June 22, 2016
by Jason Allen
When properly designed and installed, a standing seam metal roof system provides the building owner with long-term dependability and value. Standing seam roof systems fulfill requirements for durability and protection against just about any type of weather situation, and they excel in high winds. Overall, they have outstanding performance records.
In the most severe weather conditions, wind pressure can force panels to deflect. This causes the seams to open and the panels to shift in failure mode. Typical failure occurs at the corners and edge zones. As a result, standing seam metal roofs must meet certain standards and testing criteria.
While there are many performance tests out there, the ASTM E 1592 is considered most reliable for the design of standing seam panels. It is the standard test method for structural performance of sheet metal roof and siding systems by uniform static air pressure differences.
The UL 580 rating determines the uplift resistance of roof assemblies. The test evaluates the roof panel, panel clips, fasteners and the substrate.
The UL 1897 wind test is a continuation of UL 580, and is the standard for uplift tests for roof covering systems. The purpose of this test is to gain uplift resistance data for the panel assembly, and evaluate the attachment of the roof covering systems to the roof decks.
FM 4471, Approval Standard for Class 1 Panel Roofs, states the requirements for meeting the criteria for fire, wind, foot traffic and hail damage resistance.
The test sets performance requirements for panel roofs, which includes all components necessary for installation of the panel roof assembly as a whole. This includes the potential for fire spread on the underside and exterior of the roof panel. It also measures ability to resist simulated wind uplift resistance while maintaining adequate strength and durability.
This test method provides a standard for structural performance under uniform static air pressure differences, and is run to failure to find the ultimate uplift load capacity. This test measures both panels and anchors. ASTM E 1592 is not a pass/fail test; it merely shows how a roof performs under uniform static load.
ASTM E 1592 was developed to account for the many complexities of evaluating uplift properties of metal roofing. The test method “provides a standard procedure to evaluate or confirm structural performance under uniform static air pressure difference. This procedure is intended to represent the effects of uniform loads on exterior building surface elements.” (https://www.astm.org/Standards/E1592.htm)
In conclusion, while all of the standardized test protocols mentioned above were established to determine uplift capacities of roof assemblies, only the ASTM E 1592 uplift test is considered reliable enough for the design of standing seam roof panels. Among its key differentiators, the test takes into consideration the roof’s flexibility, changes in shape occurring under air pressure, and it measures both metal panels and their anchors.