10 • IIBEC Interface December 2023 By James R. Kirby, AIA; Erica Sherman, PhD; Ameyu Tolera; and Johnny Estephan This paper was originally presented at the 2023 IIBEC International Convention and Trade Show. Feature Wind Tunnel Testing of Edge Metal how those observations may be put into practice. Aerodynamic tests were performed to determine pressure coefficients, and failure assessment testing was performed to assess failure modes of various installations. EXPERIMENTAL APPROACH The overall research approach was to build multiple full-scale edge-metal systems and test them in a wind tunnel on a turntable to learn how wind speed and wind direction affect edge-metal’s wind performance based on varying cleat-fastener locations. Wind pressures acting on the edge metal and roof system and the vibration of the edge metal were recorded and analyzed to assess performance. Testing to failure was also performed to understand failure mode and performance variations during testing. Two test decks were constructed on site by J. Quintero Roofing of Miami, Florida. Each test deck included a wood structure, a thermoplastic polyolefin (TPO) roof system, and two of four different edge-metalsystems. FIU personnel instrumented each test deck to record pressures related to the fascia system and roof system and to record wind-induced vibration of the fascia system. GAF provided guidance about roofing installation practices and assisted with the installation of certain components of the roof system installation and instrumentation setup. Each test deck included two variations of the edge-metal system, with two contiguous sides installed per configuration. The corner was central to each configuration (Fig. 1). Specifically, one test deck included edge-metal configurations 1 and 2, and the other test deck included edge-metal configurations 3 and 4. In total, four configurations were tested for this research. Additional testing specifics are Interface articles may cite trade, brand, or product names to specify or describe adequately materials, experimental procedures, and/or equipment. In no case does such identification imply recommendation or endorsement by the International Institute of Building Enclosure Consultants (IIBEC). Figure 1. The overall layout of the four configurations and pressure tap locations on the two test decks. WIND RESISTANCE OF a low-slope roof system’s edge metal has improved over the past couple of decades.1 However, there continues to be a concern during high-wind events. Edge metal at perimeters and corners is often determined to be the initial point of failure of roofing systems during wind events.2 The loss of edge-metal functionality from high winds generally creates a breach in the building enclosure in regard to weatherproofing and water intrusion. A breached roof-to-wall interface can lead to localized failure of the roof, or a progressive failure of a larger portion of the roof system, potentially allowing water infiltration that may cause damage to or loss of assets in the interior. As part of the Wind Hazard and Infrastructure Performance Center (WHIP-C), GAF and Florida International University (FIU) performed fullscale wind tunnel testing at FIU’s Wall of Wind in February 2022. Four full-scale wind tunnel tests were performed using a contractor-fabricated, 24-gauge L-shaped edge-metal system with an 8 in. (200 mm) face, 4 in. (100 mm) horizontal flange, and ¾ in. (19 mm) drip edge. Two different 22-gauge cleat shapes were used—a 6 in. (150 mm) cleat and an 8 in. cleat with a 1 in. (25 mm) horizontal return. Four different cleatfastener locations were used—one low, one in the middle, one high on the vertical surface, and one on the horizontal surface. This paper will discuss the test parameters and outcomes of testing that used different cleat types and attachment locations. Observations made during testing are discussed, as well as December 2023 IIBEC Interface • 11 explained in the “Physical Testing” section of this article. Importantly, the wind tunnel base that supports and secures the test decks is able to rotate 360 degrees. The ability to rotate allows for data collection across a 360-degree rotation. Wind tunnel testing that utilizes a rotatable turntable allows a fuller set of data collection, which, in turn, provides a fuller perspective on how edge-metal systems may perform in the field during high winds. TEST APPARATUS AND TEST ROOFS Two 11 × 11 ft (3.3 × 3.3 m) wood roof decks were constructed. Each consisted of ¾ in. (20 mm) plywood over traditional “2x” construction. The roof system consisted of an underlayment minimally fastened to the wood deck, a single layer of 1.5 in. (38 mm) thick polyisocyanurate foam insulation (polyiso), and