Life Safety

Building A Storm Shelter to ICC-500 Requirements

The need for storm shelters is greater than ever as the 2017 tornado season kicks off to a powerful start. As of March 21, 2017, there have been 367 reported tornadoes and, as of April 4, there have been 26 deaths due to tornadoes in the United States. That is more tornadoes than the combined total during the months of January, February and March in 2014, 2015, and 2016 of 313. It also makes January 2017 the second-deadliest month on record due to tornadoes. The majority of people who have died in 2017, lived in mobile homes and houses; without the safety of a storm shelter.

The ICC-500 Design and Construction of Storm Shelters

In 2003 the Inter­na­tion­al Code Council (ICC) and the National Storm Shelter Asso­ci­a­tion (NSSA) began working together to develop a national consensus standard for storm shelters. It was named the ICC/​NSSA Standard for Design and Con­struc­tion of Storm Shelters (ICC-500). The FEMA P‑361 served as the framework for the devel­op­ment of the ICC-500 and the standards for the ICC-500 are accred­it­ed by the American National Standards Institute (ANSI)The purpose of the ICC-500 was to provide design standards for a storm shelter that would ensure the safety of those in a building from storms that produce high winds and flying debris. The first pub­li­ca­tion of the ICC-500 occurred the summer of 2008. Since 2009, the Inter­na­tion­al Building Code (IBC, Section 423) and Inter­na­tion­al Res­i­den­tial Code (IRC, Section R323) have utilized ICC-500 as their reference standard6 and require building storm shelters according to ICC-500. The ICC-500 provides builders, engineers, archi­tects, etc. a guide for occupancy safety require­ments along with wind speed and debris impact resis­tance for storm shelters.

The 2014 Inter­na­tion­al Code Council’s (ICC) ICC-500 is the most current ICC/​NSSA standards for con­struc­tion and design and con­struc­tion of res­i­den­tial and community storm shelters. There are several basic criteria to the 2014 ICC-500.

  • The standard is intended for use by gov­ern­ment agencies and orga­ni­za­tions along with model codes to achieve con­sis­ten­cy in the design and con­struc­tion of storm shelters
  • ICC-500 covers the design, con­struc­tion, instal­la­tion, and inspec­tion of both community and res­i­den­tial storm shelters
  • Res­i­den­tial storm shelters have a capacity not to exceed 16 people
  • Community storm shelters are not res­i­den­tial storm shelters
  • Storm shelters can be separate, detached buildings, or enclosed or partially enclosed within a host building
  • The 2015 edition of the IBC-Section 423 requires that if the following types of buildings, located in a 250 mph wind speed zone, the buildings must include a storm shelter as specified and in accor­dance with the ICC-500Figure 304.2(1).
  1. K‑12 school buildings with a capacity of 50 or more occupants, with certain exception
  2. Emergency oper­a­tions centers
  3. Fire, rescue, and ambulance stations 
  4. Police stations
  5. 911 call stations

The ICC-500 Requirements for Building a Storm Shelter

The ICC-500’s design of a storm shelter far exceeds the wind load and per­for­mance require­ments of a regular building code. A shelter’s envelope must withstand wind-borne debris, the collapse of the adjacent struc­tures, falling objects, etc. A shelter must have a strong con­tin­u­ous load path that resists over­turn­ing, uplift, and foun­da­tion con­nec­tion failure. Storm shelters in areas specified by the ICC-500Figure 304.2(1) must meet the require­ments of both the 2015 IBC and the ICC-500. These require­ments apply to shelters that are separate, detached buildings or con­struct­ed as safe rooms within a building. Here is a list of the require­ments for a storm shelter as specified by ICC-500:

  • Storm shelters must be large enough to accom­mo­date all the occupants of the building
  • The location of the storm shelters must be within the buildings they serve or located no more than 1000 feet from at least one exterior door of the building
  • The 2015 IBC requires exit doors in the envelope of the storm shelter. The number of exit doors is dependent on the number of occupants. Each exit door must have an emergency escape
  • The storm shelters must provide a minimum level of natural or mechan­i­cal ven­ti­la­tion and lighting
  • Toilets and hand wash systems have to be inde­pen­dent of city systems
  • The entire envelope of the storm shelter must meet the struc­tur­al criteria of ICC- 500. The design of the shelter must resist a 250 mph design wind speed, and resist the impact and cyclical pressure in accor­dance with ASTM E1886/​E1996. Also, the walls of the safe room must withstand a debris missile impact of a 15-pound 2‑inch X 4‑inch shot at 100 mph and the roofs must withstand an impact of a 15-pound 2‑inch X 4‑inch shot at 67 mph

Bautex™ Block Wall Assembly Exceeds ICC-500 Requirements for Storm Shelter Design

Bautex Block Wall Assembly’s concrete grid and con­tin­u­ous wall system meet the Federal Emergency Man­age­ment Agency FEMA 320 and FEMA 361 guide­lines in storm zones with possible wind speeds up to 250 miles per hour. The Bautex Block single inte­grat­ed concrete assembly also meets or exceeds the following ICC-500 and FEMA standards for debris impact.

  • Series 1 FEMA 320361 Bautex Block Panel with Brick Veneer.
  • Series 2 FEMA 320361 Bautex Block Panel with CMU Block Veneer.
  • Test pro­jec­tile 15 lb. wooden 2‑inch X 4‑inch propelled at 100 mph.

Buildings in regions with 250 mph wind speeds for tornadoes must include a storm shelter in their design. Design and con­struc­tion of the storm shelters must meet the require­ments of both the 2015 IBC and the ICC-500. An ideal choice for material for building a storm shelter is the Bautex Block Wall Assembly. It meets all require­ments for wind speed and impact resis­tance. In addition the Bautex Block is insulated, fire resistant and has above-grade moisture protection.

