Note, there are 2 tables and a list. Here's another useful link:
| In units: | |||||||||
| Pa (N/m2) | MPa | bar | atmosphere | mmHg Art. | mm in.st. | m in.st. | kgf/cm 2 | ||
| Should be multiplied by: | |||||||||
| Pa (N/m2) | 1 | 1*10 -6 | 10 -5 | 9.87*10 -6 | 0.0075 | 0.1 | 10 -4 | 1.02*10 -5 | |
| MPa | 1*10 6 | 1 | 10 | 9.87 | 7.5*10 3 | 10 5 | 10 2 | 10.2 | |
| bar | 10 5 | 10 -1 | 1 | 0.987 | 750 | 1.0197*10 4 | 10.197 | 1.0197 | |
| atm | 1.01*10 5 | 1.01* 10 -1 | 1.013 | 1 | 759.9 | 10332 | 10.332 | 1.03 | |
| mmHg Art. | 133.3 | 133.3*10 -6 | 1.33*10 -3 | 1.32*10 -3 | 1 | 13.3 | 0.013 | 1.36*10 -3 | |
| mm in.st. | 10 | 10 -5 | 0.000097 | 9.87*10 -5 | 0.075 | 1 | 0.001 | 1.02*10 -4 | |
| m in.st. | 10 4 | 10 -2 | 0.097 | 9.87*10 -2 | 75 | 1000 | 1 | 0.102 | |
| kgf/cm 2 | 9.8*10 4 | 9.8*10 -2 | 0.98 | 0.97 | 735 | 10000 | 10 | 1 | |
| 47.8 | 4.78*10 -5 | 4.78*10 -4 | 4.72*10 -4 | 0.36 | 4.78 | 4.78 10 -3 | 4.88*10 -4 | ||
| 6894.76 | 6.89476*10 -3 | 0.069 | 0.068 | 51.7 | 689.7 | 0.690 | 0.07 | ||
| Inches Hg / inches Hg | 3377 | 3.377*10 -3 | 0.0338 | 0.033 | 25.33 | 337.7 | 0.337 | 0.034 | |
| Inches in.st. / inchesH2O | 248.8 | 2.488*10 -2 | 2.49*10 -3 | 2.46*10 -3 | 1.87 | 24.88 | 0.0249 | 0.0025 | |
| To convert pressure in units: | In units: | |||
| psi pound square feet (psf) | psi inch / pound square inches (psi) | Inches Hg / inches Hg | Inches in.st. / inchesH2O | |
| Should be multiplied by: | ||||
| Pa (N/m2) | 0.021 | 1.450326*10 -4 | 2.96*10 -4 | 4.02*10 -3 |
| MPa | 2.1*10 4 | 1.450326*10 2 | 2.96*10 2 | 4.02*10 3 |
| bar | 2090 | 14.50 | 29.61 | 402 |
| atm | 2117.5 | 14.69 | 29.92 | 407 |
| mmHg Art. | 2.79 | 0.019 | 0.039 | 0.54 |
| mm in.st. | 0.209 | 1.45*10 -3 | 2.96*10 -3 | 0.04 |
| m in.st. | 209 | 1.45 | 2.96 | 40.2 |
| kgf/cm 2 | 2049 | 14.21 | 29.03 | 394 |
| psi pound square feet (psf) | 1 | 0.0069 | 0.014 | 0.19 |
| psi inch / pound square inches (psi) | 144 | 1 | 2.04 | 27.7 |
| Inches Hg / inches Hg | 70.6 | 0.49 | 1 | 13.57 |
| Inches in.st. / inchesH2O | 5.2 | 0.036 | 0.074 | 1 |
Detailed list of pressure units:
- 1 Pa (N/m 2) = 0.0000102 Atmosphere (metric)
- 1 Pa (N/m2) = 0.0000099 Atmosphere (standard) = Standard atmosphere
- 1 Pa (N/m2) = 0.00001 Bar / Bar
- 1 Pa (N/m 2) = 10 Barad / Barad
- 1 Pa (N/m2) = 0.0007501 Centimeters Hg. Art. (0°C)
- 1 Pa (N/m2) = 0.0101974 Centimeters in. Art. (4°C)
- 1 Pa (N/m2) = 10 Dyne/square centimeter
- 1 Pa (N/m2) = 0.0003346 Foot of water (4 °C)
- 1 Pa (N/m2) = 10 -9 Gigapascals
- 1 Pa (N/m2) = 0.01
- 1 Pa (N/m2) = 0.0002953 Dumov Hg. / Inch of mercury (0 °C)
