Episode 52 - How Real-World Testing Improves Roof System Safety and Performance

Ever wondered what goes on inside McElroy Metal’s testing lab? Join us with McElroy's testing specialist Hunter Langdon for an inside look at how real-world performance testing like, UL 580 and wind-uplift evaluations drive safer, stronger roofing systems. Our in-house experts share why testing matters and how it differentiates McElroy Metal from competitors.

  • 29 min

Episode 52: How Does Real-World Testing Make Roof Systems Safer?

The Building with Metal Podcast – Presented by McElroy Metal

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Notable Quotes

• "You can stand behind McElroy that we have testing for these things. You may not have this out of smaller manufacturers that they're just making a panel on site and putting it on a roof. There's often no testing to those systems whatsoever." — Hunter Langdon
• "There's reliability and safety in knowing that number. ASTM E1592 really gives us value because now we're allowed to lower our engineering design. We can now use fewer clips because we know exactly where that panel is gonna fail at." — Hunter Langdon
• "That's how research and development works. You're hoping that something magical comes out of this and sometimes it does." — Hunter Langdon

What You'll Learn

• How McElroy Metal's in-house testing facility evolved from a wood-framed chamber to a robust steel-framed system capable of higher pressure testing
• The ASTM E1592 testing procedure and why panels are tested to failure rather than to a specific rating threshold
• Why the same panel configuration must be tested three times to establish reliable averages and identify outliers
• The step-by-step process of setting up a wind uplift test, from installing panels on pleated plastic to sealing the chamber
• Common failure points in standing seam panels including seam separation, clip detachment, and seam slippage
• How panel width affects performance, with wider pans generally testing weaker than narrower configurations
• The cost and scheduling advantages of maintaining an in-house testing facility versus relying solely on third-party labs
• How in-house testing accelerates product development by enabling rapid pivots and real-time design iterations
• The unexpected challenges of testing, from plastic quality changes during COVID to a chamber that slowly "walks" across the floor

Key Timestamps

[0:00] Introduction to the Building with Metal podcast and guest Hunter Langdon, who runs McElroy Metal's in-house testing facility in Bossier City, Louisiana.

[1:30] Overview of the testing facility's 20-plus year history and the transition from wood-framed to steel-framed test chambers to handle higher pressures.

[4:15] Explanation of the test chamber dimensions and ASTM E1592 guidelines, including the 10-by-25-foot chamber and various span configurations.

[7:30] Discussion of the panels Hunter has tested over his 10 years, including 238T, Maxima 216, Medallion-Lok, and the newest Trap-Tee panel.

[10:45] Why ASTM E1592 requires testing to failure and the importance of running three identical tests to establish reliable averages.

[16:00] Walkthrough of test setup including eave plates, pleated plastic installation, panel seaming, and creating an airtight chamber.

[21:30] Common failure modes explained: seam de-seaming, clips separating from bases, and seams slipping off clips.

[28:00] Challenges of testing including plastic quality issues post-COVID, chamber maintenance, and the phenomenon of the chamber "walking" across the floor.

[35:15] Benefits of in-house testing versus third-party facilities: cost savings, faster turnaround, and ability to rapidly pivot priorities.

[40:00] Hunter's additional roles in product development, contractor certification training, and closing thoughts on the value of tested building products.

Mentioned Resources

• ASTM E1592 – Standard test method for structural performance of sheet metal roof and siding systems by uniform static air pressure difference
• McElroy Metal Website
• Connect with the host Kathi Miller on LinkedIn

Episode Deep Dive

When a metal roof fails during a storm, the consequences can be catastrophic. That's why McElroy Metal has invested more than two decades into building and maintaining an in-house testing facility at their corporate headquarters in Bossier City, Louisiana. Hunter Langdon, who has managed the facility for 10 years, recently shared an inside look at how the company tests its standing seam panels to ensure safety and reliability.

Evolution of the Standing Seam Panel Testing Facility

The testing facility has come a long way since its early days. Originally, McElroy used a wood-framed chamber for testing, but as their panel systems improved and began achieving higher performance ratings, the chamber itself became the limiting factor. "You want the test to fail and not the chamber itself to fail," Hunter explains. Years ago, a team came in over a weekend and constructed a new steel-framed chamber using structural and substructural steel, giving Hunter the robust testing environment he needs today.

The current chamber measures 10 feet wide by 25 feet long, following the guidelines set by ASTM E1592, the industry standard for testing structural performance of sheet metal roofing systems under uniform static air pressure. This size allows Hunter to configure tests at various span spacings, from clips at one foot on center up to five feet on center, depending on the specific test requirements. Most often, he works with shorter 10 or 15-foot configurations simply because they're faster and easier to manage.

Why ASTM E1592 Test-to-Failure Matters

What makes ASTM E1592 particularly valuable is its test-to-failure approach. Unlike some testing protocols that simply verify whether a panel can withstand a specific rating, this method pushes each configuration until it breaks. "ASTM wants to find out what the actual failure is," Hunter notes. "There's reliability and safety in knowing that number. We can now use fewer clips because we know exactly where that panel is gonna fail at."

