Multiple times I have asked myself that question and I have only one logical solution:
in reality, yes it is. Fire is a burning gas.

But in TPT? I think the gas filter wall should not let fire pass. I tried it multiple times to make something like a welding torch but thanks to this kind of filtering, it always burns back into the tank.

@ChargedCreeper (View Post)

 I thought about that but the pressure prevents it from happening. its mostly breaking the pipe