Pipe color change

Hi my friends i have a question if i want to chenge pipe color or branch color in design module pemenantly how can i do this
for example i want to change pipe <2 in red color and pipe >2 color is blow

You can create an auto colour rule to address this change with the given size ranges.

These topic has been discussed several times and even if you go through the forum you can find thread related to these. do a search as AUTO COLOUR