The Inter­na­tion­al Code Council (ICC) is a non-profit, mem­ber­ship asso­ci­a­tion dedicated to the devel­op­ment of a single set of com­pre­hen­sive and coor­di­nat­ed national modela con­struc­tion codes (I‑Codes). The Inter­na­tion­al Code Council (ICC) has three Family of Companies.

  • The ICC Eval­u­a­tion Service (ICC-ES) evaluates building products for com­pli­ance with I‑Codes
  • The Solar Rating & Cer­ti­fi­ca­tion Cor­po­ra­tion (SRCC) provides author­i­ta­tive per­for­mance ratings, cer­ti­fi­ca­tions, and standards for renewable energy products
  • The Inter­na­tion­al Accred­i­ta­tion Service (IAS) provides objective evidence that cal­i­bra­tion lab­o­ra­to­ries, inspec­tion agencies, building depart­ments, fab­ri­ca­tor inspec­tion programs and IBC special inspec­tion agencies.

Model con­struc­tion codes are developed and main­tained by a standards orga­ni­za­tion (like the ICC) which is inde­pen­dent of the company or gov­ern­ment insti­tu­tion that is respon­si­ble for imposing the building code on a con­struc­tion project.

Local and State gov­ern­ments use I‑Codes to design, build and com­pli­ance process to construct safe, sus­tain­able, afford­able and resilient struc­tures. Gov­ern­ment agencies depend on the ICC model I‑Codes because of the com­plex­i­ty and cost of devel­op­ing building codes and standards. Currently, fifty states and the District of Columbia have adopted the ICC model I‑Codes; altering them to fit specific local con­struc­tion practices, climate, and geography. 

The National Storm Shelter Asso­ci­a­tion (NSSA began in 2000, in Lubbock, Texas. The National Storm Shelter Asso­ci­a­tion initial purpose was to recognize and give dis­tinc­tion to storm shelter producers and products who meet high standards of quality. The first major task of the NSSA was to determine these high industry standards for storm shelters. The National Storm Shelter Asso­ci­a­tion (NSSA) worked alone to develop codes until 2002. In 2002 an agreement was reached between NSSA and ICC to develop a national consensus standard for storm shelters. Accred­i­ta­tion of the standards is by the American National Standards Institute (ANSI). The ICC/​NSSA Standard for Design and Con­struc­tion of Storm Shelters is named the Inter­na­tion­al Code Council-500 (ICC-500).

FEMA P‑361 — Safe Rooms for Tornadoes and Hur­ri­canes — was first published in 2000 and is intended for archi­tects, engineers, building officials, local officials and emergency managers, and prospec­tive safe room owners and operators. It guides the planning, design, con­struc­tion, and operation of res­i­den­tial and community safe rooms that will protect people during extreme wind events. The FEMA P‑361 is intended for those seeking more technical guidance than FEMA P‑320 provides.

The 2015 Inter­na­tion­al Building Code (IBC) is admin­is­tered by the ICC and contains com­mer­cial con­struc­tion reg­u­la­tions. The Inter­na­tion­al Res­i­den­tial Code (IRC) is admin­is­tered by the ICC and contains res­i­den­tial con­struc­tion and remod­el­ing reg­u­la­tions. The IRC is used or adopted in 49 states, Guam, the District of Columbia, Puerto Rico and the U.S. Virgin Islands. The IBC is used or adopted in 50 states, the District of Columbia, Guam, Northern Marianas Islands, New York City, Puerto Rico and the U.S. Virgin Islands. The IBC and IRC are model building codes that com­mu­ni­ties can adopt in whole or adapt to fit the local con­struc­tion practices, climate, and geography. Only If the IBC or IRC are adopted whole, they become legal in a community. The IRC and IBC are designed to provide building safe­guards to public health, safety, and welfare. The codes intend to protect public health and safety while avoiding both unnec­es­sary costs and pref­er­en­tial treatment of par­tic­u­lar materials or methods of con­struc­tion. The 2015 IBC and IRC are fully com­pat­i­ble with all other published ICC codes.

The ICC ref­er­enced standard is an industry agreement of the level of per­for­mance in the designing man­u­fac­tur­ing, testing and installing of materials, products or assem­blies. A ref­er­enced standard is a ref­er­enced reliable resource. It is not a primary law; like a model code. A model code becomes law when adopted by a juris­dic­tion. A standard becomes law when ref­er­enced in a model code. Ref­er­enced standards are an extension of the code require­ments and are therefore equally enforceable.

2015 IBC — Section 423.4 — Storm Shelters. Schools with 50 or more people and where shelter design wind speeds are 250 mph, as specified by Figure 304.2(1) of ICC 500 must have a storm shelter (safe room). The shelter must be large enough for everyone in the school.

FEMA P‑320 — Taking Shelter from the Storm — was first published in 1998 and is meant for builders, con­trac­tors, and home­own­ers for decision-making guidance on tornado and hurricane safe rooms. The FEMA P‑320 also has specific require­ments for a safe room, which use ICC 500 as a ref­er­enced standard, however, are con­sid­ered slightly more conservative. 

  • Safe rooms must be anchored to the build­ing’s foun­da­tion to resist over­turn­ing and uplift
  • A safe room must have a con­tin­u­ous load path that resists lateral and uplift loads during high winds.
  • The roof, openings, and walls of a safe room must resist per­fo­ra­tion by windborne debris.
  • The walls of the safe room are inde­pen­dent of the rest of the building.