Atmospheric pressure plays a crucial yet often overlooked role in measuring pressure using modern instrumentation. Considering how this invisible force affects many aspects of our lives is fascinating, yet most of us rarely think about it.
Did you know that the Earth’s atmosphere weighs a staggering 5.5 quadrillion tons (5,500,000,000,000,000 tons)? It’s an almost incomprehensible figure!
Thankfully, this immense weight is evenly distributed across the planet. Because of this even distribution, the pressure exerted on our bodies feels so minimal that we don’t notice it in our daily lives.
Imagine if all that weight were concentrated in one spot—the resulting pressure would be so overwhelming that no living creature on Earth could survive.
Have you ever wondered about the invisible force that surrounds us, the atmospheric pressure?
It’s the weight of the Earth’s atmosphere pressing down on us, and it’s a key factor in understanding pressure measurement.
At sea level, which is the reference point for measuring atmospheric pressure, the average pressure is about 101.352 kPa or 1 BAR. It is often considered the “baseline” for many industrial applications. However, atmospheric pressure isn’t constant—it varies depending on where you are.
For instance, in high-altitude areas or mountainous regions, the thinner air results in significantly lower atmospheric pressure. You might have experienced this phenomenon when visiting such places and noticing changes in your breathing or hearing.
What does this have to do with pressure measurement methods?
Here’s where it gets exciting. Understanding atmospheric pressure is not just a fundamental concept but a key to measuring pressure accurately in industrial processes.
In the sections ahead, the Bawalaksana Central Industrial team will guide you through the three basic pressure measurement methods and explore how they connect to atmospheric pressure. We promise to make it engaging and easy to grasp, so let’s dive in together!
What Is the Difference Between Absolute and Gauge Pressure?
When measuring pressure, understanding the differences between absolute and gauge pressure is essential. Absolute pressure measures pressure relative to a perfect vacuum, or zero pressure (0 BAR), completely ignoring the influence of atmospheric pressure around us.
On the other hand, gauge pressure measures pressure relative to the surrounding atmospheric pressure, making it more applicable to everyday situations.
As we mentioned earlier, atmospheric pressure changes with altitude. This means that the exact pressure measurement can yield different results depending on the elevation at which it is taken. This fascinating detail highlights how dynamic and interconnected pressure measurements are with the environment.
Pressure measurement methods are categorized into three main types:
- Gauge pressure
- Absolute pressure
- Differential pressure
In industrial applications, selecting the correct pressure measurement method isn’t just about precision but ensuring the data aligns with real-world conditions. Experts carefully consider factors like the process environment and instrumentation to achieve accurate and meaningful measurements.
Notably, several factors listed below can affect pressure measurement results:
- Temperature
- Humidity
- The chosen measurement method
- Calibration and condition of the instruments
- Process dynamics
- Vibrations
- And more
These factors remind us that pressure measurement is as much an art as a science. By accounting for these variables, professionals can ensure the most reliable results.
For now, we’ll focus on the three basic pressure measurement methods and their connection to atmospheric pressure. By exploring this, you’ll understand how these methods work and why they matter in industrial processes.
To help clarify the concepts, we’ll also explain the key differences between absolute and gauge pressure in more detail. The diagram below clearly illustrates how these two types of pressure differ.