a 60 mil TPO induction welded (IW) to “IW” plates. The fasteners and IW plates were installed at 1 ft (0.3 m) on center (o.c.) in both directions. A dense fastening pattern was used to help ensure the roof system itself would not fail during wind tunnel testing of the edge-metal system. A 2×6 wood nailer was fastened along the perimeter edge for securement of the edge-metal system and to create a perimeter for the polyiso (Fig. 2). Full-scale wind tunnel tests were performed on four edge-metal systems. All four configurations used a galvanized, 24-gauge, L-shaped edge-metal fascia with a galvanized, 22-gauge cleat. The fascia had an 8 in. (200 mm) vertical face, a 4 in. (100 mm) horizontal flange, and a ¾ in. (20 mm) drip edge at the bottom that engaged the cleat. The cleat also had a ¾ in. drip edge (Fig. 3). The four configurations varied based on the location of the fasteners for the cleat as well as cleat type (Fig. 4). It is important to note that the location of the fastener for the fascia metal was the same for all four configurations. For configurations 1 and 2, a 6 in. (150 mm) cleat was used. In general, it is understood that when cleats are “nailed low,” a short cleat is most commonly used, meaning the cleat does not have a horizontal flange at the upper edge. For configurations 3 and 4, an 8 in. (200 mm) cleat with a 1 in. (25 mm) horizontal return was used. For configuration 1, the cleat-fastener location was selected based on current industry approval listings for contractor-fabricated edge metal. It should be noted that most building codes require edge-metal systems to be tested to determine wind resistance using the appropriate test method(s) in ANSI/SPRI/FM 4435/ES-1.3 Manufacturers and contractors (through the National Roofing Contractors Association [NRCA] ES-1 Program) provide many edge-metal systems—both prefabricated and contractorfabricated—that have been tested to determine their wind resistance. The edge-metal system used for this research (using an 8 in. [200 mm] face) intends to imitate a currently available, ES-1-tested edge-metal system. The edge-metal profile, ITS-30, is available from NRCA.4 This is one of many contractor-fabricated edge-metal and coping profiles tested according to ES-1. ITS-30, titled Embedded Edge (L-Type), has a tested resistance of 210 lb/ft2 (1030 kg/m2 ) in the outward direction and the cleat fastener is 1¾ in. (44 mm) above the break line at the drip edge. Configuration 1 of this research used the same cleat-fastener location. For all four configurations, fastening of the horizontal flange of the fascia also imitated the ITS-30 nailing pattern. Configurations 3 and 4 are installation locations where only a single 2x wood blocking is provided on top of a wall system. The cleat Figure 2. Nailer, insulation, induction-welded plates and fasteners, and a thermoplastic polyolefin sheet being installed on one of the 11 × 11 ft test decks. Note: 1 ft = 0.305 m. Figure 3. Section view of the construction of the two roof decks. Note: 1″ = 1 in. = 25.4 mm. 12 • IIBEC Interface December 2023 fastener location for configurations 3 and 4 means the system reacts to the wind differently than configurations 1 and 2 (which are “pinned” at each end). The roofing industry has long recommended that cleats be fastened as low/as close as possible to the drip edge, and to avoid fastening “high” on the cleat. In this research, intentionally placing cleat fasteners high on the cleat provides information about these types of installations. Of the four configurations installed, three had fasteners in the vertical face and one in the horizontal. More specifically: • Configuration 1: The cleat was nailed 1¾ in. (44 mm) above the drip edge at 6 in. (150 mm) o.c. into the wood substrate (to imitate/ mimic ITS-30). • Configuration 2: The cleat was nailed 4½ in. (110 mm) above the drip edge at 6 in. o.c. into the wood substrate (3½ in. [88 mm] down from the top of the wood blocking). • Configuration 3: The cleat was nailed ¾ in. (19 mm) down from the top edge at 6 in. o.c. into the face of the wood nailer. • Configuration 4: The cleat was nailed ¾ in. back from the outer edge of the cleat at 6 in. o.c. into the wood nailer. PHYSICAL TESTING Test Decks Each 11 ft (3.3 m) square test deck was secured to the top of an 11 × 11 ft base building. The same base building was used for each test deck. The base building was secured to the turntable in the wind tunnel. The interior of the base building was accessible via a small door. Data acquisition systems, tubing, and wiring were contained within this interior space. With the roof test deck installed onto the base building, the roof membrane was approximately 6 ft (1.8 m) above the floor of the