Metal composite material (MCM) cladding systems are an attractive and popular way for architects to present the latest architectural masterpiece. They are clean and colorful, provide high-tech aesthetics, and are tough enough to protect everything inside from everything outside. MCM is the cladding choice on many of the world’s most beautiful buildings. It is not surprising that it takes a team of specialists to produce a high-quality finished product to be installed on the building.
A dive into the fabricator’s functions as part of the MCM team
MassArt Student Residence Hall, Boston
Photo: Peter Vanderwarker, Courtesy of 3A Composites USA
While there are many details and people involved, the major participants producing the finished cladding systems are a team of individual companies with specific, yet important duties. This team includes the manufacturers, fabricators and installers.
Typically, the manufacturer and fabricator are separate business entities. The manufacturer creates the composite panel and supplies it in a flat format. The fabricator receives that flat panel and makes it into the panel that can be installed on the structure. This includes cutting the panels to size; routing the perimeter of the panels to create the folded portion, which provides a clean, finished edge; attaching anchoring profiles to the folded panel to provide for a connection to the structure; and, finally, attaching the required stiffeners to the panel to limit panel deflection when exposed to wind loads.
It is often the case that the fabricator and installer are the same company (or two separate divisions of the same company), but many times these two functions are accomplished by completely different businesses. The purpose of this article is to dive into the fabricator’s major functions as part of the MCM team to better understand what they do, how they do it and why they do it.
C.H. Robinson Midwest Headquarters, Chicago
Photo: Mark Kempf Photography, Courtesy of 3A Composites USA
Without the fabricator, the flat MCM sheet produced by the manufacturer cannot be installed on the structure by the installer. The fabricator is a critical component of this three-part team. This article identifies eight major functions the fabricator follows to ensure the architect’s masterpiece meets the design expectations a long with the building code.
Design and fabricate. The fabricator designs and fabricates a panel system that meets the design performance requirements identified in the specifications or by the building code. The specification address water penetration (ASTM E331), structural wind load performance (ASTM E330), energy performance in the areas of insulation and temperature transfer (ASHRAE 90.1), and overall fire performance with the NFPA 285 multistory fire test.
One additional factor that must be considered is the handling of water that penetrates the exterior cladding. While typically associated with the level and quality of the system installation, the fabricator designed system must allow for drainage of any water or condensation that gets behind the cladding. This design could be as simple as installing weep holes to allow gravity drainage per ASTM E283 and AMAA 509 or the design could be as complex as a pressure equalization system that is commonly used in rainscreen applications per AMAA 508.
Testing. Testing of the cladding systems include dynamic wind and water testing as well as fire performances testing such as the NFPA 285 multistory test to meet the architect’s specification, International Building Code (IBC) and specific local code requirements.
Ironclad, Minneapolis
Photo: Bob Perzel Photography, Courtesy of 3A Composites USA
It is very common to find an MCM specification for façade construction that does not specifically call for the entire wall assembly to meet the requirements of NFPA 285. Don’t be fooled that not specifically referring to NFPA 285 in the specification eliminates the need for compliance to this very important test. All too often, fabricators provide quotes “as per plans and specifications,” not realizing that by simply calling out the project shall conform with local code requirements is enough to require NFPA 285. It is critical the fabricator address the specifics of any generalizations that appear in the specification when the MCM system performance is being bid.
The fabricator needs to be aware of where the NFPA 285 performance is required when bidding a project. Since the days of the model building codes prior to 2000, the codes have been quite prudent regarding when the NFPA 285 test is required to show overall fire safety for the structure. A good generalization, since the IBC was developed in 2000, is that any MCM wall assembly installed greater than 40 feet above grade must meet the performance requirements of the NFPA 285.
There is one very notable exception that is more stringent, which is when the MCM wall assembly contains foam plastic insulation. In this instance, with very few exceptions, the MCM cladding assembly must comply with NFPA 285 for any application from the ground level.
Another fabricator responsibility connected with the building code is sourcing the correct MCM sheet with compliant labeling for each sheet purchased. The labeling required in the IBC Section1406.14 states the sheets must be tested, inspected and labeled. IBC Section 1703.5 requires a third party-approved agency make inspections of the manufacturer’s facility, verifying the material tested represents the material being produced. This labeling helps reassure the fabricators of one more quality assurance/quality control reference that they received the right specified material.
Project drawings. Fabricators must create project drawings and engineering calculations showing the adequacy of the panel system design for the specific project. Many times, this duty requires the involvement of a registered design professional, usually a professional engineer, that must seal both the drawings and the calculations for a project. Often local authorities or building department require an engineer of record.
Another area fabricators need to address is the impact of the anchorage system on the overall fire performance of the wall assembly. While it is possible to create a cavity that may have some impact on flame spread, more often the controlling criteria for the anchorage system is structural performance of the cladding material in the areas of wind load and gravity load (panel/system weight). Resistance to positive and negative load has, by far, the most significant impact on the anchor profile/ thickness and fastener selection.
Shop drawings. Produce shop drawings for each panel being fabricated and identified throughout the production and erection process. These shop drawings not only direct the fabrication, but ensure that the panels provided will meet the structural and fire demands of the project.
Design, source, fabricate. Design, source and fabricate structural components such as extruded aluminum (both perimeter extrusions for anchorage and stiffener profiles), fasteners and clips required to fabricate MCM sheet into a cladding panel capable for installation on a structure. This also applies to the nonstructural fabrication components including adhesive tapes and sealants that are used to assist with water control in the finished system.
Shop fabrication. Shop fabricate MCM sheets into cladding panels and package finished panels for shipping to job site. Cladding systems typically consist of panels using perimeter aluminum extrusions or clips with either an integral or separate support system. The support system is used to attach the cladding panels to the wall substrate or studs. Specific fasteners, gaskets, and other installation components are often supplied with the fabricated panels or at the very least called out so that the installation can take place correctly.
Construction sequence drawings. Create construction sequence drawings and instructions for an efficient and coordinated installation of the entire cladding assembly. This element is too often overlooked when the fabricator and installer are not the same company. Coordination between these two entities is critical to ensure the overall performance of the cladding assembly.
Warranty. Even though the system performance capabilities such structural load resistance and deflection, air/water intrusion, and thermal performance of the system components are heavily influenced by the installation of the system, these performance characteristics are typically warranted by the fabricator.
For the MCM team, the building envelope has five basic requirements:
Manage heat, air and water for the building. Handle the design wind loads. Capture the aesthetic design vison of the architect and building owner. Meet all local code requirements for the life safety of those in and around the structure. Attain a life span of 30 to 50 years.
The fabricator’s role on the MCM team is a crucial part of a successful MCM designed system on a building façade. These eight functions are suggested requirements to ensure that the completed product from the fabricator meets the five basic requirements for a successful architectural masterpiece. The performance of the wall assembly hinges on all three members of the MCM team—manufacturer, fabricator and installer—working together and the fabricator is a pivotal part of the successful masterpiece.
The next time MCM is considered for a project, investigate the panel system fabricator, and make sure these eight critical functions are being provided for a successful MCM wall system.
Tom Seitz is the executive director of the Metal Composites Material (MCM) Alliance at the Metal Construction Association. To learn more, visit www.metalconstruction.org.