Though some time-tested ideas may fall out of favor, they often reappear, particularly if they offer new solutions for current business realities or market conditions. Such is the case with prefabrication and preassembly of components and materials needed in construction of power generation plants, refineries, manufacturing facilities and alternative energy storage buildings.
Prefabrication has historically been a method in which contractors handed off production and assembly of certain components or materials to subcontractors or original equipment manufacturers. This work would involve prefabrication of a broad range of components by multiple trades in controlled shop environments. The final modules or skids would be safely stored at off-site locations until shipped just-in-time to the job site.
For a variety of reasons, however, the construction industry moved away from prefabrication and toward installation of individual components fabricated by highly skilled trades on the job site.
Now, the industry is moving back toward the prefabrication model, with more components being prefabricated and oftentimes preassembled in controlled off-site environments. Among the key factors driving this trend is a chronic shortage of skilled trades and crafts available in the numbers needed on large construction projects.
Today’s version of “prefab” is effectively redefining how construction gets done. The industry is coming full circle, with design for manufacturing assembly (DFMA) concepts taking hold. The cost, precision, quality and safety of prefabrication and preassembly make this decision an easy one for owners and general contractors.
With more than 83,000 square feet of prefabrication space and highly skilled teams of pipefitters, welders, electricians and others working together on complex assemblies, AZCO can provide this solution to our clients. Here are four primary reasons why prefabrication is returning to relevance.
Fabricating and producing components in a controlled shop environment greatly reduces hazards both in the shop and on the job site. Large construction sites often can become congested with hundreds of trades, each jockeying for workspace, often at high elevations or other hazardous locations. With better visibility into when components will arrive, congestion can be greatly reduced, with the right trades scheduled to work only when needed at the project site. Controlled shop environments also improve safety among trades needed for off-site fabrication and assembly.
A critical enabling factor for prefab work, including at AZCO, is moving to digital 3D models that are used for precise specifications of components. With closer collaboration between engineering and fabrication centers, the interface between conceptual design and various stages of production — and then to a bill of materials — is streamlined. With that knowledge packaged and integrated, fewer errors and less rework will result.
With greater control over production schedules for materials produced in shops or controlled assembly environments, modules and skids can be precisely scheduled for delivery to the project site, just when they are needed. With specialty trades such as boilermakers, ironworkers, pipefitters, millwrights, sheet metal and electrical workers providing the know-how, components like steel, piping, equipment and control panels are now being produced for just-in-time shipment and installation upon arrival at the project site. With the construction superintendent knowing in real time the status of component assembly and delivery, crews can be kept busy, with no slippage in the ultimate completion deadlines.
Improved Cost Control
By transferring resources and labor away from costly field installation of components toward the front end, where these project elements are designed and built in more controlled environments, many cost benefits can be quantified.
For example, AZCO has introduced new technology such as advanced robotic plasma steel cutting machines into previously labor-intensive fabrication processes, reducing production times by a factor of 10 or more. With prep work now done in a few minutes, versus a full day, trades now spend their time on specialized tasks like welding and assembly. This reduction of labor has a direct benefit in cost savings.
Prefabrication is another one of those time-tested ideas that is being rediscovered — proving its worth all over again.
See how metal prefabrication helped meet schedule and budget for a Midwest EPC project.