Absolute Pressure
Absolute pressure is measured starting from a perfect vacuum, also called zero pressure, where the pressure level is 0 BAR.
As the diagram above illustrates, absolute pressure is calculated from 0 BAR, disregarding the surrounding atmospheric pressure. This makes absolute pressure unique—it’s completely independent of environmental factors like altitude or weather.
Because it doesn’t rely on atmospheric pressure, absolute pressure measurements are always positive (+) and remain consistent no matter how high or low you are. The value stays the same at sea level or atop a mountain, making this measurement method exceptionally reliable for specific applications.
Gauge Pressure
Gauge pressure, on the other hand, is measured relative to atmospheric pressure. This means its readings can vary based on your environment’s altitude and atmospheric conditions.
Most pressure measuring devices are calibrated to show 0 BAR at atmospheric pressure. For instance, when inflating a car tire, you see a pressure reading, which is gauge pressure—the additional pressure above the surrounding air. Because it’s tied to atmospheric pressure, gauge pressure values are typically positive (+) under normal conditions.
Vacuum Pressure
Vacuum pressure takes things in a different direction—literally! It measures pressure relative to atmospheric pressure, but in this case, the values are always lower than atmospheric pressure, resulting in negative (-) readings.
To put it simply, vacuum pressure represents the range between absolute zero pressure and the threshold of atmospheric pressure. Think of it as a way to measure the “absence” of pressure, often used in applications like creating suction or maintaining a vacuum in sealed environments.
Remember, atmospheric pressure is roughly 101.352 kPa or equivalent to 1 BAR. That’s why vacuum pressure values are always less than atmospheric pressure, making them inherently negative (-).
Atmospheric Pressure
Atmospheric pressure is the air pressure around us, varying depending on where you are. At sea level, atmospheric pressure is higher, while at high altitudes, like in the mountains, it decreases. This natural variation plays a vital role in understanding how pressure measurements relate to the world around us.
In the next section, we’ll explore real-world examples of how absolute pressure, gauge pressure, and differential pressure are applied. These examples will help you understand how these concepts are used in industrial and everyday settings.

Absolute Pressure
Absolute pressure is measuring pressure relative to a perfect vacuum or absolute zero pressure (0 BAR). It’s a straightforward yet powerful concept that is critical in many industries.
What makes absolute pressure unique is that it’s completely unaffected by atmospheric pressure. This means that the results remain consistent regardless of altitude or environmental conditions. The measurement stays the same whether at sea level, high in the mountains, or even in a pressurized industrial setting.
Imagine you’re using an Absolute Pressure Gauge to measure the pressure of a fluid, and the reading shows 10 BAR. That value will remain the same no matter where you are, from the lowest valleys to the highest peaks.
Absolute pressure gauges are essential tools in a wide range of industries, including:
- Petrochemicals: Ensuring safe and efficient operations in refining and processing.
- Pharmaceuticals: Maintaining precise conditions for product quality.
- Food and Beverage: Supporting high standards in production and packaging.
- And more: Wherever consistency and accuracy are paramount.
By understanding and utilizing absolute pressure, industrial processes can harmonize perfectly with the surrounding environment. This not only ensures faster and smoother operations but also guarantees high-quality production results, meeting even the most stringent standards.
In essence, absolute pressure isn’t just a measurement—it’s a critical factor driving efficiency, safety, and quality in modern industries.

Gauge Pressure
Gauge pressure is a way of measuring pressure relative to atmospheric pressure. Unlike absolute pressure, which starts from a vacuum, gauge pressure uses the surrounding atmospheric pressure as its baseline. This makes it particularly relevant in everyday and industrial applications.
A simple gauge pressure example is measuring the pressure of a gas cylinder. Imagine you’re at a low-altitude location, and the pressure in the cylinder reads 24 BAR (2400 kPa). If you take that same cylinder to a higher altitude, the reading might drop slightly to 23.7 BAR (2370 kPa).
Why does this happen? It’s because atmospheric pressure decreases as you move to higher elevations. Since gauge pressure is measured relative to atmospheric pressure, any change in atmospheric conditions directly affects the reading.
In essence, gauge pressure reflects the pressure inside the cylinder and the surrounding environment’s influence.
Gauge pressure is widely used across industries due to its practical nature and adaptability. Its importance can’t be overstated, as it supports countless processes in diverse fields. Here are nine typical applications where gauge pressure measurement plays a critical role:
- General Industrial: To maintain efficient operations in manufacturing systems.
- Food, Beverage & Dairy: Ensuring safety and hygiene in production processes.
- Chemical & Petrochemical: Controlling pressure to ensure safety and precision in chemical reactions.
- Pharmaceutical: Supporting strict quality control standards in production and research.
- Filter Systems: Monitoring pressure to maintain filtration efficiency.
- Heating Installations: Ensuring optimal pressure in heating systems for safety and performance.
- Power Generation: Overseeing turbines and key components to prevent failures.
- Oil & Gas: Monitoring pipelines and tanks to ensure safe operations.
- Shipping (Marine Applications): Ensuring reliable pressure monitoring for onboard systems in maritime environments, adapting to varying atmospheric and operational conditions.
Gauge pressure isn’t just a technical measurement—it’s an essential tool that bridges the gap between equipment, the environment, and industrial needs. By understanding its principles and applications, industries can optimize performance and ensure reliability across the board.

