CAD Layout Tutorial: Structural Steel Bar Joists for Fire Sprinkler & MEP

Learn the crucial first step in any commercial fire sprinkler or MEP (Mechanical, Electrical, Plumbing) design: accurately laying out the building's structural steel in CAD! This tutorial covers the difference between an open web bar joist (K) and a solid I-Beam (W), and shows you the exact calculation and CAD commands (Offset & Copy) to space joists perfectly across a large building span.

In this video, we dive into reading roof framing plans and translating real-world steel specifications into a clean reflected ceiling plan (RCP). You'll learn essential structural terminology like K-Series Bar Joists, W-Beams (I-Beams), Girders, and Z Purlins, and understand how each affects pipe routing and sprinkler head layout.

We walk through the calculation to divide a 98' 11" span into 20 even spaces (4' 11" on center) and demonstrate the most efficient CAD workflow:

Setting up the Steel Two layer (dash-dot line type).

Using the MIB (Move) command to correctly set the initial 3-inch offset from the wall to clear the joist flange.

Speeding up the layout process using the Offset and Copy commands for rapid spacing.

Mastering this steel layout is vital for accurate BIM modeling and avoiding costly clashes during installation!

[Timestamps/Chapters
@0:00 - Introduction to the Steel Layout Task
@0:07 - Reading the Roof Framing Plan (K-Series Joists)
@0:46 - Steel Terminology: I-Beam (W) vs. Bar Joist (K)
@1:05 - Why Steel Type Matters for Sprinkler Pipe Routing
@2:02 - Understanding A's & V's in Open Web Joists
@2:40 - The Z Purlin (Pole Barn/Warehouse Steel)
@3:15 - The Calculation: Dividing 98' 11" by 20 Spaces
@4:20 - Setting up the CAD Steel Two Layer
@5:05 - Trimming the First Bar Joist to the Wall Line
@6:29 - The Critical 3-Inch Offset (Using the MIB Command)
@7:25 - Efficiently Spacing All Joists with Offset & Copy
@9:30 - Next Steps: Head Layout and Pipe Routing