- 1 Pa (N/m2) = 0.0002961 InchHg. Art. / Inch of mercury (15.56 °C)
- 1 Pa (N/m2) = 0.0040186 Dumov v.st. / Inch of water (15.56 °C)
- 1 Pa (N/m 2) = 0.0040147 Dumov v.st. / Inch of water (4 °C)
- 1 Pa (N/m 2) = 0.0000102 kgf/cm 2 / Kilogram force/centimetre 2
- 1 Pa (N/m 2) = 0.0010197 kgf/dm 2 / Kilogram force/decimetre 2
- 1 Pa (N/m2) = 0.101972 kgf/m2 / Kilogram force/meter 2
- 1 Pa (N/m 2) = 10 -7 kgf/mm 2 / Kilogram force/millimeter 2
- 1 Pa (N/m 2) = 10 -3 kPa
- 1 Pa (N/m2) = 10 -7 Kilopound force/square inch
- 1 Pa (N/m 2) = 10 -6 MPa
- 1 Pa (N/m2) = 0.000102 Meters w.st. / Meter of water (4 °C)
- 1 Pa (N/m2) = 10 Microbar / Microbar (barye, barrie)
- 1 Pa (N/m2) = 7.50062 Microns Hg. / Micron of mercury (millitorr)
- 1 Pa (N/m2) = 0.01 Millibar / Millibar
- 1 Pa (N/m2) = 0.0075006 Millimeter of mercury (0 °C)
- 1 Pa (N/m2) = 0.10207 Millimeters w.st. / Millimeter of water (15.56 °C)
- 1 Pa (N/m2) = 0.10197 Millimeters w.st. / Millimeter of water (4 °C)
- 1 Pa (N/m 2) = 7.5006 Millitorr / Millitorr
- 1 Pa (N/m2) = 1N/m2 / Newton/square meter
- 1 Pa (N/m2) = 32.1507 Daily ounces/sq. inch / Ounce force (avdp)/square inch
- 1 Pa (N/m2) = 0.0208854 Pounds of force per square meter. ft / Pound force/square foot
- 1 Pa (N/m2) = 0.000145 Pounds of force per square meter. inch / Pound force/square inch
- 1 Pa (N/m2) = 0.671969 Poundals per sq. ft / Poundal/square foot
- 1 Pa (N/m2) = 0.0046665 Poundals per sq. inch / Poundal/square inch
- 1 Pa (N/m2) = 0.0000093 Long tons per square meter. ft / Ton (long)/foot 2
- 1 Pa (N/m2) = 10 -7 Long tons per square meter. inch / Ton (long)/inch 2
- 1 Pa (N/m2) = 0.0000104 Short tons per square meter. ft / Ton (short)/foot 2
- 1 Pa (N/m2) = 10 -7 Tons per sq. inch / Ton/inch 2
- 1 Pa (N/m2) = 0.0075006 Torr / Torr
Every person knows that air pressure is measured in millimeters mercury, since this is the unit of measurement that is used in everyday life. In physics, in the SI system of units, pressure is measured in pascals. The article will tell you how to convert millimeters of mercury into pascals.
Air pressure
First, let's look at the question of what air pressure is. This value is understood as the pressure that the atmosphere of our planet exerts on any objects located on the surface of the Earth. It is easy to understand the reason for the appearance of this pressure: for this you need to remember that each body of finite mass has a certain weight, which can be determined by the formula: N = m*g, where N is the weight of the body, g is the value of the acceleration due to gravity, m is the mass of the body . The presence of weight in the body is due to gravity.
