A look at what materials and technologies have aided metal construction
Coil Coatings and Cool Roofs
David Cocuzzi, technical director of the National Coil Coating Association (NCCA), says one of the biggest product innovations of the past 40 years related to coil coatings is the ability to convert existing technologies to coatings that reflect infrared radiation, i.e., cool roof coatings. “If you can prevent heat flow into the building, you’ve reduced the air conditioning demand and you save energy. The pigment suppliers have created new chemistries that give these heat-reflective properties.” Cocuzzi further explains that one innovation maximizing coil coating processing is thermal oxidizers. They take organic solvents used in paints and destroy them. “This means essentially no volatile organic compounds (VOCs) coming out of the plant, and the heat from the thermal oxidizer is recycled by the facilities, which maximizes energy utilization.”
Laura Lanza, immediate past president of NCCA, believes new siliconized polyesters for coil coatings mean less chalk and less fading, resulting in better color consistency. Also, “The industry moving from hot-dipped galvanized steel to Galvalume has provided coil coating life cycle benefits, improved corrosion resistance and sustainability, and cradle-to-cradle accountability.”
Andy Williams, PE, director of codes and standards, Metal Construction Association (MCA), agrees that paint finishes have continued to get better for both walls and roofs. And, acknowledging the rise and importance of cool metal roofs over the past 40 years, he explains cool metal roofing programs are expanding to walls. “Cool Roof Council (CRC) realizes that while walls are not as big of an impact as the roof to keeping buildings cool, there’s value in keeping walls cool. Not only transmitting heat into the building but also reflecting heat onto the sidewalks and the courtyards, which add to the heat island effect.”
Technology
Bob Zabcik, technical director of MCA, remembers when punch cards were used in the design work for metal buildings. But, “The advent of the computer really changed metal building frame design; you can design a frame in seconds—before, doing it by hand took a week. CAD opened up all kinds of possibilities for metal buildings. Now, everything is done from the ground up: brand new every time, easy to do, accurate and more flexible.”
Lee Shoemaker, Ph.D., PE, director of research and engineering at the Metal Building Manufacturers Association (MBMA), agrees that today’s technology has been able to expedite an architect’s creativity and innovation. “The architect’s creativity to apply metal buildings with more applications has really been an innovation.”
Patti DeWalt, director of marketing, Butler Manufacturing, Kansas City, Mo., says advancements in technology allow customers to see what their buildings will look like through virtual walk-throughs and 3-D renderings. “Before, a customer had to visualize his/her building from a drawing and a set of plans. Our technology allows us to design buildings with precision, assisting our engineers in providing the best building possible.”
Williams says there’s been a lot of innovation in the technology behind fabrication—taking a raw material and turning it into a finished good. “We’ve gone from table saws with router blades in them to CNC routing machines to vacuum tables that are very programmable. If you don’t have programmable cutting capabilities you are behind the times.”
Even welding has had its innovations via improved technology. Shoemaker asserts that welding processes have advanced considerably over the past 40 years, helping to make metal buildings more cost effective than conventional steel. Zabcik explains that wave form machines can do pulse welding, instead of just pointing direct current to weld. “The weld looks the same but the steel gets deposited at much more controllable rates. This saves on consumables like welding wire and slugs.”
Dennis Watson, director of engineering at BC Steel Buildings, Oklahoma City, asserts that those who have exploited new technology over the past 40 years have improved both the product and the process. “And, this has strengthened the position of the industry against both wood and concrete construction; or at least kept the industry from losing ground.”
Cladding
Shoemaker acknowledges that a major innovation is how traditional materials have expanded the metal building market. “Tilt-up concrete panels can be used with metal buildings, and so can masonry and glass. Fifty years ago, most metal buildings looked like a metal building. Now you can’t tell what is a metal building because of the integration of these traditional building materials for the walls.” Also, Shoemaker asserts that 25 to 30 years ago metal building manufacturers were just dealing with a metal building system. “Today, we are looking at the total envelope including insulation, fire resistance, etc.—the word system includes so much more than what we thought about 40 years ago. We are looking at how a lot of systems interact and they have to be considered together.”
When Williams was growing up in the 1950s, he explains, “You had steel siding on your house. It’s gone from steel to aluminum to commercial construction aluminum to titanium to zinc to bronze to copper: all sorts of metallic appearances that the architectural community is looking for. The manufacturing community is coming up with new products and new ideas to put on the outsides from a visual appearance perspective.” Williams has witnessed much innovation and development with metal composite materials (MCM) with the formulation of their core materials. Also, “We’ve seen a lot of new companies join MCA that are MCM manufacturers. They have brought with them new technology. The materials have changed, and emphasis in regards to corrosion and fire performance in regard to bond strength so there’s no delamination of the product.”
Insulation
Zabcik asserts that a heightened focus on energy savings in buildings has been “really good for this industry.” “There was an assumption starting out that because metal conducts heat it would be a poor performer in thermal environments,” he says. “But what we can do with coating technologies, cavity walls and rainscreens can completely mitigate that effect and turn it to our advantage.” Also, he asserts insulated metal panels (IMPs) are much better that they used to be. “[Growing up] we had IMPs in our garage— polystyrene panels—and if you used them you had used a lot of fire retardants.” Acknowledging that today’s IMPs are more stable, he asserts the flamespread numbers are much better. “It lets the IMP industry go after multistory projects and large building they couldn’t get to because of the fire performance. The higher R-values are well documented.”
Shoemaker says in terms of insulation innovations, it goes beyond just insulation in the building. “We are looking at air leakage and air barriers, and preventing condensation as buildings get tighter. Some energy models give us more advanced modelling on insulation systems. The modelling lets us predict performance without putting something in the field, and then realizing two years later there was an issue with something.”
