calcium carbonate corrosion control - i need numbers!

[liatbir]

i research the corrosion of potable water distribution systems. i know that calcium carbonate precipitation potential (CCPP) is used to control the corrosion.
i am interested in recomandations for values of this index (the CCPP)if u can give me references of the recomendations i will b really happy.
thanks a lot

 

[siretb]

I do not know of the CCPP. How is it computed?
Although designed to check for scaling, to some extent, a very low Langelier Index (LSI) may mean corrosion risk. Again, the LSI is NOT a corrosion index, but if LSI is much below, say -1, you need to be a bit careful.
A corrosion related index is the Larson Skold. search the Internet for Larson Skold on how to use it.
Hope this helps

 

[liatbir]

hi siretb,
thanks for your help.
i know the LSI index. if u follow the exact logic of it, u will c that there is no meaning for the value of it, the only thing that is importance is weather it is greater than zero, or less than zero. this is also mentioned by langelier himselv in the article where he first introduced the index.
about CCPP, this index gives an adaquate calculation of how much CaCO3 the water has potential to precipitate or to dissolate. and my question is what is the common amount of CaCO3 precipitation requirements for protecting the distribution system metal from corroding. i know that in the usa it is usually between 4 and 10 mg/l, i want to have more information about other plasec in the world, or maybe about other common values in the us.

liat