The atmosphere of our planet is a large gaseous body that also has some mass and therefore has weight. It has been experimentally established that the mass of air that exerts pressure on 1 m 2 of the earth's surface at sea level is approximately equal to 10 tons! The pressure exerted by this air mass is 101,325 pascals (Pa).
Converting millimeters of mercury to pascals
When viewing a weather forecast, barometric pressure information is usually presented in millimeters of mercury (mmHg). To understand how mmHg. Art. convert to pascals, you just need to know the relationship between these units. And remembering this ratio is easy: 760 mmHg. Art. corresponds to a pressure of 101,325 Pa.
Knowing the above numbers, you can obtain a formula for converting millimeters of mercury into pascals. The easiest way to do this is to use a simple proportion. For example, a certain pressure H in mm Hg is known. Art., then the pressure P in pascals will be equal to: P = H*101325/760 = 133.322*H.
The given formula is easy to use. For example, at the top of Mount Elbrus (5642 m) the air pressure is approximately 368 mm Hg. Art. Substituting this value into the formula, we get: P = 133.322*H = 133.322*368 = 49062 Pa, or approximately 49 kPa.
In which the pressure is balanced by a column of liquid. It is often used as a liquid because it has a very high density (≈13,600 kg/m³) and low saturated vapor pressure at room temperature.
Atmosphere pressure at sea level is approximately 760 mmHg. Art. Standard atmospheric pressure is taken to be (exactly) 760 mmHg. Art. , or 101,325 Pa, hence the definition of a millimeter of mercury (101,325/760 Pa). Previously, a slightly different definition was used: the pressure of a column of mercury with a height of 1 mm and a density of 13.5951·10 3 kg/m³ with a free fall acceleration of 9.806 65 m/s². The difference between these two definitions is 0.000014%.
Millimeters of mercury are used, for example, in vacuum technology, in weather reports and in measuring blood pressure. Since in vacuum technology very often pressure is measured simply in millimeters, omitting the words “mercury column”, the natural transition for vacuum engineers to microns (microns) is carried out, as a rule, also without indicating “mercury column pressure”. Accordingly, when a pressure of 25 microns is indicated on a vacuum pump, we are talking about the maximum vacuum created by this pump, measured in microns of mercury. Of course, no one uses a Torricelli pressure gauge to measure such low pressures. To measure low pressures, other instruments are used, for example, McLeod pressure gauge (vacuum gauge).
Sometimes millimeters of water column are used ( 1 mmHg Art. = 13,5951 mm water Art. ). In the USA and Canada, the unit of measurement “inch of mercury” (designation - inHg) is also used. 1 inHg = 3,386389 kPa at 0 °C.
