usually, you put dirt traps , or dirp legs, at the ends of the line
before you are going into the furnace, water heaters ect..
changes of direction mean nothing....
but you are messing with gas and
wishing to install it inside some walls?
and you are wondering if you need drip legs on each
change of direction??
I dont mean to insult you , but it you dont know
the bare minimnum about what you are about
to undertake ...it might be wise to get this
done by a professional..
its one thing to have minor damage
from a drain line or dripping pipe you soldered
and its quite another to take out the whole city block.