Welcome to the aboveground storage tank forum, a bulletin board dedicated to tanks, fuel tanks, plastic tanks, fuel storage tanks, and above ground storage tanks (AST) API650, API653 & UL142 aboveground storage tanks (AST) and chemical plastic tanks. Remember the forum is made up of volunteers from experts to beginners. Unfortunately, we cannot allow free commercialism that promotes products, services, or sites.
GR on What do you mean by Full Vacuum in Tank / Pressure vesselsBy: GR 
Date: Friday, May 29, 2009
Time: 2:29:59 AM
Vacuum means the internal pressure goes below atmospheric. Full Vacuum is a negative pressure equivalent to 14.7psi or 15 psirounded-off meaning full volume of the container without pressure. In some cases vessel are designed for Half Vacuum which is 7.5 psi.
Published on ast-forum.com