How LOD 350 Benefits BIM for Building Construction

BimForum 2013 LOD Spec

The BIMForum recently released the 2013 Level of Development (LOD) Specification, which includes a new LOD level – LOD 350. Prior to this development, the AIA G202 LOD definitions left a lot of room for interpretation by designers and engineers, thus creating uncertainty about model integrity by downstream users. General contractors often recreate models from scratch because they can’t rely on the quality of models coming from other project team members. The new 2013 Level of Development Specification changes all this.

Today, it is common to see LOD 300 models used to create construction documents for the building permit process. General contractors rely on these permit drawings for full trade coordination. LOD 300 specifies that building elements are located correctly with accurate slopes (such as sloped structural beams and gravity plumbing lines); however it does not include the level of model detail needed for full coordination. Information required for LOD 400 may not exist until later in the shop drawing phase, thus creating a gap in information for general contractors to perform pre-construction coordination.

LOD 350 closes this gap by requiring more model detail and model elements showing how building elements interface with other building elements or systems, with written definitions and graphics. The image below tells the story well – LOD 350 adds a base plate and anchor bolts to a steel column to show how it connects with the concrete footing.

Model based construction layout gets much easier for contractors when the building structure and systems such as MEP are developed to the LOD 350 specification. For MEP layout, this means that the model will include accurately placed hangers that contain layout points or allow these points to be added to Revit families very quickly. The layout points can then be replicated onsite using total stations or multistations for fast and accurate field execution. For building structures such as concrete slabs and footings, sleeve and anchor bolt locations are accurately modeled and ready for field layout without additional drawing or modeling.

BIMForum’s new LOD specification adds a new level of clarity for each LOD per discipline (structures, exterior skin, interior construction and building services). This is an important BIM development that provides a vehicle for clarifying BIM scopes, increasing the reliability of models and laying the groundwork for BIM permitting deliverables.

What do you think? How will LOD 350 affect your business? Share your thoughts below.

Cathi Hayes is an architect, building information modeling (BIM) pioneer and strategy leader. Today she drives BIM adoption throughout the North American construction industry with Leica Geosystems hardware and software solutions. Her duties include the development and implementation of short- and long-term BIM marketing strategies. She also serves as the voice of Leica Geosystems in the construction industry’s growing BIM conversation. Cathi holds degrees from North Carolina State (BEDA Architecture) and the University of Kansas (PBA).

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

Current month ye@r day *