Bring older buildings up to code without interrupting ongoing work

Repairing plants in real time without disrupting production.

By Joel Kramer, PE, SSOE Group

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Many owners of manufacturing facilities are faced with the twin challenges of outdated, even perhaps substandard, physical plants and aging infrastructures. When building a new facility is financially prohibitive and moving operations during renovations is impractical, the building must be repaired in real time. The design and engineering challenge is to upgrade the structure with minimal disruption of production.

Many lessons learned apply across the industry, but for the particular project that generated most of the examples in this study, architects and engineers were tasked with remediating the wood truss roof of a 1940s-era industrial plant. The roof had been rendered obsolete by new structural design standards. Each step in the solution required creative application of professional insights in both planning and technical solutions, strong relationships with good listening and communication, and abiding by the owner’s commitment to maintain production throughout the construction process.

Casing the client structure

Looking before you leap is as true in remediation design as it is in mountain climbing. Make sure the issues you include in the design scope are really there and not just in the documentation.

The designers in this case started the upgrade process by scoping the project. They first looked at the legacy drawings and blueprints of the facility. The plans had been accurate when the plant was built, but there had since been more than 70 years of renovations and changes in use of the building. Because recordkeeping had been a low priority over the decades, the old plans, though useful as a starting point, were now incomplete and inaccurate. Thus, the designers had to verify which parts of the plan were still valid. This exercise is almost always the first step toward remediation.

These circumstances can crop up in all kinds of plants. In a completely different project for another client — a renovation of and an addition to a large chemical plant — designers had to plan their work around the overhead pipelines that were shown in the original drawings. However, when they tried to corroborate this initial condition, the designers discovered that the lines had been abandoned at a time before any of the current employees could remember. No longer constrained to design around the lines, they were freed to plan much more efficiently.

Another tool gaining popularity is 3D laser scanning. This tool can scan an existing facility with accuracy as close as 1/8 in. and provide a point cloud that can either be modeled to provide an accurate 3D model of the facility or simply used to design existing elements around. It can be more expensive — although on complex projects or projects with a lot of overhead elements it may actually be less expensive — but its speed and accuracy are often worth the tradeoff.

An example project for Honda included an expansion of its assembly test plant, as well as an expansion and retrofit of an existing weld zone. Included in the scope was field verification of existing conditions and the requirement that the measurement process not interfere with ongoing production. By employing the use of laser scanning on the existing areas of the facility, the team was able to capture more detail in one day than would have been possible with an entire month of field work and measurements. When working within an existing space, a zero-errors-and-omissions policy makes it critical that the documentation of existing conditions be extremely accurate to avoid conflicts with new construction.

The cost of the project was $2,500 per day of laser scanning, which saved them from months of less-accurate manual field measurements. In addition, the lower cost of field measurements, to date zero errors have been recorded and therefore no financial impact has affected the project.

Multiple site inspections

“Many hands make light work” can, in the design world, be transformed into “many experiential backgrounds add to a project’s real-world feasibility.”

Back at the truss roof project, after the designers evaluated the surviving plans, they performed multiple site inspections, starting with a vision trip with the owner for a general site inventory. They asked the owner for three lists for the upgrade: the “have to” list, the “should do” list, and the “want to” list. The team included representatives from various departments, including facility maintenance.

The designers periodically toured the site with a contractor selected by the client that frequently performed work throughout the plant. The team’s combined backgrounds in hundreds of industrial structures enabled the team to provide accurate estimates on costs, scheduling sequences, material availability, and general project feasibility after a brief walkthrough. Diverse expertise plays a key role in both formal encounters, such as site inspections, and informal encounters, such as brainstorming and consultations in the designers’ offices. In the truss roof project, the team consisted of designers and architects, as well as structural, mechanical, and electrical engineers. All of these stated their professional opinions of what could and could not be accomplished.

At this early point in the process, designers normally compile a schedule and logistics for a remediation project, but in this case they were unable to build what the owner wanted for the budget. Throughout the preliminary stages, the project architects and engineers steered the owner toward a project vision that would match constructability. Leaders knew what they wanted for the end product but were not aware of schedule and cost implications. They put the project team in the driver’s seat and took a hands-off approach as long as the end product met expectations. They wanted a new roof. Initially, they thought the only way to do this was replace the entire roof. However, it was more cost-effective to provide an “umbrella” over the existing roof.

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