ONICON Airflow Measurement Solutions – Accurate, Reliable, and Optimized for HVAC Systems

ONICON is a world-leading brand in airflow measurement, offering comprehensive, precise, and reliable solutions that help HVAC systems and buildings operate efficiently while optimizing energy consumption. By applying advanced technology and adhering to international manufacturing standards, ONICON devices meet the most demanding requirements for monitoring, control, and airflow management across a wide range of environments and applications.

Key ONICON Airflow Measurement Solutions Include:

• Thermal Dispersion Technology: Provides accurate and stable measurements, particularly effective in applications with low or highly variable airflow.
• Pitot Tube Solutions: Utilizes differential pressure measurement to determine air velocity and flow, suitable for large ducts and high-speed airflow.
• Outdoor Airflow Measurement: Specially designed to withstand harsh conditions while ensuring precise measurement of fresh air supplied to the system.
• Sensors and Transmitters: Collect data and transmit it to central control systems, ensuring the integrity and accuracy of measured information.

In Vietnam, PGTECH is the official distributor of ONICON, offering the complete range of air flow measurement products along with professional consulting, technical support, and after-sales services. The combination of ONICON’s advanced measurement technology and PGTECH’s distribution and support capabilities delivers optimal solutions that enhance system efficiency, save energy, and ensure safe operation for all types of facilities.

With its advanced technology foundation, ONICON offers eight specialized airflow measurement solutions, each optimized for specific real-world applications, ranging from ductwork and ventilation fans to laboratories, room pressure monitoring, and outdoor airflow measurement.

1. Airflow Measurement and Control in Ductwork

In most commercial buildings, mechanical ductwork is the most common method for distributing conditioned air to various zones. Thanks to controlled dimensions and stable construction, ductwork provides ideal conditions for accurate airflow measurement. Internal obstructions in the duct often have well-defined characteristics, making calibration and maintaining measurement accuracy easier.

ONICON provides a wide range of specialized airflow measurement and control devices for this application, including:

• ELECTRA-flo 5 Series Airflow Measurement System – Uses thermal dispersion technology for precise and stable airflow measurement.
• ELECTRA-flo/CM Airflow Station – Dedicated measurement station ensuring reliable results at fixed points in the HVAC system.
• ELECTRA-flo/SD Airflow and Temperature Measurement System – Integrated solution that measures airflow and monitors air temperature, optimizing HVAC operation.
• VOLU-probe Pitot Airflow Probe – Uses differential pressure measurement, suitable for large ducts and high-speed airflow applications.
• VOLU-probe/VS Pitot Airflow Station – Combines Pitot probe and pressure splitter for accurate airflow measurement in ducts.
• FAN-E Pitot Airflow Station – Specially designed for airflow measurement at fan discharge points.
• VELTRON DPT2500-plus Differential Pressure Transmitter – Provides accurate differential pressure measurement with stable signal transmission to the control system.
• VELTRON II Ultra-Low Differential Pressure Transmitter – Ideal for applications requiring high sensitivity in very low-pressure measurements.
• VELTRON III Multi-Channel Pressure and Airflow Transmitter – Enables simultaneous measurement at multiple points, enhancing system monitoring efficiency.

With these solutions, PGTECH, the official ONICON distributor in Vietnam, delivers customers precise airflow monitoring and control capabilities, helping save energy, improve operational efficiency, and maintain a healthy indoor environment for commercial and industrial facilities.

2. Airflow Measurement at Fan Discharge

Measuring airflow at the fan discharge is critical for monitoring and optimizing HVAC system performance. However, this application presents technical challenges that require careful selection of the right technology and equipment to ensure accurate measurement without affecting fan performance.

A major challenge is the high variability in air velocity and the diverse fan configurations within the Air Handling Unit (AHU). Each fan type produces different flow distribution and vortex patterns, requiring specialized measurement solutions to maintain accuracy.

Placing measurement devices at the fan discharge offers advantages, including easier access for maintenance and calibration, as well as direct monitoring of fan walls or fan arrays at the source.

