Full vacuum pressure (and, indeed, all vacuum pressures) more-or-less refers to the absence of anything; anything, in this case, being any type of matter or substance (including molecules of oxygen and other gases). Ducts aspire to reach this level of full vacuum pressure because, when vacuums exist, air immediately rushes into fill the empty space, fueling movement. This is, in essence, how ducts and ducting, on the whole, works. However, according to www.framl.nl, “in practice achieving complete emptiness is impossible. Even the outer space is not empty of matter.” So, if full vacuum pressure does not actually exist: how do duct hoses actually work? Firstly full vacuum in an industrial hose is pulling negative pressure or sucking in.
The use of a vacuum that can be as low (or high?) as 99% of the outside pressure. Say 29.5 "Hg or 1 Bar. in fact in vacuum terminology this is considered as "Medium Vacuum". Generally for most flexible industrial ducting 29Hg is in fact the maximum negative pressure that a hose can withstand. Hoses above 4-inch in diameter are generally not capable of handling this negative pressure. In addition flex ducts made from less sturdy materials like fabric are almost always incapable of pulling a full vacuum.