Dr. David O. Prevatt – Principal Investigator Rodrigo Castillo-Perez Mariel Ojeda- Tuz

1. Study of Water Resistance Performance of Exterior Envelope Relating to Fenestration During Minimal High Winds David O. Prevatt, Ph.D., PE (MA) Associate Professor Fenestration Water Resistance Workgroup Florida Building Commission 14 June 2019

2. Acknowledgements • Dr. David O. Prevatt – Principal Investigator • Rodrigo Castillo-Perez • Mariel Ojeda-Tuz • Dr. Jean-Paul Pinelli – Florida Institute of Technology • Zhuoxuan Wei Financial Support: Building A Safer Florida (BASF) Project Manager: Mo Madani; Building Codes and Standards, Florida Department of Business and Professional Regulation

3. Motivation and Objective • Following Hurricane Irma (2017), a forensic surveys of 3,300 condo/apt units in 15 buildings 33xxx zip code revealed pervasive water damage. • Water leakage appeared associated with fenestration. (doors & windows). The wind speed was 88 mph - much lower than the 170 mph design wind speed for area. Is this water damage indicative of systemic problems not addressed within the Building Code? If so, what can done about it?

4. Scope of Work • Support efforts of the Workgroup deliberations • Review and summarize existing research on water leakage through residential building envelopes • Identify recommendations that should be included in the FBC • Evaluate costs/ benefits of modifying wind-driven rain test standards • Review/analyze the water damage report made available by Lavrich and Associates • Age, story height, orientation, building code, window system, etc. • Estimate peak wind speed and other meteorological data to estimate rain loading and wind loading on windows • Develop loss estimates using Florida Public Hurricane Loss Model (FPHLM)

5. Literature Review • Florida Building Code (2017) • Chapter 6: Wall construction • Chapter 7: Wall recovery • Chapter 9: Roof assemblies • Standard Practice for Installation of Exterior Windows, Doors and Skylights (ASTM E2112-07) • FMA/AAMA 100-12 (wood systems) and FMA/AAMA 200-12 (masonry systems) • ASTM E2112-07 vs FMA/AAMA standards • ASTM Test and inspection Standards • Modified AAMA 501.1 • D226/D226M—17 • ASTM E331 - 00(2016) • ASTM STP 1314

6. Previous Research Studies • Beers, P. E., and Smith, W. D. (1998). "Repair Methods for Common Water Leaks at Operable Windows and Sliding Glass Doors." Water Leakage Through Building Facades, ASTM International. • Katsaros, J. D., and Carll, C. G. (2009). "Extreme Exposure Fenestration Installations—The Florida Challenge." Journal of ASTM International, 6(5), 1-17. • Salzano, C. T., Masters, F. J., and Katsaros, J. D. (2010). "Water penetration resistance of residential window installation options for hurricane-prone areas." Building and Environment, 45(6), 1373-1388. • Lopez, C., Masters, F. J., and Bolton, S. (2011). "Water penetration resistance of residential window and wall systems subjected to steady and unsteady wind loading." Building and Environment, 46(7), 1329-1342.

7. Previous Research Studies • Beers and Smith (1998): • Outline industry best-practices for repairing operable windows to prevent / minimize water leakage. • Katsaros and Carll (2009): • Florida-specific design and details for residential building envelopes • Water flows past terminations of water barriers. • The sill pan flashing is recommended below windows – seat in full adhesive bed to window frame. • A “whole wall” approach to water management is recommended.

8. University of Florida Research Studies • Solzano et al. (2010) • little structural damage to post 2001 FBC houses. • Majority of damage occurs to building enveloped systems, roofing, walls, windows • Wind driven rain enters building interior and damage its contents. • Lopez et al. (2011) • Experimentally demonstrates a whole wall approach for testing residential buildings envelopes. • Specimens fabricated by professional building contractors and trained mechanics • WDR under range of surface pressure from 0 to 50% of design pressure – most systems leaked.

9. Literature Review Summary • Research studies have demonstrated the benefits of using holistic water testing procedures for building envelope systems in Florida construction • Many times leakage occurs at or around windows and doors, at or around the building envelope systems as well as through the windows and at the interfaces of these systems. Page II – Executive Summary - Final Report

10. Causes of interior water damage? • Rain driven high winds may enter the wall cavity of a home or building at any number of points . • Even though the window was properly anchored for structural integrity, it may leak if not correctly flashed and sealed.

11. 130 140 150 160 170 State of Florida’s Design Wind Speed vs. Irma Winds Category II (3-sec. gust) 180

12. Water Damaged Building Survey Lavrich & Associates

13. Water-Damaged Buildings Database Analysis

14. Direction of Peak Wind during Hurricane Irma E

15. Direction of Peak Wind during Hurricane Irma SE SE SSE SSE SSE SSE ENE SSE SE SSE ESE

16. Florida Public Hurricane Loss Model • Florida Office of Insurance Regulation funded and commissioned the FPHLM catastrophe model to assist in insurance rate making • Certified by the Florida Commission on Hurricane Loss Projection Methodology • Version 7.0 was certified in 2019. • FPHLM is valuable as • forecast of insurance losses and the • to evaluate mitigation strategies for residential buildings.

