3

are used with fluids that have very low vapour pressures (usually less than 1.5 psia) and have air in the head space . Tank designs are generally for working pressures < 2.5 inches water gauge (0.09 psi) positive pressure and 0.5 oz/in2 (0.86 in H20 , 0.03 psi) vacuum, but can be designed for pressures up to about 15 psig for smaller tanks. ................
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