How to Measure Air Pressure & the Applications of Monitoring Devices

Posted on Wednesday Feb 22, 2023 at 09:12AM  


We are all familiar with the influence low- and high-pressure systems have on our mood and energy. But few of us know how to measure air pressure or why employing monitoring devices positively impacts commercial endeavors. By knowing the facts about how to measure air pressure and what influences it, business professionals can make informed decisions about investing in advanced technology.

What Is Air Pressure?

Also referred to as “atmospheric” or “barometric” air pressure, it is essentially the force exerted at various points along the Earth’s surface and altitudes. Based on the weight and frequency of air molecules that press down on people, wildlife, and objects, lower altitudes typically experience greater air pressure than their higher counterparts.

That’s largely due to fewer molecules being packed together at heights, such as in the mountains or while traveling in an airplane. When people talk about the air being “thinner” at higher altitudes, they are actually referring to reduced atmospheric pressure. When scientists and weather professionals provide a metric, it is usually based on a temperature of 59 degrees Fahrenheit at sea level equaling one Atm or Hg. These measurements are often determined by using a barometer.

How Is Air Pressure Measured?

A barometer is a type of absolute pressure sensor that calculates air pressure based on wide-reaching factors. The mercury in the unit is affected by the air pressure around it. The force exerted by the weight of the surrounding molecules causes the sensor to rise or fall. These are hard numbers that reflect what everyday people experience as high or low pressure based on readings.

High-Pressure Experience

When a barometric measure exceeds 30.20 Hg, the air pressure is deemed high. If you look outside on a high-pressure day, you can anticipate seeing blue skies and relatively serene weather. When the reading hovers between 29.80 and 30.20 Hg, conditions usually remain static. The same holds true when the Hg only dips modestly.

Low-Pressure Experience

A low-pressure experience occurs when the barometric number drops below 29.80 Hg. These fronts are often accompanied by warm air and precipitation. If the figure begins to drop rapidly, some form of a storm may present.

Factors That Affect Air Pressure

The mixture of nitrogen, oxygen, and other trace gasses that we commonly call air bounce off each other. They are also affected by the surrounding environment, causing changes in air density. When the air is dry and cool, the barometric pressure reading tends to increase. By contrast, stormy weather is generally associated with low pressure, and the Atm or Hg usually declines. These rank among the most prevalent reasons for air pressure rising and falling.

How Temperature Influences Pressure

The relationship between temperature shifts and air pressure is relatively straightforward. Hot temperatures result in reductions in air pressure. When temperatures drop, barometric pressure rises. The scientific reason for temperature impacting air pressure involves molecules. Heat tends to make them expand, increasing low pressure. Cold temperatures cause molecules to contract, resulting in higher pressure experiences.

How Altitude Influences Pressure

Because air is generally spread over wider areas at higher altitudes, its weight is relatively low. This equates to lower air pressures. One of the driving factors behind high altitudes having lower air pressure is reduced gravitational pull. Less density, coupled with less gravitational exertion, reduced air pressure at high altitudes.

While the inverse holds true at sea level, other factors contribute to higher pressures at low altitudes. The lowlands are also where pollutants, carbon dioxide, and dust particles are concentrated.

How Humidity Affects Pressure

When moisture interacts with air, it naturally increases the atmospheric density. Humidity is closely associated with high pressure, and arid conditions are linked to low pressure. That’s also why the shift in the seasons is accompanied by differences in air pressure. During hot summers, greater levels of evaporation occur. Greater humidity and vapor create low pressure. The opposite holds true of winter when the sun is farther away.

How Rotation of Earth Impacts Pressure

It may come as something of a surprise, but air pressure is not affected equally around the globe. As the Earth rotates, it creates a natural centrifugal force that exerts a greater influence along the Equator than in Polar regions. Because centrifugal force pushes things away, Polar areas experience higher pressure than places closer to the Equator.

Applications For Measuring Air Pressure

It’s important to understand that air pressure monitoring devices are highly sensitive technologies that can be used for many different applications. They can be broken down into fundamental classes that include absolute, gauge, and differential pressure sensors. These are the ways each type of sensor is typically employed.

Absolute pressure sensors, also known as barometers, are primarily used to forecast the weather. They start with a baseline of absolute zero pressure and track the increases and decreases that have an impact on changing weather conditions. Absolute pressure sensors can also be used to identify leaks in sealed containers.

A differential pressure sensor arrives at a pressure measurement based on the difference between two ports. These highly sophisticated devices offer significant commercial uses that include the following.

Monitoring Industrial Units

A differential pressure sensor can be strategically placed in and around the industrial units for monitoring purposes. For example, a device could provide ongoing calculations involving vats or other containers. Unexpected reductions in pressure may indicate loss of liquids or compressed gas, among other applications.

Detecting System Leaks

Differential pressure sensors are excellent monitoring devices for tracking leaking pipes. They can be connected to water mains, gas pipes, and other commercial infrastructure. This level of oversight alerts business professionals about potential reductions and increases in pressure that could impact their operations.

Automating the Flow of HVAC Systems

One of the key benefits differential pressure sensors provide is cost-effective HVAC automation. These sensitive devices can be integrated into HVAC systems and measure airflow. The internal calculations are sent to micro-controllers that provide actionable data.

Knowing how to measure air pressure using reliable devices has proven effective across industries. Business leaders are finding increased uses for pressure sensors to automate and regulate systems. Investing in this advanced technology delivers benefits that include avoiding losses, improved safety, and higher profitability.

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