FEMA Proposed Research Topics for Consideration by the
Florida Building Commission’s (FBC)
Hurricane Research Advisory Committee (HRAC)
1 Mar 21
The following is a list of seven (7) FEMA proposed research topics selected from various FEMA Mitigation Assessment Team (MAT) report Recommendations developed from recent Presidentially declared disasters. They are being submitted for consideration by the Florida Building Commission’s Hurricane Research Advisory Committee (HRAC).
Each proposal includes responses to “Research Topic Requirements” per the FBC research work plan:
FEMA Proposed research topics:
These research topics are numbered only for reference purposes; they are NOT listed in priority order as to their importance, preference, difficulty or ease in research, cost or potential greater or lesser mitigation impacts to buildings or communities. Priorities can be determined by the FBC HRAC according to their own purposes. All of these research proposals are intended, and expected, to help the State of Florida and the Florida Building Commission with improving building performance, reducing vulnerabilities and enhancing building and community resilience.
A) FEMA P-2077 Mitigation Assessment Team Report; Hurricane Michael in Florida; Building Performance Observations, Recommendations, and Technical Guidance; February 2020; https://www.fema.gov/sites/default/files/2020-07/mat-report_hurricane-michael_florida.pdf
1) Recommendation #FL-10a. Industry groups, interested stakeholders, and/or academia should further evaluate the performance of the concrete pile foundations that failed during Hurricane Michael to determine why they failed.
The MAT observed instances where scour and erosion exceeded the ability of the
pile/column foundation to remain vertical. There were also some instances where
lateral loads and bending moments appeared to exceed the material properties of
the foundation piles/columns, causing them to crack and break. Industry groups and
interested parties (e.g., FEMA Building Science Branch, DHS Science and Technology
Directorate, the National Institute of Standards and Technology’s Disaster and Failure
Studies Program, National Science Foundation, NOAA Sea Grant, IBHS, ASCE, and
FBC), as well as academia, should consider collaborating to determine the cause of the
observed failures, whether by undersized piles, improperly embedded piles, insufficient lateral bracing, defective manufacturing, or some other cause. The analysis should also
evaluate material properties versus flood load foundation calculations, such as the
flood loads methodology presented in ASCE 7, Minimum Design Loads and Associated
Criteria for Buildings and Other Structures, and FEMA P-550, Recommended Residential
Construction for Coastal Areas: Building on Strong and Safe Foundations (2009b).
Reinforced concrete piles should not be failing in the manner observed; what is the cause(s) and how can failure be prevented?
Conclusion FL-10 Multiple concrete pile foundations, some with unknown pile embedment depth, suffered rotational failure.
The MAT observed numerous concrete piles that failed from rotational forces. When assessing the piles, the MAT observed no labels or markers that could help determine embedment lengths or help building officials in their assessments.
§ Sections 3.3 and 3.3.1 of the FEMA H. Michael MAT report provides information and observations on the poor performance of concrete pile foundations, starting on page 3-28.
2) Recommendation #FL-14b. Industry groups should assess the causes for the widespread asphalt shingle roof covering loss that was observed by the MAT.
Installation issues of asphalt shingles were observed at many sites. More research should be considered by industry groups (e.g., manufacturers, insurers, builders) and academia to explain why post-FBC asphalt shingle damage was observed to be widespread. In particular, this research should focus on areas where wind speeds were below design level. The research should attempt to determine whether these failures were the result of design, installation, testing, inspection, manufacturing, or other issues.
Conclusion FL-14 The roof coverings for many residential buildings appeared to have inadequate resistance to wind loads; the loss of the primary roof covering contributed to significant water infiltration in many buildings.
Similar to historical and Hurricane Irma in Florida observations, widespread damage to asphalt shingles was observed on post-FBC residential buildings. The MAT was not always able to determine the reason(s) for this damage. In addition, observations of roof replacements indicated underlayment was not being installed as required by the FBC. Multiple MAT observations revealed contractors were not repairing roof coverings and installing replacements in conformance to the FBC requirements.