wind tunnel. Wind Tunnel The wind tunnel can generate a maximum wind speed of 157 mph (261 km/h). However, maximum wind speed occurs approximately 10 ft (3.0 m) above the floor of the wind tunnel; the wind speed was lower at the height of the roof deck used in our testing. The reported wind speeds were measured at the roof height, with a maximum of approximately 134 mph (215 km/h) being achieved. Two sets of tests were performed on each of the four edge-metal configurations: aerodynamic and failure assessment. This paper provides an overview of the aerodynamic testing; however, the primary focus, perhaps having a more immediate effect on the roofing industry, is the failure assessment portion of the research. Figure 5 shows the test deck in the wind tunnel. Aerodynamic and Failure Assessment Testing Aerodynamic tests were performed to determine pressure coefficients, and failure assessment testing was performed to assess failure modes of various installations. Aerodynamic experiments were conducted at mean wind speeds ranging from 26 to 87 mph (41 to 140 km/h) at the mean roof height of 5 ft 9 in. (1.75 m) using simulated Exposure Category C (Open Terrain). At each wind speed used, pressures were recorded (using 58 pressure taps) at 15-degree rotations from 0 degrees to 360 degrees for the aerodynamic data collection testing. This work was done to incorporate a wide range of wind directions to determine pressure coefficients at many wind directions. This helps determine the most vulnerable wind direction acting on edge-metal systems. This information, ultimately, could be Figure 4. Cleat types and cleat fastener locations for configurations 1, 2, 3, and 4. Stripping ply not shown. Note: 1″ = 1 in. = 25.4 mm. Figure 5. An inactive test deck in the wind tunnel. December 2023 IIBEC Interface • 13 Figure 6. Wind directions used for failure assessment testing. Figure 7. Pressure tap locations on the roof and edge metal, with a section view showing the number of pressure taps at each tap location. Figure 8. Pressure taps. The left photo shows outermost pressure taps on the fascia. The right photo shows the pressure taps for the membrane. The pressure taps were trimmed flush to the fascia and membrane prior to testing. Figure 9. Graphic showing a 15-degree wind direction (“near parallel”) creates the highest wind pressures on the vertical face of the fascia and the horizontal roof surface. 14 • IIBEC Interface December 2023 implemented into standards and test methods that might be used for code reference. In addition to aerodynamic tests, high-speed failure assessment tests were also performed. Wind speeds started at approximately 80 mph (128 km/h) and peaked at approximately 134 mph (215 km/h). Seven wind speed levels were used, increasing by roughly 8 to 9 mph (12 to 14 km/h) each level. The same terrain exposures were used. Each level (Fig. 6) included three wind directions: 0 degrees, 45 degrees, and 90 degrees. Wind testing was halted immediately after a system failure was observed so that the team could further investigate and document the system performance and determine the mode and extent of the failure. DATA COLLECTION The deck systems were instrumented with pressure sensors and accelerometers to collect data throughout the wind tunnel testing. Pressure taps were installed across the roof membrane system and the edge-metal systems to quantify the wind-induced pressure differential. Accelerometers were installed on the edge metal to investigate wind-induced dynamic effects in the system. Each configuration had 58 pressure taps (Fig. 7). Pressure taps were located on the outer vertical surfaces of the fascia, cleat, and substrate, respectively, as well as on the upper (or top) horizontal surfaces of the insulation and membrane. Data were recorded for one configuration at a time due to the symmetry of the test deck. For the edge metal, pressure taps were placed at 6 in. (150 mm) from the corner, then spaced every 12 in. (305 mm) (Fig. 8). Each side of the configuration has a total of six pressure tap locations. The pressure taps on the roof surface were placed to match the spacing of the pressure taps on the vertical faces of the edge-metal system. At each rooftop pressure tap location, a pressure tap was installed on the exterior surface of the insulation and on the exterior surface of the TPO. RESULTS AND OBSERVATIONS Aerodynamic Testing The results of the aerodynamic testing showed the following: • Wind direction affects peak outward and upward pressures • Area averaging influences pressure coefficients Analysis of the data obtained during the aerodynamic testing was done by FIU students and the primary investigators who were part are straight-line wind storms, many