Standardiatmosfääri

Standardiatmosfääri, often abbreviated as atm, is a unit of pressure defined as 101,325 pascals. It was established as a reference point for various scientific and engineering applications. This unit is approximately equal to the average atmospheric pressure at sea level at a temperature of 15 degrees Celsius.

The concept of standard atmosphere was developed to provide a consistent and reproducible standard for pressure measurements, eliminating variations due to altitude, temperature, and weather conditions. Before its standardization, different laboratories and industries used their own definitions of atmospheric pressure, leading to potential confusion and errors in calculations and experimental results.

While the International Standard Atmosphere (ISA) is a more detailed model that describes atmospheric conditions at different altitudes, the standard atmosphere unit (atm) specifically refers to a fixed pressure value. One standard atmosphere is equivalent to 760 millimeters of mercury (mmHg) or 760 torr, and also approximately 14.696 pounds per square inch (psi).

In many contexts, the pascal is the preferred SI unit for pressure, and the standard atmosphere is often used in more historical or specific applications. It is commonly encountered in fields such as chemistry, physics, and engineering, particularly when discussing gas laws, fluid dynamics, or diving depths. The use of standard atmosphere helps ensure comparability of data across different studies and regions.