At a recent TPI 3rd Party Audit, the In-Plant Inspector (IPI) and I were inspecting trusses coming off the line as is normal in an audit. A stacked truss caught my eye, mainly because the top plate did not line up with the plate on the opposite side of the truss. Upon careful examination, indeed the truss plate was misplaced and required further investigation. Because the truss was under a stack of trusses, we decided that we should run the Plate Placement Method (PPM) template for this specific plate to determine if it would meet the design requirements before we started dragging the truss out for repair.
This is where this story begins.
Without any real discussion, the IPI and I headed back to the office to run the inspection paperwork. Watching the IPI step by step, I noted his action. On the computer, he found the job folder, located the truss tag, then loaded the truss design into the connector plate software. The next step would have been to print the inspection paperwork using the Approved truss (blue in diagram—View in Full Issue or see PDF), which is the actual design that was sent to the shop. To my astonishment, the IPI proceeded to run engineering on the truss creating a new design using a concept (pink in diagram—View in Full Issue or see PDF) and then printed the paperwork. Fortunately, in this particular case, the plate in question (joint 3) did not produce a PPM critical output—not because it was under the 80 percent threshold, but because the joint would not plate. The truss did not design completely. It had several plates that would not plate. To make matters worse, the IPI had no idea that they were creating another design that may or may not have reflected the shop drawings used to build the truss. Herein lies the problem. The IPI must use the design that has been approved for the shop. It’s the design approved by the designer. It’s the design that the checker approved and it’s the design that uses the proper inventory, plates, and follows the correct design criterion. It is essential that it is followed. A vigorous discussion ensued. Apparently, this redesign method (shown as dashed red line—View in Full Issue or see PDF) has been happening for years.
The IPI prior to the current IPI apparently had also used the same technique. It’s amazing more trusses weren’t found to be “in error” considering the variations that must have occurred over the years. The irony is we may not have realized that dichotomy had that truss not plated when we re-ran the truss.
Is this happening at your plant? This plant is almost certainly not the only plant committing this breach.
Take a good look at your system and network.
Glenn Traylor is an independent consultant with almost four decades of experience in the structural building components industry. While he is a TPI 3rd Party In-Plant Quality Assurance Authorized Agent covering the Southeastern United States and performs 3rd party safety auditor services, these articles represent his personal views, knowledge, and experience. Glenn serves as a trainer-evaluator-auditor covering sales, design, PM, QA, customer service, and production elements of the truss industry. He also provides project management specifically pertaining to structural building components, including on-site inspections and ANSI/TPI 1 compliance assessments. Glenn provides new plant and retrofit designs, equipment evaluations, ROI, capacity analysis, and CPM analysis