5-Step Process to Checking Engineering Calculations

The secret to minimizing blunders is checking engineering calculations! Buckle up, as I show you how with my tried-and-true 5-step process.

Picture this: a tiny, seemingly harmless misplaced decimal throws an entire design into chaos, causing catastrophic consequences. But don’t worry – after years of design work under my belt, I’ve got your back.

First, though, let’s talk about an engineer’s most significant responsibility – keeping everyone safe.

An engineer’s duty: Keeping the public safe

Just like a surgeon’s mission to safeguard each patient’s well-being, the engineering code of ethics puts public safety front and center for every engineer.

Consider this eye-opening study from the Swiss Federal Institute of Technology in Zurich. Out of 800 cases of structural failure, a jaw-dropping 504 lives were lost, with millions of dollars in damages!

Cause of engineering structural failuresPercentage rate of occurrence
Insufficient knowledge36%
Underestimation of influence16%
Ignorance, carelessness, negligence14%
Forgetfulness, error13%
Relying upon others without sufficient control9%
Objectively unknown situation7%
No clear definition of responsibilities1%
Choice of bad quality1%

It’s a hard pill to swallow, but many of these disasters could’ve been dodged with meticulous calculation checks. That’s why a lot of engineers champion the idea of engineering licenses – it’d hold more engineers accountable and help reduce careless blunders.

STEP #1: Include all your math steps and add notes

Put yourself in the shoes of someone reviewing your work for the first time. How can you make their job a breeze?

Start by laying out all your math steps, even for the easy-peasy calculations. You want readers to have zero questions about your thought process. Plus, who knows, in a few years, you might need a refresher yourself!

Don’t forget to pepper in some notes alongside your calculations. Here are some examples of what I like to jot down:

  • References: Where did you get your info? A textbook, perhaps?
  • Codes and standards: Which code sections are you adhering to, like a section from the National Electrical Code?
  • Variables: Define each variable you’re using.
  • Processes: Explain your calculation decisions and assumptions.

As good practice, add your notes in a different color. This makes following your calculations easier.

STEP #2: Be your own toughest critic

After you’ve crunched the numbers, let them marinate for a day or two. Then, circle back with a fresh perspective, ready to sniff out any errors lurking around.

I make a point of scrutinizing my calculations several times. Each run-through, I toss in extra notes and fill in any missing steps. If I hit a snag and have to ponder something, it’s my cue to add more clarity.

Think of it like writing. Your first draft will always have a few hiccups, no matter how much of a wordsmith you are. But after you’ve combed through it time and again, it starts to shine.

Important Note: Carve out time for double-checking calculations in your design process. Nothing should ever hit the road without a solid once-over (or twice, or thrice!).

STEP #3: Pass your calculations to a qualified reviewer

Find a reviewer with equal or more experience than you, otherwise, it’s a bit like the blind leading the blind.

Here are some tips to help your reviewer:

  • Give ’em the lowdown on your calculations before they dive in. Explain what you’re calculating and anything unique about your approach.
  • Allow plenty of time for the review – nobody likes to be rushed.
  • Encourage your reviewer to add comments to your calculations. So print out your calculations with room for scribbling.

STEP #4: Double-check your reviewer’s feedback

Once your reviewer’s done their thing, take a quiet moment to go through their comments. This way, you’re not swayed by their opinions on the spot.

See if their remarks make sense to you, but remember, you don’t have to agree with everything. Jot down any points you want to challenge.

Next, sit down with your reviewer to hash out any disagreements. The aim is to reach a consensus on the accuracy of your calculations.

If you’re at a stalemate, call in a third party for a fresh perspective. Ultimately, everyone needs to be on the same page about your calculations.

Important Note: Document everything you learn during the review discussion. You’ll thank yourself later when you don’t have to relearn the same lessons for similar calculations.

Build a lasting bond with your reviewer

If your reviewer is more experienced than you, nurture a student-mentor relationship. It’s a fantastic way to turbocharge your learning.

Just don’t expect them to do the heavy lifting for you. They’re here to guide, not take over. And don’t be shy about asking stupid questions – that’s how we learn!

Important Note: Before seeking help, though, make sure you:

  • Do as much work as possible on your own.
  • Research any parts of the calculation you’re unsure about, so you can grasp their explanations better.

STEP #5: Submit your polished calculations and keep taking notes

Hand in your calculations to your client or boss, and brace yourself for more feedback. If it’s substantial, you might need to loop back to steps 1 through 4.

The endgame? Crafting top-notch calculations every single time, ensuring public safety, which is the heart and soul of the engineering code of ethics.

To drive the point home, check out this list of epic failures caused by simple mistakes. These easily avoidable fiascos could’ve been averted with proper review and attention to detail.

