Green building standards and the additional requirements necessary to attain accreditation are here to stay.
Even as today’s highly competitive market squeezes profit margins, Leadership in Energy and Environmental Design-certified projects challenge contractors to provide more sophisticated services without increasing project costs.
In order to remain viable, prudent contractors must search for opportunities to implement lean practices at all points of performance. One way is by being lean. Lean companies avoid waste and redundancy. This pertains to increasing labor productivity in the field as it does to increasing manufacturing efficiency in the shop. Great opportunities for improved labor efficiency exist in material handling and distribution processes.
Prior to green-building standards, sheet metal contractors enjoyed much greater efficiency in material handling. They packed significantly more pounds of ductwork on each truck, ultimately reducing the number of trucks required to send materials to a jobsite. As a result, their average cost per pound to deliver materials also decreased. With the advent of the LEED building rating system, the U.S. Green Building Council mandated that sheet metal contractors “seal all duct and equipment openings with plastic” to qualify for an indoor air quality credit.
It follows that to facilitate LEED compliance in this category, sheet metal contractors commonly seal duct segments individually, and load them (see photo). This results in gross inefficiency as the industry now ships trucks full of empty, sealed duct, as opposed to the pre-LEED method of stacking smaller segments of ductwork inside of larger segments of ductwork.
More efficiencySome sheet metal contractors estimate that this practice has cut material handling efficiency up to 50 percent. Contractors suffer additional inefficiency when field labor leaves their work areas to unload twice as many trucks. To further complicate matters, they handle individually sealed segments of duct, and then carefully distribute them while protecting the airtight plastic seal.
The Mechanical Contractors Association of America reports that LEED-compliant field labor spend up to 20 percent of their time on material handling alone. MCAA defines these tasks as unloading trucks, hoisting, and moving materials and tools to installation areas.
A better way may be using wheeled sheet metal - or equivalent airtight material - bins to allow prudent contractors to reduce their handling costs while meeting the intent of LEED IAQ credits. It is acceptable to gain maximum use of the bin by stacking small ducts within larger ducts - all within one large, sealed, bin (see photo). Rather than covering individual duct segments, you cover the whole bin. Shipping materials within a single, airtight container provides excellent protection for materials while reducing plastic waste. To further increase efficiency, bins are loaded with materials sorted by location.
For example, each bin will contain ductwork that goes to one specific area of a jobsite. By delivering “area-configured loads” in this manner, field labor can offload ductwork for an entire area at once, rather than by individual segments that require delicate handling. Contractors reduce their distribution costs again if one worker can push a single wheeled bin with several pieces of duct to a specified location as opposed to moving joints by hand, one or two at a time.
Assuming a 40-hour workweek, MCAA estimates that material handling and distribution will consume 20 percent or eight hours per week. While it’s not realistic to achieve “pre-LEED” material handling and distribution efficiency, a 5 percent increase is certainly attainable. Over the lifespan of a job, diverting two hours from material handling and distribution to installation every week results in an additional 2.6 weeks of installation every year compounded with the benefit of reduced trucking costs.
At times green building requirements compete against the lean building practices that increase productivity and reduce the cost of construction. Savvy contractors must find the best balance between these competing requirements in order to recognize the benefits of the important LEED rating system while continuing to improve productivity. Updating handling practices to meet the USGBC’s intent while simultaneously gaining efficiency at multiple points of performance is an important part of adapting to these changes while defending productivity.
Lee Feigenbaum is a LEED-accredited professional and a project manager at Emcor-owned Heritage Mechanical Services in Deer Park, N.Y. He can be reached at LFeigenbaum@emcor.net. For reprints of this article, contact Jill DeVries at (248) 244-1726 or e-mail email@example.com.