high-wind storms (for example, hurricanes) have a spiral effect, effectively covering all wind angles. Configuration 1 Configuration 1 used cleat 1, the 6 in. (150 mm) cleat. The cleat fastener was located 1¾ in. (44 mm) above the break line for the drip edge. Configuration 1 was the only configuration to have a failure before reaching the wind tunnel’s maximum wind speed. During the “low-speed” aerodynamic testing, the fascia released from the cleat nearly the entire length of the test deck, but it did not flip up and onto the roof. It was observed that the cleat was likely set too high, and therefore, the engagement of the cleat and the fascia was greatly reduced. The failure assessment testing was initiated without adjustment of the fascia or cleat. During the next wind-speed level, the fascia completely folded back onto the roof its entire length. At that point, the system was considered to have failed. Observations made of the failure found the cleat was indeed set too high (approximately ¼ in. [6 mm]) relative to the location of the drip edge portion of the fascia. This reduced the amount of engagement between the cleat and the drip edge (Fig. 10). Interestingly, configuration 1 was believed to be the most robust of the four installation methods; building-code-required tests for edge-metal systems generally confirm this of this research. Using the data from the aerodynamic testing, pressure coefficients were determined for each pressure tap location. One result of the aerodynamic testing showed that near-parallel wind flows (that is, 15 degrees from parallel) created the highest outward and upward wind pressures on the fascia and roof surface5 (Fig. 9). It is important to note that when wind hits a building, a negative pressure is exerted on the fascia (due to suction) and positive pressure is exerted on the inner face of the fascia (due to wind getting behind the edge metal). In effect, the fascia is simultaneously being pulled off from the outside and pushed off from the inside. Failure Assessment Testing Failure occurred when the fascia (with or without the cleat) flipped upward and back onto the roof. Wind-induced actions such as bending, oscillation, fastener pull-out, and cleat disengagement as well as the location of these actions were also observed and recorded by video. The wind speeds at which these actions and failures occurred were recorded. Importantly, field observations of post-storm damage have documented edge-metal failure when the wind angle was presumed to be perpendicular to the edge metal. It is likely that the overall context of the building and its specific environment might affect the most damaging wind angle. Additionally, while there Figure 10. Failure mode of configuration 1. Figure 11. Failure mode of configuration 2. December 2023 IIBEC Interface • 15 assumption. During this testing, however, this configuration failed at the lowest wind speed due to the misalignment of the cleat fastener. This emphasizes the importance of a wellengaged cleat–drip edge interface. Configuration 2 Configuration 2 used cleat 1, the 6 in. (150 mm) cleat. The cleat fastener was located 4½ in. (110 mm) above the break line for the drip edge. A small amount of cleat/drip edge separation with some minimal fluttering of the fascia was seen in the higher wind-speed levels. The small amount of fluttering was located adjacent to the corner where the drip edge receiver was disengaged from the cleat (approx. 6 to 10 in. [150 to 250 mm] in length). There was little outward permanent deformation of the fascia and cleat system; the edge-metal system appeared to remain able to perform until the point it failed. The failure occurred at approximately 134 mph (215 km/h). The failure was immediate; there was a small amount of flutter at the corner, then it was folded up and on top of the roof (Fig. 11). Configuration 3 Configuration 3 used cleat 2, the L-shaped cleat. The cleat fastener was located on the vertical portion of the cleat approximately ¾ in. (19 mm) from the top. Like the other configurations, there was some separation at the corner seam, some fluttering where the cleat became unattached from the receiver (approximately 18 in. [450 mm] from the corner), but overall the fascia stayed in place and was observed to be able to perform until failure occurred. At approximately 134 mph (215 km/h), the fascia folded up and over the horizontal surface (Fig. 12). The drip edge separated from the cleat. The cleat did not have any permanent deformation and remained in place (Fig. 13). Configuration 4 Configuration 4 used cleat 2, the L-shaped cleat. The cleat fastener was located on the horizontal leg approximately ¾ to 1 in. (19 to 25 mm) from the face. This