Are 2 traps allowed on 1 line.
Not so quick and easy actually. . .
If you are referring to two traps in series (where waste flows through one trap and then through another), no, this is not allowed and is considered a “double trap.”
If you are asking about two separate traps, joining a common trap arm (waste flows through one trap and wye’s into the trap arm), that would be dependent upon the codes adopted by your area. The UPC prohibits this installation while the IRC allows it.
here is a picture
Nope, that’s not right.
Ditto.