ONICON provides a variety of dedicated airflow measurement devices for fan discharge applications, including:

• ELECTRA-flo 5 Series Airflow Measurement System – Thermal dispersion technology for stable measurement under variable air velocity conditions.
• ELECTRA-flo/CM Airflow Station – Flexible station solution suitable for various fan discharge configurations.
• VOLU-probe Pitot Airflow Probe – Measures airflow accurately with minimal pressure drop.
• VOLU-probe/VS Pitot Airflow Station – Designed for precise airflow measurement downstream of fans.
• FAN-E Pitot Airflow Station – Optimized for direct measurement at fan discharge without affecting airflow.
• VELTRON DPT2500-plus Differential Pressure Transmitter – High-accuracy differential pressure measurement with stable signal transmission.
• VELTRON II Ultra-Low Differential Pressure Transmitter – Ideal for high-sensitivity, very low-pressure measurements.
• VELTRON III Multi-Channel Pressure and Airflow Transmitter – Advanced solution for simultaneous multi-point measurement in complex fan systems.

With this solution, PGTECH – the official ONICON distributor in Vietnam – enables businesses and commercial buildings to accurately monitor and control airflow, optimize fan performance, save energy, and extend equipment lifespan.

3. Airflow Measurement at Fan Inlet

Measuring airflow at the fan inlet is one of the most technically challenging locations. Air velocity here varies significantly, and turbulence occurs due to the fan’s suction characteristics and different AHU fan configurations. Measurement devices must handle uneven airflow while maintaining high accuracy.

A key challenge is measuring accurately without impacting fan performance. Any obstruction at the inlet can cause pressure drop or alter fan operation, leading to lower efficiency or increased energy consumption.

Advantages of inlet measurement include:

• Easy access for maintenance since it is usually inside the AHU fan section.
• Direct monitoring of fan walls or fan arrays at the source, enabling quick detection of airflow issues.

ONICON provides specialized solutions for fan inlet applications, including:

• ELECTRA-flo/FI Inlet Airflow Probe – Thermal sensor technology optimized for turbulent airflow at the fan inlet.
• VOLU-probe/FI Pitot Airflow Probe – Aerodynamic design reduces pressure drop and ensures accurate measurement under highly variable flow.
• VELTRON DPT2500-plus Differential Pressure Transmitter – High accuracy, fast and stable signal processing.
• VELTRON II Ultra-Low Differential Pressure Transmitter – Suitable for very low-pressure, high-sensitivity applications.
• VELTRON III Multi-Channel Pressure and Airflow Transmitter – Enables simultaneous measurement at multiple points, ideal for complex fan or multi-inlet systems.

With these solutions, PGTECH – ONICON’s authorized distributor in Vietnam – provides commercial and industrial projects with precise airflow monitoring at fan inlets, optimizing system efficiency, saving energy, and enhancing HVAC reliability.

4. Fan Tracking to Maintain Building Pressure

Fan tracking is a method of measuring and controlling actual airflow to maintain desired positive or negative building pressure. Unlike traditional static pressure measurement at scattered locations, fan tracking provides a comprehensive and accurate overview, enabling HVAC systems to respond quickly and efficiently to load changes or environmental conditions.

Accurate fan tracking requires monitoring airflow across the entire fan system, including:

• Supply Air
• Return Air
• Outside Air
• Relief Air

Simultaneous monitoring ensures balanced airflow, minimizes unwanted air infiltration, optimizes energy usage, and maintains indoor air quality (IAQ).

Compared to traditional static pressure measurement, flow-based fan tracking offers:

• Higher accuracy through direct measurement rather than estimation from differential pressure.
• Faster response to system changes.
• Reduced errors caused by environmental factors or building structure.

