A WCB body can be substuted for a LCC body up to 89mm OD in a low temp application?

[CALGARY007]

I am revising my company's piping specification 'CSA Z662 - Pipline risers at low temp. (-45C to 120C)', and I found a note "A WCB body can be substuted for a LCC body up to 89mm OD".
I know WCB body is for regular temp application, so how does this note come from? I just did a quck go through the CSA Z245.15 and did not find any reference. Any help is going to be appreciated.

 

[hsbcn]

I would be surprised to see something like "You can substitute WCB with LCC" on a low-temperature application, but find it strange that the reverse is allowed.

LCC (or LCB, which has a marginally lower tensile strength, lower yield, and a higher max allowed carbon content compared to LCC), and WCB are very close in chemical compostion, so much so that some raw-material manufacturers dual-certify the same forging/bar/casting as both standards. Still, WCB is not the steel of choice for low temp below -30ºC, so the note you found is odd.

Any particular need to move from LCC to WCB?



Oxidation-proof valves for offshore environments.

 

[SNORGY]

It probably has more to do with the fact that CSA Z662 exempts line sizes under 4" NPS from having proven notch toughness per Clause 5.2.2.1. So, if the pipe does not require the notch toughness, neither does the valve.