R. Eliezer says: Sixteen cubits, as (the distance of) the public way. R. Akiva says: Fifty cubits. R. Shimon says: "Pay shall he pay, he that lights the fire" — all according to the fire (i.e., according to the height of the fire and its mass. The bigger it is, the farther it travels.)
When Fire Spreads from One Person's Property and Damages a Neighbor's
Mekhilta Tractate Nezikin 14:11