Raised Face vs Flat Face — Valve Flange Facing Selection
Raised face (RF) is the default on most steel process valves. Flat face (FF) is common when mating to flat-face cast iron flanges. RTJ is a separate high-pressure facing.
Quick selection
Steel-to-steel: usually RF. Mating to FF cast iron / DI: use FF. High pressure: consider RTJ. See RF vs RTJ.
Comparison table
| Factor | Raised face (RF) | Flat face (FF) |
|---|---|---|
| Gasket | Ring gasket inside bolt circle | Full-face gasket typical |
| Common materials | Steel / SS process valves | CI / DI waterworks mating |
| Risk if mismatched | RF into FF CI can crack CI flange | Confirm both faces FF |
| Higher pressure | RF or step to RTJ | FF uncommon at high Class |
| Buyer action | “Class __ RF” | “FF for CI flange mating” |
Related end options
Screwed (NPT/BSP), SW, BW are separate from facing.
- Never assume FF when the datasheet says RF.
- Gasket material still depends on fluid and temperature.
RFQ wording that works
- “WCB gate, Class 150, ASME B16.5 RF flanged.”
- “DI butterfly / gate, PN16, flat face for CI piping.”
FAQ
Can I machine RF to FF?
Sometimes in controlled shop conditions — prefer ordering the correct facing.
Is FF the same as RTJ?
No. RTJ uses a ring groove for metal ring gaskets.
Do wafer butterflies have RF/FF?
Wafer bodies seal to flange faces with the seat; confirm mating flange facing.
EN raised face types?
Cite EN 1092 facing type on PN valves.
Related RFQs and hubs
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