| Pascal (Pa, Pa) |
Bar (bar, bar) |
Technical atmosphere (at, at) |
Physical atmosphere (atm, atm) |
Millimeter of mercury (mm Hg, mmHg, Torr, torr) |
Water column meter (m water column, m H 2 O) |
Pound-force per sq. inch (psi) |
|
|---|---|---|---|---|---|---|---|
| 1 Pa | 1 / 2 | 10 −5 | 10.197 10 −6 | 9.8692 10 −6 | 7.5006 10 −3 | 1.0197 10 −4 | 145.04 10 −6 |
| 1 bar | 10 5 | 1 10 6 din / cm 2 | 1,0197 | 0,98692 | 750,06 | 10,197 | 14,504 |
| 1 at | 98066,5 | 0,980665 | 1 kgf/cm 2 | 0,96784 | 735,56 | 10 | 14,223 |
| 1 atm | 101325 | 1,01325 | 1,033 | 1 atm | 760 | 10,33 | 14,696 |
| 1 mmHg | 133,322 | 1.3332·10 −3 | 1.3595 10 −3 | 1.3158 10 −3 | 1 mmHg. | 13.595 10 −3 | 19.337 10 −3 |
| 1 m water Art. | 9806,65 | 9.80665 10 −2 | 0,1 | 0,096784 | 73,556 | 1 m water Art. | 1,4223 |
| 1 psi | 6894,76 | 68.948 10 −3 | 70.307 10 −3 | 68.046 10 −3 | 51,715 | 0,70307 | 1 lbf/in 2 |
see also
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See what “Millimeter of mercury” is in other dictionaries:
- (mm Hg, mm Hg), non-system units. pressure; 1 mmHg art. = 133.332 Pa = 1.35952 10 3 kgf/cm2 = 13.595 mm water. Art. Physical encyclopedic dictionary. M.: Soviet encyclopedia. Chief Editor A. M. Prokhorov. 1983. MILLIME... Physical encyclopedia
Non-system units pressure, app. when measuring atm. water vapor pressure, high vacuum, etc. Designation: Russian. - mmHg art., int. — mm Hg. 1 mmHg Art. equal to hydrostatic pressure of a column of mercury with a height of 1 mm and a density of 13.5951... ... Technical Translator's Guide
- – non-system units. pressure; 1 mmHg art. = 133.332 Pa = 1.35952 10 3 kgf/cm2 = 13.595 mm water. Art. [Physical encyclopedia. In 5 volumes. M.: Soviet Encyclopedia. Editor-in-chief A. M. Prokhorov. 1988.] Term heading: General terms... ... Encyclopedia of terms, definitions and explanations of building materials
Off-system unit of pressure; designation: mmHg Art. 1 mmHg Art. = 133.322 Pa = 13.5951 mm water column. * * * MILLIMETER OF MERCURY COLUMN MILLIMETER OF MERCURY, non-systemic unit of pressure; designation: mmHg Art. 1 mmHg Art. = 133.322... encyclopedic Dictionary
Torr, an off-system unit of pressure used when measuring atmospheric pressure of water vapor, high vacuum, etc. Designation: Russian mm Hg. Art., international mm Hg. 1 mm of mercury is equal to hydrostatic... Encyclopedic Dictionary of Metallurgy
- (mmHg) unit of pressure, as a result of which mercury in the column rises by 1 millimeter. 1 mmHg Art. = 133.3224 Pa... Dictionary in medicine
Torr, a non-systemic unit of pressure used in measurements of atmospheric pressure, partial pressure of water vapor, high vacuum, etc. Designations: Russian mm Hg. Art., international mm Hg. 1 mmHg see equal... ... Great Soviet Encyclopedia
Non-system units not subject to use. pressure. Designation mm Hg. Art. 1 mmHg Art. = 133.322 Pa (see Pascal) ... Big Encyclopedic Polytechnic Dictionary
Off-system unit of pressure; designation: mmHg Art. 1 mmHg Art. = 133.322 Pa = 13.5951 mm water. st... Natural science. encyclopedic Dictionary
Pascal (Pa, Pa)
Pascal (Pa, Pa) - unit of measurement of pressure in International system units of measurement (SI system). The unit is named after the French physicist and mathematician Blaise Pascal.
Pascal is equal to the pressure caused by a force equal to one newton (N) uniformly distributed over a surface of one square meter normal to it:
1 pascal (Pa) ≡ 1 N/m²
Multiples are formed using standard SI prefixes:
1 MPa (1 megapascal) = 1000 kPa (1000 kilopascals)
Atmosphere (physical, technical)
Atmosphere is an off-system unit of pressure measurement, approximately equal to atmospheric pressure on the Earth's surface at the level of the World Ocean.
There are two approximately equal units with the same name:
- Physical, normal or standard atmosphere (atm, atm) - exactly equal to 101,325 Pa or 760 millimeters of mercury.
Technical atmosphere (at, at, kgf/cm²)- equal to the pressure produced by a force of 1 kgf, directed perpendicularly and uniformly distributed over a flat surface with an area of 1 cm² (98,066.5 Pa).
