I recently accompanied a friend to buy a torch,regulators and
bottles(Oxygen and LPG). At the store (BOC gases, in West
Australia). We were informed that it was now a legal
requirement in WA and probably the rest of Australia, to have
flashback arrestors attached to regulators to avoid the flames
travelling back through the hoses before exploding and killing
the operator. Fatal accidents apparently occur in workplaces
once every 3 months. According to our advisor, flames can
travel back up the hoses when: a)there is unequal pressure in the
two tanks ie. one may be almost empty b)when the tip touches the
work, c)when flames jump up from the work (very easy when
alloying!) In fact, the regulation even exists for single
cylinder (LPG) operation but we were advised that it is
virtually impossible for flashbacks to occur using a single
cylinders and that this requirement was absurd.
Flashback arrestors are made for O2,acetylene, LPG, etc and have
a nylon component in them which shuts down the hose.
I have used my set up for 5 years and had never heard of
flashback arrestors. Nor would I have known had I not
accompanied my friend. There was certainly no such thing on our
cylinders when I was at college. My question is whether others
are aware of this potential danger and whether other countries
have regulations in place to counteract it.
Look forward to any responses