A couple of years ago, in a PHA, I came across a scenario where a “capture device” had quite “the pull” on several small tanks that were NOT rated for a vacuum. As usual, my inquiry was met with the old “this is the way all the other plants were built and they have not experienced any issues“. But I learned about the power of even a small vacuum the hard way in 1996, and now I am very keen on identify process opportunities for these vacuum scenarios. Plus, I am always surprised at how many people literally believe the vacuum “sucks the container in“, when in fact, it’s the atmospheric pressure that crushes the container from the outside. So lets us a vac of 0.6 psig (or 16.63 inches of water vac) as the “small vac” scenario…