2018 Technical Code for Fiber-Reinforced Plastic Chemical Equipment, Section 5.7: Flange Design (P45). I haven’t seen any standards related to other non-metals