Taking Shelter From the Storm:

Building a Safe Room For Your Home or Small Business

Includes Construction Plans and Cost Estimates

FEMA 320, Third Edition / August 2008



Preface


Since the First Edition of FEMA 320, Taking Shelter From the Storm: Building a Safe Room Inside Your House, was printed in August 1998, nearly 600,000 copies of the publication have been released. Initiatives attributed to FEMA 320 have resulted in almost 20,000 residential safe rooms being constructed with federal funding assistance. Further, other initiatives since the publication was first released include tens of thousands of safe rooms being constructed with private funds to meet these protection criteria, the creation of the National Storm Shelter Association (NSSA) as a self-monitoring safe room and shelter governing body, and the development of a new consensus standard from the International Code Council_ (ICC_) for the design and construction of storm shelters. The existence of this document, and the safe room designs provided herein, have helped to save the lives of thousands of individuals and families. FEMA is pleased to have this opportunity to update and improve the guidance through this new edition of FEMA 320, Taking Shelter From the Storm: Building a Safe Room For Your Home or Small Business.



Table of Contents


Preface	I


Introduction   v


Section I: Understanding the Hazards 	1


What Is a Tornado?	1


Figure I-1.  Typical tornado damage	2 


Figure I-2.  The number of tornadoes recorded per 2,470 square miles 	3


What Is a Hurricane?	4


Figure I-3.  Typical hurricane damage 	5


Do You Need a Safe Room?	6


Figure I-4.  Wind zones in the United States 	7


Figure I-5.  Storm surge	8


Homeowner's Worksheet: Assessing Your Risk	8


Table I-1.  Homeowner's Worksheet 	10


Emergency Planning and Emergency Supply Kit	10


Section II: Planning Your Safe Room	13


Building Damage	13


Figure II-1.  Effect of extreme winds on building roof and walls	13


Basis of Safe Room Design   15


Safe Room Size	17


Foundation Types	18



Basement Foundation Applications 	18


Figure II-2.  Cross-section: typical basement foundation, with safe room 	18


Slab-on Grade Applications 	19


Figure II-3.  Cross-section: typical slab-on-grade foundation, with safe room 21


Crawlspace or Pile Applications 	21


Figure II-4.  Cross-section: typical crawlspace foundation, with safe room 	22


New vs. Existing Homes or Buildings 	25


Figure II-5.  CMUs were used for the exterior walls 

at this home under construction (New Smyrna Beach, Florida)	25


Figure II-6.  View of an in-home safe room under construction. 

The CMU walls of this safe room are fully grouted and are reinforced, 

vertically, with steel reinforcing bars from the foundation to the 

concrete roof deck (New Smyrna Beach, Florida). 	26


Safe Room Location   27


Floor Plan 1: basement 	28


Figure II-7.  Floor plan 1: basement 	28


Floor Plan 2: safe rooms on the primary level of a home or 

small business	29


Figure II-8.  Floor plan 2: home on a slab-on-grade or crawlspace foundation   29


Floor Plan 3: below-grade safe rooms	30


Figure II-9.  Floor plan 3: in-ground (below-grade) safe rooms 

in a home on a slab-on-grade foundation 	30


Floor Plan 4: multi-purpose safe rooms in a small business 	30


Figure II-10.  Floor Plan 4: multi-purpose safe rooms in a small 

business or public building 	31


Table II-1.  Appropriate types of safe rooms for new homes and buildings 	32


Table II-2.  Appropriate types of safe rooms for existing homes 

and buildings 	32



Construction Materials	33

Safe Room Cost	34


Table II-3.  Average costs for both 8-foot by 8-foot and 14-foot by 14-foot 

safe rooms in new homes or buildings	35


Section III: Building Your Safe Room	37


Index of the Design Drawings 	38


How to Use the Drawings	38


Consumer Guide	39


Safe Rooms Save Lives 	40


Appendix A: Acknowledgments 	45