1. Wind, Water, Codes, Coverage
Myths & Reality
South Florida 2017 Hurricane Irma Effects on Fenestrations and the Exterior Envelope
Daniel L. Lavrich, P.E., SI, SECB, F.ASCE, F.SEI
Presented February 18, 2019 at the FBC Water Intrusion Workgroup Meeting
at the Hyatt Regency Hotel in Jacksonville, Florida
© Daniel L. Lavrich 2019

2. Daniel L. Lavrich, P.E.
SI, SECB, F.ASCE, F.SEI
Structural Engineer in private practice. Worked as Building Inspector, General Contractor, and Structural Design and Consulting Engineer for over 43 years in Broward County, Florida and is a Fellow of ASCE, Fellow of SEI, Member of FSEA, AAMA, and others.
Current Chair of Broward County Board of Rules and Appeals, and is their designated liaison to the Florida Building Commission.
Member of the Florida Building Commission Structural Technical Advisory Committee (Structural TAC).
Designed several thousand buildings and structures in South Florida over the last 44 years.
Inspected more than 500 Significant Buildings and Structures for Hurricane Damage during the last 25+ years.

3. Discussion Summary
Wind and water damage from high wind events particularly relating to fenestrations and the building envelope will be discussed including:
Design issues
Code issues
Construction issues
Insurance issues
How did it happen?
Why did it happen?
Did it actually happen?
Some examples from Hurricane Irma (Sept. 2017)
Existing problems and how can we make it better

4. Design Requirements Relating to the Building Envelope Including Fenestrations
Structural Wind Pressure Design & Testing
Design to Code-Required Wind Velocities (set by Region) & the Resulting Pressures
Test to 150% of Design Pressure for structural
Water Intrusion Resistance Testing
Test to 15% of Design Pressure for Water Intrusion (Building Code and AAMA 101)
Impact Resistance Testing
Test According to Building Code Requirements for Large or Small Missile Impact

5. Design Requirements Continued:
Impact design is required to resist impact testing standards required by Building Code jurisdiction for fenestrations and the envelope.
Perhaps impact requirements should be considered in more high wind areas not only for fenestrations; but also for the entire envelope.

6. Building Code Issues
The Florida Building Code Requires Design and Testing of Fenestrations to Resist ASCE-7 Wind Loads According to Region and Requires Conformance to AAMA 101
Structural Testing is required to 150% of Design Loads
This ensures an appropriate safety factor above the inherent design safety factors so that failure is avoided except under the most extreme conditions. Additional safety factors are employed in the design procedures.
Water Intrusion Testing is required to only 15% of Design Loads
This relaxed testing threshold recognizes that water intrusion will likely occur during high wind-driven rain events, with wind speeds far less than the required design wind speeds.

7. Water Intrusion Testing (continued)
On November 28, 2005 AAMA published a statement entitled” Storm-Driven Rain Penetration of Windows and Doors”
The purpose of the document is stated as follows: “In the aftermath of tropical storms and hurricanes, questions have been raised by some residents who experienced wind-driven rain leaking through or around their windows and doors that otherwise remained unbroken and structurally intact during these extraordinary events. AAMA has chosen to publish this document in order to provide information to homeowners, distributors, and builders as well as code officials regarding water penetration during severe wind-driven rain events.”
AAMA states “Water resistance performance of a window or door product is often affected by a variety of design parameters, including operational or functional concerns, market or economic preferences, life safety and egress codes, or other physical limitations to water control capacity.”
They further include a table (illustrated in the next slide as Table 1) that compares:
Design Pressure
Water Test Pressure, based on 15% of Design Pressure
Approximate Wind Speed equivalent to the test pressure
They further note that although 15% of design pressure is listed as “test pressure required”, Building Codes cap the required test pressure at a maximum of 12 psf.
Let’s look at Table 1 in the next slide.

9. Water Intrusion Testing (continued)
It is interesting to note that a maximum test pressure of 12 psf is equivalent to a wind speed of 68 mph.
For comparison, the wind pressure at a wind speed of 150 mph is almost 5 times the wind pressure at 68 mph. (Remember that pressure varies with the square of the velocity.)
This seems to indicate that the Building Code and AAMA are willing to accept water intrusion through fenestrations at a wind speed of approximately 68 mph.
IS THIS A REASONABLE PREMISE?

