Controlling Building Pressure

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities and you. In this blog we’ll discuss proper indoor versus outdoor pressure in commercial buildings.

Controlling Building Pressure

Proper indoor versus outdoor pressure is important in commercial buildings. When indoor pressure is less than the outside pressure, outdoor air leaks, or infiltrates into the building. In addition to impacting heating, ventilation and air conditioning (HVAC) effectiveness, excessive infiltration can also cause uncomfortable drafts, especially in stairways, as well possible odor migrations and even encourage microbial growth depending on the outside weather conditions.

The opposite pressure condition, exfiltration, occurs when indoor pressure is greater than the outside pressure, indoor air leaks out of, or exfiltrates from the building. Excessive exfiltration negatively impacts temperature control by reducing supply airflow into occupied spaces, makes opening and closing doors difficult and creates noisy high-velocity airflow around doors and windows.

In addition to the operation of its mechanical ventilation system, a building’s pressure can be positive or negative due to the impact of wind and weather. Using either a return fan or a relief fan, for direct control of building pressure, manages the combined effects of weather, wind, and mechanical ventilation. This control requires pressure sensors mounted inside and outside of the building to determine the actual pressure difference. Depending on the desired exfiltration and infiltration goals, the pressure difference is typically less than 0.1-inch water gauge (wg) and can be either positive or negative.

What do you think/Comments?
Do you have a pressure sensing question? Let me know and I’ll address it in an upcoming blog.
-Dan DeFalco, Marketing Manager, All Sensors Corporation (ddefalco@allsensors.com)

Summertime and the Livin’ is Easy – with Pressure Sensors

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities and you. In this blog we’ll discuss pressure sensors for pool filters.

Summertime and the Livin’ is Easy – with Pressure Sensors

Well, it’s officially summer and one of the “livin’ is easy” moments occurs when you get to spend some time in a pool. While the pool is refreshing, there is a maintenance side and work involved in keeping it clean. The pool filter maintenance indicator is a pressure sensor that typically has a 0-60 PSI gage readout.

The pressure sensor measures a gage reading, the pressure in the filter, since it does not have to record flow. A normal operating pressure is observed when the pool filter is clean and running at a specified rpm. When the pressure in the filter increases by a few psi, it’s time for backwashing.

Since the gauge requires an operator to determine if it is time for backwashing, the sensors are simple mechanical sensors. For other filter applications that require an electronic signal, a MEMS pressure sensor usually is preferred to other sensor technology options for cost, ease of interface and reliability reasons. This is the case for commercial air filters and healthcare applications such as high-efficiency particulate air (HEPA) ultra-low penetration air (ULPA) filtration systems or ventilation units.

HEPA and ULPA filters are typically operated under pressure of approximately 203 mm (8in.) of water column. For these types of applications flow is typically measured, so a differential rather than static pressure measurement is made to determine when it is time to replace the filter. While measuring air simplifies the mechanical interface and avoids problems with liquids, the small ∆P measurement requires a specially designed pressure range to produce an easily managed output. In any case, this is an application easily handled by MEMS pressure sensors.

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What do you think/Comments?
Do you have a pressure sensing question? Let me know and I’ll address it in an upcoming blog.
-Dan DeFalco, Marketing Manager, All Sensors Corporation (ddefalco@allsensors.com)

New XHM Series Pressure Sensor

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities and you. In this blog we’ll discuss All Sensors’ new XHM Series Pressure Sensors.

NEW XHM Series Pressure Sensor

All Sensors has announced a new XHM Series Pressure Sensor. The XHM Series Pressure Sensors provide a precision calibrated and temperature compensated millivolt output. A DIP package allows for through-hole PCB mounting. The XHM Series is available from 5 inH2O to 30 PSI pressure ranges and is intended for use with dry air and non-corrosive gases. This series provides a calibrated and compensated output over a temperature range of 0°C to 50°C.

The XHM Series embodies innovative features:

  • 5 inH2O to 30 PSI
  • Calibrated and temperature compensated output
  • High impedance for low power
  • Small DIP packages
  • RoHS compliant

Ideal applications for this device include:

  • Medical devices
  • Instrumentation
  • HVAC/Environmental controls


Datasheet download here. Samples are available for product testing.

What do you think/Comments?
Do you have a pressure sensing question? Let me know and I’ll address it in an upcoming blog.
-Dan DeFalco, Marketing Manager, All Sensors Corporation (ddefalco@allsensors.com)

Pressure Sensing in Drones

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities and you. In this blog we’ll discuss the application of pressure sensing in drones.

Pressure Sensing in Drones

Aircraft of all sorts have different applications for pressure sensing. Drones in particular employ altimeters and barometers similar to even the most and least sophisticated aircraft. A basic surveillance drone can also use accelerometers, gyroscopes and magnetometers as well as cameras, temperature sensors and more.

The altimeter is an integral part of the altimeter control. While some drones have been developed and sold with ultrasonic sensors, pressure sensors improve the hovering mode of the most basic drones. With the altimeter, the air pressure in flight can be compared to the ground pressure for higher, safer operation of the drone.

Altimeters and barometers are mounted in protected internal compartments so their environment tolerance does not have to take into account external conditions that demand more rugged packaging. Recreational drones operating specifications fall well within the capabilities of commercial 100 kPa pressure sensors.

Other pressure sensor applications are found in other types of aircraft. For example, in light aircraft the simple form of an air speed indicator (ASI) measures the difference in pressure between the normal pressure around the craft and the increased pressure caused by propulsion. In more complex aircraft, pressure sensors can also monitor and help control the hydraulics, engine oil pressure and more.

With requests to expand the rules for drones from companies including Amazon, even the Federal Aviation Administration (FAA) is sensing drone pressure these days.

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What do you think/Comments?
Do you have a pressure sensing question? Let me know and I’ll address it in an upcoming blog.
-Dan DeFalco, Marketing Manager, All Sensors Corporation (ddefalco@allsensors.com)