The Metal Construction Association (MCA) offers its members technical support in both product use and code compliance. In 2013, MCA technical staff will be submitting code changes to support the roofing industry in both the Florida Building Code and the International Residential Building Code. Both code documents are to be updated in the 2013 cycle.
Metal industry councils discussed code changes during the MCA Annual Meeting in January. Councils representing metal roofing, insulated metal panels, metal composite material (MCM) panels, and single-skin metal wall panels met to discuss research projects and technical developments required to advance the use of metal in the construction industry. MCA has an acclaimed history of funding research projects in various aspects of metal construction. Past areas of research include structural performance of roof and wall assemblies, fire performance required by the building code authorities, and high wind/impact performance particularly in the hurricane areas of North America.
Councils at the Annual Meeting also continue to define areas where research is required. Different manufacturers within the same industry were able to discuss issues affecting the entire industry. This cooperative effort initiates changes that benefit the entire industry rather than a single manufacturer or industry segment. Several current projects include:
Florida Building Code
The challenge is separating prescriptive-based code from performance-based code. The Florida code already calls for a level of structural performance, and submitted code change proposals also call for a minimum roof deck metal thickness. If a product meets the test performance required, metal thickness should not be a consideration, unless other performance issues exist. No other performance issues have been identified to support the proposed code change.
International Residential Code
All the proposed code changes deal with fire performance of a roof assembly. In short, if a Class A roof assembly is required, the roof assembly integrity should remain Class A over the life of the building. When repairing or reroofing, the materials used must maintain the Class A performance of the overall roofing assembly. By highlighting requirements already in the code and identifying the risk of these non-compliant assemblies, the goal is to enforce, by code, replacement roofing that is completed using high-quality materials and roof assemblies that will meet the requirements of the code.
ORNL Dynamic Building Envelope Research
This is the final year of a three-year research program on Dynamic Building Envelope Assemblies in which full-size test samples are evaluated at Oak Ridge National Laboratory (ORNL) for thermal performance of metal roof retrofit systems. Components include insulation, above sheathing ventilation, radiant barriers and phase-change materials. The program is also investigating the effect of cool metal roofing on the performance of photovoltaics.
Department of Defense Demonstration Project
A demonstration project, funded by the DOD’s Environmental Security Technology Certification Program (ESTCP), was installed at the Goodfellow Air Force Base in San Angelo, Texas. This retrofit metal roof system, installed in June 2012, features retrofit sub-framing, solar thermal air/water heating, passive cooling
(above sheathing ventilation), solar energy (thin film PV), radiant barrier, cool metal roofing and rainwater harvesting. A data acquisition system, developed by ORNL, monitored energy usage before the installation and will continue to collect data through summer 2013.
Life Cycle Analysis Project
The final report on MCA’s Life Cycle Assessment (LCA) and Product Category Rules (PCR) have been completed and are posted on the MCA website. Plans are being made to use the PCR to develop three Environmental Product Declarations for insulated metal panels, metal composite material panels and metal cladding (roofs and walls). The work will be done in cooperation with PE International and UL Environment, and the LCA data will be included in the Life Cycle Inventory databases, including the ATHENA database.
Metal Roofing Service Life Project
Inspections of existing Galvalume metal roofing across the country continue as part of the metal roofing service life project started in 2011. Roofs are being inspected in a variety of climate zones. The analyses include performance of sealants and other materials. The goal is to calculate an estimated service life for unpainted Galvalume roofs.
Washington State Ecotoxicity Project
A project coordinated through the Washington Department of Ecology is underway to study the composition of rainwater run-off from various roofing materials. The goal is to assess the potential sources of aquatic toxicity in the Puget Sound. Unpainted Galvalume, prepainted hot dip galvanized and copper roofing are part of the evaluation. The plan includes capture of rainwater from low- and steep-slope mockups in the Seattle area and analysis for metals and chemicals suggested by the Department of Ecology. A roofing task force formed by the Department of Ecology, which includes several MCA members, is reviewing the test plan and providing materials for the project.
Scott Kriner is the president of Green Metal Consulting Inc., Macungie, Pa., and a principal in RSK Avanti Partners LLC, Richardson, Texas. He is a LEED Accredited Professional (Operations and Maintenance) and wrote a book titled “Wait and See.” He also serves the Metal Construction Association as technical director.
Andy Williams is the director of codes and standards for the Metal Construction Association. He is a professional engineer that began his career in the wall cladding industry in 1982.
For more information about MCA, go to www.metalconstruction.org and www.themetalinitiative.com.