Calculates the required airflow based on room volume and air changes per hour.
1. Room Dimensions
2. Space and ACH Selection
Preliminary pressure calculation: duct length × Pa/m + internal unit pressure loss. Default preliminary selection values are 1 Pa/m and 100 Pa. Exact fan pressure cannot be calculated without knowing elbows, dampers, filters, grilles, coils and actual duct sizes.
When you select a space from the Excel list, the Low / Medium / High ACH values are shown here.
Calculation Result
Room Volume— m³
Selected ACH— ACH
Equivalent in Other Unit—
Estimated Fan Pressure— Pa
Recommended Motor Power— kW
Required Airflow—
Calculation: Volume = Length × Width × Height and Airflow = Volume × ACH. For CFM conversion, 1 CFM ≈ 1.699 m³/h is used. Preliminary fan selection: Estimated pressure = duct length × friction loss + internal unit pressure loss. Motor power is selected conservatively using the provided fan motor selection chart as a reference. The chart is calibrated so that the 5,000 m³/h and 250 Pa operating point corresponds to the 2.2 kW motor class. Required power increases proportionally with airflow and total pressure, and the calculated value is rounded up to the next standard motor size.
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ASROYAL MECHANICAL CONSTRUCTION CONTRACTING INC.Airflow Calculation Report
AIRFLOW CALCULATION REPORT
Room Volume—
Selected ACH—
Required Airflow—
Selection Parameters
Space / Room Type
—
Length (A)
—
Width (B)
—
Highlik (H)
—
ACH Level
—
Air Changes per Hour (ACH)
—
Selected Result Unit
—
Air Duct Length
—
Estimated Fan Pressure
—
Recommended Motor Power
—
Calculation Method and Equations
1. Room volume: V = A × B × H
Here, V is room volume (m³), A is length (m), B is width (m), and H is room height (m).
2. Required airflow: Q = V × n
Here, Q is the required airflow (m³/h), V is room volume (m³), and n is the air changes per hour for the selected space type (ACH, 1/h).
3. CFM conversion: CFM = Q (m³/h) ÷ 1.699
4. Preliminary fan pressure: ΔP = Lduct × R + ΔPunit
R is the duct friction loss (Pa/m), while ΔPunit is the internal unit pressure loss used for preliminary selection.
5. Motor power chart reference calculation: P = 2,2 × (Q / 5.000) × (ΔP / 250)
According to the provided fan motor selection chart, the 5,000 m³/h and 250 Pa operating point is calibrated to the 2.2 kW class. Changes in airflow and pressure are applied proportionally to motor power; the calculated value is rounded up to the next standard motor size.
The program uses the selected Low, Medium or High ACH value from the supplied Excel list for the selected space type.
Parameters Used in This Calculation
Space type; room length, width and height; selected Low/Medium/High air-change level;
corresponding ACH value and result unit (m³/h or CFM). The calculated airflow is based on multiplying room volume by the selected air-change rate.
This report is intended for preliminary selection and quick airflow calculation. Final design airflow must also be checked according to occupancy,
process loads, outdoor-air requirements, local regulations and project specifications.
ASROYAL MECHANICAL CONSTRUCTION CONTRACTING INC.
Mehmet Akif Neighborhood, İlkbahar Street No: 2-C, Çekmeköy / Istanbul / Türkiye
Phone: +90 533 498 99 58 | Email: info@asroyal.com
