How to Read a General Arrangement (GA) Drawing – Part 2
Welcome back to our GA Drawing Masterclass! In Part 1, we laid a solid foundation by exploring the fundamentals of General Assembly (GA) drawings — from reading the title block and identifying key piping systems to tracing routes using elevation markers and gridlines. If you haven’t read Part 1 yet, we highly recommend starting there.
In Part 2, we’re taking things a step further. This guide is tailored for QA and QC inspectors, field engineers, and anyone involved in piping inspections, construction quality, or mechanical verification. Let’s dive in.
Step 6: Recognize Supports, Hangers, and Structures
One of the most overlooked elements in GA drawings is the piping support system. These supports are crucial for maintaining mechanical integrity and operational safety.
🔍 What to look for:
-
S01 – Standard Support
-
SPR – Spring Support
-
HGR – Hangers
These notations often tie back to support detail sheets or structural drawings. Always verify if special supports like spring cans or guides are needed — especially under extreme service conditions (e.g., high temp, vibration).
📌 Pro Tip: Document missing or misaligned supports early — they can impact hydrotesting, stress analysis, and long-term performance.
Step 7: Pay Attention to Notes, Legends, and Special Instructions
The notes and legend section is your key to decoding the GA drawing. Don’t skip this — it’s often packed with abbreviations, symbols, and project-specific instructions.
Common notations include:
-
ABV – Above Ground
-
UG – Underground
-
Insul Required – Insulation is needed for that line
Reading this section carefully can prevent costly misinterpretations in the field.
📌 Pro Tip: If your legend is unclear or missing details, don’t guess. Reach out to your supervisor or engineering lead for clarification.
Step 8: Cross-Reference with Isometric Drawings
While GA drawings give you the overall layout, isometric drawings provide the detailed information you need for inspections.
Why it matters:
-
Identify weld joints, field welds, and dimensions
-
Verify the material specs
-
Confirm elevation differences that may not be obvious on the GA
Always keep the corresponding iso drawing handy when reviewing GA data — they complement each other.
📌 Pro Tip: Mark up your GA drawing with isometric reference numbers to speed up field inspections.
Step 9: Use the GA Drawing for Field Inspections
Once you’re on-site, the GA drawing becomes a critical tool for verification and compliance checks.
Use your GA drawing to:
✅ Verify piping routes
✅ Check elevation levels
✅ Confirm that supports match the design
✅ Ensure pipe clearance from structural elements
This step is essential before mechanical completion or hydrotesting, where accuracy matters most.
📌 Pro Tip: Highlight critical lines and known problem areas in your printout or tablet app before heading into the field.
Step 10: Pro Tips for QA and QC Inspectors
Here’s a collection of field-tested tips from seasoned inspectors:
🛠️ Always use the latest drawing revision – Outdated drawings lead to wrong installations.
🛠️ Highlight critical systems – Color-code or underline important lines before inspection.
🛠️ Never assume — ask – Unclear? Confirm with your supervisor or engineering team.
🛠️ Log changes – Any site modifications must be captured in As-Built markups and forwarded for formal updates.
Bonus: Are You Using AI Tools for QA/QC?
We’re seeing a rise in AI tools helping inspectors automate checks, digitize markups, and even flag potential discrepancies between GA and iso drawings. If you’ve tried any of these tools, share your experience in the comments. Your insights could help fellow professionals improve their workflow.
Final Thoughts
Understanding GA drawings is a skill — and like all skills, it improves with training and real-world practice. This series aims to bridge the gap between theory and fieldwork for QA and QC professionals.
📺 Want More?
Subscribe to our YouTube channel for in-depth video training on piping inspections, construction drawings, and QA/QC tips.
Follow us for more QA/QC training content, inspection tips, and technical walkthroughs.
Experience the Difference
Contact
Phone
+1 (780) 800-6297
info@engrity.com
Address:
201-9403 63 Ave NW, Edmonton, AB T6E 0G2