Shop drawings are a critical part of any project, but are often surrounded by confusion and misunderstanding that leads to disputes and unique legal challenges. In terms of risk management, it’s essential that these drawings provide a strict flow of information between the contractor’s means and methods, and the construction documents prepared by the engineer. In this Q&A session, ADF Engineering President Alex Fishman answers some of your top questions about shop drawings.
1. Your design team creates drawings as part of your contract for the project design. So, what is the difference between IFC (issue for construction) drawings and shop drawings?
At the end of a design phase, an engineer completes a set of plans and specifications for a project. This set of documents is called “IFC Documents” or “Construction Contract Documents.” This set of drawings and specifications is like a roadmap that gives the client and the contractor a full view of the project in its final assembled form. When construction starts, the contractor will need to fabricate parts, purchase materials, and procure equipment to build a structure, a project, a plant, etc. In order to fabricate or manufacture parts and pieces, the contractor (or a detailer) will interpret IFC documents and prepare detailed drawings for their fabrication shop. These are called Shop Drawings. Shop Drawings contain detailed instructions for the contractor’s shop for fabrication, assembly, bill of materials, welds, and all other information on miscellaneous “nuts and bolts.”
2. Why does a design engineer need to review shop drawings? And who will carry liability for mistakes on shop drawings?
Shop drawings are communication tools. They only exist to provide contractors’ instructions to a fabricator or manufacturer. It’s a standard industry practice that the design team reviews and approves shop drawings to ensure that the contractor strictly follows the design intent outlined in the IFC documents and specifications. This practice is also outlined in most building codes due to major structural failures in the past caused by misinterpretation of IFC drawings. Therefore, I would highly recommend retaining our design team during the construction phase. Since shop drawings are not part of the contract documents, the approval of the shop drawings by the design team does not relieve the contractor of liability for defective or nonconforming work.
3. Can ADF’s team prepare shop drawings or piping ISO’s?
Our team has all of the necessary design tools and experience to prepare shop drawings for structural steel, piping ISO’s, or sheet metal spouting. However, since the work must be based on contractors’ preferences and instructions, any such work could be done directly for the contractor.
What other questions do you have? Contact us to ask!