Learning how to check engineering drawings is an art. If you don’t know how to properly check your engineering drawings, you’ll be in a world of pain.
I’m going to go over 6 techniques I use to check my engineering drawings. Also, I’ll sprinkle in a lot of tips for you to follow.
Not only will this help you increase your design review efficiency, but it’ll help you sleep better at night.
What’s more, a copy of your engineering drawings will almost forever stay with your client. I see some engineering drawings with clients dated back to almost 100 years ago.
This should be reason enough to motivate you to properly review and check your drawings.
#1 Self-review drawings
After you complete your design drawings, set the drawings aside. Let several days pass before you review your drawings.
This allows you to review with a fresh mind without any lingering biased thoughts.
I always find I can catch mistakes better this way. My mind isn’t tainted with my recent design decisions. Plus, I’m over my design fatigue.
Here are several other tips to follow in your review:
- Check every drawing: don’t dismiss a drawing because it’s simple. Every drawing requires your attention.
- Print out your drawings: preferably on large-sized sheets. Surprisingly, once you print your drawings, the mistakes will pop out right at you. Somehow, mistakes go unnoticed on computer monitors.
- Review environment: find a quiet area where you can focus without distractions.
- Questions: write down any design elements you’re not 100% certain over.
Since your name is on the designs, you need to put the greatest effort into your review. Don’t expect a stranger to put more effort than you.
No different than if you assemble a baby crib for your newborn.
You want to make sure you follow the crib assembly instructions perfectly. Also, check if all the screws are properly tightened.
#2 Yellow line drawings
In engineering, many design elements are dependent on one another. Elements on drawing #2 may somehow relate to elements on drawing #8.
By yellow lining, you make sure your drawing elements all properly cross-check together.
As an example, in electrical drawings, you have a conduit schedule and site plan. These two drawings go hand in hand.
The site plan shows the routing of conduits from point A to point B. These conduits are then tagged with specific conduit numbers.
The conduit schedule then lists the ‘from’ and ‘to’ routing as well. But also, it lists the size and the fill for each conduit.
So with a highlighter, I highlight a conduit tag from the conduit schedule against the site plan.
I want to cross-check the accuracy of conduits from my conduit schedule against my site plan. This technique verifies the ‘from’ and ‘to’, and the conduit fill.
For example, the following is a site plan and conduit schedule I’ve started to yellow line:
You can see if I mistakenly label a conduit on the site plan, the contractor will use the wrong size conduit and fill.
For example, the use of a conduit with 4160-volt power conductors instead of 24-Volt DC control wires.
Important Note: place yourself in the shoes of the contractor or fabricator. Do your drawings include everything someone would need to make heads or tails of what you want?
This requires a strong understanding of all aspects of your engineering design. This way, you can properly check your drawings for what’s wrong and not clear.
#3 Global drawing checklist
Every type of engineering will have certain review checks in common. The common drawing review checklist includes:
- Codes & standards
- Format check
- Real-world check
So always be sure to check these elements in your drawings. Let’s go through them one by one.
Codes & standards
Find all codes and standards that apply to your drawings. Then look for any violations.
Be sure you use the latest codes and standards in your review. With each latest code edition, you can find big changes.
You don’t want to review your drawings using a 1990s edition codebook.
Also, only experience allows you to quickly tell if something doesn’t appear correct. Because honestly, it’s not easy to check design compliance against a 500 plus page codebook.
Double-check your calculations. Even the simple calculations.
I can’t tell you how many times I’ve seen basic arithmetic mistakes.
Even more, check your units. A simple unit mistake can propagate through an entire design process.
Once a mistake is deep enough into a design, it’ll become very difficult to spot. It’ll perfectly blend in with all your other calculated values.
This is why it’s important you properly review a design from the start.
Check all your specified products against the latest vendor cut-sheets for compliance. You want to be 100% sure you’re properly using a product.
For example, a cut-sheet reads a product connects at 240-volts. You then show the product connected at 480-volts in your design.
This is not only a code violation, but it’s a huge safety concern.
Equally important, you may have used the same product for several years. So you think you know the product’s specs like the back of your hand.
But, the vendor updated the product a month ago and you weren’t aware. If you forgot to verify the cut-sheet, you’ll have a mistake on your hands.
Check the format of your drawings. No different than when you edit the format of a Microsoft Word document.
The format check includes such things as:
- Line types: consistency with lines used in CAD
- View orientation: are section views properly shown
- Symbology: are you following the industry standard
- Appropriate border: is the correct drawing title block used
- Text size: is the font size consistent and not too small or large
Do your designs cross over from paper to the real-world?
