The True Test of Enclosure Performance: Results Vary

by Marcy Marro | May 1, 2023 12:00 am

This challenges the architect to properly specify and detail these many pieces, and the contractor and their subs to faithfully execute the design intent in the field. As we strive for more resilient, more air-tight, high-performance buildings, all players must be active participants in the game of connect-the-dots, and field performance testing should be integrated into the process.

Let’s illustrate this principle using insulated metal panels as an example. The panel itself is an assembly made up of an insulating core bonded to metal on both interior and exterior sides and joined to other panels in the field with additional components to create the fully assembled system. While an individual panel may excel at controlling the key environmental factors, water (both liquid and vapor), air, and thermal, the system’s performance relies on all the components working together. As with most building materials and assemblies, this product must be tested to meet or exceed industry standards. But exactly how was the product tested, and what was the test specimen configuration? This may be the most important question project teams must ask about any cladding or fenestration system or assembly that is a part of the primary control layers of the building enclosure.

It is a given that a product has been tested, but the how matters, because that gives us insight into its limitations—the literal edge of the test specimen is the extent of where that level of performance is provided, and this is where the product must tie into the adjacent systems to create a continuous enclosure that can manage what environmental conditions will throw at it. Asking for the shop drawings that go with the product test report can provide insight into how the product met the high-performing qualities, in a lab setting, that the manufacturer is promoting in product data, and what the field installation will have to replicate to get close to seeing the lab-tested performance in the completed building.

These conditions, especially identification of the primary control layers, are typically reinforced by the product installation instructions, and the trade partner shop drawings, but they aren’t writing “this will leak if X component isn’t installed properly” in bold red font. Additionally, if the design team does not understand where the primary control layers are up front, there is a chance that the design will not meet performance expectations. Manufacturers do not promise performance beyond the extent of their products, so the tie-ins to adjacent air barriers, fenestration, roofing or waterproofing must be designed into the project as early as possible to maintain performance across the entire enclosure.

If issues with these transitions are not caught in the design phase or early in the installation process, it can be costly to make corrections. Worse still, if they are completely missed, the building manager will be playing whack-a-mole, chasing leaks in the form of water and air (moisture and heat moving through gaps and cracks), with repairs being costly or nearly impossible to execute.

This is where field testing comes in as a critical part of the building enclosure commissioning process. With an appropriately executed testing plan, the project team can often catch installation or design errors. The testing can also serve as a learning experience for the team, applicable to future projects.

Unfortunately, it is not uncommon to see specifications that require testing that is not tailored to the project. These specifications are often close but not quite right for the system to be tested, and hence have little value as not all testing is equal. It is critical to include testing that is appropriate for the project to get the most useful information about how the system will perform. The key is to make sure the specified testing will tell us how well, either qualitatively or quantitatively, the field-installed assembly is performing. In some cases, we end up with testing that does not give us sufficient indication of the performance of a system once installed. For example, testing of continuous systems requires compartmentalization, which is difficult on-site without modification of the specimen due to inaccessibility to the primary control components of the system.

This also applies to the insulated metal panel example (sometimes tested using window test methods). We may see a lab test report with performance obtained via ASTM E283. The field test version of that is ASTM E783; however, the field version of the lab test may not always be the best choice for continuous systems like insulated metal panel. Selecting the optimal testing plan requires diving into the details of the product or system, how it was tested in the lab, and what the primary control components are. For example, knowing whether the lab-tested sample included a metal mending plate, an interior gasket or butyl sealant joint, or the framing that then ties into a sealant joint or an integrated transition membrane that ties to the air, vapor, and water control layer of the wall is critical to developing a useful field-testing plan. The right test will encompass as many components as possible that are important for the overall performance of the assembly.

From specifications and details to installation and testing, it is critical for the members of the project team to work together to ensure that the enclosure systems achieve the performance required for the building, whether meeting energy codes or striving for net zero. In a future column, we will dive into more detail on successful approaches to specifying and executing field testing in support of building performance goals.

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Alan Scott, FAIA, LEED Fellow, LEED AP BD+C, O+M, WELL AP, CEM, is an architect and consultant with over 35 years of experience in sustainable building design. He is director of sustainability with Intertek Building Science Solutions (BSS) in Portland, Ore. Alex Connor, R.A., LEED AP, BECxP, CxA+BE is a senior consultant with Intertek BSS in Washington, D.C. To learn more, follow Scott on LinkedIn at www.linkedin.com/in/alanscottfaia/[1].

Source URL: https://www.metalarchitecture.com/articles/the-true-test-of-enclosure-performance/

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