Failures: Avoiding post-fabrication damage in prefab systems

by arslan_ahmed | January 12, 2024 12:40 pm

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When specifying prefabricated building enclosure systems, project-specific quality assurance (QA) procedures, including a step-by-step review and documentation of the panel assembly during off-site fabrication, are often required. Beyond addressing critical fabrication steps, it is essential to establish procedures for proper transport, storage, handling, and installation of the completed assembly.

Following fabrication, assembled panels are typically grouped by installation sequence and crated (bunked) for shipment. As the performance of prefabricated panel assemblies is often reliant on strategically placed sealant joints, and recognizing the time-sensitive nature of project schedules, it is important to avoid bunking or reorienting completed units until sealants are sufficiently cured to avoid damage due to premature movement. During bunking, panels should be separated appropriately and protected to avoid unintended contact or rubbing during transport. In addition, any temporary bands, blocking, or wraps intended to prevent panel movement or damage during shipment should not compress malleable components that could experience permanent deformation (i.e. compressible gaskets), risking the integrity of the panel system.

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During transport, panels must also be adequately supported to prevent undesirable shear and/or bending forces. Effective scheduling and coordination can limit unnecessary handling or prolonged exposure of completed product to a construction environment. Depending on the construction schedule, arrangements for temporary storage or increased protection may be necessary to safeguard panels from excess handling or exposure.

As a continuation of the QA program, protocols should be established to inspect and document unpackaged units to confirm they are in good condition. Any damage should be evaluated and addressed as appropriate prior to installation. During installation, care should be taken to avoid racking, distortion, or other damage of the units; temporary bracing or surface protection may need to be provided to alleviate these concerns. Where appropriate, consider temporary protection for installed units to avoid damage from adjacent construction activities.

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Similar to the development of QA procedures during fabrication, post-fabrication QA procedures are project-specific and usually developed by the assembly fabricator and installer. However, the need for such protocols or procedures should be outlined in the specification for each assembly to ensure proper consideration of post-fabrication activities. Reinforcing the need for these protocols in the list of discussion topics during mock-up and preconstruction meetings can set expectations, identify potential challenges, and facilitate coordination among the project team members. Similar to other QA procedures, post-fabrication procedures should be reviewed early in the construction process and adjusted as necessary.

Jeffrey Sutterlin, PE, is an architectural engineer and associate principal with Wiss, Janney, Elstner Associates’ (WJE’s) offices in Princeton, New Jersey and New York, N.Y. He specializes in the design, investigation, and repair of the building envelope. He can be reached at jsutterlin@wje.com.

David S. Patterson, AIA, is an architect and senior principal with Wiss, Janney, Elstner Associates’ (WJE’s) office in Princeton, N.J. He specializes in the design, investigation, and repair of the building enclosure. He can be reached at dpatterson@wje.com.

The opinions expressed in Failures are based on the authors’ experiences and do not necessarily reflect that of The Construction Specifier or CSI.

Source URL: https://www.constructionspecifier.com/failures-avoiding-post-fabrication-damage-in-prefab-systems/

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