BCA’s Code Checking within Revit

Architects in Singapore are required by law to design in compliance with Code on Accessibility in the Built Environment 2007 (Barrier-Free Accessibility Code). By creating special Revit families, we can check some of these requirements that all architects are familiar with. In this example, we can modify a Revit door family to enable Minimum Doorway Manoeuvring Space checking between the door and other model elements such as walls. The evaluation can be determined by hovering over a door to see clearances or by using Revit’s Interference Check tool. This door type specifically tests minimum front approach clearances for a door as defined by Accessibility Code 2007 clause 3.8.4, as shown in Figure 1. These represent very common door clearance conditions.

Figure 1 – Minimum Doorway Manoeuvring Space (Accessibility Code 2007)

Our custom door will allow Minimum Doorway Manoeuvring Space checking to be used in two ways: 
(1) By hovering over a door, or (2) By using the Interference Check tool.

When we hover over the door type, outline linework displays to indicate the Minimum Door Manoeuvring Space clearance area. Similar display occurs when the door is selected.

Our custom door contains extrusions that represent the 3D volume of the Minimum Door Manoeuvring Space clearance. Type Parameters and Formulas are used to control the extrusion location between different door sizes and wall types. These extrusions are hidden in the project views but allowed the user to turn on or off in views via a visibility parameter. The families also have the 2D graphics as an object style to allow the user to turn on or off on floor plan views.

Figure 2 – Hovering over door displays Minimum Door Manoeuvring Space clearance boundaries

Figure 3 – Extrusions in door family

Even though the extrusions are hidden in the model, Interference Check detects collisions between them and other objects.

Figure 4 – Highlighted wall interferes with Minimum Door Manoeuvring Space clearance

Figure 5 – Visibility of 3D extrusion and 2D boundary lines can be control by Type parameter

Checking Minimum Door Manoeuvring Space clearance is an architectural task that happens on most building types other than single family residential. Using customized door families will make this process easier and ultimately reduces errors in our design.

(Reference: Autodesk WikiHelp. ADA Door Clearance Checking using Revit Interference Tool)