Pressure conversion
Pressure conversionPressure calculator is a practical tool for engineers, service technicians, or automation specialists who work with sensors and pneumatic systems. It allows for quick conversion of the most popular pressure units, such as pascals, bars, atmospheres, or PSI. With it, you can easily compare data from different sources and adjust values to the requirements of a specific system.
What is a pressure calculator used for?
The TME pressure calculator allows for efficient conversion of pressure values between different units without the need for manual calculations or reference tables. The tool is particularly useful for:
- comparing technical specifications of components from different markets (e.g., Europe vs USA),
- selecting valves, sensors, or pressure transducers,
- configuring pneumatic and hydraulic systems,
- analyzing documentation from manufacturers who use different unit systems.
With the calculator, you can quickly convert pressure from bars to PSI, from atmosphere to pascals, or from mmHg to Pa, which facilitates daily work in service, laboratory, or engineering positions.
Most commonly used pressure units
Around the world, several different pressure units are used depending on the industry, country, and specific applications. The table below presents the most popular ones and their conversion factors relative to the SI base unit, the pascal (Pa).
| Unit | Symbol | Value in Pa | Typical Application |
|---|---|---|---|
| Pascal | Pa | 1 | SI unit, science, laboratory measurements |
| Hectopascal | hPa | 100 | meteorology |
| Kilopascal | kPa | 1,000 | industry, automotive |
| Bar | bar | 100,000 | engineering, hydraulic and pneumatic systems |
| Technical atmosphere | at | 98,066.50 | hydraulics, industrial engineering |
| Standard atmosphere | atm | 101,325 | physics, chemistry, reference data |
| PSI (pound per square inch) | PSI | 6,894.76 | USA, automotive, compressed air |
| Millimeter of mercury | mmHg | 133.32 | medicine, laboratory measurements |
| Torr | Torr | 133.32 | scientific applications, vacuum |
It's important to remember that different units are used interchangeably, but they are not identical values. Therefore, accurate conversion is essential, especially in engineering applications and automation.
Practical use of the pressure converter
Knowledge of pressure units and the ability to quickly convert them is crucial in many fields of engineering. Here are a few examples where the calculator can be helpful:
- Selecting pressure sensors, e.g., a sensor described in PSI, while the system reads values in bars;
- Conversion of data in documentation, e.g., a valve from a US manufacturer has a range of 0–100 PSI, but the system is designed in kPa;
- Working with industrial pneumatics – actuators, compressors, and valves often use pressure expressed in bars or atmospheres;
- Measuring pressure in vacuum systems, where mmHg, Torr, or Pa are used.
Correct conversion of pressure units helps prevent errors in system design, increases safety, and facilitates the integration of components from different sources.
FAQ - Frequently asked questions about pressure conversion
Is bar and atmosphere the same?
No. 1 bar is exactly 100,000 Pa, whereas 1 technical atmosphere (at) is 98,066.5 Pa, and 1 standard atmosphere (atm) is 101,325 Pa. They are close in everyday practice, but precision is important in technical calculations.
When are pascals used, and when are bars used?
Pascals (Pa) and kilopascals (kPa) are SI units, mainly used in science, electronics, and technical documentation. Bars (bar) are popular in industry, service, and automation because they are better suited for expressing working pressure (1 bar = 100,000Pa).
Why is PSI used in the USA?
PSI (pounds per square inch) is a unit derived from the imperial system, which is still the standard in the USA. It is commonly used in automotive, hydraulics, and compressed air systems.
What is the difference between hPa and mbar?
They are exactly the same value. 1 hPa = 1 mbar = 100 Pa. Both units are used interchangeably, especially in meteorology.
Are absolute pressure and relative pressure the same?
No. Absolute pressure (abs) is measured relative to a vacuum (0 Pa). Relative pressure (relative) measures the difference relative to atmospheric pressure. Therefore, a gauge showing "0 bar" actually measures about 1 atm relatively.
Did you know...
- 1 atmosphere is the pressure exerted by a column of mercury 760 mm high – formerly measured by raising and lowering tubes filled with mercury.
- Pressure affects the boiling temperature of water, e.g., at an altitude of 3000m above sea level, water boils at 90°C.
- At the bottom of the Mariana Trench, the pressure is about 1086 bars. It's like having a weight of about 1100 kg on every cm².
- In automotive engineering, bars and PSI are often confused – 1 bar is about 14.5 PSI. Typical tire pressure is about 2.2–2.5 bars, which corresponds to 32–36 PSI.
- Bar is a unit not belonging to the SI system, but it is very popular in industry and automation. It was introduced in 1909 by Norwegian meteorologist Vilhelm Bjerknes.
- In medicine, mmHg (millimeters of mercury) is still used to measure blood pressure, although it is not an SI unit. The "mmHg" unit comes from the times of the mercury barometer by Evangelista Torricelli (1643). At atmospheric pressure, mercury rose in the tube to a height of about 760mm – hence 760mmHg = 1 atm.
- In meteorology, until the mid-20th century, millibars were used, which were formally replaced by hectopascals. 1 mbar = 1 hPa.
- The term "pascal" was introduced in 1971 in honor of French physicist Blaise Pascal, who studied the properties of liquids and gases. Previously, "N/m²" was mainly used.
- Underwater, the pressure increases by 1 atm every 10 meters of depth. According to Boyle's law, the volume of gas is inversely proportional to the pressure, meaning that the volume of a diver's lungs decreases with increasing depth. At a depth of 10m, the lung volume drops to half, at 30m – to one quarter, and at greater depths, there is a risk of lung pressure injury (so-called barotrauma) if the diver does not equalize the pressure or ascends too quickly. Therefore, divers should never hold their breath while surfacing, as it can cause the lung alveoli to burst.
- Humans can feel ear pain with a pressure difference of about 0.2 atm, which is why regulating pressure in airplane cabins is so important.
