FAQ: 5 Questions Contractors Ask When a Project Requires BIM
What is BIM?
BIM, or Building Information Modeling, is a process that gives architecture, engineering, and construction (AEC) professionals greater insight to more efficiently plan, design, construct, and manage buildings. BIM often involves tools including project management software and 3D modeling, but it’s important to remember that BIM is a process, not a type of software.
The inspiration for BIM came from scientists, whose informational models were derived from tests, data and research collected over time that further helped them understand their subject. The goal was to apply these concepts to building and construction, and collect the information and data in one place.
The definition of BIM can vary based on the needs and goals of a specific project. BIM could mean a more collaborative way of working together, or it could mean putting together a data-rich, 3D digital model. It’s important for the team to determine what BIM means for each stakeholder on each project.
One of the goals of BIM is to have the right information available when you need it so you can make an informed decision at the ideal time — not too early, not too late. The goal is to improve communication between all key project stakeholders. This results in greater insight and better decision making, minimizing errors, improving efficiency, and providing a successful project outcome.
What are the different Levels of Development (LOD) for BIM, and how do contractors determine which level they need?
The Level of Development (LOD) concepts were originally developed by the American Institute of Architects (AIA) as a tool to help clarify the content and reliability of BIM models at various stages in the design and construction process. The definitions are organized by CSI UniFormat and detailed in the Level of Development (LOD) Specification compiled by BIMForum.org. The standards are designed to help participants understand the reliability and the limitations of models they are receiving at each stage of the construction process.
The levels range from 100-500. LOD 100 is the most rudimentary level — a sort of napkin sketch conveying basic intent and listing components but without details such as shape, size, scale, or precise locations. LOD 200 includes more general information, basic masses, and approximate locations, and dimensions. In LOD 300, users start to define specific assemblies, including the quantity, size, shape, location, and orientation of elements. LOD 350 details specific assemblies, products, and manufacturers. At LOD 400, trades produce shop drawings used to build the actual systems. LOD 500 is the as-built level, which includes a detailed, field-verified record of the completed project and other information, including warranties, training videos, and maintenance schedules, which can be continuously updated over the building’s life cycle.
The LOD for each project can vary depending on the goals of the project and the end use of the model. If a detailed analysis of how the building is going to perform is needed, LOD 500 might be the best route. If the model is used to make sure the systems are compatible and provide layout drawings, LOD 350 or 400 might be optimal. A consultant can help contractors strategically determine which systems need to be designed at which level. In a re-roofing project, for example, the roof system might be designed to LOD 500, but that might not make sense for the rest of the building.
The first step on a project should include a BIM execution planning meeting that defines the objectives on the project and who is going to be responsible for each aspect. Through that process, the team can develop a project-specific definition for BIM.