EventIncident YearWhat happenedCause
The Hyatt Regency walkway collapse1981Suspended walkways on the second and fourth floors collapsed killing 114 peopleDoubling the load on the upper walkway connections without adding additional structural support
Gulf War patriot missile failure1991U.S. missile failed to intercept an Iraqi missile, thus killing 28 soldiersArithmetic programming error in calculating and measuring time
Explosion of the Ariane 5 rocket1996Exploded 40 seconds after liftoff, costing $500 million dollarsSoftware error in the inertial reference system
Loss of Mars orbiter spacecraft1999Lost in space costing NASA $125 million dollarsDue to wrong units being used; English versus Metric units
Tokyo Disneyland’s Space Mountain derailment2004 Roller coaster car derailed because of broken axleAxle broke because of conversion error from English to Metric units
New Orleans’ levee system2005New Orleans was flooded killing 1,833 peopleStrength of soil not properly estimated, and flawed data used on land elevation

12 must-know tips on checking engineering calculations

checking engineering calculations

Use these 12 tips whether you’re doing or reviewing calculations.

#1 Master your engineering concepts

Dive deep into the science behind engineering concepts, so you don’t have to rely on arithmetic checks alone. This way, you can quickly spot calculation blunders even when the math checks out.

For instance, if a calculation says the top speed of a Ford Mustang is 10,000 mph, you’ll know right away that something’s fishy—no car can go that fast!

#2 Double-check your equations

Make sure you’re using the right equations. Sometimes your math is perfect, but you used the wrong equation. This happens a lot when engineers don’t fully grasp the science behind their work.

#3 Keep an eye on your inputs

Check your equation inputs. If you start with the wrong inputs, your output will be off even if you did everything else right.

Also, ensure your inputs are accurate and reasonable too. For example, if you’re doing a ground grid analysis for a new substation and someone gives you soil resistivity from a site 100 miles away, your results won’t be accurate.

#4 Create a master file for all calculations

Keep a master record of calculations in one place for all engineers to use. This becomes a fantastic resource for maintaining and transferring knowledge.

So, once your calculation is complete and approved, add it to a master folder for other engineers to access.

#5 Don’t forget your units of measurement

Include units with your values. This helps you know if you’re using the right equations and if your calculated values make sense in the real world.

Think about our Ford Mustang example. If your equation says the top speed of a regular Ford Mustang is 160 meters per second, you’ll know something’s off. But if the result was 160 mph, it’d be way more believable.

#6 Be mindful of significant figures

Stay consistent with the number of digits you use in your calculated values. This helps with the accuracy of your calculations.

Usually, in engineering, a lack of significant digits won’t lead to failures, thanks to safety factors in designs. But regardless, just be attentive to what you’re designing and the level of accuracy required.

#7 Embrace your mistakes

Even 10x engineers make mistakes. The more you rush your work, the more likely you’ll slip up. That’s why you shouldn’t rush your designs, even with a looming deadline. Your client won’t be happy if you hand in a shoddy design a week early.

When planning your work schedule, consider both design and review time. Sometimes, you’ll miss deadlines with cutting-edge engineering work. It’s normal and, frankly, expected.

#8 Format your design notes

Add neatly formatted notes to your calculations, and stick with that format for all your calculations.

This makes your calculations uniform and easy to follow. For example, with blue written notes, your eyes always know where to look for clarifications.

#9 Know your material

To do top-notch calculations, you need to know your material inside and out. Understand exactly what you’re designing and how it’ll fit into the real world.

This emphasizes the importance of hands-on engineering skills. It helps you perform better reality checks on your calculations: do your results seem practical?

#10 Never become lazy

In some companies, checking engineering calculations isn’t common. Experienced engineers might go by feel, thinking they know a given design can hold a certain load, so they don’t review their work.

No matter how much you think you know, don’t get complacent. Build good habits, and you’ll sleep better at night while avoiding engineering failures.

#11 Ask questions as a reviewer

As a reviewer, when you spot calculation errors, have a chat with the engineer on record. Then, ask them questions about other parts of their design too.

If any of their answers seem off, dig deeper into their design work. Chances are, you’ll find more issues lurking beneath the surface.

#12 Don’t blindly follow another engineer’s math and logic

As a reviewer, be careful not to blindly follow another engineer’s math. You could end up duplicating their mistakes.

I recommend starting your review with the assumption that the calculation might be wrong. Then, scour their work for errors. And remember, don’t rush through your review by just going through the motions.

“Checking Engineering Calculations” wrap up

Checking calculations is a critical part of engineering. It’s the reason we have so few failures in designs today, even with the massive volume of design work engineers churn out.

Keep in mind, the more calculations you do, the easier they become. However, this doesn’t make you immune to mistakes. If you do something wrong once and it works, you’ll likely make the same mistake again. Sooner or later, your luck will run out. That’s why you should never feel ashamed or rushed to double-check your calculations.

I bet engineers at NASA, Jet Propulsion Laboratory (JPL), and Lockheed Martin wish they’d done a proper review of the Mars orbiter. JPL used the metric system, while Lockheed Martin used the English system. This unit mix-up led to NASA losing its $125 million Mars orbiter!

What do you think is the best way to check engineering calculations? How often are you checking engineering calculations?


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