Use the filters below to find answers to frequently asked questions about Building Science guidance regarding:
If you need additional information, please email the FEMA Building Science Helpline or call at 866-927-2104.
Please visit the Building Science Resource Library to reference all hazard-specific publications and guidance documents.
FEMA P-361 provides the design criteria to be used with applicable building codes and code-referenced standards. This means that the underlying building code (such as the International Building Code® or International Residential Code®) applies and building construction must comply with the many items that are regularly governed by code requirements. Standards such as ASCE 7 also apply but are used in conjunction with the safe room design criteria described in FEMA P-361 to produce a structure capable of resisting loads much higher than those for normal buildings.
In December 2020, the International Code Council® (ICC®), with the support of the National Storm Shelter Association® (NSSA®), released a third edition of the consensus standard titled Standard for the Design and Construction of Storm Shelters, also known as the ICC 500. This standard provides minimum requirements for storm shelters and is referenced throughout Part B of FEMA P-361 which also includes FEMA Funding Criteria (required only for FEMA-funded safe rooms). If there are any conflicts between the codes and standards, the most conservative criteria should apply.
A summary of ICC 500 requirements and changes made to the 2020 edition compared to the 2014 edition can be found in Highlights of ICC 500-2020.
For residential safe rooms, the usable tornado safe room floor area should include the protected occupant area between the safe room walls at the level of fixed seating, where fixed seating exists, minus the area of sanitary facilities or other items that impede usage of the safe room area. Table 3 shows the minimum safe room floor area per occupant for residential tornado and hurricane safe rooms.
| Weather Event | Residential Safe Room Types | Minimum Usable Floor Area per Safe Room Occupant |
|---|---|---|
| Tornado | One- and Two-Family Dwellings | 3 square feet |
| Other Residential | 5 square feet | |
| Hurricane | One- and Two-Family Dwellings | 7 square feet |
| Other Residential | 10 square feet |
*See FEMA P-361 for more information on usable safe room floor area.
For a hurricane community safe room, the number of spaces for standing or seated, wheelchair-bound, or bedridden people should be determined based on the expected occupancy of the safe room as calculated by the designer and the applicable authority having jurisdiction. As a minimum, each community safe room should be sized to accommodate at least one wheelchair space for every 200 occupants.
It is also important to note that community safe rooms should provide equal access for all persons in accordance with all federal, state, and local Americans with Disabilities Act (ADA) requirements and ordinances. Table 2 shows the minimum safe room floor area per occupant for hurricane community safe rooms. The minimum usable floor area per safe room occupant is larger for a hurricane community safe room than for a tornado community safe room because occupants require a longer sheltering time for hurricanes.
| Hurricane Community Safe Room Occupant | Minimum Usable Floor Area* per Safe Room Occupant |
|---|---|
| Standing or Seated | 20 square feet |
| Using a Wheelchair | 20 square feet |
| Relocated to a Bed or a Stretcher | 40 square feet |
*See FEMA P-361 for more information on usable safe room floor area.
For a tornado community safe room, the number of spaces for standing or seated, wheelchair-bound, or bedridden people should be determined based on the expected occupancy of the safe room as calculated by the designer and the applicable authority having jurisdiction. As a minimum, each community safe room should be sized to accommodate at least one wheelchair space for every 200 occupants.
It is also important to note that community safe rooms should provide equal access for all persons in accordance with all federal, state, and local Americans with Disabilities Act (ADA) requirements and ordinances. Table 1 shows the minimum safe room floor area per occupant for tornado community safe rooms.
| Tornado Community Safe Room Occupant | Minimum Usable Floor Area* per Safe Room Occupant |
|---|---|
| Standing or Seated | 5 square feet |
| Using a Wheelchair | 10 square feet |
| Relocated to a Bed or a Stretcher | 30 square feet |
*See FEMA P-361 for more information on usable safe room floor area.
No. FEMA does not endorse, approve, certify or recommend any contractors, individuals, firms or products. Contractors, individuals, or firms shall not claim they or their products are "FEMA approved" or "FEMA certified." Any claims of compliance with FEMA P-361 and ICC 500 criteria should be verified through independent testing or engineering analysis. Producers, contractors, or firms that wish to indicate that their safe room products have been properly designed and tested should notify consumers whether the products meet or exceed the safe room criteria found in FEMA P-361 and provide supporting documentation such as test certification documents.
Some states maintain their own certification programs. Please contact your state Emergency Management Agency for information on becoming certified by your state to build safe rooms. View contact information for state offices and agencies of emergency management. There is no federal certification.
No. FEMA does not verify or certify design calculations for any product. The registered design professional who signs the certification attests that the product in question meets the requirements specified on the certification. The design professional should be licensed in the state in which the product will be used. All products must be properly installed for their intended use(s) only.
Due to federal regulations, FEMA does not endorse, approve, certify, or recommend any contractors, individuals, firms, or products. Contractors, individuals, or firms shall not claim they or their products are “FEMA approved” or “FEMA certified.” You should work with a registered design professional, such as an architect or engineer, who is familiar with safe rooms to verify that your safe room meets or exceeds current FEMA criteria.
For project eligibility and financial assistance questions, please contact your State Hazard Mitigation Officer (SHMO). Your SHMO can tell you what information must be provided for your project to be considered for funding, as well as any applicable federal, state, and local design requirements. Your SHMO can also provide you with information on funding sources.
Local jurisdictions generally do not require residential safe rooms or storm shelters. However, some communities have offered incentives (such as reduced property taxes) for owners who wish to build a safe room or storm shelter for their home. Some state and local governments have engaged in grant programs with the federal government to partially subsidize the construction of both residential and community safe rooms.
The 2015, 2018, and 2021 International Building Code® (IBC®) require the construction of community storm shelters to be included when K-12 schools and first responder facilities are constructed in areas where the storm shelter design wind speed for tornadoes is 250 mph. These storm shelters must comply with the adopted code’s referenced edition of the International Code Council’s (ICC) Standard for the Design and Construction of Storm Shelters, also known as the ICC 500.
ICC 500 provides the minimum design and construction requirements for extreme-wind storm shelters and has been incorporated by reference as a standard to be followed for storm shelter design and construction in the 2009, 2012, 2015, 2018, and 2021 International Building Code (IBC) and International Residential Code (IRC), as well as the 2018 and 2021 International Existing Building Code (IEBC). Those involved in the design, construction, and maintenance of safe rooms should become knowledgeable about both FEMA guidance and ICC code and standard requirements that pertain to sheltering from extreme winds. Knowledge of the information in these publications will help those involved navigate local applicable codes, employ best practices to provide near-absolute protection, and apply for FEMA funds that may be available (if desired).
Some strong tornadoes have resulted in loss of floor framing, collapse of basement walls potentially leading to death and injuries to individuals taking refuge in a basement. The acceptable level of protection is an individual decision. A basement may be the safest place to seek shelter in a home without a safe room, but the basement will not provide the same level of protection as a safe room unless it has been designed and constructed in accordance with the criteria in FEMA P-361.
A basement is a good location to install or build a safe room, but access for handicapped or physically challenged individuals may be limited. The flood risk of your location may also help determine whether your basement is an appropriate place for a safe room. If your house or neighborhood is prone to flooding, the basement may not be suitable for taking refuge.