Differential Pressure
Differential pressure is a method of measurement used to determine the pressure difference between two points. This approach is essential in many industrial processes, offering a reliable way to monitor and manage system performance.
Imagine you need to measure the flow rate of a fluid—whether gas or liquid—within a pipeline. Differential pressure can help you compare the pressure before and after a narrowing in the pipe or a filtration system.
The diagram below illustrates this concept, showing how differential pressure is applied to measure the pressure difference between two points: the upstream (before the narrowing or filter) and the downstream (after it).

Knowing the differential pressure between these two points provides valuable insights. For instance, if the upstream pressure is significantly higher than the downstream pressure, it indicates that a filter or strainer is clogged. Detecting such issues early can help prevent system failures and maintain operational efficiency.
For a deeper understanding of differential pressure, we recommend reading our article, What is a Differential Pressure Gauge and Its Crucial Role in the Petrochemical Industry.
Differential pressure measurement is a cornerstone of many industries, ensuring processes run smoothly and safely. Some of its key applications include:
- Filter Systems: Monitoring filters to detect clogs and maintain efficiency.
- Chemical & Petrochemical: Ensuring precise control in critical operations.
- Heating Installations: Regulating pressure to optimize heating systems.
- Oil & Gas: Tracking pressure changes in pipelines to ensure safe operations.
In essence, differential pressure is more than just a measurement technique—it’s vital for maintaining reliability, safety, and efficiency across various industries.
Why is Pressure Measurement So Crucial in Industrial Processes?
Accurate pressure measurement is more than a technical necessity—it’s a cornerstone of safe and high-quality production. Monitoring a substance’s or fluid’s pressure during industrial processes can ensure smoother operations while safeguarding both products and personnel.
Choosing the correct type of pressure gauge is vital for precise monitoring and control. With the appropriate tool, your engineering team can receive timely “warning signals,” allowing them to address potential issues before they become serious problems. This proactive approach not only prevents system failures but also improves overall efficiency.
Every method of measurement and sensor type has its strengths and limitations. That’s why selecting the correct pressure gauge involves carefully considering several factors:
- The measurement’s purpose
- The type of fluid
- Operating environment
- Accuracy Class
Equally important is the ability to accurately and precisely read a pressure gauge. Interpreting readings can become more challenging in certain situations—such as when dealing with vibrations, fluctuating pressures, or aging instruments. Developing strong gauge-reading skills is crucial to maintaining reliable results.
To help you master this skill, we recommend our article, How to Read a Pressure Gauge Accurately and Precisely, which provides practical tips to ensure consistent and reliable measurements.

Your Trusted Partner for Industrial Instrumentation
At PT. Bawalaksana Central Industrial, we understand the importance of reliable pressure measurement in your operations. That’s why we proudly serve as an authorized distributor of high-quality pressure gauges manufactured by Instruments To Industry (ITI).
ITI is a globally recognized specialist in instrumentation. It offers many products, including pressure gauges, temperature sensors, dial thermometers, chemical seals, e-gauges, and more. With over 150 years of industry expertise, ITI is synonymous with precision, durability, and excellence.
You’ve come to the right place if you’re looking for pressure gauges that deliver unmatched reliability and performance.
Our professional team is here to help you find the perfect instrumentation tools tailored to your industry’s needs. You can optimize your processes and achieve superior outcomes with the right equipment.
Ready to take the next step? Click the consultation button below and connect with our expert engineers today. Let us help you elevate your industrial processes with confidence and precision.

Romanta Pinrih Linuwih
Pneumatic Automation Systems Expert
This article was written in collaboration with Romanta Pinrih Linuwih, an expert in Pneumatic Automation Systems, to ensure accuracy and high quality.