§ Chapter 4. Wind-Related Observations: Residential has information on poor roof covering performance for residential structures beginning on page 4-1 with more specific observations in section 4.2.1 of the of FEMA P-2077. Furthermore, FEMA P-2023 which is the MAT Report for Hurricane Irma in Florida, also has this same recommendation (Recommendation FL-9a) just below.
§ Recommend researchers coordinate with the Florida insurance commission to gather much more detailed data on this issue.
Recommendation FL-9a. Industry groups should investigate the causes for the widespread asphalt shingle roof covering loss that was observed by the MAT.
More research needs to be done by industry groups (e.g., manufacturers, insurances, builders) to explain why post-FBC asphalt shingle damage was observed to be widespread following a below design-level event and whether these failures were the result of design, installation, testing, inspection, or other issues. Appropriate mitigating actions should then be taken.
Conclusion FL-9 The MAT observed evidence of inadequate resistance to wind loads for roof coverings of residential buildings.
In particular, the MAT observed widespread damage to asphalt roof coverings on post-FBC residential structures; the reason(s) for this damage was not determined by the MAT.
§ Observations on roof covering performance for residential structures begins on page 4-6, with more specific observations of asphalt shingle roof coverings in Section 220.127.116.11.
3) Recommendation #FL-16. Industry groups and academia should perform research on commonly used ridge vent products to better determine the causes of ridge vent failure and develop solutions.
More research should be considered by industry groups (e.g., manufacturers, insurance organizations—IBHS, builders, trade associations—NRCA) to determine why ridge vent failure was observed to be widespread and whether these failures were the result of design, installation, testing (including for wind-driven rain infiltration), inspection, manufacturing, or other issues. Information to help improve the performance of ridge vents in high-wind areas can be found in Hurricane Michael in Florida Recovery Advisory 2, Best Practices for Minimizing Wind and Water Infiltration Damage (in FEMA P-2077, 2019a).
Conclusion FL-16 The failure of ridge vents contributed to significant water infiltration at many sites.
The loss of ridge vents can expose large openings in the roof deck to water infiltration. Water infiltration can cause extensive interior damage, contribute to the growth of mold and mildew, and result in degraded building function or downtime until repairs are made.
§ Chapter 4. Wind-Related Observations: Residential has information on poor roof covering performance for residential structures beginning on page 4-1 with more specific observations in section 18.104.22.168 on ridge vents. Information to help improve the performance of ridge vents in high-wind areas can be found in Hurricane Michael in Florida Recovery Advisory 2, Best Practices for Minimizing Wind and Water Infiltration Damage (in FEMA P-2077, 2019) but more research is needed as to their failure and how best to mitigate them.
4) Recommendation #FL-21b. The State of Florida and FDEM should consider re-evaluating EHPA criteria and re-assess safety of existing EHPAs, particularly those designed prior to the 6th Edition FBC (2017).
While new EHPAs are required by the 6th Edition FBC (2017) to be designed and constructed in accordance with the hurricane wind load provisions of ICC 500, structural criteria for EHPA as designed and constructed prior to 6th Edition FBC (2017) were less stringent and non-mandatory. The State of Florida and FDEM should consider reassessing existing EHPAs that were designed and constructed prior to the 6th Edition FBC (2017) to identify and retrofit their vulnerabilities or explore incentivizing local authorities to replace the more vulnerable aging EHPAs with new EHPAs, or better yet, storm shelters or safe rooms.
Conclusion FL-21 The HESs observed by the MAT demonstrated significant vulnerabilities to high-wind hazards.
The Bay County HESs, which the County identified through assessment and mitigation of existing spaces, incurred significant damage during Hurricane Michael and exposed shelter occupants to hurricane hazards. The Calhoun County HESs, which were designed to meet earlier EHPA criteria, incurred significant damage as well. Based on damage observations, roof systems of both types of HES are particularly vulnerable to high winds.
5) Recommendation #FL-30. The FBC should provide more specific criteria with restrictions on how, when, and where roof aggregate can be used.