ONICON devices commonly used for fan tracking include:

• ELECTRA-flo 5 Series Airflow Measurement System – High-accuracy thermal sensors suitable for ducts and fan plenums.
• ELECTRA-flo/CM Airflow Station – Multi-sensor integration for stable, reliable readings.
• VOLU-probe Pitot Airflow Probe – Simple, durable, and accurate.
• VOLU-probe/VS Pitot Airflow Station – Aerodynamically optimized for accurate average flow measurement.
• ELECTRA-flo/FI Fan Inlet Probe – Direct high-accuracy airflow measurement at the fan inlet.
• VOLU-probe/FI Pitot Probe – Minimizes impact on fan performance.
• VELTRON DPT2500-plus Differential Pressure Transmitter – Wide pressure range, precise calibration.
• VELTRON II Ultra-Low Differential Pressure Transmitter – Optimized for very low-pressure measurement.
• VELTRON III Multi-Channel Transmitter – Simultaneous multi-point measurement for complex fan systems.

With extensive experience in precise and energy-efficient HVAC solutions, PGTECH – the authorized ONICON distributor in Vietnam – delivers optimized fan tracking solutions to maintain stable building pressure, enhance system performance, and ensure ideal indoor conditions.

5. Measurement of Fume Hood and Laboratory Exhaust Airflow

In laboratory environments, safety and air quality control are top priorities. Accurately measuring fume hood exhaust airflow not only ensures proper system operation but also provides several key benefits:

• Protecting operator health by maintaining proper capture velocity to prevent toxic fumes or chemicals from entering the workspace.
• Maintaining room pressure relative to other building spaces, reducing leakage or unwanted air infiltration.
• Verifying the operational status of each fume hood for monitoring and laboratory management purposes.

In practice, fume hood airflow measurement also helps:

• Optimize energy usage by adjusting fans and dampers based on actual demand.
• Ensure compliance with safety standards such as ASHRAE, ANSI/AIHA Z9.5, and other international or local regulations.
• Support predictive maintenance by detecting abnormal airflow or pressure early.

ONICON devices commonly used for this application include:

• ELECTRA-flo/SD Airflow & Temperature Measurement System – Integrated sensors for airflow and temperature, allowing multi-parameter monitoring in a single device.
• VOLU-probe/VS Pitot Airflow Station – Provides stable and accurate airflow data, even in complex turbulent flows.
• FAN-E Pitot Airflow Station – Optimized design for laboratory environments, ensuring long-term reliability.
• VELTRON DPT2500-plus Differential Pressure Transmitter – Suitable for a wide range of pressures.
• VELTRON II Ultra-Low Differential Pressure Transmitter – Ideal for extremely low-pressure, high-sensitivity applications.
• VELTRON III Multi-Channel Pressure and Airflow Transmitter – Enables simultaneous monitoring of multiple locations, suitable for large laboratory systems.

With expertise in deploying accurate exhaust airflow measurement solutions, PGTECH – the official ONICON distributor in Vietnam – provides solutions that simultaneously ensure operational safety, energy efficiency, and long-term reliability in compliance with international standards.

6. Outdoor Airflow Measurement

In modern buildings, controlling outdoor airflow into the HVAC system is not only a technical requirement but also essential to:

• Maintain proper positive or negative pressure in different areas, preventing unwanted air infiltration.
• Comply with energy efficiency standards (e.g., ASHRAE 90.1, LEED) and local building codes.
• Ensure indoor air quality (IAQ) and protect occupant health.
• Monitor and optimize ventilation performance, especially in high-performance buildings.

Challenges include:

• Low air velocity, especially when economizer controls reduce airflow for energy savings.
• High humidity in certain climates affecting sensor durability.
• Dust and airborne contaminants that can adhere to sensors and distort measurements.

ONICON solutions overcome these challenges, providing high accuracy and reliable long-term operation.

Commonly used devices include:

• OAM II Outdoor Airflow Measurement System – Advanced sensors for accurate measurement of low-velocity fresh air, reliable in harsh environmental conditions, with easy integration to BMS.

