Indoor burner / flame failure device - worth it?

[Kev888]

I'm moving to propane gas (from electricity) for the boil kettle/copper and am (still!) choosing my gas-burner/boiling-ring. I've narrowed it down to two designs, but each are available with or without Flame Failure Devices.

I believe these are required in professional circles for anything vaguely enclosed, even under gazebos. I'm only brewing at home so the legalities don't matter much to me, but I'm quite interested in the implication that it may be a very good idea to have. Also the paella burners with FFD advertise themselves as being suitable for indoor use, which would be a great benefit; even the huge ones say they are, and I'd be looking at a modest 350mm/400mm one max. The obvious downside being that a £45 paella burner triples in price with FFD.

I'd be willing to pay that premium if I could really use it indoors, but not if thats still not sensible for some reason (even assuming the propane tank could be on a long hose outside). Can I really use such a burner indoors?

Cheers
Kev