The horror stories in regards to burners are from boil overs while frying turkeys. Many wooden decks caught fire from the combustable hot oil! A wort boil over will not catch fire, and I would not worry about it.
Use a spray bottle filled with water to knock down the foam done!
I even have a sheild to protect the flame from the wind, which you would think would divert some heat to the wooden deck, around the base of my burner. Haven't had an issue with too much heat on the deck yet.
How do you BBQ an elephant....first you get your elephant....