Rumus Airflow rate secara manual
Q = Cd x A ((Cp1 - Cp2)) v^2)^1/2
Q = Volumetric flow rate
Cd = Coefficient discharge
A = Luas Bukaan
Cp = Coefficient pressure
v = Wind Velocity
Cp = P / (1/2 ρ x (v^2))
Cp = Coefficient pressure
P = Pressure
ρ = Tekanan udara
v = wind velocity
Typical discharge coefficient (Cd) for single inlet or intermediate openings in buildings
| Description of opening | Typical range of discharge coefficients for normal incidence | Jet characteristics |
| Small openings in thin walls less than 10% of wall area near the centre of the wall | 0.5-0.65 | small inertia due to small mass of air in jet |
| Openings 10-20% near the centre of wall with aspect ratio similar to cross section of the downwind space | 0.65-0.7 | Significant inertia due to increased mass of air in jet |
| Openings 10-20% of a wall with one edge common with the downwind space such as a doorway | 0.7-0.8 | wall effect reduces energy losses on one side of jet |
| Openings similar in size to the cross section of the downstream space | 0.8-0.9 | wall effect around the perimeter of the jet significantly reduces turbulent energy losses |
Nilai Coefficient discharge (Cd) dengan membandingkan Oulet dgn Inlet
| Ao/Ai | Cd |
| Approacing | |
| 0 | 0.63 |
| 0.2 | 0.64 |
| 0.4 | 0.67 |
| 0.6 | 0.71 |
| 0.8 | 0.81 |
| 1 | 1 |
Standar Ventilation Rate untuk Tipe-Tipe Ruangan
| Fungtion of space | Ventilation rate (m3/h fresh air) |
| Residence | |
| Living room | 45 |
| Kitchen | 60-90 |
| Bedroom | 25 |
| Bathroom | 25 |
| School Classrooms | 40 / person |
| Factories (no smoking) | 30 / person |
| Community halls (heavy smoking) | 50 per person |
Sumber : Aerodynamics architecture, Aynsley
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