McGraw Hill Construction, the Lean Construction Institute and Dassault Systèmes teamed up recently to produce an in-depth report on Lean Construction. Below is an excerpt we wanted to highlight.

Lean Strategies for Employing Prefabrication

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Lean design and construction focuses on improving total project performance, rather than reducing the cost or accelerating the delivery of single activities or phases.

While the use of prefabricated components and modular construction is not new to the industry, their application has increased dramatically in recent years.

Tangible Benefits to a Lean Prefab Approach

Greg Howell, co-founder of the Lean Construction Institute, points out that Lean prefabrication is particularly useful on complex, uncertain and quick projects, such as hospitals, data centers, semiconductor fabrication plants or other high-end manufacturing centers.

Here the advantage is much more than speed.

All trades (such as design architect, general contractor, mechanical, electrical, plumbing and fire protection) are involved from the beginning of the project, ensuring that well-coordinated design decisions are made at the “last responsible moment,” when uncertainty is lowest.

Victor Sanvido, senior vice president at Southland Industries, adds that a Lean prefabrication strategy delivers high performance on safety.

By building components offsite rather that at the jobsite, the project can avoid some of the dangerous challenges that characterize building projects.

For example, when prefabricated components are built offsite and purposely made too heavy to be picked up manually, each unit is lifted and moved mechanically into position.

Jobsite ladder and scaffolding accidents, as well as back injuries, are virtually eliminated.

Working With Prefabricators

Well-sequenced object-based design is central to high-performance fabrication.

Rebecca Bettler, national director of Lean construction and Mike Dennis, vice president, both for JE Dunn Construction, note that to maximize the benefits of prefabrication, you must identify the elements early in the design process.

This allows the design to conform to the requirements of these elements.

Without this focus, the design can sometimes preclude prefabrication.

In short, designers need to allow for dimensional and spatial requirements that prefabrication may require.

BLOX CEO Chris Giattina emphasizes that his firm’s approach is “all about reduction in waste.” BLOX prefabricates medical modules.

He explains that a typical hospital patient room bathroom contains 800 components field-installed by a dozen trades over a span of three months.

BLOX removes that complexity from the site by completing the work in an offsite, Lean production line and inserting completed modules back into the site construction in a day.

This works only if he is able to include all of the trades in design coordination discussions at the start of the project.

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Planning and Costing Logistics

Handling components as few times as possible reduces waste and minimizes safety hazards.

Thus the decision on where to locate prefabrication and how to manage the logistics of transporting components to the jobsite are increasingly important considerations.

How close to the jobsite is optimal?

Nick Loughrin, production manager for the Welty/Boldt Joint Venture’s Akron Children’s Hospital project, works with partners that have prefabricated components in warehouses just a few miles from the jobsite as well as those who ship the modules across hundreds of miles.

Using the decision-making process, Choosing by Advantages, the decision for Loughrin is always case by case.

JE Dunn’s Bettler and Dennis point out that ideally the prefabrication shop is set up onsite or very close by. This lowers the complexity of Just-In-Time delivery.

BLOX’s Giattina counters that the distance from his prefabrication site in Alabama and the jobsite is not a major cost issue.

Transportation accounts for less than 2% of his unit cost if shipping less than 1,000 miles. All waste counts, but transportation costs are modest and do not typically justify setting up offsite plants just to be closer to the project.

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ADDITIONAL RESOURCES:

Dassault Systèms’ Lean Construction 3DEXPERIENCE® Solution
Lean Construction Institute
McGraw Hill Construction