Recently, there has been a rise in the use of prefabrication and modular construction methods, even though both have been used in the construction industry for centuries. After falling out of popularity, it is re-emerging thanks to the rise of building information modeling (BIM) and the influence of green building, according to McGraw- Hill Construction.
Prefabrication methods are increasingly used in residential and commercial projects and include everything from in-floor and in-wall products to switches, receptacles and other visible components.
“Electrical contractors are increasingly using prefabrication as a way to improve productivity by reducing the amount of time it takes to install and terminate the products on-site,” said Kevin Kohl, product manager, commercial wiring devices for Pass & Seymour, Syracuse, N.Y. “By improving installation efficiency, the contractor should be able to increase the volume of jobs it takes on, or it can take on more sophisticated, complex projects.”
The benefit of improved productivity realized from modularization and prefabrication activities is borne out in McGraw-Hill’s 2011 SmartMarket Report, “Prefabrication and Modularization: Increasing Productivity in the Construction Industry.” In this report, 35 percent of prefabrication users reported their project schedules were decreased by four weeks or more, 41 percent reported their project budgets were decreased by 6 percent or more, and 44 percent reported that construction site waste was decreased by 5 percent or more.
Lemberg Electric Co. Inc., Brookfield, Wis., established its prefabrication shop three years ago after president Dave Washebek learned of its value at various peer group meetings. The company prefabs outlet boxes, conduit bends for both power and low-voltage applications, temporary power units, larger precut cables and wires, and precut Unistrut racks for conduit runs.
“Prefabbing improves productivity on the job site. There’s far less material handling on-site and the preassembled electrical components are shipped out in a complete fashion,” Washebek said.
Lemberg Electric cited faster project schedules, less trash and scrap at the job site (and less work to do to comply with green-building trash-separation requirements), and reduced labor needs and costs.
Sachs Electric Co., St. Louis, prefabricates industrial and commercial raceway assemblies, wire bundling, raceway support assemblies, panelboard/transformer assemblies, metal clad cable to box assembles, duct bank assemblies, and structural steel assemblies.
“Labor savings is certainly driving the use of prefabrication,” said Robert Moeller, vice president of Sachs Electric’s technology, health and entertainment group. “A prefab shop is better suited to employ a higher ratio of apprentices and commercial workers and the manufacturing nature of the shop’s environment promotes improved productivity.”
Don Stockton, executive vice president, Baker Electric Inc., Des Moines, Iowa, said prefabrication’s effect on scheduling is another benefit of its use.
“When used correctly, prefabbing allows contractors to perform installations more productively, speeding up the schedule,” he said.
A lack of qualified electricians in the area is one of the drivers of the company’s prefabrication activities, which include everything from branch-circuit wiring and switching and power devices to concrete generator pads.
“You can use less-expensive labor in the prefab shop because it is considered a manufacturing function and not an electrical construction function,” Washebek said.
“We believe there is a 15 percent or better labor savings on components preassembled in a prefab environment compared to components built in the field,” Moeller said.
“The repetitive nature of prefabbing cuts down on the amount of work needed to be performed in the field, and the controlled environment in which prefabbing takes place means greater productivity creating assemblies, less time spent on-site and a more cost-effective project,” he said.
Another benefit of prefabbing is that it makes the supply chain easier to manage. In theory, whether the electrical component assemblies are manufactured or put together in the electrical contractor’s shop, prefabbing consolidates components that would otherwise be delivered separately.
“Prefabrication reduces the number of shipments and deliveries to the job site, which reduces the amount of material that needs to be moved around or disposed of,” Stockton said.
Not having to move as much material also makes the job site safer.
“The less activity you can have on the job site and the more work you can perform in a clean, prefab shop, the safer the project will be,” Washebek said.
According to Kohl, the best prefab strategy starts with a thorough and honest skills assessment.
“The contractor must examine its current staffing, tools and facilities and then, if deciding to perform prefab work in house, must hire or train a person or staff to plan prefab activities, establish the appropriate prefab shop space, and ensure that the shop has the right tools and equipment,” he said.
