- Daniel Brooks
- Page
- May 26, 2017
Many highrise office buildings have thick concrete shear walls encasing part or most of the largest major vertical penetrations (elevators and stairs). Yet this is a structural element far thicker than what would be required by code to enclose the shaft - i.e. the concrete may be 2 feet thick, versus a shaftwall that is 5" thick. Is it required to include the full thickness of the monolithic concrete wall in with the MVP, or can an assumption be made for a code compliant thinner shaftwall, and the remainder of the wall thickness be counted in the adjacent area?
- Adam Fingret
- Extreme Measures Inc.
- May 26, 2017
Hi Daniel,
The Standard specifically states that:
"Major vertical penetrations include stairs, elevators shafts, flues, pipe shafts, vertical ventilation ducts and their enclosing walls."
It does go on to say that:
"Additional walls added outside the fire-resistive enclosing walls of a major vertical penetration are not included in its area..."
Beyond this, the Standard has nothing to say about the thickness of MVP enclosing walls, whether code compliant or not. Of course you can make any assumption you like, but doing so may deviate from the Standard - a slippery slope in the context of a future legal challenge. We wouldn't do it without specific direction from our client and appropriate disclaimers on the relevant documentation.