configuration began fluttering at a lower wind speed relative to configurations 2 and 3, which was not unexpected considering the location of the cleat fastener. There was some separation of the cleat and drip edge (approximately 12 to 18 in. [300 to 450 mm] from the corner) as fluttering increased with the increase in wind-speed levels. The portion of the cleat closest to the corner stayed in place while the portion of the cleat farthest from the corner folded upward (Fig. 14). Some of the nails pulled out at the far end of the fascia. This seemed to imply that there was a greater pressure at the far end of the “left side” of configuration 4 relative to the other configurations. Overall, the edge-metal system appeared to remain able to perform up to the point of failure, albeit there was larger outward permanent deformation with increased wind-speed levels. Permanent outward deformation, even at a small scale, creates vulnerability (that is, reduced weatherproofing performance) at the roof-to-wall interface. It is noteworthy that when the cleat and fascia lifted and were folded back, the edge of the roof was exposed, which is more likely to compromise the weathertightness of the roof-to-wall interface. This type of failure only occurred with the L-shaped cleat when it was nailed in the horizontal flange. Summary of Test Results Pressure coefficients • Pressure coefficients (that is, GCp values) for specific pressure tap locations were found to be higher than GCp values used in codereferenced standards. • Historically, the most conservative wind direction has been presumed to be “near perpendicular” relative to edge metal, and as such, is reflected in the code-required test methods. In contrast, this research showed “near-parallel” winds (15 degrees from parallel) were most conservative when determining wind pressures acting on the edge metal. Performance • For all cases (except the mis-installation previously noted), the edge-metal system did not fail until the wind speeds reached approximately 134 mph (215 km/h) at the test deck. • The structural dynamics of an edge-metal system change based on the location of the cleat fastener. With a low-fastened cleat (that is, near the drip edge), the fascia is constrained at both ends. Conversely, with a high-fastened cleat (that is, near the top of the fascia or into the horizontal), the edge-metal system can flutter more easily because there is no substrate attachment on the lower portion of the cleat or fascia. The stiffness of the metal (that is, gauge and yield strength) becomes an important factor. Figure 12. Failure mode of configuration 3. Figure 13. Failure mode of configuration 3 up close. Figure 14. Failure mode of configuration 4. 16 • IIBEC Interface December 2023 Failure assessment • During the failure where the cleat was set too high, a small (approximately ¼ in. [6 mm]) misalignment reduced the amount of engagement between the cleat and the drip edge and significantly reduced the wind speed at failure of the edge-metal system. • Failure occurred when the fascia (with or without the cleat) flipped upward and back onto the roof, resulting in a roof edge condition that was considered to have been immediately vulnerable to high winds as well as water entry into the building. ○ As noted in the “Failure Assessment Testing” section, there was some disengagement of the fascia from the cleat at wind speeds less than 134 mph (215 km/h). This could compromise long-term performance and would likely need to be repaired if this were to occur on an existing building. • For configurations 1, 2, and 3, the fascia became detached from the cleat at the corner for a short length. The fascia remained nearly in place (with small [1 to 2 in. {25 to 50 mm}] permanent deformation) and appeared to be largely functional. The extent of functionality reduction due to permanent deformation was not attempted to be quantified during this research. • For configurations 1, 2, and 3, the failure (that is, complete displacement of the fascia piece) was initiated because of the disengagement/ release of the drip edge “receiver” from the cleat. Once disengaged, the fascia was more easily folded up and over onto the horizontal rooftop by high winds. • For configuration 4, the cleat did not entirely disengage from the fascia. Both pieces of metal failed—the metal folded up and over along the length—while still engaged at the drip edge. Failure occurred because the metal yielded; only a few nails pulled out, and only at the far corner. • Only configuration 4 had nails pull out of the substrate. A small number of nails fastening the fascia on the horizontal at the furthest end from the corner pulled completely out of the 2×6 wood nailer. No specific