My understanding is that when people started increasing the psi to
cast Pt, the flashback potential became critical and municipalities
began requiring the arresters to be installed. As you pointed out,
the natural gas (NG) line pressure is quite low (only about a quarter
pound here), and unless a pressure booster is installed, there are no
flashback arresters available. The scientific glass blowing lab on
campus has a NG pressure booster and the necessary flashback
arrester. According to the NG company representative with whom I
spoke, your comments about the lengthy gas line, etc. are correct. I
don’t cast and I like NG with an air compressor for the torch. If I
did cast, it would be a different story.
Judy in Kansas, who is puzzled by birds eating snow when unfrozen
water is available nearby.