Levels of Development for Fire Protection Models: What LOD 100 to 500 Means for Sprinkler, Alarm, and VESDA
Meta Description: What LOD 100, 200, 300, 350, 400, and 500 mean for fire protection BIM: what gets modeled at each level for sprinklers, fire alarm, and VESDA, and how to specify it in a BIM Execution Plan.
A project specification that says "model fire protection to LOD 300" tells a fire protection designer very little. Three contractors can read it three ways, and the model that comes back may be too rough to coordinate or far more detailed than anyone needed. Level of development (LOD) is a simple idea that gets misapplied constantly. This post explains what each level means for sprinkler, fire alarm, and aspirating smoke detection work, and how to ask for the right one.
Where LOD comes from
The levels come from the AIA's level of development framework, which the BIMForum's Level of Development Specification turned into an element-by-element reference. The key point is that LOD is set per element, not per model: a sprinkler main and a fire alarm device can sit at different levels in the same file. It describes how far the author will stand behind an element's size, shape, location, and detail, so that other trades can rely on it.
What each level means for fire protection
| LOD | What the element is reliable for | Fire protection example |
| 100 | Concept only; a symbol or a zone, not real geometry | System areas and riser locations indicated; ASD coverage areas outlined |
| 200 | Approximate size, shape, and location | Mains and risers roughly sized, with space allowances above ceilings; device counts by area |
| 300 | Specific size, shape, location, and orientation | Mains and branch lines sized and located from the hydraulic calculation; heads and alarm devices positioned; ASD pipe network with sampling holes positioned from the ASPIRE model |
| 350 | LOD 300 plus the interfaces with other trades | Pipe coordinated against ductwork and structure; hangers, bracing, and clearance zones shown where they affect other systems |
| 400 | Fabrication and installation detail | Pipe spools with fittings, couplings, hangers, and sway bracing; ASD pipe with cut lengths and fittings; conduit and supports |
| 500 | Field-verified as-built | Model updated to match what was actually installed, confirmed in the field |
LOD 500 is different in kind from the others. The lower levels describe how much design has been done. LOD 500 describes verification: the model matches the built condition because someone checked it in the field. That means it depends on survey or field information that the modeler does not have until construction is underway.
What fire protection actually needs, and when
Most fire protection coordination happens at LOD 300 to 350. That is the level where a head position, a branch line, or an ASD pipe run has a real location that can be tested against ductwork, structure, and light fixtures. Stopping at LOD 200 leaves the coordination questions open, and going to LOD 400 before the design is stable is how teams end up remodeling.
LOD 400 belongs at fabrication. Sprinkler contractors prefabricate, and ASD installers cut pipe to length, so both need spool-level detail. It should be requested after the hydraulic calculations and the ASPIRE report are final, because every later change to head count, pipe size, or hole position ripples into a fabrication-level model.
The model is also not the document of record. As we covered in NFPA 13's working drawing requirements on BIM-coordinated projects, the stamped drawings and calculations are what get permitted, so a model at any LOD has to be kept aligned with them.
Four mistakes that cause rework
One LOD for the whole model. A single number across every element either under-specifies the critical ones or over-specifies the rest. Specify by system and by milestone.
Confusing LOD with information. LOD covers geometry. It says nothing about what data rides on the element, such as manufacturer, model, hydraulic node, circuit, or zone. Specify the level of information separately in the BIM Execution Plan.
Asking for LOD 400 before the design is final. Fabrication detail on an unsettled design means remodeling every time the engineer makes a change.
Expecting LOD 500 without field data. An as-built model needs survey data, field markups, or installer records. Say in the BIM Execution Plan who provides them and when.
Specifying LOD in the BIM Execution Plan
The BIM Execution Plan is the right place to settle this. For each system, name the LOD required at each milestone, who authors each element, and how often models are exchanged. A typical fire protection setup runs LOD 100 to 200 in schematic design, LOD 300 through design development and into coordination, LOD 350 for final coordination, LOD 400 for shop drawings and prefabrication, and LOD 500 at closeout. Writing it down removes the ambiguity that otherwise gets resolved in the field.
How ProTech CDS approaches projects like this
We model fire alarm, sprinkler, and VESDA systems in Revit at any level of development from LOD 100 through LOD 500, and we coordinate them with architecture, structure, and MEP so conflicts involving our systems are resolved, and the ones that need other trades to move are documented, before they become RFIs. For LOD 500 work, we build the as-built model from the field-verified information you provide. We deliver on a white-label basis, so the package reaches the AHJ under your firm's title block. Project files and submittal status are managed at lockin.protechcds.com. The full scope of our BIM modeling and coordination service (LOD 100 to 500) is on the services page.
Need fire protection modeled to a specific LOD, or help writing it into your BIM Execution Plan? Contact ProTech CDS to discuss your project, read about the BIM modeling and coordination service, or start a submittal at lockin.protechcds.com.