Aircol 130 Window and Wall Type Plastic Aspirator - Aircol 130

Factors to Consider When Selecting a Radial Fan

When selecting a fan, four parameters should be considered:

1. Required Airflow
2. Pressure Losses
3. Acceptable Noise Level
4. Electrical Power Connection Type

The required air changes for the environment to be ventilated depend on the purpose of the space, the number of people and items inside, and the activities conducted. The table below shows the required air change rates for different environments.

ENVIRONMENT | AIR CHANGE RATE

• Classrooms: 5-7
• Libraries: 4-5
• Home kitchens: 15-25
• Bathrooms: 5-7
• Home toilets: 4-5
• Public toilets: 8-15
• Meeting rooms: 6-8
• Offices: 4-8
• Dressing rooms: 6-8

Based on the activity, the amount of air required per person in living and working spaces can help determine the required airflow.

• Normal Activity (Non-smoking): 29 m³ / hour
• Normal Activity (Smoking): 58 m³ / hour
• Light Activity: 45 m³ / hour
• Heavy Activity: 60 m³ / hour

According to the above information, the required airflow is determined as follows:

• Q [m³ / hour] = Air change rate (per hour) * Room volume (m³)
• Or
• Q [m³ / hour] = Number of people * Airflow required per person

After determining the required airflow for the space, proper duct design (considering noise and airflow velocity criteria) should be made, and pressure losses must be calculated. Depending on the environment in which the fan will operate, the fan type (axial, radial, roof, smoke extraction, etc.) should be selected, and it should be chosen from the appropriate fan curve based on the determined airflow-static pressure pair.

To briefly explain the above and the table, let’s consider an example: In an office with 5 people, the ceiling height is 2.6 meters, and the floor area is 50 m². Therefore, the volume is 2.6 * 50 = 130 m³. According to the air change rate table, the value for an office is 4-8. Let's take 5 as the rate. So, 130 * 5 = 650 m³/h of required airflow. Assuming normal activity, the airflow required for the workers is 5 people * 29 m³ = 145 m³. Therefore, the total airflow required is 650 + 145 = 795 m³ / hour.

The fan selection is then made based on this airflow requirement.

After calculating the airflow, the location for fan installation should be determined. Where will the fan be installed? On the ceiling, wall, chimney, or ventilation duct? Another consideration is the voltage for the fan. In our example, we are focusing on an office. Fans are typically mounted on walls or windows in offices. For household use, a single-phase fan should be preferred. For industrial use, a fan that operates with three-phase (380 Volt) electricity should be used.