Standard atmospheric pressure, also known as average atmospheric pressure, has a value equal to 14.7 psi, 101.3 kPa, 760 mm of mercury, or 1 atmosphere.
This value is a reference point for pressure measurements and calculations in various scientific and engineering fields. It's crucial for understanding vacuum conditions, where the pressure is less than this standard. Let's break down these different units of measurement:
Understanding Different Units of Standard Atmospheric Pressure
Here is a table summarizing the different units used to express standard atmospheric pressure:
| Unit | Value |
|---|---|
| Pounds per square inch (psi) | 14.7 psi |
| Kilopascals (kPa) | 101.3 kPa |
| Millimeters of Mercury (mm Hg) | 760 mm Hg |
| Atmosphere (atm) | 1 atmosphere |
Practical Insights
Understanding the different units is important because:
- 14.7 psi: Commonly used in the United States, particularly in engineering and automotive applications.
- 101.3 kPa: The preferred standard in many parts of the world and in scientific contexts.
- 760 mm Hg: Historically used due to the ease of measuring atmospheric pressure using a mercury barometer.
- 1 atmosphere: Provides a convenient way to express pressure relative to standard conditions.
Examples
- Vacuum Technology: Devices operating in vacuums have pressures significantly lower than 101.3 kPa (1 atmosphere).
- Weather Reports: Barometric pressure readings are often given in mm Hg or kPa, with standard atmospheric pressure as the reference.
- Pressure Gauges: Pressure gauges display readings in psi, kPa, or other units, all referenced to standard atmospheric pressure.
The reference provided states that "The average atmospheric pressure, called the standard atmospheric pressure, is equal to 14.7 psi, 101.3 kPa, 760 mm of mercury, or 1 atmosphere," highlighting the different ways standard atmospheric pressure is expressed.