1 technical atmosphere = 1 kgf/cm² (“kilogram-force per square centimeter”). // 1 kgf = 9.80665 newtons (exact) ≈ 10 N; 1 N ≈ 0.10197162 kgf ≈ 0.1 kgf
On English language kilogram-force is denoted as kgf (kilogram-force) or kp (kilopond) - kilopond, from the Latin pondus, meaning weight.
Notice the difference: not pound (in English “pound”), but pondus.
In practice, they approximately take: 1 MPa = 10 atmospheres, 1 atmosphere = 0.1 MPa.
Bar
A bar (from the Greek βάρος - heaviness) is a non-systemic unit of pressure measurement, approximately equal to one atmosphere. One bar is equal to 105 N/m² (or 0.1 MPa).
Relationships between units of pressure
1 MPa = 10 bar = 10.19716 kgf/cm² = 145.0377 PSI = 9.869233 (physical atm.) = 7500.7 mm Hg.
1 bar = 0.1 MPa = 1.019716 kgf/cm² = 14.50377 PSI = 0.986923 (physical atm.) = 750.07 mm Hg.
1 atm (technical atmosphere) = 1 kgf/cm² (1 kp/cm², 1 kilopond/cm²) = 0.0980665 MPa = 0.98066 bar = 14.223
1 atm (physical atmosphere) = 760 mm Hg = 0.101325 MPa = 1.01325 bar = 1.0333 kgf/cm²
1 mm Hg = 133.32 Pa = 13.5951 mm water column
Volumes of liquids and gases / Volume
1 gl (US) = 3.785 l
1 gl (Imperial) = 4.546 l
1 cu ft = 28.32 l = 0.0283 cubic meters
1 cu in = 16.387 cc
Flow speed
1 l/s = 60 l/min = 3.6 cubic meters/hour = 2.119 cfm
1 l/min = 0.0167 l/s = 0.06 cubic meters/hour = 0.0353 cfm
1 cubic m/hour = 16.667 l/min = 0.2777 l/s = 0.5885 cfm
1 cfm (cubic feet per minute) = 0.47195 l/s = 28.31685 l/min = 1.699011 cubic meters/hour
Throughput / Valve flow characteristics
Flow coefficient (factor) Kv
Flow Factor - Kv
The main parameter of the shut-off and control body is the flow coefficient Kv. The flow coefficient Kv shows the volume of water in cubic meters per hour (cbm/h) at a temperature of 5-30ºC passing through the valve with a pressure loss of 1 bar.
Flow coefficient Cv
Flow Coefficient - Cv
In countries with an inch measurement system, the Cv coefficient is used. It shows how much water in gallons/minute (gpm) at 60ºF flows through a fixture when there is a 1 psi pressure drop across the fixture.
Kinematic viscosity / Viscosity
1 ft = 12 in = 0.3048 m
1 in = 0.0833 ft = 0.0254 m = 25.4 mm
1 m = 3.28083 ft = 39.3699 in
Units of force
1 N = 0.102 kgf = 0.2248 lbf
1 lbf = 0.454 kgf = 4.448 N
1 kgf = 9.80665 N (exactly) ≈ 10 N; 1 N ≈ 0.10197162 kgf ≈ 0.1 kgf
In English, kilogram-force is expressed as kgf (kilogram-force) or kp (kilopond) - kilopond, from the Latin pondus, meaning weight. Please note: not pound (in English “pound”), but pondus.
