Strengthen Existing Areas Against Extreme Wind Events During Remodels


In the Best Available Refuge Area (BARA) - When You Don't Have a Safe Room or Storm Shelter blog, we covered that a structure designed specifically as a storm shelter will provide reliable safety from an Extreme Wind event.

But what can be done about an existing space (not specifically designed as a storm shelter) to make it safer?  

Existing spaces that were not designed for resistance to the effects of a tornado can be augmented to provide additional protection for occupants as an interim measure.

Efforts to strengthen an existing area are often undertaken during a planned remodel. While it’s important to note that exact performance of an augmented area can’t be known for sure (because it is part of a larger building system that was not designed for the increased forces applied during a tornado), strengthening measures are available to protect against flying debris.

Flying debris during a tornado causes damage to building components and is called "missile impact" by building design codes. The missile impact test historically used is a 15-pound, wood 2x4 shot from an air cannon at 100 mph!  Increasing resistance to missile impact can significantly increase occupant safety in a tornado event.

There are a few things that can be done to address common deficiencies in school construction with respect to tornado safety. Here are a few suggestions that can increase student and staff safety:

  • Replace standard doors for door assemblies tested and rated for storm shelters.
  • Replace standard windows with shatter resistant windows rated for shelters.
  • Brace the tops of masonry walls to the roof deck and framing.
  • Reinforce roof framing connections to walls.
  • Add grout and reinforcement to existing masonry walls.
  • Supplement or replace roof framing and replace the roof deck with a concrete over metal deck system at short spanning roofs like corridors.

A Shive-Hattery structural engineer can work with you for an in-person assessment to customize an improvements plan specifically for your facility.

Follow our Extreme Wind Event biweekly-series intended to help walk you through identifying vulnerabilities and opportunities to improve safety: