The commonly used units of pressure are the pascal (Pa), the standard atmosphere (atm), the bar, the millimetre of mercury (mmHg) and the psi. The pascal is the international and legal unit of pressure, corresponding to 1 newton per square metre (1 Pa = 1 N/m²). Other pressure units are converted from the pascal. For example, 1 bar equals 100,000 Pa and 1 atm equals 101,325 Pa. There are also other pressure units, such as millimetres of mercury, centimetres of water and psi, which are used in specific fields.
Pressure is a fundamental physical quantity used to measure the force exerted on a given surface. It plays a crucial role in various fields such as meteorology, industry and physics. Understanding what is a pressure transmitter, the units of pressure and how to convert them is essential for correctly interpreting pressure measurements and assessments.
Pressure is defined as the quotient of a force (F) over the area of the surface (S) to which it is applied: p = F/S. There are different units of pressure used around the world, each with its own specific field of application and equivalences.
In this article, we'll give you a detailed explanation of the most commonly used pressure units and show you how to convert between them. Here's all you need to know:
The pascal (Pa) is the unit of pressure in the International System of Units (SI). It is defined as the pressure exerted by a force of 1 newton on a surface of 1 square meter.
The pascal is the reference unit for all other pressure units.
The table below provides a list of the main pressure units with their respective conversion factors to Pascal.
| Pressure units | Equivalence in Pascal |
|---|---|
| Technical atmosphere | 98066.5 Pa |
| Standard atmosphere | 101325 Pa |
| Centimeter of water | 98.0638 Pa |
| Centimeter of water at 4°C | 98.0638 Pa |
| Centimeter of water at 60°F | 98.0638 Pa |
| Centimeter of water at 68°F | 98.0638 Pa |
| Centimeter of Mercury | 1333.22 Pa |
| Feet of water column | 2988.98 Pa |
| Feet of water column at 4 °C | 2988.98 Pa |
| Feet of water column at 60°F | 2986.116 Pa |
| Feet of water column at 68°F | 2986.116 Pa |
| Kilogram-force per square centimeter | 98066.5 Pa |
| Hectopascal | 100 Pa |
| Inch of water column | 248.082 Pa |
| Inch of water column at 4 °C | 248.082 Pa |
| Inch of water column at 60°F | 248.843 Pa |
| Inch of water column at 68°F | 248.843 Pa |
| Inch of Mercury | 3386.389 Pa |
| Inches of water column | 249.082 Pa |
| Torr | 133.3224 Pa |
| Unit | 1 Pa |
| Bar | 100000 Pa |
| Kilogram-force per square meter | 9.80665 Pa |
| Kilonewton per square metre | 1000 Pa |
| Millibar | 100 Pa |
| Meter of water column | 9806.38 Pa |
| Meter of Mercury | 133322 Pa |
| Millimeter of water column | 9.80638 Pa |
| Millimeter of water column at 4°C | 9.80638 Pa |
| Millimeter of water column at 60°F | 9.80638 Pa |
| Millimeter of water column at 68°F | 9.80638 Pa |
| Millimeter of Mercury | 133.3224 Pa |
| Millimeter of Mercury at 0 °C | 133.3224 Pa |
| Megapascal | 1000000 Pa |
| Ounces force per square inch | 430.92233 Pa |
| Pascal | 1 Pa |
| Pounds per square inch | 6894.757 Pa |
A1: The commonly used units of pressure measurement are the pascal (Pa), the standard atmosphere (atm), the bar, the millimetre of mercury (mmHg), and the psi. Other units are also used, including the pound per square inch (lbf/in²), kilogram-force per square metre (kgf/m²), kilonewton per square metre (kN/m²), and millibar.
A2: To convert pressure to bar, divide the pressure value in pascals by 100,000.
A3: To convert bar into kilograms, use the relationship 1 bar = 1 kg/cm².
A4: To convert a pressure value to another unit, use the specific conversion relationship between the two units and multiply the pressure value by the appropriate conversion factor. To convert pressure units, you can use an online converter or apply the appropriate conversion factors.
A5: A unit of pressure is a measurement used to quantify the force exerted on a surface.
A6: In the international system, the basic unit of pressure is the pascal (Pa). There are also multiples of the pascal, such as the hectopascal (hPa), the megapascal (MPa) and the gigapascal (GPa).
A7: The technical atmosphere (at or ATA) is a unit of pressure equivalent to the kilogram-force per square centimetre (kgf/cm²).
A8: Yes, there are online converters that allow you to convert pressure values between different units. These tools can be useful for making quick and accurate conversions.
A9: The centimetre of water column is a unit of pressure that measures the pressure exerted by a column of water 1 centimetre high. It is often used in medical and ventilation applications.
A10: The inch of mercury is a unit of pressure which measures the pressure exerted by a column of mercury one inch high. It is often used in the aviation and meteorology industries.
A11: Absolute pressure measures pressure in relation to an absolute vacuum, whereas relative pressure measures pressure in relation to atmospheric pressure. Gauge pressure is equal to absolute pressure minus atmospheric pressure. The formula for calculating absolute pressure from relative pressure is as follows:
Gauge pressure represents the difference in pressure compared with atmospheric pressure, while absolute pressure is measured in relation to the absolute vacuum, where pressure is zero. By adding atmospheric pressure to gauge pressure, we obtain absolute pressure.
It is important to note that atmospheric pressure varies according to altitude and atmospheric conditions. It is therefore essential to take atmospheric pressure into account when calculating absolute pressure.
This formula converts a gauge pressure measurement into an absolute pressure measurement by taking into account the zero reference for absolute pressure, which is the absolute vacuum.
A12: In industry, pressure units such as bar, psi, kg/cm², MPa and inHg are commonly used to measure pressure in different contexts and applications.
A13: The hectopascal is a unit of pressure equivalent to 100 pascals. It is often used in meteorology to measure atmospheric pressure.
A14: The pascal symbol is Pa, in reference to the French physicist Blaise Pascal.
We hope this article has provided you with a clear understanding of pressure units and their conversion. Feel free to use online converters to make your conversion calculations easier.
Always remember to consider the appropriate units when interpreting pressure measurements, as this may vary depending on context and application.
Remember to consult the standards and references specific to your area of interest for more detailed information on pressure units and their use.
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