Units of mass
1 lb = 16 oz = 453.59 g
Moment of force (torque)/Torque
1 kgf. m = 9.81 N. m = 7.233 lbf * ft
Power Units / Power
Some values:
Watt (W, W, 1 W = 1 J/s), horsepower (hp - Russian, hp or HP - English, CV - French, PS - German)
Unit ratio:
In Russia and some other countries 1 hp. (1 PS, 1 CV) = 75 kgf* m/s = 735.4988 W
In the USA, UK and other countries 1 hp = 550 ft*lb/s = 745.6999 W
Temperature
Fahrenheit temperature:
[°F] = [°C] × 9⁄5 + 32
[°F] = [K] × 9⁄5 − 459.67
Temperature in Celsius:
[°C] = [K] − 273.15
[°C] = ([°F] − 32) × 5⁄9
Kelvin temperature:
[K] = [°C] + 273.15
[K] = ([°F] + 459.67) × 5⁄9
Atmospheric pressure is created by the air envelope and is experienced by all objects located on the surface of the Earth. The reason is that air, like everything else, is attracted to to the globe through gravity. In weather forecast reports, information about atmospheric pressure is given in millimeters of mercury. But this is a non-systemic unit. Officially the pressure is like physical quantity, in SI since 1971 expressed in “pascals”, equal to a force of 1 N acting on a surface of 1 m2. Accordingly, there is a transition “mm. rt. Art. in pascals."
The origin of this unit is associated with the name of the scientist Evangelista Torricelli. It was he who, in 1643, together with Viviani, measured atmospheric pressure using a tube from which air had been pumped out. It was filled with mercury, which has the highest density among liquids (13,600 kg/m3). Subsequently, a vertical scale was attached to the tube, and such a device was called a mercury barometer. In Torricelli's experiment, the column of mercury, balancing the external air pressure, was established at a height of 76 cm or 760 mm. It was taken as a measure of air pressure. Value 760 mm. rt. st is considered normal atmospheric pressure at a temperature of 00C at sea level latitude. It is known that atmospheric pressure is very variable and fluctuates throughout the day. This is due to temperature changes. It also decreases with height. After all, in upper layers atmosphere, the air density becomes less.
Using physical formula, it is possible to convert millimeters of mercury to pascals. To do this, you need to multiply the density of mercury (13600 kg/m3) by the acceleration of gravity (9.8 kg/m3) and multiply by the height of the mercury column (0.6 m). Accordingly, we obtain a standard atmospheric pressure of 101325 Pa or approximately 101 kPa. Hectopascals are also used in meteorology. 1 hPa = 100 Pa. How many pascals will be 1 mm? rt. Art? To do this, divide 101325 Pa by 760. We get the desired dependence: 1 mm. rt. st = 3.2 Pa or approximately 3.3 Pa. Therefore, if you need, for example, to convert 750 mm. rt. Art. in pascals, you just need to multiply the numbers 750 and 3.3. The resulting answer will be the pressure measured in pascals.
Interestingly, in 1646, the scientist Pascal used a water barometer to measure atmospheric pressure. But since the density of water is less than the density of mercury, the height of the water column was much higher than that of mercury. Scuba divers are well aware that atmospheric pressure is the same as at a depth of 10 meters under water. Therefore, using a water barometer causes some inconvenience. Although the advantage is that water is always at hand and is not poisonous.
Non-systemic pressure units are widely used today. In addition to meteorological reports, millimeters of mercury are used in many countries to measure blood pressure. In human lungs, pressure is expressed in centimeters of water. Vacuum technology uses millimeters, micrometers, and inches of mercury. Moreover, vacuum specialists most often omit the words “mercury column” and talk about pressure measured in millimeters. And here's mm. rt. Art. No one converts to pascals. Vacuum systems assume too low pressure, compared to atmospheric. After all, vacuum means “airless space.”
Therefore, here we already have to talk about a pressure of several micrometers or microns of mercury. And the actual measurement of pressure is carried out using special pressure gauges. So the McLeod vacuum gauge compresses the gas using a modified mercury manometer, maintaining a stable state of the gas. The instrument's technique has the greatest accuracy, but the measurement method takes a lot of time. Conversion to pascals is not always of practical importance. After all, thanks to an experiment once carried out, the existence of atmospheric pressure was clearly proven, and its measurement became publicly available. So on the walls of museums, art galleries, and libraries you can find simple instruments - barometers that do not use liquids. And their shala is graduated for convenience both in millimeters of mercury and in pascals.