10. Building Code Issues Continued:
Impact Testing
The Florida Building Code High Velocity Hurricane Zone (Dade and Broward County) Requires Impact Testing for Large Missile Impact Up to 30 ft. and Small Missile Impact Testing Above 30 ft. – Impact Testing is Required for all Fenestrations and the Envelope
Should this requirement be considered by other Building Codes and Jurisdictions?
Product Approval and Testing is required under certain Building Code jurisdictions, particularly the Florida Building Code, to ensure that design and performance requirements are met by manufactured products.

11. Protection of the Envelope
More damage was caused during Hurricane Andrew and subsequent hurricanes due to breach of the “Envelope” of buildings rather than direct building damage. Unprotected and/or deficient fenestrations were a major part of the failures.
Water and wind intrusion into the interior of the building caused considerable secondary damage.
Impact Protection of the “Entire Envelope” is necessary, not just glazed openings – Dade and Broward requires this Countywide. Perhaps it should be considered elsewhere.
Protection of the Occupants and Contents is of primary concern, not just protection of the structure.

12. Installation, Maintenance and Design Issues
Great Attention Must be Paid to the Installation of Assemblies
Failure of the Fasteners
Failure of wood bucks and/or substrate
Ensure that all weather seals are installed properly
Maintenance Issues – Assemblies Must Be Maintained
Worn Weather Seals and deteriorated perimeter caulking result in water intrusion
Corroded Fasteners and Frames
Worn Rollers and Guides may result in water intrusion
Broken or Deteriorated Balances result in difficult operation
Follow Product Approval and/or Installation Details Carefully!
More attention to Design of the Envelope by Building Designers to resist water intrusion is essential!

13. Insurance Issues
Insurance companies will generally only pay for water intrusion damages to the interior when caused by breaches from storm-related damage to fenestrations caused by failure of the assemblies to withstand wind or impact.
Insurance companies will generally not pay for entry of wind driven rain unless a breach has been caused by wind, impact or other externally applied force.
Insurance coverage is regulated by the terms of the policies.
Identification of point of entry and cause of water intrusion is essential in evaluating water intrusion issues.
Insurance claims are routinely made after a storm to attempt to replace all of the fenestrations in the building even if there has been no direct damage to the assemblies.

14. How Did Failure Occur? Common Actual Causes of Structural Failure (The Reality)
Structural Failure of the assembly due to wind.
Structural Failure of the assembly due to impact.
Structural Failure of the attachment of the assembly due to wind or impact.

15. Why Did Failure Occur? Structural Failure Due to Wind - Considerations
Was the wind speed of the storm sufficiently greater than the design wind speed of the assembly to exceed the design strength of the assembly?
Was the assembly properly designed and tested to meet Code?
Did the assembly fail or did the attachment of the assembly fail?
Was the attachment and the substrate of the assembly installed according to Code.
Was the assembly properly maintained?
Was the assembly deteriorated or corroded to such an extent that it had become weakened?
Did the assembly actually fail?

16. Why Did Failure Occur? – Continued:
Structural Failure Due to Impact
Was the assembly protected with an impact resistant device such as a shutter or was the assembly impact resistant?
If the assembly was not protected or was not impact resistant, then impact failure was inevitable.
Can impact damage to the fenestration take place even if an impact resistant device (such as a shutter) is installed or if the assembly is Impact Rated?
Yes, but it is much less likely.

17. Did Failure Actually Occur? - (The Myths)
Some Common Claims Made After a High Wind Event
Since the assembly experienced a High Wind Event, the structural capacity of the assembly must be “compromised” and the assembly must be replaced.
The assembly or components are “bent”
Is there proof that components are actually bent?
If so, was it due to the storm or otherwise such as operator error?
The elements of the assembly have undergone “fatigue” failure and the assembly must be replaced.
Since the assembly “leaked”, It must have been damaged and Is now “compromised” and must be replaced.
The assembly is “hard to operate” and is therefore “compromised” and must be replaced.
Do the manufacturers of fenestrations marketed for use in high wind applications agree with these claims?

