Creative Design Alternatives Using Metal Building Systems

There are differences between design perceptions and realities
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Sponsored by Metal Building Manufacturers Association (MBMA)
By Peter J. Arsenault, FAIA, NCARB, LEED AP
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Cost of Construction

Generally speaking, most people, including architects, presume that it costs less to construct an MBS than most other forms of construction. In this case, that perception matches reality in almost all cases. Economical design and construction is achieved primarily from the fabrication and delivery of all metal building components being together from one source, the building manufacturer. This single-source purchasing gives the architect and owner control over every aspect of building cost, design, and construction. This single-source approach can also provide faster, more consistent, and more efficient construction, which can save on labor costs. Beyond the initial construction, expansion of an MBS can be very cost-effective too since it can be built into the original design. In many cases, removal of just one wall opens the opportunity to many add-on configuration options.

Speed of Construction

The generally held perception about scheduling is that it is quicker to build using an MBS. Once again, this is generally true. According to the MBMA, construction of a metal building structure is at least 30 percent faster than conventional construction. This is because the parts of an MBS are custom designed and fabricated in a plant ready to be bolted into place on-site. This allows greater precision, reducing the likelihood of errors and omissions such as material clashes, system conflicts, or measurement mistakes. All of that means the parts and pieces can be more quickly put together with more predictability of the needed labor hours, allowing construction time schedules to be more accurate. The customized nature of the package means that only what is needed is shipped, so there is very little waste to clean up or remove, saving more time and labor cost. These attributes are not only good for the contractors but also welcomed by owners who need minimum disruption or to have a facility open as quickly as possible.

Durability/Long-Term Performance

Some architects and others assume that if something is faster and less expensive to build, then it may not be as good or durable as other construction methods. That may be the case for some other products, but the reality when it comes to MBSs is very different. In fact, metal buildings have been shown to be just as durable and strong as any other type of construction. The speed and cost savings come from better engineering design, more efficient processes, and inherent economies. The quality of the materials and products remain high throughout. To that point, a metal building structural system can routinely last for many decades—longer than many buildings constructed with other typical building materials.

Over the long term, metal roofing in particular is essentially maintenance free and long lasting. This is due to the superior life-extending coatings that are routinely used on the metal panels to retain color, resist dirt, and otherwise hold up well. In fact, it is not uncommon to see metal roofing on a conventionally built building which lasts as long as or even longer than the building itself. The smooth surfaces also mean that sloped metal roofing is essentially self-cleaning. Further, the coatings on the steel do not support mold growth, resist rust and decay as well as or better than other building materials, and generally retain their appearance and integrity over time. That helps the building owner with lowered maintenance and operating costs for the life of the building. If metal wall panels are used, many of these traits would apply there as well.

MBSs offer structural integrity, durability, and great design flexibility by being custom fabricated to suit variable needs for structure, interior, and exterior design.

Structural Standards

The perception about the structural standard that metal buildings are held to and the integrity of MBSs seems to vary based on the experience (or lack thereof) of the person involved. Some may think that the structures are not as strong or capable as using hot-rolled structural-steel shapes. Others are unsure what to make of the use of the steel tapered frames or “bents” that often form wall and roof structural support in a single angled piece. The truth is that strength is designed and manufactured into each structural metal building component by combining proven engineering with lighter cross sections and higher-strength steel. The optimized tapered steel building frames are designed that way to “put the steel where it is required,” thus maximizing strength and efficiently using only as much material as needed. That translates into less dead-load weight and material cost. Of course, the primary advantage of steel is its strength, which can allow for significant load-carrying capabilities as well as resistance to abuse and wear. Steel used in an MBS is delivered to the manufacturer from a mill with very exacting specifications, enabling engineers to design each structure with a high degree of accuracy. If the situation warrants, hybrid structures can be used that blend the advantages of MBS construction with the conventional steel members.

The configuration of combining steel structural members with metal panels also provides substantial increases in panel strength. This is based on using standard details such as the longitudinal raised profile of a metal building panel or a stiffener lip added to the flange of cold-formed structural members. Through coordinated design, extensive research confirms that metal buildings withstand significant imposed forces such as earthquakes. This has been demonstrated in a test building subjected to a simulated earthquake at University of California San Diego. Metal buildings also stand up well against strong wind events. Further, metal roofing achieves the highest classification (Class 4) for hail resistance when tested to UL 2218: Standard for Impact Resistance of Prepared Roof Covering Materials.

Code Compliance/Safety

Similar to the perception about structural standards and integrity, it appears that some architects do not always think that MBSs are code compliant or meet safety standards for fire and other hazards. The reality is just the opposite: all MBSs are designed, constructed, and inspected to be fully code compliant and as safe (or more so) than any other construction type. All bear the stamp and seal of a licensed design professional, and virtually all require building permits, which means they are reviewed and inspected just like any other building.

To assist with code compliance and quality control, the MBMA has taken the proactive role of developing a recognized accreditation program in conjunction with the International Accreditation Services (IAS). Participation in this program is mandatory to be a member of the MBMA. It is referred to as the Inspection Program for Manufacturers of Metal Building Systems or by its accreditation number IAS AC472. This is a comprehensive accreditation program based on the requirements of Chapter 17 of the International Building Code (IBC).

Any architect or code-enforcement official can require IAS AC472 accreditation of the manufacturer as a quality and safety qualification for a project. Doing so means that the building official and others are assured that suppliers have passed the stringent audit requirements of the IAS AC472 accreditation program. Among other things, this accreditation requires that the manufacturer only use raw materials meeting applicable ASTM specifications. When the building supplier is also doing the structural design, accreditation assures that the product is being designed by professional engineers who have demonstrated knowledge of building systems and applicable codes. It also requires that all letters of certification, design calculations, and drawings are clearly communicated and stamped by a fully qualified design professional.

Specifying only accredited companies and facilities is straightforward by checking the complete list of accredited companies and facilities on the IAS website. If a company is being proposed that is not listed, then it is reasonable to ask why the manufacturer has not been accredited or simply reject it as not qualified under the specifications.

 

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Originally published in Architectural Record
Originally published in December 2019

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