Stair Pressurization Explained: Pressure, Door Force and Stack Effect | UAE Code and NFPA 92

When there is a fire on one floor of a high-rise, how do we keep the staircase smoke-free? The stair is the way down for the people in the building and the way up for the fire service. This video explains stair pressurization one step at a time: enough pressure to keep the smoke out, not so much that a person cannot open the door. In this video: Why air moving out of the stair stops smoke coming in (at least 1 m/s through the open door on the fire floor, UAE code) The minimum pressure difference: 12.5 Pa sprinklered, 25 to 45 Pa non-sprinklered The maximum pressure, from the 133 N door-opening force limit Leakage, the orifice equation and the open-door cases Stack effect in tall stairs, summer and winter, and where to inject the air Relief, a clean air intake, emergency power and an automatic start References: UAE Fire and Life Safety Code 2018 (Chapter 10) and NFPA 92, with IBC and EN 12101-13 side by side. Requirements differ by country and project; always confirm them with your local authority and the project specification. Run the calculation yourself in MEP Automate - Smoke Management Calculations, Stairwell tab: https://www.mepautomate.com Chapters 0:00 Welcome 0:41 What it is for 1:24 How it works 2:02 Quick question: why not more pressure? 2:31 Design criteria 3:57 Door-opening force 4:37 Tall stairs and the stack effect 6:07 Equipment: relief, intake, power 7:07 How it starts 7:23 The tool 8:33 Close Presented by Hussein Ragab - Chartered Engineer (CEng), Member CIBSE, ASHRAE member, Certified Fire Protection Specialist (CFPS). One MEP concept at a time. More videos coming on the principles and on how to use each tool - subscribe so you do not miss them. Built by engineers, for engineers. #StairPressurization #SmokeControl #FireLifeSafety