Aggregate roof surfacing provides a ready source of wind-borne debris that can damage unprotected glazing in high wind. The 2003 through 2018 editions of the IBC prohibit the use of aggregate roof surfacing in hurricane-prone regions. This is a stark contrast to the FBC, which permits roof aggregate. Chapter 15, Roof Assemblies and Rooftop Structures, of the FBC includes some requirements for roof aggregate, including size and percent embedded. However, additional criteria should be incorporated to prevent aggregate blow-off or to specify that roof aggregate is prohibited.
Conclusion FL-30 Roof aggregate can cause glazing damage to other floors on existing buildings or to nearby buildings.
The MAT observed incidents of blown-off roof aggregate causing glazing damage to other floors of the same building as well as adjacent buildings. This is a frequent observation made by previous MATs.
B) FEMA P-2023; Mitigation Assessment Team Report Hurricane Irma in Florida; Building Performance Observations, Recommendations, and Technical Guidance December 2018; https://www.fema.gov/sites/default/files/2020-07/mat-report_hurricane-irma_florida.pdf
(NOTE: Recommendation FL-9a above is from the H. Irma MAT in Florida report. It was added to and in support of the H. Michael MAT asphalt shingle recommendation above, since they are both related to the same research topic and to avoid duplication.)
6) Recommendation FL-12a. Industry groups and/or academia should study debris generation and strikes to protective systems during hurricanes to determine whether the wind speed triggers for the ASCE 7 wind-borne debris region are appropriate.
Industry groups and/or academia should study debris generation and associated debris strikes to protective systems from the 2017 hurricane, as well as for future storms, to determine whether the current wind speed triggers for the wind-borne debris region as defined in ASCE 7 are appropriate. Data collected and analyzed during the study can be used to make recommendations on ASCE 7-required protection of windows and glazed doors.
Conclusion FL-12 The MAT observed evidence of wind-borne debris, but very few instances of glazed openings being breached.
ASCE 7-required protection of windows and glazed doors in the wind-borne debris region appears to have been widely applied. However, the few instances of observed damage to protected glazed openings occurred in areas where estimated wind speeds during Hurricane Irma were well below the 130 mph wind-borne debris trigger for which ASCE 7 requires glazed opening protection. This suggests that wind-borne debris was generated at wind speeds well below the 130-mph trigger.
o If available, technical data/research in support of the research topic
§ Could check if data is available through any insurance consortiums, especially those which are FL-specific and able to share their data
C) FEMA P-2022 Mitigation Assessment Team Report; Hurricane Harvey in Texas; Building Performance Observations, Recommendations, and Technical Guidance; February 2019 https://www.fema.gov/sites/default/files/2020-07/mat-report_hurricane-harvey-texas.pdf
7) Recommendation TX-22a. FEMA should work with industry partners to evaluate whether ASTM testing requirements for debris impacts and wind pressures should be adjusted.
Using damage observations made after Hurricane Harvey, the FEMA Building Science Branch should collaborate with industry partners and identify trends in damages (e.g., interior finishes subject to water intrusion/wind driven rain) that are potentially a result of inadequate testing requirements. For example, ASTM E1886, the standard for glazing protection systems impacted by missiles and exposed to cyclic pressure differentials, does not consider water leakage after debris impact, nor does it consider debris impact to the framing around the opening. The current testing standard evaluates missile impacts to the window, but the framing around the glazing is not impacted during testing.
Conclusion TX-22 Current testing standards may need to further consider debris impact.
In multiple locations, the MAT observed broken laminated glass that remained in the frame, but allowed water infiltration; the leakage may have been related to flashing deficiencies, glass breakage, or both. The MAT also observed one instance where a window subframe blew out of the main window frame because windborne debris impacted a jack stud; the stud was pushed inward, which caused the main window
frame to twist. While the products observed were tested for the region in which they were installed, the damage indicates the performance measures in current testing requirements may need to be reevaluated and adjusted, especially with respect to limiting infiltration of wind-driven rain.
o If available, technical data/research in support of the research topic
§ See section 4.1.6 Windows and Shutters
§ See section 4.1.8 Debris Impacts