Short Spool at Spec Break
Short Spool at Spec Break
(OP)
Hi Guys,
I have a spec break with 600# SS (Globe Valve) to 300# LT CS (Ball Valve). Between these 2 valves, a short spool was introduced.
Apparently severe corrosion was identified onto this spool. It is recommended to change short spool material (LT CS A350-LF2).
Having said, should we maintain the same spec with insulation gasket in between or completely remove the short spool?
Thanks,
Mark
I have a spec break with 600# SS (Globe Valve) to 300# LT CS (Ball Valve). Between these 2 valves, a short spool was introduced.
Apparently severe corrosion was identified onto this spool. It is recommended to change short spool material (LT CS A350-LF2).
Having said, should we maintain the same spec with insulation gasket in between or completely remove the short spool?
Thanks,
Mark





RE: Short Spool at Spec Break
So, assuming you are going to replace the spool with the "other" code material that apparently had not failed, what would you change the insulating (?) or gasket material into?
RE: Short Spool at Spec Break
1. What is inside pipes?
2. What is temperature?
3. How long doesn it take to see accessive corrosion?
4. How long is SS and LTCS portion of piping?
5. What kind of insulation gaskets were used?
6. Anything else?
Thanks,
Curtis
RE: Short Spool at Spec Break
RE: Short Spool at Spec Break
Ensure that it is an insulating gasket set with sleeves and washers etc.
RE: Short Spool at Spec Break
1. Blowdown service (gas flaring)
2. -45 F
3. 5 years, give and take
4. 160mm with Flange-to-flange connection, i could't accounted for the whole line length of LTCS and SS, if you asking.
5. Neoprene-faced phenolic
6. Whole line is cold insulated with rockwool
Thanks
RE: Short Spool at Spec Break
No, we don't have on the previous design. Currently using Gasket SPW SS/Graphite/SS and Stud A193-b8m.
RE: Short Spool at Spec Break
RE: Short Spool at Spec Break
You have a spool piece in between the two valves.
1. This spool is of SS or LTCS?
2. Can I assume that the line size is at least 4" or more? Because, the required dimensions to bolt a 3" or smaller 300# flange to a 600# flange match as per B16.5 in which case you wouldn't have provided the spool piece in the first place.
3. If this spool gets corroded, won't the pipe of the same MOC upstream / downstream of the valve also get corroded?
If not, can I assume that the fluid was entrapped in between the two valves for a long time and the spool ultimately started losing to pitting corrosion?
Regards,
L. Hariharan.
Never forget what you are. The rest of the world won't. Wear it like an armor and it can never hurt you.
RE: Short Spool at Spec Break
RE: Short Spool at Spec Break
Never forget what you are. The rest of the world won't. Wear it like an armor and it can never hurt you.