Flame arresters are fitted in the dumping nozzels of the l1011. We were of the opinion that if things were so bad that you were returning at max gross with a fire then dumping was a viable option as it couldn't really make things worse unless the flame arrestors didn't work in which case why were they get fitted to the jet. In this scenario missed approach climb gradients were not a consideration but stopping on the runway and not braking the wings on touchdown was.
Note: This was on the mill tanker version where we had more fuel than you could shake a big stick at on board.