BIM forum and AIA jointly advocated and proposed LOD 350, which describes ‘assemblies for coordination’. The level of development 350 is defined as “the model element graphically represented to enable necessary cross trade coordination and construction layout”. Construction firms rely upon LOD models of BIM to collaborate with architectural, structural and MEP disciplines across the building construction project.
Amongst all, MEP teams are the most complex one having very crucial element across the building systems as their elements are spread across the buildings. Additionally, MEP teams also require 2D installation drawings, fabrication drawings and MEP shop drawings for accurately using spatial arrangement at the construction site, which are a bit more as compared to other disciplines. They also have a complicated hierarchy and are included at later stages of building design development. MEP contractors and consultants have a very sharp inclination on having LOD 350 models for their very specific reasons.
LOD 350 adds a new level of clarity for MEP, structure, exterior skin, construction, etc., increasing the reliability of models, ultimately increasing the popularity and demand of BIM deliverables.
LOD 350 for preconstruction MEP coordination
Earlier general contractors had to recreate models from scratch to suit their requirements, however with LOD 350 the certainty of models has increased, and general contractors can use MEP models with level of development 350 for preconstruction coordination. Also, developing structural and MEP BIM to LOD specifications, allows easy model based construction layout for contractors.
Specifically for MEP systems, an apt level of development model includes accurately placed hangers with layout points, allowing points to be added to Revit families quickly. For building structures, elements such as concrete slabs and footing, sleeve and anchor bolt locations are accurately modeled, which save time and efforts of creating additional models and drawings for field layouts.
LOD 350 models to improve BIM delivery
For permit MEP drawings, elements are typically modeled to LOD 300, however for full trade coordination higher LOD is required. If you go higher and seek an LOD 400 model, it requires information that may not yet be available. Hence, Level of development 350 was proposed and the requirement for apt information was quelled.
BIM implementation across large scale construction projects with multiple complexities has reached a high point, increasing the need for detailed 3D coordination. LOD 350 resolves a lot of rework and redundant modeling and finds opportunities in clearly defined BIM scopes.
LOD 350 models for cross trade coordination
Let us cite an example to understand why you need LOD 350 model in a better manner. Now consider this situation. A model is developed for a structural engineer, this model does not include all connection details like miscellaneous steel, gussets, and connection material and it is still good enough for structural engineer.
What about cross coordination with MEP trades?
Having a model developed so that it allows such cross trade coordination is important and this is where LOD 350 steps in and clears the clutter. Our extensive experience in delivery of LOD (200, 300, 350, 400, 500) for more than a decade, has taught us that the most appropriate LOD for a BIM deliverable, proposes tremendous opportunity to the clients in terms of lower risks, increased coordination and hence better ROI.