What is LOD?
Level of Development (LOD) enables practitioners in the AEC Industry to specify and articulate with a high level of clarity the content and reliability of model elements at various stages in the design and construction process. The BIMForum has provided an updated 2016 LOD Specification, available here. This defines and illustrates characteristics of model elements of different building systems at different LODs. This allows model authors define what their models can be relied on for and allows downstream users to clearly understand the usability and the limitations of models they are receiving. The different levels are as follows:
- LOD 100 – General concept of where physical elements will be within a structure
- LOD 200 – Design development; refined geometry that starts to replace generic blocks with more detailed components
- LOD 300 – Documentation; Property specifications, such as measurements, are suitable for design intent like cost and bidding
- LOD 350 – Proper cross-trade coordination definitions, including connections and interfaces between disciplines
- LOD 400 – Construction; supports detailing, fabrication and installation/ assembly
- LOD 500 – Facilities Management – suitable geometry and information to support operations and maintenance that should be as-built, and field verified
What does the owner need to know?
Owners should focus their sights on the information provided by LOD 400-500. Keep in mind, that LODs represent the progressive maturity of an element included in a facility. For instance, let’s focus on an AC unit within a building. An LOD 100 would only specify the general placement of an AC unit in the building. As an owner, you will benefit from having detailed specifications of the AC unit as it comes in – manufacturer information, size specifications, warranty details, to best service the element down the road.
From an owner’s perspective, it’s valuable to identify two types of elements to specify in their LOD request – high-touch service devices and big-ticket items. High-touch service devices are not necessarily expensive, but represent a volume of elements in a system, like VAV boxes, florescent ceiling lights, and sinks, things that are typically in a near-constant run status. Having an LOD 400 in place for these items, that will require regular updates and maintenance, gives an owner information on how to install and update their functional elements.
Big-ticket items include elements that are costly upfront, like elevators and water chillers. LOD 500 will provide you with all the information you need to know to service these elements down the road, like the maintenance requirements, when the item was first turned on, and the length of the warranty.