What Is the Lowest Pressure a Pressure Gauge Can Measure (in kPa)?

The minimum pressure a pressure gauge can measure depends on the type of pressure gauge and its intended application. Pressure gauges are typically designed to measure positive pressure (above atmospheric pressure), vacuum (below atmospheric pressure), or both. Here’s an overview:

1. Standard Pressure Gauges:

• Typical Measurement Range: Standard pressure gauges are designed to measure positive pressures starting from 0 kPa (atmospheric pressure) and can go up to hundreds or even thousands of kPa, depending on the model.

• The minimum measurement for positive pressure is typically 0 kPa (or 0 bar, which is atmospheric pressure), but most gauges will have a tolerance range that allows them to measure slightly below 0 kPa (vacuum pressure) in some cases.

2. Vacuum Gauges:

• Measuring Negative Pressure: Vacuum gauges are used to measure pressures below atmospheric pressure (negative gauge pressure). The minimum pressure for these gauges can go as low as -100 kPa or even lower, depending on the type.

• Common Range for Vacuum Gauges: Vacuum gauges typically have ranges from 0 kPa (atmospheric pressure) down to -100 kPa or -1,000 kPa (which is considered a high vacuum).

3. Absolute Pressure Gauges:

• Absolute Pressure measures the total pressure, including atmospheric pressure. For these gauges, the minimum measurable pressure is typically 0 kPa absolute, as it can measure pressures relative to a vacuum (0 kPa absolute is a perfect vacuum).

• Range: Depending on the specific model, absolute pressure gauges can measure pressures as low as 0 kPa (absolute) but typically start measuring from 1 kPa or higher, depending on the sensitivity of the instrument.

4. High-Sensitivity Low-Pressure Gauges:

• For high-sensitivity applications, such as vacuum systems, gauges can be designed to measure pressures down to micropascals (µPa), which are well below 1 kPa.

• Extreme Low Pressures: In scientific and industrial applications, ultra-high vacuum gauges (such as ionization gauges or thermocouple gauges) can measure pressures in the range of 0.0001 kPa (0.1 Pa) or even lower, reaching the high vacuum or ultra-high vacuum ranges.

Conclusion:

The lowest pressure a pressure gauge can measure depends on its type:

• Standard gauges measure pressures starting from 0 kPa (atmospheric pressure).

• Vacuum gauges can measure pressures as low as -100 kPa or lower.

• Absolute pressure gauges can measure down to 0 kPa absolute (perfect vacuum).

• High-sensitivity gauges can measure pressures much lower than 1 kPa, reaching the micropascal range.

If you are looking for a specific gauge or application, feel free to ask for more details!