To ensure accuracy, Hunter runs three identical tests for each configuration. A single test provides just one data point, which could be an outlier that doesn't represent real-world performance. Three tests establish an average and confirm that failures occur consistently at the same point. While results usually align closely, Hunter has encountered situations where interpolated values between tested configurations didn't land where engineers predicted, making physical testing essential for certain spacings.

How Wind Uplift Pressure Testing Works

The testing process itself requires meticulous preparation. Hunter sets down eave plates on the sides and front of the chamber, then installs a layer of six mil poly plastic that acts as an air barrier. He lays panels on top of the plastic, seams them together, and seals around the edges with a large metal angle. The result is an airtight box with the panels serving as the lid. A large blower then injects air into the chamber, simulating negative wind uplift pressure. Engineers monitor pressure readings on manometers at opposite ends of the chamber, holding each pressure level for about 60 seconds before increasing to the next increment. The process continues until something fails.

Common Standing Seam Panel Failure Modes

Failure can take several forms depending on the panel design. Some panels experience seam separation, where the mechanically seamed joint comes apart. Others see clips detach from their bases or seams slip off clips entirely. "Generally, something will deform and something will lift off of the system and I can no longer keep injecting air," Hunter describes. "It just will tear apart."

The Critical Role of Air Barrier Materials

The seemingly simple plastic barrier has proven surprisingly critical to test success. Hunter uses a six mil poly plastic as specified by ASTM guidelines, originally sourcing a product called Husky. However, material formulations changed during the COVID pandemic, affecting products across many industries. "Your Saran wrap doesn't Saran wrap as good as it used to," Hunter observes. He noticed tests failing because the plastic was perforating unexpectedly, so he ordered samples from five or six manufacturers and conducted his own testing. Uline emerged as the winner, though Hunter acknowledges he's using the plastic for a purpose quite different from its intended use as a vapor barrier under concrete.

Maintaining a Metal Roof Testing Chamber

Maintaining the chamber itself presents ongoing challenges. The steel structure requires regular inspection and reinforcement as testing reveals new weak points. Several years ago, Hunter spent two weeks resealing the entire chamber to regain the ability to reach 80 inches of pressure. More recently, he discovered that the massive metal box actually moves during testing. As air pressure inflates the chamber, it lifts slightly off the floor and sets back down in a slightly different position, inching its way across the room about a sixteenth of an inch per test. "Here in about 100 tests I'm gonna be against the wall," Hunter notes, adding that he moved it back three feet about a year ago using equipment dollies but it's already creeping forward again.

Benefits of In-House Panel Testing

The advantages of maintaining an in-house facility extend beyond cost savings, though those are significant. Working with third-party testing organizations like FM in Rhode Island requires sending materials six months in advance and scheduling around their availability. If McElroy discovers they need a different test configuration, they might wait two years to get back on the schedule. With Hunter on staff, priorities can shift instantly. "They just call and say, 'Hunter, don't worry about testing the 238T. We need to take a look at Medallion-Lok.' I go, 'Okay.' And that's it."

Accelerating Metal Roofing Product Development

This flexibility proves particularly valuable for product development. When engineers have an idea for improvement, they can iterate rapidly, testing variations in clip length, gauge, fastener specifications, or pan width. Hunter has been involved in product development from initial concepts through implementation, sometimes starting with 3D-printed prototypes. Ideas come from all directions, including sales teams who hear customer requests and bring them back for evaluation. "That's how research and development works," Hunter reflects. "You're hoping that something magical comes out of this and sometimes it does."

Contractor Certification and Training

Hunter's role has expanded over the years to include contractor certification training conducted in the same facility where he performs testing. While he's careful not to call it teaching since no one can learn everything about metal roofing in a short session, he helps contractors understand proper installation techniques and earns their certification.

Why Tested Metal Roofing Systems Matter

The investment McElroy makes in testing ultimately benefits contractors and building owners who need confidence in their materials. Smaller manufacturers might produce panels on site and install them without any testing whatsoever. "You can stand behind McElroy that we have testing for these things," Hunter emphasizes. When contractors stake their livelihood and employee safety on their material choices, working with a manufacturer that has made this level of investment in testing provides genuine peace of mind.

For Hunter, the most exciting moments still come when engineers enter the lab to run a test. He admits to standing nose-up against the blast shield, watching with bated breath and hoping he didn't make any installation mistakes that would cause premature failure. The blast shield, fitted with Lexan glass, protects the team from debris when panels finally give way under pressure, including fine particles of drill casting that could otherwise cause injury. It's a dramatic conclusion to a meticulous process, and one that Hunter has witnessed hundreds of times over his decade in the lab.

As metal roofing systems continue evolving with new panel designs and higher performance requirements, the testing facility evolves alongside them. Hunter is currently running through Trap-Tee testing for McElroy's newest panel offering, adding to the comprehensive database of test results that inform engineering specifications across the product line. Each test contributes to the body of knowledge that allows designers to specify appropriate clip spacings with confidence, knowing exactly how each configuration will perform when the wind blows.