If prefabbing activities are to be successful, the contractor needs to be heavily involved in the project’s preconstruction meetings. Foremen, project managers, purchasing personnel, estimators and the prefab shop director are critical in deciding what assemblies will need to be prefabbed to fit the project’s needs. Discussions include how long cable runs need to be, mounting methods, material acquisition needs and how assemblies should be packaged, shipped and identified.
“The biggest issue is getting field personnel to completely accept the prefab process,” Washebek said.
To help gain that acceptance, management needs to demonstrate that, although field fabrication work for the electricians may be reduced, prefabbing actually enables the company to improve overall productivity, win more contracts and widen the opportunities for work.
Since prefabbing takes additional coordination and design effort on the front end of a project, early preplanning is a necessity.
“Discussions, however, need to be held with the local workforce to determine if prefabbing is allowed in the jurisdiction,” Moeller said. “Some areas are very traditional and have not performed a lot of shop prefabrication, requiring that the contractor develop a plan that will enable it to effectively work well with the local workforce.”
However, since it doesn’t take highly skilled craftsmen for simpler, prefabbed installations, it can be demonstrated that prefabbing frees up the skilled labor pool to work on more sophisticated, complex projects.
Supply chain and pricing are other issues that can affect the contractor’s prefab strategies. Vendors can be helpful in offering suggestions that improve the flow of material within the prefab shop and the shipment of assemblies to the job site.
“One key item that must be reviewed prior to creating large assemblies is the logistics associated with shipping them on public roadways and how they will enter the job site and building interior,” Moeller said.
Contractors can examine integrating set pricing into their estimating process so that project manager have a standardized price to use for prefab assemblies.
“Because many assemblies are unique to each project, it can be difficult to offer accurate pricing early enough in the project- planning process without set prices,” Moeller said, adding that the best prefab strategy ends with tracking productivity along the way. “The contractor needs to quantify success to help it focus future efforts and identify places for improvement.”
In addition to personnel that are able to handle preplanning, scheduling and logistical requirements, the assets required for successful prefabbing center around fairly inexpensive project management software, transportation assets, tools and materials, and space. Depending on the number of jobs that require prefabrication, the contractor may need up to 20,000 square feet of space.
“Anyone can perform prefab work,” Stockton said. “It can be done on a large or small scale, and the size of the company is not essential to success.”
Other tangible requirements include production equipment such as metal-clad-cable cutters, big band saws, workbenches, material storage and stock, packaging materials and transportation bins.
“It is important to remember that you are building a miniature manufacturing facility that requires manufacturing, rather than field, equipment,” Washebek said.
Perhaps the most important asset is the BIM software.
“BIM can drastically improve a contractor’s prefab strategy. It enhances building layout capabilities and helps avoid job site conflicts that could significantly reduce productivity,” Kohl said.
BIM software is critical for enabling contractors to become best-of-class prefabricators because it enables companies to theoretically prefabricate a whole building’s electrical distribution system from its three-dimensional drawings.
“Not many contractors are using BIM yet,” Washebek said. “It is quite an investment and requires an additional person or persons to operate the software and integrate its capabilities with the company’s prefab activities.”
“The information offered by BIM not only enables the contractor to prefab all the necessary electrical components for the project, but to be assured that the delivery and installations are accurate,” Stockton said.
Moeller believes that, although 3-D modeling helps, it is not absolutely necessary.
“There does, however, need to be coordination between the designer and prefabrication supervisor to ensure that the prefab components are being designed to specification standards and that the prefabrication concepts are being incorporated into the design,” he said.
Prefabricated electrical components are newer, more progressive and efficient, and more often comply with green-building certification programs. The process enables contractors to creatively manage a project’s systems and discover new ways of creating, shipping and installing entire assemblies. It allows them to increase their reach, sustain a competitive advantage, answer the demand for higher productivity and faster project schedules, offer value, and improve profitability.
“Contractors that don’t embrace prefabrication will find it increasingly difficult to maintain profit margins and the ability to compete,” Stockton said.