reason was determined. • None of the nails fastening any of the cleats in any configuration pulled out of their respective 2×6 wood blocking. CONCLUSION AND RECOMMENDATIONS Testing of edge-metal roof systems completed as part of WHIP-C provided the opportunity to investigate the aerodynamic and failure performance of four different cleat and fascia systems. The following is worth noting: • Installation practices ○ Three configurations (2, 3, and 4) failed at the wind speed of 134 mph (215 km/h). ○ Considering the low wind speed that was needed to prematurely fail the edge metal with a misaligned cleat, and that all four configurations failed at the same wind speed, this suggests that the drip edge/cleat engagement is as critical to long-term wind performance as the location of the nail. ○ High-nailed L-shaped cleats performed well—in fact, better than expected. Edge metal, with an L-shaped cleat, fastened high (either face) performed equivalently (to failure) to the low-fastened cleat installations that have been presumed to have higher wind resistance. This finding does not align with previous field investigations that concluded that high-nailing reduces wind uplift resistance. However, it is still recommended to locate cleat fasteners as low on the cleat as possible. ■ The L-shaped cleat is a very simple, cost-effective way to increase accuracy during installation. An L-shaped cleat is considered to be “self-locating.” This provides an effective quality control advantage for installers and inspectors, which helps to ensure proper cleat/drip edge engagement. It is a very reasonable approach to help protect against blow-offs due to cleat/drip edge misalignment. Additionally, using an L-shaped cleat does not preclude nailing low on the cleat. ■ Oftentimes, there is only a single wood blocking on the top of a wall, which can mean that fastening low on the horizontal surface becomes difficult. This research shows that this does not necessarily reduce the wind resistance of edge-metal systems. However, an ES-1-tested edgemetal system should be installed as tested to meet building code requirements. ■ High-nailing would be found to be very weak (low resistance) when using test methods that are in the building code as requirements. Publish in IIBEC Interface is seeking submissions for the following issues. Optimum article size is 2,000 to 3,000 words, containing five to ten high-resolution graphics. Articles may serve commercial interests but should not promote specific products. Articles on subjects that do not fit any given theme may be submitted at any time. XXX xxx FP colour p. 1 Waterproofing Challenges in Hydrostatic Conditions T h e Te c h n i c a l J o u r n a l o f t h e I n t e r n a t i o n a l I n s t i t u t e o f B u i l d i n g E n c l o s u r e Consultants APRIL 2023 | Vol XLI No. 4 | $15.00 Leak Diagnosis ISSUE SUBJECT SUBMISSION DEADLINE May/June 2024 IIBEC International Convention January 15, 2024 and Trade Show July/August 2024 Restoration/Forensics March 15, 2024 September 2024 Climate Adaptation May 15, 2024 T h e Te c h n i c a l J o u r n a l o f t h e I n t e r n a t i o n a l I n s t i t u t e o f B u i l d i n g E n c l o s u r e Consultants MARCH 2023 | Vol XLI No. 3 | $15.00 Energy Issues Practical Considerations for Whole-Building Air-Leakage Testing December 2023 IIBEC Interface • 17 ○ Cleat/drip edge engagement is critical to long-term wind resistance. Using a cleat that “self-locates” is prudent. Note that the attachment of the substrate for the edge metal (for example, a 2x wood nailer) is of critical importance.1 The edge metal is only as good as the substrate it is attached to. Designers should ensure there is a properly designed and executed load path that has appropriate capacity to resist the anticipated design loads. • Performance evaluation ○ Failure assessment testing (that is, testing to failure) helps uncover issues or expand knowledge so that performance can be assessed more confidently. ○ The highest wind pressures acting on the face of the edge metal came from a “nearparallel” direction. ○ The highest wind pressures were within 1 to 2 ft (30 to 60 m) of the corner. Averaging pressure coefficients across a large area may underestimate the wind pressures that should be used for design of edge-metal systems at the immediate corner. ○ Load sharing happens between the L-shaped cleat and the fascia when the cleat is nailed on the horizontal top flange (for example, configuration 4). This is to be expected, given that both pieces of the edge-metal system—the fascia and the cleat—are nailed in the horizontal portion of the substrate, allowing the two individual pieces to move simultaneously. Remember, the cleat is one gauge