Ultimate Guide to Structural Steel Shop Drawings: CSA S16.1 & OBC Requirements (2025)
Are you struggling to ensure your structural steel shop drawings meet all Canadian code requirements? Whether you're a steel detailer, structural engineer, or project manager, understanding the exact requirements specified in CSA S16.1 and the Ontario Building Code (OBC) is essential for project success and regulatory compliance.
What Are Structural Steel Shop Drawings?
Structural steel shop drawings are detailed fabrication and erection drawings that translate structural engineering designs into precise instructions for manufacturing and assembly. These critical documents serve as the communication bridge between engineers, fabricators, and erectors.
Why Proper Shop Drawings Matter:
Prevent costly fabrication errors and field modifications
Ensure compliance with Canadian standards and building codes
Streamline construction by providing clear assembly instructions
Maintain project schedule by reducing RFIs and clarifications
Document quality control measures for inspection and verification
CSA S16.1 Requirements for Steel Shop Drawings
The Canadian Standards Association's S16.1 "Design of Steel Structures" establishes comprehensive requirements that all structural steel shop drawings must meet. Here are the key specifications:
Essential Information Required on All Shop Drawings:
Material specifications - Grades of structural steel (350W, 300W, etc.), bolts (A325, A490), and welding electrodes (E70XX)
Connection details - Complete information on all connections including bolt sizes, quantities, edge distances, and weld specifications
Dimensional data - Precise dimensions of all members, holes, cuts, and assemblies
Surface preparation - Requirements for cleaning, preparation, and shop painting/coating
Fabrication procedures - Special fabrication instructions including heat treatment or cold-forming requirements
Erection sequence - Order of assembly and temporary bracing requirements
Identification marks - Piece marks consistent with erection plans
CSA S16.1 Welding Requirements:
The standard specifies that shop drawings must include:
Weld types (fillet, groove, plug)
Weld sizes and lengths
Welding process to be used (SMAW, FCAW, etc.)
Complete joint penetration (CJP) details
Special inspection requirements
Compliance with CSA W59 "Welded Steel Construction"
Ontario Building Code (OBC) Structural Steel Requirements
The Ontario Building Code provides additional requirements specific to provincial construction projects. Understanding these regulations is crucial for project approval and occupancy permits.
Key OBC Requirements for Shop Drawings:
Professional engineer's review stamp - Shop drawings must be reviewed and stamped by a Professional Engineer licensed in Ontario
Compliance with Division B, Part 4 - Structural design must conform to OBC's structural requirements
Fire resistance ratings - Documentation of fire protection measures for structural steel
Load path integrity - Clear demonstration of load transfer mechanisms
Seismic design provisions - Specific details for structures in designated seismic zones
Common Shop Drawing Errors to Avoid
Even experienced detailers can make mistakes. Here are the most frequent issues identified during shop drawing reviews:
Incorrect steel grades or material specifications
Missing or incomplete connection details
Inconsistent dimensioning or coordinate systems
Failure to account for thermal movement
Inadequate edge distances for bolted connections
Conflict between architectural and structural elements
Weld symbols that don't conform to AWS A2.4/CSA W59 standards
Best Practices for Steel Shop Drawing Preparation
To ensure your shop drawings meet all requirements and sail through approval processes:
Before Starting:
Review contract documents thoroughly - Understand all special provisions and project-specific requirements
Conduct coordination meetings - Engage with engineers and architects to clarify expectations
Establish clear QC procedures - Define internal review processes before submission
During Production:
Use standardized templates - Maintain consistency across drawing sets
Implement clash detection - Utilize 3D modeling to identify interferences
Document assumptions - Clearly note any interpretations of design intent
Follow layering standards - Organize CAD files logically for efficient review
Steel Shop Drawing Submission and Approval Process
The typical workflow for structural steel shop drawings in Ontario includes:
Initial preparation by steel detailer or fabricator
Internal review for quality control
Submission to structural engineer of record (typically 3-4 sets)
Review and markup by engineer (allow 10-15 business days)
Revision and resubmission if required
Final approval with professional engineer's stamp
Distribution to fabrication shop and construction site
Advanced BIM Integration for Steel Detailing
Modern steel detailing increasingly leverages Building Information Modeling (BIM) to enhance accuracy and coordination:
Tekla Structures for comprehensive steel detailing
Revit Structure for integration with architectural and MEP models
SDS/2 for connection-focused detailing
Navisworks for clash detection and coordination
Cost Implications of Quality Shop Drawings
Investing in thorough, accurate shop drawings pays dividends throughout the project lifecycle:
Reduces RFIs by up to 70%
Minimizes field modifications that can cost 3-5 times more than shop corrections
Prevents schedule delays that typically cost $10,000+ per day on large projects
Improves material optimization, reducing waste by 5-8%
Conclusion: Ensuring Compliance and Project Success
Meeting CSA S16.1 and OBC requirements for structural steel shop drawings is not just about regulatory compliance—it's about ensuring project success through clear communication and precise documentation. By following the guidelines outlined in this article, you'll streamline approvals, reduce errors, and deliver higher quality results.
For professional steel detailing services that meet all Canadian standards and building code requirements, contact our expert team for a consultation on your next project