What is the difference between RF and FF flange?

Flat face (FF) flanges are similar to the RF flanges, but they do not have the raised area like the RF flange. Instead, the whole surface is flat. They are commonly used in low temperature and pressure environments such as pump suctions or water treatment flanges.

What is FF in flanges?

The Flat Face flange has a gasket surface in the same plane as the bolting circle face. Applications using flat face flanges are frequently those in which the mating flange or flanged fitting is made from a casting. Flat face flanges are never to be bolted to a raised face flange.

Can we connect RF with FF flange?

Some codes such as ASME B31. 1 prohibit connecting FF flanges to RF flanges. Although it does not directly address FF cast brass flanges used with raised face flanges, the intent of the specification is to prevent the cracking of the more brittle flange.

What is FF gasket?

A full face gasket covers the entire flange face and includes bolt holes, typically used in flat faced flanges. A gasket for a raised face flange is typically a RING gasket.

Can a full face gasket be used on a raised face flange?

Full-Face Gasket Like the ring-type gasket, this can also seal raised flange faces, but will have an OD the same as the flange. That means it needs holes for the securing bolts to pass through, and these help locate the gasket on the flange, making alignment easier.

What is difference between RF and RTJ flanges?

Answer: RF means “Raised Face.” RTJ means “Ring Type Joint.” RF flanges seal with a flat gasket, formerly made of asbestos but now made of more environmentally friendly material, designed for installation between the raised faces of two mating flanges (both with raised faces).

Should flange faces be painted?

So for corrosion protection of internally lined pipe with raised face flanges, YES you must definitely coat the faces. Normally, the raised surface of a flange is never blasted or painted. (Those surfaces are sometimes referred to as machined, and this is where the gasket sits.)

Why raised face flange is used?

The raised face is intended to decrease the surface area of the seal, thus concentrating the surface pressure applied when mating the flange. The result is a stronger seal. The raised face has a machined serrated finish that will bite into the gasket whenever pressure is applied.

Can you bolt raised face to flat face?

Flat face flanges are never to be bolted to a raised face flange. ASME B31. 1 says that when connecting flat face cast iron flanges to carbon steel flanges, the raised face on the carbon steel flange must be removed, and that a full face gasket is required.

What is difference between full face gasket and flat ring gasket?

The gasket must be the correct interior diameter, exterior diameter and have the bolt holes and spacing correct for the flange. A ring gasket, on the other hand, is positioned inside of the securing bolts. It sits only around the pipe bore, which may include on the raised surface of a raised faced flange.

Can you mate a flat face flange with a raised face flange?

Is O ring a gasket?

O-rings are circular, ring-shaped pieces that sit in a groove between two (usually cylindrical) parts. Terminology note: Any o-ring can technically be called a gasket since they prevent the transfer of liquid and air, but while o-rings are a specific shape of gasket, any gasket cannot be called an o-ring.

How to convert RF flange to FF?

Have your gasket supplier fabricate an adapter ring from a hard, compatible gasket material (Teflon, Gylon, Blue Guard, etc). The adapter ring is a full-face gasket with the ID cut 1/32″ larger than the RF diameter. Adhere the adapter ring to the RF flange, and you’ve essentially turned the RF flange into a FF flange.

How are the filler materials designated on the filler ring?

The filler materials are designated by colour stripes at equal intervals on the outside edge of the centering ring. Flexitallic colour coding meets the industry standard for metal and filler materials listed in ASME B16.20. 5. GASKET MATERIALS NOTES Figures stated are for information only.

What is a filler flange used for?

Filler Flanges, also known as Compensation Rings, are used to connect flanges with raised faces or sealing surfaces – especially those of plastic lined steel pipe – to flat faced plastic flanges. Without filler flanges, when the bolts are tightened on such a joint, the plastic flange will, most likely, break.

What is a PTFE filler flange?

FLUOR-O-FLO® Filler Flanges/Compensation Rings – PTFE. Filler Flanges, also known as Compensation Rings, are used to connect flanges with raised faces or sealing surfaces – especially those of plastic lined steel pipe – to flat faced plastic flanges.