PCI’s Architectural Precast Concrete Services Committee explains key considerations in specifying architectural precast panels.
This document provides a basis for specifying in-plant fabrication including product design not shown on contract documents, and field erection of architectural precast concrete panels. It does not include precast structural concrete, nor does it include coatings applied to the panels or sealing the joints between panels.
The architect’s or engineer’s drawings should show panel locations and necessary sections and dimensions to define the size and shape of the architectural precast concrete panels, indicate location and size of reveals, bullnoses and joints (both functional and aesthetic) and illustrate details between panels and adjacent materials. When more than one type of panel material or finish is used, indicate the extent and location of each type on the drawings. The location and details of applied and embedded items should be shown on the drawings. Plans should clearly differentiate between this work and structural precast concrete if both are on the same job. Illustrate the details of corners of the structure and interfacing with other materials. Sizes and locations of reinforcement and details and locations of typical and special connection items and inserts may or may not be shown depending on local practices. If reinforcement and connections are not detailed, identify the requirements for design and design loads, and indicate load support points and space allowed for connections.
SPECIFICATIONS:
Describe the type and quality of the materials incorporated into the units, the design strength of the concrete, the finishes and the tolerances for fabrication and erection. It is important in the event of a performance specification that an appropriate test method be agreed upon as providing the basis of assessment.
Specifiers should consider permitting variations in production, structural design, materials, connection and erection techniques to accommodate varying plant practices. Specifying the results desired without specifically defining manufacturing procedures will ensure the best competitive bidding. This may be done by stating structural and aesthetic results to be achieved and by requiring complete details in shop drawings. Required submittals should also include range-bracketing samples for color and texture.
The panel specification section should include connection components embedded in the precast concrete, related loose connection hardware and any special devices for lifting or erection, if required, as responsibilities of the panel manufacturer. Items to be specified in other sections include any building frame support provisions required to support panels, including portions of connectors attached to the structure, joint sealing and final cleaning and protection.
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