Shop drawing

A shop drawing is a drawing or set of drawings produced by the contractor, supplier, manufacturer, subcontractor, or fabricator. Shop drawings are typically required for prefabricated components. Examples of these include: elevators, structural steel, trusses, pre-cast concrete, windows, appliances, cabinets, air handling units, and millwork. Also critical are the installation and coordination shop drawings of the MEP trades such as sheet metal ductwork, piping, plumbing, fire protection, and electrical. Shop drawings are produced by contractors and suppliers under their contract with the owner. The shop drawing is the manufacturer’s or the contractor’s drawn version of information shown in the construction documents. The shop drawing normally shows more detail than the construction documents. It is drawn to explain the fabrication and/or installation of the items to the manufacturer’s production crew or contractor's installation crews. The style of the shop drawing is usually very different from that of the architect’s drawing. The shop drawing’s primary emphasis is on the particular product or installation and excludes notation concerning other products and installations, unless integration with the subject product is necessary. A shop drawing is a drawing or set of drawings produced by the contractor, supplier, manufacturer, subcontractor, or fabricator. Shop drawings are typically required for prefabricated components. Examples of these include: elevators, structural steel, trusses, pre-cast concrete, windows, appliances, cabinets, air handling units, and millwork. Also critical are the installation and coordination shop drawings of the MEP trades such as sheet metal ductwork, piping, plumbing, fire protection, and electrical. Shop drawings are produced by contractors and suppliers under their contract with the owner. The shop drawing is the manufacturer’s or the contractor’s drawn version of information shown in the construction documents. The shop drawing normally shows more detail than the construction documents. It is drawn to explain the fabrication and/or installation of the items to the manufacturer’s production crew or contractor's installation crews. The style of the shop drawing is usually very different from that of the architect’s drawing. The shop drawing’s primary emphasis is on the particular product or installation and excludes notation concerning other products and installations, unless integration with the subject product is necessary. The shop drawings should include information for the architect and engineer to compare to the specifications and drawings. The shop drawing should address the appearance, performance, and prescriptive descriptions in the specifications and construction drawings.The shop drawing often is more detailed than the information shown in the construction documents to give the architect and engineer the opportunity to review the fabricator’s version of the product, prior to fabrication. References to the construction documents, drawings, and specifications assist the architect and engineer in their review of the shop drawings. Attachment of manufacturer’s material specifications, “catalog cut sheets,” and other manufacturer’s information may be helpful to accompany these drawings. Because shop drawings facilitate the architect’s and engineer’s approval of the product, they should be as clear and complete as possible. Notes concerning changes or differences from the original documents should be made on the shop drawing for the architect’s and engineer’s approval. Ultimately, they are responsible for changes in these drawings and should have the opportunity to analyze any modifications. A dialogue should occur between the fabricator and the architect and engineer about any areas needing clarification. Successful installations are the result of collaboration between the designer, fabricator, and contractor. Dimensions, manufacturing conventions, and special fabrication instructions should be included on the shop drawing. It should be clear to fabrication personnel what will be manufactured from the shop drawings alone. The construction documents are rarely used as a reference in fabrication, with the fabricators relying on the shop drawing for all information. Most jobsite dimensions, such as the dimensions between two surfaces on the jobsite, need to be verified. A dimension may be shown on the construction drawings, but the actual dimension may vary, from very small to large increments, depending on jobsite conditions. It is extremely important that the fabricated item arrive on the jobsite ready to be installed without field modification. Special care must be taken by the contractor to measure and verify dimensions. In new construction, plan dimensions usually are sufficient for ordering many fabricated items such as structural steel or precast concrete. In remodeling and renovation work, it is essential that field dimensions be verified prior to fabrication. Some fabricators, such as cabinet and casework suppliers, prefer not to rely on the contractor’s verification and will verify the dimensions with their own personnel. Some fabricators and manufacturers will provide symbols, data, or instructions concerning installation. This can include a list of other materials, such as fasteners or adhesives, appropriate but not included for the product. Third party review may be required for major building systems. An example of this would be a commercial chiller which would be furnished by the mechanical contractor, but would require electrical connections, plumbing, rigging, insulation and commissioning. Various third parties will need to review the installation information and confirm they are furnishing compatible equipment and proper layout of services. Review of installation information for major equipment should be reviewed with field supervisors including the project superintendent, trade foremen and field engineer. Installation of major equipment will dictate structural clearances and temporary openings. Some fabrications will require a sample submittal with the shop drawing, primarily for color and texture selection of finishes.