
Description


•

Pressure (or stress) has the dimension mass per length time squared. The SI unit of pressure is the pascal, which is defined as a newton per square meter, or a kilogram per meter second squared.

•

Maple knows the units of pressure listed in the following table.

Name

Symbols

Context

Alternate Spellings

Prefixes






bar

bar

SI *

bars

SI






atmosphere

atm @, atmos@

standard *

atmospheres



at @

technical








barye


standard *

baryes

SI

pieze


standard *

piezes

SI

torr

Torr

standard *

torrs

SI

vac


standard *

vacs

SI

pound_per_square_inch

psi

standard *

pounds_per_square_inch







meter_mercury

mHg

standard *

meters_mercury, metre_mercury, metres_mercury

SI



`0degC`


SI

foot_mercury

ftHg

standard *

feet_mercury




`32degF`





`60degF`



inch_mercury

inHg

standard *

inches_mercury




`32degF`





`60degF`








meter_water

mH2O

standard *

meters_water, metre_water, metres_water

SI



`4degC`


SI

foot_water

ftH2O

standard *

feet_water




`39.2degF`



inch_water

inH2O

standard *

inches_water




`39.2degF`



kipf_per_square_inch

ksi

standard



pascal

Pa

SI

pascals


planck_pressure


planck *

planck_pressures





An asterisk ( * ) indicates the default context, an at sign (@) indicates an abbreviation, and under the prefixes column, SI indicates that the unit takes all SI prefixes, IEC indicates that the unit takes IEC prefixes, and SI+ and SI indicate that the unit takes only positive and negative SI prefixes, respectively. Refer to a unit in the Units package by indexing the name or symbol with the context, for example, pascal[SI] or mmHg[standard]; by using an abbreviation, for example, at; or, if the context is indicated as the default, by using only the unit name or symbol, for example, pascal or mmHg.


The units of pressure are defined as follows.


A bar is defined as $100000$ pascals.


A standard atmosphere is defined as $101325$ pascals.


A technical atmosphere is defined as a kilogramforce per square centimeter, that is, $98066.5$ pascals.


A barye is defined as a dyne per square centimeter.


A pieze is defined as a sthene per square meter.


A torr is defined as $\frac{1}{760}$ standard atmosphere.


A vac is defined as a millibar.


A pound per square inch is defined as a poundforce per inch squared.


A planck pressure is defined as a planck mass per planck length per planck time squared.


Mercury


•

The meter, foot, and inch of mercury are the pressures exerted by columns of mercury $1$ meter, foot, and inch in height, respectively.


A standard meter of mercury is defined as $\frac{25}{19}$ atmospheres.


A 0 degree Celsius meter of mercury is defined as approximately $133322$ pascals.


A standard foot of mercury is defined as $0.3048$ standard meter of mercury.


A 32 degree Fahrenheit foot of mercury is defined as approximately $40636.6$ pascals.


A 60 degree Fahrenheit foot of mercury is defined as approximately $40522.2$ pascals.


A standard inch of mercury is defined as $0.0254$ standard meter of mercury.


A 32 degree Fahrenheit inch of mercury is defined as approximately $3386.38$ pascals.


A 60 degree Fahrenheit inch of mercury is defined as approximately $3376.85$ pascals.



Water


•

The meter, foot, and inch of water are the pressures exerted by columns of water $1$ meter, foot, and inch in height, respectively.


A standard meter of water is defined as the pressure exerted by $1000$ kilograms per square meter assuming standard acceleration of free fall.


A 4 degrees Celsius meter of water is defined as approximately $9806.38$ pascals.


A standard foot of water is defined as $0.3048$ standard meter of water.


A 39.2 degree Fahrenheit foot of water is defined as approximately $2988.98$ pascals.


A standard inch of water is defined as $0.0254$ standard meter of water.


A 39.2 degree Fahrenheit inch of water is defined as approximately $249.082$ pascals.




Examples


>

$\mathrm{convert}\left('\mathrm{Pa}'\,'\mathrm{dimensions}'\,'\mathrm{base}'=\mathrm{true}\right)$

$\frac{{\mathrm{mass}}}{{\mathrm{length}}{}{{\mathrm{time}}}^{{2}}}$
 (1) 
>

$\mathrm{convert}\left(42.0\,'\mathrm{units}'\,'\mathrm{inHg}'\,'\mathrm{mmHg}'\right)$

>

$\mathrm{convert}\left(1.0\,'\mathrm{units}'\,'\mathrm{inHg}\left[\mathrm{`32degF`}\right]'\,'\mathrm{inH2O}\left[\mathrm{`39.2degF`}\right]'\right)$

>

$\mathrm{convert}\left(1.0\,'\mathrm{units}'\,'\mathrm{at}'\,'\mathrm{atm}'\right)$

>

$\mathrm{convert}\left(1.231\,'\mathrm{units}'\,'\mathrm{bar}'\,'\mathrm{atmosphere}'\right)$

>

$\mathrm{convert}\left(34.21\,'\mathrm{units}'\,'\mathrm{pieze}'\,'\mathrm{torr}'\right)$



