Know the Facts: Stairwell Pressurization

For any high rise applications, it is required to provide a stairwell pressurization system as part of the building smoke control system.  International Building Code (IBC) Section 909 details the design, analysis and testing requirements for the system.  When designing the system, it is imperative to consider the following possible effects:

1. Stack effect

2. Temperature effect of fire

3. Wind effect

4. Other building HVAC systems

5. Climate

6. Duration of operation

During the design process, these effects are analyzed, calculated and planned for.  Providing system flexibility is imperative as it will provide what will be the necessary design requirements.  There are a few concepts that may contribute to the necessary system flexibility and testing requirements to ensure a safe and operable system. A few of these concepts include: providing  a supply fan(s) with variable speed drives, providing a comprehensive commissioning and TAB specification and coordination with the architect to own the sealing/air tightening of doorways. Coordination with the local Authority Having Jurisdiction (AHJ) is another important aspect of the design process. The AHJ will be performing the tests and ultimately providing acceptance of the system upon completion.  The AHJ will measure stairwell differential pressure to ensure the system is operating as intended.  Additionally, the force to open the stairwell doors will be measured during pressurization in order to ensure it does not exceed 30 lbs.  These are just a few of the tests that an AHJ may require in order to get final approval of a safe and functioning smoke control system.

For more information, please contact Matthew Merli, PE, Project Manager, at Fitzemeyer & Tocci at mmerli@f-t.com or 781.285.2283.