Optimal Cleanroom Airflow Measurement Service for Businesses

In modern industries such as pharmaceuticals, electronics, and clean rooms, ensuring quality, product safety, and service reliability is paramount. Cleanroom air velocity is a critical factor in controlling air cleanliness, preventing contamination, and ensuring safe working conditions. Let’s explore cleanroom air velocity and the steps for measuring it through this article with INTECH Service!

What is Cleanroom Airflow rate?

Cleanroom air velocity, according to ISO 14644 standards, is the volume of clean air supplied to a cleanroom per unit of time, typically measured in cubic meters per second (m³/s) or liters per second (L/s). It plays a crucial role in maintaining a clean, safe environment and meeting cleanliness requirements according to cleanroom classifications.

Cleanroom Airflow rate

Why is measuring cleanroom air velocity necessary?

Compliance with Standards and Regulations: International standards like ISO 14644, GMP, GLP specify minimum air velocity requirements for different cleanroom classifications. Measuring air velocity ensures cleanrooms operate in accordance with these standards, meeting regulatory requirements.

Ensuring Air Cleanliness: Controlling air velocity ensures uniformity of air within the cleanroom. Insufficient air velocity can lead to areas of non-uniform air distribution, allowing bacteria and particles to persist.

Assessing HVAC System Air Changes per Hour (ACH): The required air velocity for a cleanroom also serves as a metric to evaluate the performance of HVAC (Heating, Ventilation, and Air Conditioning) systems. Measuring air velocity helps determine whether the system is operating effectively.

Methods for Measuring Cleanroom Airflow

Using a Vane Anemometer

A vane anemometer is a popular device used to measure wind speed and airflow in cleanrooms. This type of meter operates on the principle of using a rotating vane to measure the speed of the air stream and calculate airflow based on the cross-sectional area.

wind speed meter 1


Easy to use: The vane anemometer is very user-friendly. You simply need to direct the vane towards the air stream and read the value displayed on the screen.

Low cost: Compared to other types of airflow meters, the vane anemometer is more affordable.

Compact size: The vane anemometer is compact and portable, making it easy to carry and use anywhere.


Lower accuracy: Compared to other types of airflow meters, the vane anemometer is less accurate.

Affected by wind direction: The readings from a vane anemometer can be influenced by the direction of the wind.

Difficult to measure low wind speeds: The vane anemometer is less accurate at measuring low wind speeds.

Using a Pitot Tube Anemometer

A pitot tube anemometer is a device that measures airflow based on the Bernoulli effect. This device consists of two small tubes, one pointing directly into the airflow and one positioned perpendicular to the airflow.

air flow meter SAUERMANN DBM 620 1

When the air flows through the pitot tube, the speed of the air in the tube facing the flow is higher than in the tube perpendicular to the flow. This speed difference creates a pressure differential between the two tubes. This pressure differential is measured by a pressure gauge and is used to calculate the airflow.


High accuracy: Pitot tube anemometers are more accurate than vane anemometers, especially when measuring high wind speeds.

Can measure in hard-to-reach places: Pitot tube anemometers can be used to measure airflow in hard-to-reach places, such as inside air ducts.

Unaffected by wind direction: The measurements of a pitot tube anemometer are not affected by wind direction.

Can withstand harsh conditions: Pitot tube anemometers can endure harsh conditions such as high temperatures, high humidity, and dust.


More difficult to use: Pitot tube anemometers are more challenging to use compared to vane anemometers.

Higher cost: Pitot tube anemometers are more expensive than vane anemometers.

Using a Hot-wire Anemometer

A hot-wire anemometer is a device that measures airflow based on the principle of changing the resistance of a heated wire when exposed to an air stream. This heated wire is made of a highly conductive metal, typically platinum or tungsten.

Measure clean room air flow 1


High accuracy: Hot-wire anemometers are highly accurate, particularly when measuring low wind speeds.

Can measure in hard-to-reach places: Hot-wire anemometers can be used to measure airflow in difficult-to-reach places, such as inside small gaps.

Unaffected by wind direction: The measurements of hot-wire anemometers are not affected by wind direction.

Compact size: Hot-wire anemometers are compact and portable, making them easy to carry and use anywhere.


High cost: Hot-wire anemometers are more expensive than vane and pitot tube anemometers.

Frequent calibration needed: Hot-wire anemometers require frequent calibration to ensure accurate measurements.

Affected by humidity and dust: The measurements of hot-wire anemometers can be influenced by humidity and dust in the environment.

Cleanroom Airflow Measurement Procedure

wind flow measurement procedure

Choosing an Appropriate Location to Measure Airflow Velocity

To measure airflow, you need to take measurements in areas that are open and free of obstacles, as obstructions can interfere with airflow and lead to inaccurate results. When measuring airflow from devices like air conditioners or fans, the distance between the device and the energy source is extremely important. The shorter this distance, the more accurate and reliable the airflow measurement will be.

Selecting the right location for airflow measurement ensures that you can perform the measurement conveniently and quickly, saving you time during operation.

Checking the Anemometer Before Measurement

Checking the battery and sensor are two important steps when using this device. You need to ensure your anemometer has enough power to operate effectively. These devices typically use replaceable batteries, which can be swapped out if necessary.

Inspecting the sensor is crucial before using the anemometer. Airflow sensors often come in the form of vanes or pistons, and these sensors must be clean and undamaged to ensure accurate operation.

Conducting Airflow Measurement with an Anemometer

If you have an anemometer on hand, here is how to use it accurately. To measure airflow characteristics such as velocity, volume, and temperature, you can follow these steps:

Step 1: Turn on your anemometer. When you power on the device, check the battery level to ensure optimal usage.

Step 2: On the device, there are buttons to adjust and select measurement modes. You need to determine the purpose of the measurement and set the appropriate parameters.

Step 3: Point the sensor head towards the airflow source for devices with separate sensor units. For integrated anemometers, direct the sensor head towards the airflow source to facilitate easy measurement.

Step 4: The anemometer will display the measurement results directly on the screen. Record the results and continue measuring if necessary.

Important Notes When Measuring Cleanroom Airflow

Choosing the Appropriate Measurement Method

There are various methods to measure airflow, such as the Pitot method and the vane anemometer method. The appropriate method depends on the size and type of airflow outlet, the desired accuracy, and other factors.

ensure the accuracy of the measuring machine 1

Ensuring the Accuracy of the Airflow Meter

The airflow meter must be calibrated according to international standards. Calibration helps identify and eliminate measurement errors, ensuring high accuracy and reliability of the results. It is recommended to calibrate the airflow meter periodically according to the manufacturer’s recommendations or at least once a year.

Using Professional Cleanroom Airflow Measurement Services

Measuring airflow can be time-consuming and requires a high level of expertise. Therefore, utilizing services from companies specializing in testing and calibration services is an optimal and reliable solution for businesses.

INTECH Service specializes in providing cleanroom airflow measurement services with modern equipment calibrated to international standards. Detailed reports are provided by a team of highly skilled technicians and specialists, ensuring the accuracy and reliability of measurement results, while saving time and costs for businesses. Contact us today to receive the earliest consultation on cleanroom airflow measurement services.