The Collaborative International Dictionary
Overpressure \O"ver*pres"sure\, n.
Excessive pressure or urging.
--London Athen[ae]um.
Wiktionary
n. excess or markedly elevated pressure, especially a transient high pressure due to a shock wave vb. To subject to a high pressure
WordNet
n. a transient air pressure greater than the surrounding atmospheric pressure; "the overpressure of the blast kills by lethal concussion"
Wikipedia
Overpressure (or blast overpressure) is the pressure caused by a shock wave over and above normal atmospheric pressure. The shock wave may be caused by sonic boom or by explosion, and the resulting overpressure receives particular attention when measuring the effects of nuclear weapons or thermobaric bombs.
Overpressure is a pressure difference, relative to a normal pressure, in various circumstances:
- In engineering, the pressure difference over the wall thickness of a pressure vessel
- In geology, geologic overpressure, the pressure regime that is the primary cause of " oil gushers"
An overpressure protection system is one designed to protect an individual or group of individuals in a chemical, biological, radiological and nuclear ( CBRN) environment. The two parts of the system are a safe area which as far as possible is sealed from possible contaminated air and an air filtration system which will filter out all possible toxins. Air pumps force clean air through the filters into the safe area such that the air pressure within the safe area will always be higher than that outside of the safe area. This pressure differential means that any flows of air will always be from the safe area to the outside, preventing the ingress of toxins.
The safe area may be as small as a protective hood for an individual, to a full body hazmat suit, to a fallout shelter or warship. Most modern armoured fighting vehicles will have such a system with the safe area being the crew and passenger compartments, these systems being first adopted to protect against poison gas attack. On a larger scale an overpressure system may be designed into the structure of a building or mobile prefabricated military structures to provide collective protection.
In a civilian context the same principles of filtration and positive pressure is used in positive pressure personnel suits.
Usage examples of "overpressure".
This close, I could feel the overpressure from the submachine gun like slaps to my face.
The pressure gauges were really wavering because of the thirty-pound overpressure waves pulsing through the system.
The overpressure could still be felt to slap structures as far away as the Toledo suburb.
The Abrams was rocked by the blast-wave and the terrific overpressure but all the seals, designed back in the 1970s for full-scale war against the long-defunct Soviet Union, held and the crew survived.
Shortly after, the outer layer of the overpressure wave hit, but at the distance they were from the explosion it amounted to not much more than a strong wind that shook the brown leaves from the surrounding trees and dropped streams of frigid water onto their backs.
Prompt radiation, superstellar temperatures, electromagnetic pulse, thermal pulse, blast overpressure, fallout, disease, loss of immunity, cold, dark, contamination, inherited deformity, ozone depletion: with what hysterical ferocity, with what farcical disproportion, do nuclear weapons loathe human life.
The sudden overpressure, pressure which could not escape the sealed armored vehicle, burst the eardrums of every man trapped inside.
Suddenly there was a dull roaring noise, and a brilliant flare, and heat ravaged her mantle and dreadful overpressure strained her tubules.
The acceleration imparted to a space-cylinder was relatively gentle now, and created less overpressure than a driver test, but there was still a sonic boom to brace oneself against.
Now the blasts came as overpressure he could feel with his own body, jarring motions that rocked Able and blurred the instruments in front of him.
It requires an overpressure of nearly half a ton per square inch to redden diamond-protected skin in this manner.
The shock wave slammed into his body with an overpressure of three hundred thousand pounds, crushing his chest, rupturing his liver, spleen, and lungs, and separating his unprotected hands.
Even though it was just black powder and dynamite, it had to hit you with an overpressure of almost sixty thousand pounds.
In fact, as he began to understand, he had been raised in something like an asylum of eccentrics, people bent hard by those first overpressured years on Mars.
It's especially common to overpressured leader types like Star Fleet captains.