Prior to the June 2017 Grenfell Tower fire in the United Kingdom, relatively little focus was placed on the factors that contribute to vertical fire spread. Tragically, the Grenfell fire claimed more than 70 lives as flames climbed 20 stories in just 35 minutes. The rapid vertical fire spread greatly limited time for first responders to rescue people in the high-rise. In the aftermath of Grenfell, much conversation has focused on what factors may have conspired to accelerate the fire’s vertical spread and how post-fire findings can be applied to prevent future loss of life in high-rise fires.
This article will address two important factors that can contribute to vertical fire spread. First, we will look at a situation referred to as “leap-frog.” Next, we will consider the risk posed by combustible building materials used in the exterior wall cavity or exterior facade. We will also consider a new testing method—ASTM E2874-19 for assessing risk of fire spread vertically from floor to floor. In designing and specifying exterior wall components and systems, this testing method should be considered in future updates of the International Building Code.