Jeff Hanson
When working on a building design, many factors must be balanced. One factor that must always be considered is that of life safety, where distances to the exits are essential calculations for compliance with fire codes. Revit 2020 introduced the path of travel tool to assist in measuring travel distance requirements to make fire life safety simple and fast to calculate. Both Revit 2020.1 and 2020.2 added functionality to the path of travel tool to make it even more flexible, helping you analyze exiting distances in your design in a number of ways.
The path of travel tool in Revit lets you select 2 points in a floorplan and calculate the shortest route between those 2 points, avoiding elements you have defined as obstacles. The calculated path uses a 300mm clearance allowance to keep the center of the path from passing too close to an obstacle. The path of travel tool is not able to calculate vertical distances, i.e. it does not work on stairs.
There are 3 primary calculations Revit makes, let’s review:
- Travel Distance Limit: the distance to the nearest exit
- Dead-End Limit: the distance of a corridor with no end exit
- Common Path Limit: the portion of exit access that must be traversed before two separate and distinct paths are available)
The examples shown in the videos below refer to terms in the NFPA 101 Life Safety Code, but the principles apply to other fire codes.
You can use Path of Travel tools to help you analyze plans for travel distances related to life safety in your designs, but this is only scratching the surface of what you might be able to do. Analyze traffic patterns through a space, organize spaces to facilitate access, find optimal routes for people or other elements, etc — we’d love to hear what you do. Share with us in the comments below if you’ve found a helpful way to use Path of Travel.
Without further ado, here’s a short tutorial on the path of travel tool, starting with how to make life safety calculations.
Maximum travel distance to the nearest exit
Typically, you will be able to narrow down which room(s) are going to have the maximum travel distance in your design. Use the path of travel tool to verify your assumptions and quantify the actual travel distance. In the video below 2 path of travel lines are added to the most distant corners of the room farthest from the exits. By looking at the schedule view of the path of travel lines, Path ‘A’ ends up being just slightly longer than path ‘B’.
Path ‘A’ goes diagonally through the middle of the room, this may not be realistic when possible furniture placement needs to be considered. In the video below a waypoint (a Revit 2020.2 enhancement) is added to the path of travel line and the path altered so it goes around the edge of the room avoiding possible furniture placement in the room. Once this is considered, Path ‘B’ ends up being a shorter path to an exit.
Dead-End Limit
You can also check for dead-end corridor length. Looking at the same plan from before, a design change has created a dead-end corridor condition. In the video the length is checked by placing a path of travel line from the exit position to the end of the corridor without an exit. In this video you will see a view filter added to the view to change the color of the path of travel line as it exceeds the allowed length of a dead-end corridor.
Common Path Limit
When multiple rooms or spaces share a portion of the exit path it is known as a “common path”. The common path limit is how much of the overall exit path can be part of a common path. Use the path of travel tool to reveal common path conditions in your designs. In the video you see exits from 2 rooms that have a common path before they reach a point where 2 distinct paths to exits are available.