With the OAM II system and ONICON’s optimized solutions, PGTECH – ONICON’s official distributor in Vietnam – ensures precise control of outdoor air, balancing ventilation requirements, energy efficiency, and indoor air quality in accordance with international standards.

7. Outdoor Reference Pressure Measurement

Maintaining proper room or space pressure requires measuring pressure relative to a reference pressure. In most HVAC applications, the reference is outdoor air pressure.

In some cases, the reference may be:

• An adjacent room
• A corridor or stable-pressure area

Even when the reference is within the building, outdoor pressure is often needed for calibration and accurate measurement.

Measuring outdoor reference pressure helps:

• Maintain differential pressure between areas (e.g., cleanrooms, positive or negative pressure rooms).
• Prevent infiltration of contaminated air from outside or unwanted zones.
• Ensure ventilation effectiveness and occupant safety.

Challenges include weather fluctuations, atmospheric pressure changes, and long-term sensor stability.

ONICON devices for outdoor reference pressure measurement:

• S.O.A.P. Outdoor Static Pressure Sensor – High-sensitivity sensor designed for outdoor pressure measurement, resistant to harsh environments, ensuring stable and accurate signals for BMS or room controllers.

With S.O.A.P. and ONICON technical solutions, PGTECH ensures accurate and reliable outdoor reference pressure monitoring, optimizing HVAC operation and meeting both international standards and project-specific requirements.

8. Room or Space Pressure Control

Maintaining proper pressure in rooms or enclosed spaces is key for indoor air quality (IAQ), energy efficiency, and occupant comfort.

Without proper pressure control, buildings may face issues such as:

• Moisture infiltration causing mold or material damage.
• Cold drafts in winter or hot air intrusion in summer, leading to energy loss.
• Doors that are difficult to open or slam shut, impacting safety and user experience.

The principle of pressure control is to maintain proper differential pressure between protected spaces and surrounding areas through accurate measurement and timely adjustment of supply, return, and exhaust airflow.

ONICON devices commonly used for pressure control include:

• S.A.P. Static Pressure Sensor – Measures room air pressure and sends signals to the control system.
• STAT-probe Static Pressure Probe – Optimized for ducts or spaces.
• VELTRON DPT2500-plus Differential Pressure Transmitter – High accuracy for various HVAC applications.
• VELTRON II Ultra-Low Differential Pressure Transmitter – Ideal for high-sensitivity areas such as cleanrooms.
• VELTRON III Multi-Channel Pressure and Airflow Transmitter – Simultaneous multi-point measurement, saving installation space.
• VOLU-trol/E Airflow Measurement & Control Station – Maintains stable airflow based on room pressure settings.
• VOLU-trol/P Pitot Airflow Control Station – Uses Pitot tube technology for accurate duct airflow measurement.

With ONICON’s room or space pressure control solutions, PGTECH – ONICON’s official distributor in Vietnam – delivers fully integrated systems that maintain optimal pressure, reduce risks, save energy, and improve occupant experience.

Conclusion

With nearly four decades of experience in airflow measurement and control, ONICON offers a comprehensive portfolio of solutions: from duct airflow measurement, fume hood and laboratory exhaust monitoring, outdoor airflow measurement, to room pressure control. Each product is designed for high accuracy, durability, and flexible integration into modern BMS or HVAC systems.

In Vietnam, PGTECH is the official distributor of ONICON, providing international-standard airflow and pressure measurement devices along with consulting, technical support, and turnkey deployment services. The combination of ONICON’s advanced technology and PGTECH’s local expertise ensures commercial, residential, and industrial projects achieve optimal operational efficiency, energy savings, and air quality compliance.

For reliable and precise airflow measurement solutions, choose ONICON with PGTECH to elevate efficiency and sustainability for your HVAC systems.

PGTECH GROUP LIMITED – Authorized Distributor of HVAC System Products in Vietnam and Regional Markets

Copyright © – This article is the property of PGTECH Vietnam

News Editorial Board: PGTECH

Engineer: Manh Thang

PGTECH GROUP LIMITED

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