I don't think you have to worry about the tank.
Truck shops use a similar tank with a 1&1/4"+ outlet size line and a dump
valve.
They point the discharge tube at the rim / tire bead area ofa newly mounted
tire and 'dump' the contents of the tank in about a half second. The wave of
high pressure air blows the tire up far enough that it catches the bead so
the tire will stay mounted for the rest of the inflation process through the
valve stem.
What you are doing sounds tame by comparison.
Some more info is at:
http://www.uniquetruck.com/products/...ategory&catego
ryid=9&subcategoryid=10
Hope it helps....
Jeff



"adam smith" wrote in message
m...
I have a couple questions about air receiver safety. I have a 20
gallon ASME carry tank (Grainger 4TK10). It has two 1/2" air outlets,
but I want to use it to honk an old fire horn which is not working
when I plumb from just one of the 1/2" outlets. I need more flow to
maintain proper blowing pressure at the horn. So my questions are
these:

1. Is there a known maximum safe discharge rate for a 20 gallon ASME
tank? The tank has a plate rating of MAWP 175 PSI @ 475 F. I need to
meter out half-second blasts at a rate of approximately 80 CFM. Is
this safe to do from a 20 gallon tank? What about from a pair of 20
gallon tanks?

2. Can I plumb the two 1/2" outlets into a common 3/4" or 1" tee? Is
there any safety reason not to?

3. Lastly, the tank has a 1-1/2" NPT inspection port that has a 1/4"
hole tapped in it for a guage. Can I replace this plug with a
1.5"-to-1" hex bushing and plumb right from there, or is this a no-no.

I want to get full flow to the horn, but I don't want to do anything
that is likely to cause the tank to lose integrity or fail
explosively/implosively. I've found lots of useful information about
maximum tank pressures, but I can't find anything on the web about
maximum discharge rates or air tank implosion.

Thanks,

Adam
adam at airraidsirens dot com