6 Horrible Mistakes in Prefabrication

23 April 2019All, Construction, Fabrication



The pre-construction phase of any project is critical: understanding the job flow, determining materials, bringing subs up to speed. So many things can go wrong on a project, sometimes it’s daunting. Avoid the following mistakes that burn up profit, and you’ll be more likely to have a profitable fabrication process.

Horrible Mistake #1: Not verifying specifications.
During a project’s pre-construction phase, your team(s) will hold coordination meetings to plan the installation of the job. By making sure your shop standards are adhered to and fittings manufacturers are approved, you eliminate one source of mistakes that can leave a project stalled mid-installation.

Horrible Mistake #2: Poor coordination.
The pre-construction phase is best supported by high detail fabrication models such as those produced by the Autodesk Fabrication products. Workflows are improved if the model is a Revit fabrication model using the Autodesk Fabrication database and products such as eVolve Mechanical. The larger the project, the more important coordination is. “Value engineering” the job according to your company’s established processes – for instance, maximizing duct lengths or pipe lengths and minimizing fittings or offsets that may not be figured during estimating – saves money. Also during this phase, pre-coordinate hanger locations with other trades to ensure they are clash free.

Horrible Mistake #3: Inadequate document annotation.
Once the BIM process has been completed or after the drawings are signed off, documentation is crucial for a successful production run. Labeling pipe or duct lengths, sizes and elevation of the installation will help prevent expensive mistakes on the job after your shop has fabricated the project. Tag placement on your shop drawings needs to be clean and clear to ensure the right piece gets installed at the right location. Dive deeper with this video blog post by Mark Siebert on the Renumbering Tool.

Horrible Mistake #4: Underestimating costs.
With the Fabrication workflow, once your detailing department is finished with coordination and signoff of the project, it can be sent back to the estimating department for a summary comparison to the original quote. This will determine if you are on track to complete the job on budget or if it appears you’ll exceed the original number. By having this information before fabrication and installation, the project team can try to find different setups or processes to help bring the job back into line with the budget. This can often lead to changes in your standards or installation practices. Autodesk Fabrication ESTmep is ideal for handling this process. If you’re using another estimating system, the estimator would need to do a hand takeoff of the job to accomplish the same thing. Not only is that too time-consuming, but it would utilize a different library, resulting in numbers that would not make sense.

Horrible Mistake #5: Short-shipping materials to the job site.
Once the job has been fabricated in the shop, it is time to ship the products to the job site. A useful but less common Fabrication product is Fabrication Tracker, which is part of the CAMduct package. (Visit this 2017 blog for more about using CAMduct to manage multiple sheet sizes.) CAMduct allows you to scan the item as it’s loaded on the truck to make sure all the pieces get delivered to the site. Nothing gets lost, and there aren’t wasted trips from the shop to the job site. When the truck arrives with the pre-fabricated pieces, and the hangers are already installed in the field, all the field crew needs to do is elevate the ductwork and pipe systems and connect them. Follow this link if you’d like some expert Revit piping tips.

Horrible Mistake #6: Slow change order process.
Once the material is on the field, the job site is teeming with the various trades trying to get their services installed cost-effectively. Even though project teams try to discover all the job issues during the BIM process, it may not always work out that way, and issues can pop up on the field that will require a change order. By using Fabrication Remote Entry for any fittings required from a change order, the installation process can proceed with minimum loss of productivity because of faster information exchange. In the past, if a sheet metal contractor needed a fitting on the job site, they would hand write it on paper and give that to the project foreman or the truck driver making deliveries to the job. Once the shop finally received the order, they would then have to key it into the system and begin the fabrication process through the shop, onto the truck and back out to the field. Alternately, with Remote Entry, the foreman can specify the fittings and dimensions required and transmit that by email to the shop within minutes. When the shop receives it, they simply need to verify the seams and joints are correct, process the order without any re-entry, and get it to the shop floor quicker for fabrication, saving downtime.

The goal of any MEP job is to be profitable after the installation is complete. The best way to track and ensure this profit is to leave nothing to chance. Control your fabrication process in the pre-construction phase once the job is awarded. Redraw the contract drawing entities to your shop standards using Revit. Add elevations to your duct systems with hangers that are pre-coordinated to be clash free long before the materials arrive on the job site. After coordination, verify drawing annotation to ensure sure all tags, labels, elevations, and dimensions are on the plans – the field installation team should have no questions on the installation of the project. Determine if there might be a surplus or deficit on the final budget. If you have that number in advance of fabrication, you can actively be looking for better processes or practices to recoup any shortfall in the coordinated project . . . or planning a party to celebrate coming in under budget!

Using Fabrication software, the job flows the way the coordination team envisioned it. If you use Fabrication software to better understand the job flow and materials required, you’ll avoid the horrible mistakes that burn up profit on a job. For a demo of Autodesk Fabrication products, Fabrication Value Pack, Revit or eVolve MEP, contact Applied Software today.



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