Short Hand, SH, SHH, SLL etc

The standard cited by Mikerho pertains more to the instruments and controls than to the fluids contained in the piping. I doubt that there is any universal standard that could cover all types of fluid, so you may be dealing with a semi-standard for an industry, a specific company, or a contractor. If there is no legend on the piping drawing, check the whole drawing set to see if there is a master legend.

I share most of your guesses so far: S = steam, L = low pressure, H = high pressure, HH = even higher pressure. I don't get WB, though.

you are right, there is a universal standard for symbols and representations. for the sake's of specific company and contractor, they use a little different kind of representatives which, you and i have to guess. Even, the symbol masterlist does not show all. I am dealing with palm oil processing from RBD hydrogenated stearin/olein to produce monoglycerides.

thank !

thank sir!!

You're welcome. You are asking the right sorts of questions, and I will try to be helpful.