How to perform stair case pressurization? how much pressure we have to maintain during the test? what will be pressure inside stair case ( + or - )

The Staircase Pressurisation calculation is based on the following design criteria: a) Airflow velocity of not less than 1 m/s through doors when all 3 doors are open (1 main exit door + 2 consecutive floors). b) Minimum Pressure Differential between staircase & adjacent accommodation space is 50 Pa when all doors are closed. Unlike BS EN 12101-6 (old BS5588-4), there is no pressure differential requirement when doors are in open conditions. c) Maximum Force required to open any door at the door handle shall not exceed 110 N. To determine the air flow required to maintain a specified pressure differential, the following equation is used: Q = 0.827 A (ΔP)1/2 Q = Air Flow rate (m3/s). A = Flow area or leakage area (m2). ΔP = Pressure difference (Pa). To determine the door-opening force, the following equation is used: F = Total door-opening force (N). Fr= Force to overcome the door closer and other friction (N). A = Door area (m2). d = Distance from doorknob to the knob side of the door (m). K = Coefficient (=1.0). W = Door width (m). ΔP = Pressure difference across the door (Pa). Example Staircase Pressurisation Calculation for a 10-storey building The following calculation is done using pocketDP2 program. Staircase Pressurisation calculations Door Width =0.9 m Door Height =2.1 m Vel thru door =1 m/s Pressure differential =50 Pa Door leakage (open inward) =0.001786 m2/m Nos. door open inward stair =9 Door leakage (open outward) =0.003571 m2/m Airflow (3 door open) =20,412.0 CMH Total leakage area =0.12 m2 Airflow (door leakage) =2,481.4 CMH Total airflow =22,893.4 CMH Air Relief Opening =0.97 m2 Door Force calculations Door Closer Force =44 N Door Width =0.9 m Door Height =2.1 m Distance, DoorKnob to Door Edge =0.064 m Differential Pressure across door =50 Pa Door Opening Force =94.87 N