Best Dairy-Free Shortening. Shortening is an even fattier form of butter. Where butter is made with about 85 percent fat and 15 percent water, shortening is 100 percent fat. For those who can't tolerate lactose, there is a dairy free version of this ultra rich spread.
For example, the standard aluminum 80-cubic-foot tank weighs about 35 pounds, while similar capacity steel tanks weigh in at about 30 pounds. There have been lengthy discussions about the service life of steel tanks vs. aluminum tanks.
Figure 1. Head Pressure Measurement. The pressure on a scuba diver swimming in the ocean would be the diver's depth multiplied by the weight of the ocean (64 pounds per cubic foot). A scuba diver diving 33 feet into the ocean would have 2112 pounds of water on every square foot of his body. That translates to 14.7 PSI.