Staircase Pressurization Calculations

Staircase Pressurization - Definition

A type of smoke-control system in which stair shafts are mechanically pressurized, with respect to the fire area, with outdoor air to keep smoke from contaminating them during a fire incident.

Staircase Pressurization - Application

High-Rise Building: According to NFPA 101, Life Safety Code; “Any building greater than 75 feet in height, measured from the ground level access to the highest floor level intended for occupant use” is categorized as a high-rise building

Stair Pressurization - Injection

Single Injection – A single-point injection system shall be permitted to be used where the stairwell height is less than 30.5 m

Multiple Injection – Stairwells more than 30.5 m high shall be provided with multiple-injection systems

Smoke can enter the staircase through leakage points in the building, including gaps in walls, cracks in construction materials, and through door gaps—whether the doors are closed or open.

Primary Objective of Staircase Pressurization:

To maintain a smoke-free escape route by preventing smoke and fire gases from entering the staircase during a fire emergency.

Formula:

Q_T ^​=Q_L ​+ Q_O​