Static pressure is a term used in ventilation engineering, airspeed indication, fluid statics, hydraulics and flow measurement. It is defined as the potential pressure exerted in all directions by a fluid or gas at rest. For a fluid or gas in motion, static pressure is measured in a direction at right angles to the direction of flow. Thus static pressure shows a tendency to burst or collapse a ventilation duct, a water dam or balloon. Static pressure in a ventilation system is usually expressed in inches of water gauge, which can be either negative or positive. Other units that are used to express static pressure are: pascals and millimeters of mercury (mmHg). A vacuum is a special case of static pressure. Fluid pressure is another case of static pressure. Airspeed Indicator The airspeed indicator is an instrument used in an aircraft to display the crafts airspeed, typically in knots, to the pilot. ... Fluid statics (also called hydrostatics) is the science of fluids at rest, and is a sub-field within fluid mechanics. ... Hydraulics is a branch of science and engineering concerned with the mechanical properties of liquids. ... The flow rate of a fluid can be measured in a variety of ways. ... Scrivener Dam, in Canberra, Australia, was engineered to withstand a once-in-5000-years flood event A dam is a barrier across flowing water that obstructs, directs or retards the flow, often creating a reservoir, lake or impoundment. ... Balloons are given for special occasions, like greeting cards or flowers. ... The pascal (symbol Pa) is the SI unit of pressure. ... For other uses, see vacuum cleaner and Vacuum (musical group). ... Fluid pressure is the pressure on an object submerged in a fluid, such as water. ...

Examples

• The air pressure inside a latex baloon is a static pressure and so is the atmospheric pressure.
• The water pressure at the bottom of a dam is a static pressure and so is the pressure exerted on ones thumb when stopping the water flow in a garden hose.
• The vacuum pressure in a vacuum tube is a static pressure.
• The static pressure of the blood pressure in a artery ore vein must be above the atmospheric pressure or the blood vessels would collapse.
• If the static pressure inside a ventilation duct is below the atmospheric pressure it may collapse unless the duct is rigid enough to withstand the force. Round ducts can withstand atmospheric pressure better than rectangle size ducts due to its geometry.
• Sucking in or blowing out ones cheeks shows the effect of static pressure. When the cheeks are sucked in the pressure inside the mouth is below atmospheric pressure. When the cheeks are blown out the pressure inside the mouth is above atmospheric pressure.

diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure above any area in the Earths atmosphere caused by the weight of air. ... In electronics, a vacuum tube (U.S. and Canadian English) or (thermionic) valve (outside North America) is a device generally used to amplify, or otherwise modify, a signal by controlling the movement of electrons in an evacuated space. ... Blood pressure is the pressure exerted by the blood on the walls of the blood vessels. ... Section of an artery An arterial road is a class of highway. ... In geology, a vein is a finite volume within a rock, having a distinct shape, filled with mono or poly mineralic crystal aggregates, which were precipitated from an (aqueous) fluid or melt. ... diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure above any area in the Earths atmosphere caused by the weight of air. ... Geometry (Greek γεωμετρία; geo = earth, metria = measure) arose as the field of knowledge dealing with spatial relationships. ...

Equations

In ventilation engineering:

Velocity pressure + Static pressure = Total pressure

For the equation calculating water pressure see Hydrostatic pressure. The basic concept is that the hydrostatic pressure is directly dependend on the density of the liquid, the acceleration due to gravity and the height of the water column. For practical calculation this is further simplied by using standard values for density and and gravity. The pressure increases linear with the water depth, which means that at ten times the depth the static pressure will be ten times higher. Fluid pressure is the pressure on an object submerged in a fluid, such as water. ... Density (symbol: ρ - Greek: rho) is a measure of mass per unit of volume. ... g (also gee, g-force or g-load) is a non-SI unit of acceleration defined as exactly 9. ... The word linear comes from the Latin word linearis, which means created by lines. ...

Related physical laws are:

• Pascal's law