heavier than the fascia in these studies and often in the field. • Codes and industry practices ○ Cleat engagement is critical; the margin of error is small. Current designs, listings, and specifications typically use a ¾ in. (19 mm) cleat. Is this adequate? Perhaps drip edges and cleats should be longer, as was recommended decades ago.6 Any improvement in the strength of the cleat/ drip edge engagement (for example, stiffer cleat, larger engagement) may prove beneficial to the overall performance of the edge-metal system. Future Work Additional research on this topic would be beneficial to better understand if “high-nailed” L-shaped cleats really do perform as well as was indicated by this full-scale wind tunnel research program. Also, it is important to consider the development of new test methods that might better replicate outcomes discovered during fullscale wind tunnel testing. Current test methods use static testing; dynamic testing methods may better replicate field conditions as well as potentially address long-term fatigue of metal components. Other questions that may need to be addressed include the following: • What is the most conservative wind direction to test edge metal? • Are more stringent requirements at corners appropriate based on what was learned about area-averaging of pressure coefficients? ACKNOWLEDGMENTS This work was sponsored in part by the National Science Foundation and the Industry-University Cooperative Research Center (IUCRC) Wind Hazard and Infrastructure Performance (WHIP) center. The project was conducted at the 12-fan NSF-NHERI Wall of Wind (WOW) Experimental Facility at FIU in Miami, Florida. The FIU team included Deijang Chen, Arindam Chowdhury, Walter Conklin, Steven W. Diaz, James Erwin, Johnny Estephan, Roy Liu Marques, Manual A. Matus, Ameyu Tolera, and Ioannis Zisis. REFERENCES 1. Smith, Thomas L., “Facing the Wind: Nailer Attachment Is One Key to Achieving Good WindUplift Performance,” Professional Roofing, March 2015. 2. “Which Is the Weakest Link: How Can It Be Stronger? Lesson Learned from the 20 Years of Hurricane Investigations” (Paper presented at the IIBEC International Convention & Trade Show, March 2020). 3. SPRI (Single Ply Roofing Industry), Test Standard for Edge Systems Used with Low Slope Roofing Systems, ANSI/SPRI/FM 4435/ES-1 2017, https://www.spri. org/download/ansi-spri_standards_2020_restructure/es-1/ANSI_SPRI_FM-4435-ES-1_2017-TestStandard-for-Edge-Systems-Used-with-Low-SlopeRoofing-Systemsv4.pdf. 4. “NRCA’s ITS Certification for Compliance with ANSI/ SPRI ES-1,” NRCA, https://www.nrca.net/technical/ guidelines-resources/shop-fabricated-edge–metaltesting/its. (Page 61). 5. Toleru, Estephan, et al., “Evaluation of Wind Loading on Edge Metal for Roofing Systems Using FullScale Experiments” (Paper presented at the Eighth European-African Conference on Wind Engineering, Bucharest, Romania, September 2022). 6. “Hurricane Hugo’s Effects on Metal Edge Flashings,” Thomas Smith, AIA, CRC. International Journal of Roofing Technology, NRCA, Rosemont, IL, 1990. ABOUT THE AUTHORS JAMES R. KIRBY, AIA James R. Kirby, AIA, is an architect for Siplast. He has a Master of Architecture— Structures Option. His 30-plus years in the roofing industry have covered low-slope, steep-slope, metal, and SPF roofing, as well as green roofs and rooftop solar. He writes and speaks about building science topics related to roofing, represents Siplast across the roofing industry, and helps manage Siplast’s compliance documents. He is a board member for Cool Roof Rating Council and SPRI, a member of American Institute of Architects, Asphalt Roofing Manufacturers Association, ASTM International, International Code Council, IIBEC, National Roofing Contractors Association, and Western States Roofing Contractors Association. ERICA SHERMAN, PhD Erica Sherman, PhD, is the manager of GAF’s R&D Process Engineering group within the Residential Roofing business. She has a PhD in mechanical engineering with a research focus on experimental fluid dynamics and has over six years of experience in roofing material- and system-specific research and development. She previously worked as an engineer within GAF’s Building Enclosure Research + Innovation group. Her work has included new product development and testing in the residential roofing space. Sherman is a member of ASTM, IIBEC, and National Women in Roofing. Ameyu Tolera is a PhD candidate at Florida International University in Miami. Johnny Estephan is a PhD candidate at Florida International University in Miami. Please address reader comments to chamaker@iibec.org, including “Letter to Editor” in the subject line, or IIBEC, IIBEC Interface, 434 Fayetteville St., Suite 2400, Raleigh, NC 27601.
