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What's RFSF?
5

What's RFSF?

What's RFSF?

(OP)
What do you mean by "RFSF" when you specify flanges?

Maybe I think it's raised face smooth finish.

Am i right?

RE: What's RFSF?

Yes, That is correct.
RFSF = Raised Face Smooth Finish

RE: What's RFSF?

Really?  Where do you find this nomenclature?  It could as easily be serated flange, separable flange, etc.  I poked around MSS SP-6 and ASME B16.5 and found nothing to support this.  I also searched for RFWN (I use this all the time) and found nothing.

John

RE: What's RFSF?

2
pennpiper is correct. RFSF means Raised Face Smooth Finish but this isn't official terminology that you'll find in the published codes.

Back in the old days the standard finish on raised face flanges was around 500 microinch roughness. Some users and licensors (UOP for one) desired a smoother flange finish for services like hydrogen to get a better flange seal when used with spiral wound gaskets. The term RFSF was used to differentiate these smooth face flanges from those with the rougher standard finish. When an RFSF flange is specified, the required finish should also be defined. I remember seeing finishes like 63-125Ra or 125-250Ra.

In recent editions of ASME B16.5, the standard finish is defined as 125-250 Microinch average. Because the standard finish is now much smoother than before, the RFSF requirements have pretty much been abandoned. You'll find that the smooth finish requirement for flanges and valves in most old piping specifications are equivalent or close to the standard finish for flanges today.

NozzleTwister
Houston, Texas

RE: What's RFSF?


Worth double checking it is not a typo for commonly used RFSO (Raised Face Slip On) flange. Does the flange specification mention what type of flange it is (Weld neck, slip on, etc)?

Cheers,
Amin

RE: What's RFSF?

2
I have built this list of abreviations over the years.  It usually has what I am looking for.

ANSI    American National Standards Institute
API    American Petroleum Institute
ASME    American Society of Mechanical Engineers
ASSY    Assembly
ASTM    American Society of Testing Materials
AVG    Average
BB    Bolted Bonnet
BC    Bolt Circle
BF    Blind Flange
BLDG    Building
BM    Bill of Material (Also BOM)
BOP    Bottom of Pipe
BW    Butt Weld
CI    Cast Iron
CO    Clean Out
CONC    Concentric
COND    Condensate
CPLG     Coupling
CS    Carbon Steel or Cast Steel
CSC    Car Sealed Closed
CSO    Car Sealed Open
°C    Degrees Celsius
°F    Degrees Fahrenheit
DI     Ductile Iron
DIA    Diameter
DWG    Drawing
ECC    Eccentric
ELEV    Elevation
FF    Full Face
FIG    Figure
FLG    Flange
FOB    Flat on Bottom
FOT    Flat on Top
FS    Forged Steel
FT    Feet or Foot
FW    Field Weld
GALV    Galvanized
GR    Grade
HDR    Header
ID    Inside Diameter
INS    Insulate
INV    Invert (Inside Bottom of Pipe)
IPS    Iron Pipe Size
I-ST    Insulate and Steam Trace
LBS    Pounds
LR    Long Radius
M&F    Male and Female
MFG    Manufacturer
MI    Malleable Iron
MIN    Minimum
NC    Normally Closed
NO    Normally Open
OD    Outside Diameter
PE    Plain End
PSIA    Pounds per Square Inch Absolute
PSIG    Pounds per Square Inch Gauge
RB    Return Bend
RED    Reducer
RF    Raised Face
RTJ    Ring Type Joint (Also RJ)
SCH    Schedule
SCRD    Screwed
SF    Smooth Finish
SMLS    Seamless
SO    Slip-On
SOL    Sock-O-Let
SPEC    Specification
SR    Short Radius
SS    Stainless Steel
STD    Standard
STL    Steel
STM    Steam
SW    Socket-Weld
SWG    Swage
TE    Threaded End
TEMP    Temperature
TOC    Top of Concrete
TOG    Top of Grade
TOL    Thread -O-Let
TOS    Top of Steel
TYP    Typical
VERT    Vertical
W/    With
WE    Weld End
WN    Weld Neck
WOL    Weld-O-Let
WT    Weight
XH    Extra Heavy (Also XS)
XXH    Double Extra Heavy (Also XXS)
 

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