What is overpressure used for?
Overpressure is a type of pressure brought about by shockwaves more powerful than average atmospheric pressure. Overpressure can be used in the measurement of the effects of thermobaric bombs and nuclear weapons.
What does a shockwave do to your body?
Shockwave is an acoustic wave which carries high energy to painful spots and myoskeletal tissues with subacute, subchronic and chronic conditions. The energy promotes regeneration and reparative processes of the bones, tendons and other soft tissues.
What is the effect of 3 psi of overpressure?
Overpressure
Overpressure | Physical Effects |
---|---|
10 psi | Reinforced concrete buildings are severely damaged or demolished. Most people are killed. |
5 psi | Most buildings collapse. Injuries are universal, fatalities are widespread. |
3 psi | Residential structures collapse. Serious injuries are common, fatalities may occur. |
What is the blast effect?
A fraction of a second after a nuclear explosion, the heat from the fireball causes a high-pressure wave to develop and move outward producing the blast effect. The front of the blast wave, i.e., the shock front, travels rapidly away from the fireball, a moving wall of highly compressed air.
What overpressure lethal?
The extent of damage from the blast wave mainly depends on five factors: (1) the peak of the initial positive-pressure wave (an overpressure of 690–1,724 kPa, for example, 100–250 psi, is considered potentially lethal) (Champion et al., 2009); (2) the duration of overpressure; (3) the medium of explosion; (4) the …
What is overpressure in physical therapy?
Overpressure: the additional movement in a joint beyond the normal range that is applied by the therapist during assessment. It can be passive (i.e. no effort from the patient required as the therapist moves the joint) or active (the patient does all the work). The opposite is accessory movement.
How powerful is a shockwave?
Close to an explosion, a shock wave can travel at several times the speed of sound and reach pressures of ten or more atmospheres, producing devastating effects.
What is overpressure in a tank?
Overpressure refers to the maximum pressure value a transducer can withstand without affecting performance; it can also refer to a situation where the pressure value exceeds the limits. 0-150 PSI device would mean an overpressure of 225 PSI.
What are the 5 types of blast injuries?
This taxonomy assigns blast injuries to five categories—Primary, Secondary, Tertiary, Quaternary, and Quinary—based on the mechanism of injury….Tertiary blast injuries
- Bone fractures.
- Traumatic amputations.
- Blunt injuries.
- Crush injuries.
- Closed or open brain injuries.
What is the expected damage from an overpressure of 1 psig?
Level of damage expected at specific overpressure values
Overpressure* (psig) | Expected Damage |
---|---|
14.5-29.0 | Range for 1-99% fatalities among exposed populations due to direct blast effects. |
* These are peak pressures formed in excess of normal atmospheric pressure by blast and shock waves. |
What is the force recommended for cervical traction?
Based on our experience and the evidence available in the literature, we typically use a force of 25 to 40 lb for the midcervical and lower cervical spine. Less force is necessary when treatment is directed to the upper cervical area.
What is the maximum amount of blast over pressure?
A 5 psi blast overpressure will rupture eardrums in about 1% of subjects, and a 45 psi overpressure will cause eardrum rupture in about 99% of all subjects. The threshold for lung damage occurs at about 15 psi blast overpressure.
Can we predict the trend of the blast overpressure?
Although it underestimates the peak values of the blast overpressure for all the blast scenarios, the empirical prediction is still able to provide a good prediction of the trend of the blast overpressure experimental results, especially the trend of the blast overpressure. Figure 4.6.
What are the effects of blast injuries?
violently into objects and receive blunt force trauma; conversely, large objects may be thrown into persons resulting in crush injuries, or else projectiles launched by the blast wind may penetrate the body. The susceptibility of personnel to blast effects depends on their proximity to nearby objects and possible projectiles.
What is the threshold for lung damage from blast damage?
The threshold for lung damage occurs at about 15 psi blast overpressure. A 35-45 psi overpressure may cause 1% fatalities, and 55 to 65 psi overpressure may cause 99% fatalities. (Glasstone and Dolan, 1977; TM 5-1300, 1990) Table 1 also shows the maximum wind speed associated with the given overpressure.