If you have ever worked on the design of a high-rise building, you almost certainly have come across a stairway pressurization system. Fans located on the roof, a shaft next to the stair, extra ductwork – all are common in high-rise design. But even though nearly all high-rise buildings have these systems, there are many wide-spread misconceptions and misunderstanding about stair pressurization.

For example, did you know that stairway pressurization is not actually required by the IBC?
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What?!?

Or did you know that there is a detailed analysis that must be conducted as part of the stair pressurization design process?
In this article, we will dispel some of these common misconceptions and misunderstandings about stair pressurization systems.

The 2021 IBC includes several changes that impact Group I-2 occupancies. These changes build upon updates from 2018 edition and continue with the sub-grouping of occupancies into either Condition 1 or 2 that started in the 2015 edition. As a quick reminder, IBC 308.3 defines these as:

Group I-2, Condition 1: "facilities that provide nursing and medical care but do not provide emergency care, surgery, obstetrics or in-patient stabilization units for psychiatric or detoxification, including but not limited to nursing homes and foster care facilities."

Group I-2, Condition 2: "facilities that provide nursing and medical care and could provide emergency care, surgery, obstetrics or in-patient stabilization units for psychiatric or detoxification, including but not limited to hospitals."