Many times something looks great on paper, but it’s not buildable.
So put on your construction or manufacturing hat to do this part of your review. The more experience you have in the real world, the better.
Here are some things to consider in your review:
- Geometric accuracy
- Laws of physics
#4 Coordination with other engineering trades
With engineering projects, almost always several trades will work together.
So you need to ensure your design conforms with the other trades involved in your project. This requires close coordination.
If you’re the prime engineer, you need to cross-check your design work with all your subs.
I’ve seen one too many times, where one trade makes a change but doesn’t tell others about it. This then can disrupt the entire design.
Important Note: for every project, request all the latest design information in an email. Then use this information for your design work.
This way you have a record of the latest information you are to use.
#5 Review by another qualified engineer
Have another qualified engineer in your team thoroughly review your drawings.
I never recommend pushing out drawings without a second set of eyes reviewing them.
It doesn’t matter how long you’ve been an engineer, or how great you think you are.
All humans make mistakes. This includes all engineers. No exceptions!
Just be sure, the other engineer is as qualified as you. Otherwise, it defeats the purpose of a peer review.
Helpful Tip: use colored pencils to mark up drawings in a review. Use yellow for items that are correct, blue for comments, and red for errors. Find a model that works for you and your team and follow it.
#6 Create a global review process
Create an in-house process for reviewing drawings. Include a list of review checks every drawing set must go through before going out the door.
Find what works for your team and what doesn’t.
This way, you create a standard review structure to always follow. No matter if a project is small or large.
This will greatly reduce design mistakes.
Management’s involvement in the review process
Make sure management is on board with the review process. This will ensure everyone follows the established review protocol for every project.
This helps eliminate laziness with people skipping over review process steps.
Also, you need to set ground rules in the review process. Otherwise, reviews can become chaotic with endless back and forth discussions.
Further, review processes should only include qualified people. Because if everyone can make comments, then it’ll become a bloody mess.
A design can be torn apart in countless ways from too many or unqualified commenters. This could force a design to start from scratch.
Important Note: if any design element remains in doubt, the designer must get the benefit of the doubt. Because in the end, the designer signs off on the drawings.
#7 Learn what good drawings look like
I learned so much about what good drawings look like by reviewing older designs.
I’m talking about hand-drawn designs before CAD came into the picture. I find these older drawings are much more detailed than many drawings of today.
Not to say these older engineers didn’t make mistakes. And of course, design standards have changed since 40 plus years ago.
But, the level of detail was greater compared to modern drawings.
Also, you learn how easy to follow these drawings are. The simpler your drawings are to follow, the better.
What do I consider simple? If an average non-electrical engineer can pick up my drawings and understand them.
This simplicity begins with great labels and notes. I don’t want someone to look at my drawings and curse me out because of their confusion.
#8 General tips on how to check engineering drawings
Here’s a list of tips I’ve picked up over the years, that I find helpful:
- Be consistent with the units you use – Metric versus English
- Before you review someone else’s design, form a preliminary design concept yourself. This way you’re not influenced by someone else’s design.
- Check for number discrepancies in all your documents. For example, you list the same beam as 10′ in one drawing and 20′ in another.
- Fill out your title block completely, and ensure it’s accurate.
- If your company uses an error checking system, check what the most common errors are. Then learn from these errors.
- Show all necessary equipment and product clearances.
- List all important equipment and product dimensions.
- Check ALL dimensions.
- Specify other drawings sheets on drawings when necessary. Make it easy for someone to find related design elements between drawings.
- For schematics, check for proper symbols, reference designators, and polarity markings.
- Check spelling and grammar.
- Review all drawing notes for accuracy. Many times, notes get incorrectly copied over from one project to the next.
Learning how to check engineering drawings is a critical part of engineering. It’s definitely a skill.
I would go as far as saying it’s something every engineer needs to learn how to do great.
Great drawing review practices, allows us to enjoy the many luxuries of today.
What are your thoughts on how to check engineering drawings? What’s your favorite technique on how to best review drawings?
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Koosha started Engineer Calcs in 2019 to help people better understand the engineering and construction industry, and to discuss various science and engineering-related topics to make people think. He has been working in the engineering and tech industry in California for over 15 years now and is a licensed professional electrical engineer, and also has various entrepreneurial pursuits.
Koosha has an extensive background in the design and specification of electrical systems with areas of expertise including power generation, transmission, distribution, instrumentation and controls, and water distribution and pumping as well as alternative energy (wind, solar, geothermal, and storage).
Koosha is most interested in engineering innovations, the cosmos, our history and future, sports, and fitness.