This month we continue to discuss common specification pitfalls and challenges related to metal composite material (MCM) and its various components.
Core
Another area that is often misunderstood when preparing specifications is whether the MCM must contain a Fire Retardant
(FR) Core or Polyethylene (PE) Core (often called a standard core). Complex building codes and laboratory testing results have established building areas and elevations where an FR core is required. The basic requirement is that if you use an MCM panel higher than 40 feet above finish grade, you will be required to provide an FR core. Although local codes may allow some variation, the 40-foot FR core requirement is almost always mandatory. In addition, certain major cities like New York, Chicago and Los Angeles will ONLY allow an FR core. The cost for an FR core panel is significantly higher than PE core material, so it is critical to determine panel core requirements when establishing a project budget.
Finish
In an effort to achieve an MCM panel finish that matches certain window systems, architects often mistakenly specify “clear anodized finish” for metal composite material. Good MCM fabricators will quickly steer owners and architects away from using a clear anodized finish for MCM as there are potential downfalls to specifying this finish. MCM manufacturers cannot provide a satisfactory warranty for this type of finish. It is impossible to match should a replacement panel be needed and it is cost-prohibitive.
However, all major MCM manufacturers offer a finish that simulates clear anodized finish, often satisfying the design intent. Third-party companies have the ability to anodize sheet metal material and provide warranties for this work, but these warranties are often limited and can be voided if the material is modified during typical fabrication processes. Additionally, the warranty from anodizing companies LE FT: Duke Energy, Charlotte, N.C.; RI GHT : Children’s Museum of Arts & Sciences, Daytona Beach, Fla. typically only covers re-anodizing the material if the finish fails and will not cover costs for replacing the material. Obviously, a “clear anodized finish” has no place in the MCM world.
Specifying Fabricators
Material suppliers are almost always specified in contract documents; however MCM manufacturing companies are often not specified. The complexity of designing and manufacturing MCM panels, especially for large projects, makes it critically important to select an experienced and highly qualified fabricator. This could be the difference between getting a subcontractor who fabricates panels in his garage with a router from The Home Depot and having a reputable fabricator on the team who fabricates panels in a controlled shop environment with computer-controlled machinery and laboratorytested attachment systems. A good place to start seeking out high-quality MCM manufacturers is the Metal Construction Association’s “Premium MCM Fabricators” program
(www.metalconstruction.org/ premium/).
It is clear that having a solid understanding of the various MCM components and issues such as core and finish, along with specifying qualified material suppliers and MCM manufacturers, is of great benefit to the design team preparing project specifications and contract documents.
Zeke Miller is the president and sales manager at The Miller-Clapperton Partnership Inc. in Austell, Ga. For more information, visit www.millerclapperton.com.