Shop drawings might be prepared by contractors, subcontractors, suppliers, manufacturers, or fabricators. They generally relate to pre-fabricated components, showing how they should be manufactured or installed. They take design intent drawings and specifications prepared by the project design team and develop them to show in detail how the component will actually be manufactured, fabricated, assembled, or installed.
Shop drawings might be prepared for components such as structural steelwork, reinforcement, lifts, building services equipment, appliances, ductwork, piping, plumbing, windows, cabinets, electrical and data layouts, fire protection, and so on.
They may be reviewed by the project design team prior to fabrication to verify that they comply with design drawings and specifications and to ensure that different packages of work and components are properly coordinated. This means that they need to contain relevant information to enable this to be done, which might include the provision of samples for approval. However, this does not relieve the originator of the drawings from responsibility for their correct preparation.
Shop drawings may also be used to check installation on site. Suppliers may wish to visit the site before, or during the preparation of shop drawings to verify key dimensions are accurate, particularly on refurbishment or renovation projects.
Where shop drawings vary from design drawings, these variations should be highlighted on the shop drawings and brought to the attention of the design team. This is particularly important to ensure proper coordination on site, as fabricators are likely only to refer to the shop drawings and not the design drawings.
Procedures may be in place for the electronic handling of drawings for comment, review, and coordination. Where digital drawings are required, file formats, naming and layering conventions may have to be adhered to. Increasingly, building information modeling is used as a means of managing project information, coordinating the design, and detecting clashes. This can be useful to suppliers in providing clear information upon which shop drawings can be based, and allowing the shop drawings themselves to be re-incorporated back into the building information model, eliminating time-consuming manual practices and minimizing errors.
PAS 1192-2:2013 Specification for information management for the capital/delivery phase of construction projects using building information modeling (now replaced by BS EN ISO 19650) states that, ‘There shall be a 'change of ownership' procedure for the information and objects that specialist sub-contractors introduce to replace the original designers’ intent such that the resulting graphical models can be used for fabrication, manufacture and installation… This change of ownership should be fully understood, specialist teams do not alter the models produced by the professional designers: they build new models defining the virtual construction model (VCM).'
Some suppliers may not yet have the capability of producing BIM information, and this may prove a barrier to winning work.
Increasingly, the preparation of shop drawings is outsourced where the supplier does not have the appropriate skills, software, hardware or resources necessary, or where they may be able to obtain lower rates or faster turnaround. However, this may not properly exploit the expertise of the supplier and places responsibility for preparing important design information with an organisation that is not contractually responsible for it and may not have the detailed knowledge necessary. The supplier should carefully check any shop drawings that are outsourced in this way.
Mechanical Shop Drawings
MEPF contractors need the capability to analyze intricate building systems and to manage construction workflows cost-effectively so they can deliver quality customer service. They want to minimize construction costs, complete tasks faster, meet construction standards and local building codes, and optimize all construction materials and resources. Today, contractors can barely achieve their BIM objectives without accurate onsite and offsite prefabrication information. This is why MEPF shop drawings are a top priority for architects, engineers, and fabricators involved in building construction. Layout drawings give multi-dimensional views based on predefined user rules, and they include annotations, schedules, and other details needed to construct, analyses, lift, move, and put up a range of mechanical elements.
A design coordination workflow actively supports either 2D design layouts or 3D and BIM models for clash avoidance during the construction phase that have traditionally been detected only in the field. In a 2D layout, shop drawing coordination may reveal a large number of system clashes and point to areas that need to be modeled in 3D. Projects that are based on a 3D model will translate the design-level concepts into fabrication-level documentation. Three-dimensional models streamline the entire coordination process by resolving connection issues and allowing details to be based on a comprehensive structural view. Streamlined shop drawing submittal process which can include a vast amount of information from many vendors and fabricators, such as, assemblies, mock-ups, schedules, diagrams, technical specifications and product data information.
Fire Safety Shop Drawings
A contractor responsible for the design and installation of a fire detection and notification system needs to use shop drawings to get their project right each time. Typical fire alarm blueprints must meet requirements of the state, including being drawn to a specified scale. The models should show details such as the type and make of all equipment, number and type of circuits, zoning information, and wire types and sizes for every circuit.
Electrical Shop Drawings
Electrical drawings are essential to the accurate fabrication of electric components and systems within a building. These drawings include details such as network loops, user-defined dimensions and ratings, component location relative to adjacent grid lines, and material schedules. Intelligent electrical shop drawings can be produced for control systems that automate the task of generating wiring lists for control panel builder and the creation of wire number labels, component tagging, and electrical load analysis. We can supply electrical schematics with wiring and component information which can be downloaded into spreadsheets for further use.
Electrical Outlines : Electrical outlines can detail all of the electrical components of a building. This will allow contractors to know where everything is going. It will also help all of the electricians to know what they need to install and where so that there are no issues with maintaining code guidelines
Plumbing Shop Drawings
Plumbing drawings serve as a guide for the development of plumbing lines, from concept to the ultimate piping system setup. These technical diagrams meet prefabrication standards and the contractor’s specifications. For instance, detailed and accurate plumbing drawings help on site personnel, such as plumbers and pipefitters, to understand all pipework and its interactions with other building systems and components. A technical drawing also depict the physical assemblage of equipment and the spatial relationships between systems.
Consider outsourcing the drafting of your prefabricated pipe assemblies to document all pipe sections along with their connected flanges and fittings. You will benefit from decreased labor costs and save critical time spent in the field connecting and welding or bolting pipes and fittings.
Prepared by M.AjmalKhan.
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