17. FPHLM models mid/high-rise buildings: 4+ stories mainly condominium buildings

18. Geometry Open vs. Closed Buildings Closed Building Open Building 6.4

19. Define Building by Apartments • Buildings are modeled as an aggregation of apartment unit • Vulnerability of each unit depends on the vulnerability of its openings Number of openings per apartment type

20. Probabilistic hurricane rain hazard model Accumulated wind-driven rain as a function of maximum wind speed. Mean accumulated impinging rain: a) before max wind speed; b) after max wind speed

21. FPHLM VulnerabilityModel • Compute exterior damage to openings • Compute interior damage due to water ingress through openings defects and breaches • Combine exterior and interior damage and compute building and contents damage Hurricane vulnerability assessment of MHR

22. FPHLM MID/HIGH-RISE MODEL • Interior hurricane damage model is based on a mechanistic model of rain intrusion, including: • •    Deficiencies as a damage source @ low wind speeds; • •    Water penetration through all openings components; • •    Water percolation from story to story; and, • •    Conversion of water accumulation into interior damage. • Interior Hurricane Irma damage data can be used to calibrate the model • The calibrated model can be used to estimate the benefits/cost ratios of possible mitigation measures

23. The FPHLM Building Portfolio 3,492 commercial residential policies with known number of building four stories or higher, distributed throughout Florida Frequency distribution of buildings by number of stories Frequency of buildings distributed by county

24. Description of portfolio analyses • Irma scenario analyses produced the overall expected loss for this portfolio. • Stochastic analyses produced the annual average losses (AAL) for the portfolio, from 56,000 year simulations.

25. Distribution of losses due to fenestration defects in Irma scenario

26. Distribution of losses due to fenestration defects in Irma scenario

27. Distribution of AAL due to fenestration defects

28. Distribution of AAL due to fenestration defects

29. Summary • FPHLM scenario showed little difference between pre- and post-2002 buildings regarding the influence of fenestration defects on losses. The FPHLM does not model improvements in that respect due to the implementation of the FBC. • FPHLM analyses do not capture the magnitude of absolute loss reported by Lavrich and Associates, suggesting that hurricane catastrophe models like the FPHLM might need to be recalibrated to give a truer projection of magnitude of the problem.

30. Conclusion • The FPHLM public loss model as expected predicts losses due to water leakage through fenestration. • However, the FPHLM model does not capture the extent of damage from water leakage observed by the Lavrich and Associates summary. • At low wind speeds the FPHLM shows that defects within the fenestration will govern losses but the magnitude of those losses predicted range from few dollars to a few hundred dollars. • The Lavrich and Associates Dataset predicts losses due to fenestration failures valued in the thousands of dollars per apartment unit.

31. Conclusion • If the Lavrich and Associates data is representative, the current catastrophe model under predicts the potential losses due to water leakage by one possibly two orders of magnitude. • Therefore, there is a need for pursuing further investigation to calibrate the FPHLM model so that it better reflects the real risk of water leakage losses. • The approach to gather data on interior losses from water leakage may require involvement of insurance companies directly, and consumers (apartment owners).

32. AAMA (2005) Storm-Driven Rain Penetration of Windows and Doors

33. AAMA (2005) Storm-Driven Rain Penetration of Windows and Doors

34. Limitation of Water Resistant Windows • AAMA in 2005 recognized the fact that windows and doors will leak in a “highwind” event. The water intrusion testing standard is typically capped at about 12 pounds per square foot which relates to a wind velocity of about 68 mph. This confirms the fact that the testing criteria for water intrusion that is employed in the manufacturing and design of fenestrations is inferior and probably does not adequately protect the public from water intrusion in a hurricane prone-zone region.

35. Revision of Current Standards

36. Revision of Current Standards • The current standard for water intrusion testing of 15% of design pressure is far too low for the following reasons: • the testing is for a brand new assembly installed and tested in a laboratory environment, • there are no provisions or requirements for in situ testing after installation, and • there is no justification for the selection of 15% of design pressure to be used as a standard.

37. Water Intrusion Assessment Form • Proposed Water Intrusion Assessment Form: • To collect and organize the evidence of leakage on a floor by floor, elevation by elevation and building by building • To record the maximum water leak distances per floor. • To show the propensity of the forensic evidence of water leakage towards the specific cladding elevation. • One of the parameters that the FPHLM uses is the number of apartment per floor, which can be recorded through this form. Additionally, apartment are self-enclosed units, and it is useful to track the propagation if any of one unit to the other.

38. Water Intrusion Assessment Form

39. Improvement to Data Collection Conduct a public survey: • Advantages: • Asking the homeowners individually is a good opportunity to notice particular issues. • Disadvantages: • High cost • Low response rate regarding to the large number of surveys sent (3-5% responds).

40. Thank You for Your Attention! David O. Prevatt dprev@ufl.edu