A860 & A694 vs MSS SP75 & SP44
A860 & A694 vs MSS SP75 & SP44
(OP)
All,
I've gone back & forth on how best to specify & order high yield steel piping buttweld fittings & flanges. I primarily work under B31.4 & API 1104 for welding procedures. H For grade B material, we commonly will specify ASTM A234WPB with B16.9 for fittings & A105 with B16.5 for flanges. This is fairly standard across the pipeline industry from my experience.
However, for high yield material it's a different story. We used to specify the appropriate MSS SP75 grade with B16.9 for fittings & MSS SP44 grade with B16.5 for flanges. In an effort to be consistent with how we specify grade B material we've since switched to specifying the ASTM A860 or A694 high yield steel with the ASME/ANSI dimensional standard. From some of the previous posts I've read on this site, it appears the most common way is to specify to MSS standards instead. Can anyone explain why?
Also, if you do specify a high yield flange to both MSS SP44 & B16.5, what pressure-temperature rating do you follow since MSS SP44 states its flanges are full rated up to 250 F I believe whereas B16.5 flanges typically derate beyond 100 F for common materials?
Thank you for your input
I've gone back & forth on how best to specify & order high yield steel piping buttweld fittings & flanges. I primarily work under B31.4 & API 1104 for welding procedures. H For grade B material, we commonly will specify ASTM A234WPB with B16.9 for fittings & A105 with B16.5 for flanges. This is fairly standard across the pipeline industry from my experience.
However, for high yield material it's a different story. We used to specify the appropriate MSS SP75 grade with B16.9 for fittings & MSS SP44 grade with B16.5 for flanges. In an effort to be consistent with how we specify grade B material we've since switched to specifying the ASTM A860 or A694 high yield steel with the ASME/ANSI dimensional standard. From some of the previous posts I've read on this site, it appears the most common way is to specify to MSS standards instead. Can anyone explain why?
Also, if you do specify a high yield flange to both MSS SP44 & B16.5, what pressure-temperature rating do you follow since MSS SP44 states its flanges are full rated up to 250 F I believe whereas B16.5 flanges typically derate beyond 100 F for common materials?
Thank you for your input





RE: A860 & A694 vs MSS SP75 & SP44
If you spec B16.5, you get to use the B16.5 temperature allowable. If you spec MSS SP-44, you get to use the SP-44 temperature allowable.
MSS SP-44 was written to address the need for high pressure flanges and SP-75 hi press fittings, that were developed specifically for high pressure, pipeline use. It allows the material's high yield stress at lower temperatures than B16.5, up to 250°F, then derates more quickly above 250°, as based on pipeline industry experience.
B16.5 is primarily a dimensional spec that at one time only addressed low carbon steel and sizes up to 24" for typical low grade, carbon steel, plant piping which was no longer suitable for high pressure, high strength, large diameters being used in pipelining at the time.
To specify a high yield strength, large diameter, pipeline flange, all you really (normally) need to do is write
36" Diameter,
Flange,
RF x WN (might be something like RTJ x WN, etc.)
0.375" wall thickness,
Bore 35.250" (that is redundant, but not harmful)
ANSI#600,
MSS SP-44,
F65
Design Code B31.8
Design Factor 0.60
Beveled 30° for welding
It may also be helpful to specify the wall and grade of the adjoining pipe.
The mfgr may select the (any) base material as referenced within MSS SP-44 that matches the yield strength grade that you specify, unless you choose to specify a particular material, in which case he will use that one and probably charge you more for having to read your spec.
Include any additional requirements, such as Charpy Test Temperature, Taper bored to some other ID, etc. as applicable to your specific requirements.
RE: A860 & A694 vs MSS SP75 & SP44
RE: A860 & A694 vs MSS SP75 & SP44
I too have always used A105 and 234 WBP For Grade B flanges and fittings to B16.5 or 9 when size is <= 24", as they nearly all are in plant piping, and when temperatures are below the B16.5 & .9 limits. That's normally not a problem, hi temp pipelines have been few in the past, but their use is becoming more frequent with the more unusual oils coming to market these days. If I had a hot pipeline, I would be tempted to use MSS SP 44 F36 too.
They have a number of other useful standards as well,
http://msshq.org/Store/Results.cfm?category=6
RE: A860 & A694 vs MSS SP75 & SP44
B16.5 is to MSS SP-44
as B16.36 is to .... ?
In other words,
B16.36 refers back to B16.5 for materials, but what is the best/easiest way to specify orifice flanges to go with the higher grade pipe?
For regular non-orifice flanges, MSS SP-44 provides a way to use the higher strength material (like A694 GR. XX), but as far as I can tell, MSS SP-44 doesn't cover orifice flanges.
Any suggestions?
RE: A860 & A694 vs MSS SP75 & SP44
Order whatever flanges you want and machine bore the taps, if you want flange taps, or alternatively tap only the pipe.
Plate
http://www2.emersonprocess.com/en-us/brands/daniel...
OR
Use an orifice fitting,
http://www2.emersonprocess.com/en-us/brands/daniel...