Why Do Dryers Installed In Garage Need To Be 18" Above The Floor?

Any gas appliance with a pilot or flame in a garage where a car or cycle can fit in should be raised 18 inches so that if a vehicle has a gas leak the fumes being heavier then air would flow out  the air vents before rising to the pilot and starting a fire

All of these people don't talk say anything about law or ordinances, obviously when most homes were built in California, there was no issue.  These answers are from complete idiots. Give the answer, did some EPA or State idiot make this a mandate or was it a law? Created by who? Your answers show pure ignorance.