Three allowable flex connections that i know of.
2 Range or wall oven
3 Bottom of a dumpster or garbage can
All others get hard piped with gas cocks and unions.
WE LIVE IN THE LAND OF THE FREE,
ONLY BECAUSE OF THE BRAVE
Havent seen style type of NPT to Flare adaptor before..
Thats those new fittings Made 100% out of teflon.
Top of the line stuff!
CHAUNCEY many more allowed applications in certain areas. we use them on furnaces which are attic suspended , water heaters , and on some occasions residential package units. also mandatory in alot of earthquake zones..... ???????
Guys teflon is the miracle cure for leaks just "spread it on" like butter that plumbers motto was "can't see it from my house" btw