Pressurization Sizing & Selection
1. Design Parameters
Project Information
Technical Basis
Design Capacity0CFM
Suggested Fan0CFM
2. Calculation Summary
MEPVAULT PRESSURIZATION DESIGN REPORT
PROJECT: --
DESIGNER: --
DATE: --
| Ref | Type | Floors | Door (m) | Gap | Vel. | Open Doors | Design CFM | Fan Selection | Force (N) | Act |
|---|
Engineering Calculation Methodology
1. Closed Door Air Leakage Flow
The flow required to maintain pressure when all landing doors are closed is based on the orifice flow equation (NBC 2016):
Flow (m3/hr) = 0.839 x Total Leakage Area x Square Root(Pressure Difference) x 3600Total Leakage Area = Perimeter of each door x Leakage Gap x Number of Floors.
2. Open Door Air Flow Protection
To prevent smoke entry when escape doors are opened, the fan must maintain a design velocity (usually 1.0 m/s) across the doors:
Flow (m3/hr) = Door Area x Design Velocity x Number of Open Doors x 36003. Total Fan Capacity Selection
The final design airflow is calculated as the sum of leakage flow and open door flow, plus a 15% Factor of Safety (FOS).
Suggested Fan CFM = Rounded Up to the nearest 100 CFM of Calculated Flow.4. Door Opening Force Verification
Escape doors must not require more than 133 Newton of force to open (NFPA/NBC):
Force = Force of Door Closer + [ (Door Width x Door Area x Pressure) / (2 x (Door Width - Handle Offset)) ]Note: This check is not applicable for Liftwell landing doors (Sliding type).