18. Some Photo Examples of Fenestrations and the Envelope After Hurricane Irma

19. Design Issue

20. Design Issue

21. Design Issue

22. Design Issue

23. Design Issue

24. Design Issue

25. Windows and Building were only about 4 years old
Windows and Building were only about 4 years old. No structural damage, but they leaked.

26. Old windows – No structural damage, but leaked
Old windows – No structural damage, but leaked. Blue tape applied to try to resist water intrusion during storm.

27. Newer windows – No structural damage but leaked.

28. New windows in 2006 – No structural damage, but leaked.

30. Building and fenestrations only 8 years old – No structural damage but leaked air and water at sgd’s

31. 8 years old

32. Significant Air leakage at bottom of door – Obviously water intrusion also. 8 years old

33. Hurricane Irma Fenestration Performance
Inspection of several thousand fenestrations in numerous high-rise buildings ranging in age from 55 years old to 4 years old found:
Although the condition of the fenestrations varied greatly due to age, the water resistance to high wind was similarly deficient in every case.
Water intrusion was most significant on the east and south exposures (the direction from which the wind was blowing).
Water intrusion on the leeward sides of the building was minimal but still took place.
Structural damage to the fenestrations was almost non-existent in every case with very few minor exceptions.

34. Conclusions
There are some serious defects in the production and delivery of an effective water resistant exterior envelope, particularly in high wind events, and particularly relating to fenestrations.
The designers of the exterior envelope must pay better attention to providing water resistance, particularly where fenestrations are incorporated into the envelope.
Fenestrations do not perform well to resist water intrusion in a high wind event. This is due in part to the Building Codes and Standards that only require a greatly reduced water intrusion performance requirement at high wind pressures.
Building Codes and Standards should be re-evaluated to provide for better water resistance during high wind events.
Installation of fenestrations as well as the envelope in general is suspect. Installation must be better defined and monitored.
Effective maintenance of fenestrations and the envelope is of great importance and must be highly stressed to the consumer.

35. Conclusions (continued)
Hurricane Irma in South Florida was mostly only a Tropical Storm or minimal hurricane, and certainly not a “Design Event”. Although Fenestrations and the envelope performed structurally very well, the amount of water intrusion through fenestrations and the envelope, both new and old, was staggering.
Shouldn’t the consumer expect better performance?
How as an Industry can we produce and deliver products and assemblies that perform better during a high wind event?
Why is it that an automobile travelling at highway speeds during a driving rain storm does not experience any leaks whatsoever, but windows and doors in a building during a high wind event leak?
How can we make the performance better? – Perhaps Consider
Stronger Building Codes and Standards relating to fenestrations
Better Design of the Envelope as well as fenestrations
Better Installation of The Envelope and Fenestrations
Better Maintenance of the Entire Envelope

36. What’s Next?
Broward and Dade Counties have authorized a study of the issues relating to water intrusion during a high wind event.
As a result, a state-wide workgroup has been appointed through the Florida Building Commission to evaluate the issues and propose solutions. Participants include:
Code Officials
Designers (Architects and Engineers)
Manufacturers of Fenestrations
AAMA (American Architectural Manufacturers Association)
Other Stake Holders
Ultimately the results of the study should reach the State of Florida Structural TAC and Florida Building Commission for further evaluation and implementation.

37. Suggested Goals from the First Meeting of the Workgroup
Define and rank by importance the major areas of concern. Suggested Starting Topics Are:
Design of the Envelope for Water Intrusion Resistance
Design and Testing Requirements for Fenestrations to Resist Water Intrusion
Requirements and Inspection of the Installation of Fenestrations
Maintenance Requirements of Fenestrations and the Envelope
Determine what areas of further investigation or testing are necessary to fully evaluate the issues.
Hopefully we can progress to provide some guidance and direction to reduce the water intrusion experienced during Hurricane Irma.

38. THE PUBLIC DESERVES BETTER!
WE CAN DO BETTER!
THE PUBLIC DESERVES BETTER!

39. DISCUSSION & QUESTIONS
Dan Lavrich can be reached at: or