Friday 31 December 2021

5 Top Tips and Tricks to Pass the PE Environmental Exam

It's no secret that the PE Environmental exam is difficult. If you are curious about taking this exam or haven't passed it after multiple attempts, you're not alone-in fact, the exam took me three tries to pass! In this blog, I will share why I believe I didn't pass my first two times as well as the tips that aided in my eventual success.

Even though I was getting ready to take the last pencil-and-paper PE Environmental exam before it transitioned, these tips will also apply when preparing for the computer-based testing (CBT) exam or even a completely different discipline altogether.

The First Two Tries

When I took the PE Environmental exam for the first time in April 2017, I had been out of school for nearly ten years and had to refresh my skills on many topics. I decided to start studying five weeks before the exam, spending my evenings preparing on the couch while my fiance watched TV. I didn't work through many problems-I thought having a good grasp of engineering theory was all I needed.

When results came out the next month, I saw the dreaded red box on the NCEES website: I had failed. Undeterred, I signed up for the next exam. Since I'd been close with my first attempt, I thought I should be able to pass with no problems! I continued studying and reading my engineering books to get a conceptual understanding of the material.

I was devastated when I learned I had failed a second time - and with an even lower score.

How was this possible?

The Third (Successful) Try

When I walked out of my testing site the third time, I felt confident but also concerned that somehow, I could have failed this exam again. As soon as I heard results had been released, I sat on the couch and made my husband sit next to me for emotional support as I logged into the NCEES website. Words cannot describe the feelings of pride and elation I experienced when I saw that green box indicating I had passed. My journey to becoming a PE was finally over! Celebrating this milestone is one of my happiest memories.

Now, you may be wondering, how did she do it?

After spending time not only processing but also grieving my two failures (which involved a lot of retail therapy and sweets), I ended up completely overhauling my study technique and preparing to start a new journey to success. I have summarized this plan into the following five steps:


5 Top Tips and Tricks to Pass the PE Environmental Exam

Tips for Success

1. Prepare your exam battle plan.

If you're going to conquer this exam, you need a solid battle plan-and the first component of any successful plan is a schedule. Plan a realistic study schedule that you will feel comfortable achieving by the test date. I knew that for my third try, I wanted to study for six months and/or for 200 hours (note: this number will be different for everyone). I started studying slowly and ramped up the intensity with each passing month. By the last month, I was studying both before and after work.

Everyone is different (see Tip #4) so just because someone else studied X hours, it doesn't mean that you need to study that same amount to pass the exam. You know your study habits and motivators, so focus and rely on what you know will work best for you. I knew that I would feel anxious about my chances of passing the exam unless I met my study goals, so I kept a spreadsheet of my study hours to hold myself accountable and give myself the additional peace of mind that I was meeting my targets.

An important component of a study schedule is rest. If you're keeping track of your study hours, increasing the duration of your study sessions can be tempting, especially as you get closer to the exam date. Be mindful of taking breaks and resting-sitting in a chair for three hours when you're unfocused and exhausted is not productive. Take breaks, grab a bite to eat, or try moving around until you feel more energized. Be sure to build rest days into your plan.

The next component of your battle plan is study location. Unless you live by yourself, you're likely sharing your home with other people like your spouse, roommates, children, and/or parents, etc. Now, finding alone time to study may be challenging. During my third attempt to pass this exam, I knew I could not study in front of the TV anymore. Although the empty spot on my couch taunted me every night, I lugged all my books to our kitchen table, opened Spotify's "Perfect Concentration" playlist, and studied there. Minimizing my distractions helped me focus on the material and I had much higher quality study sessions.

Maybe studying in your home is too distracting for you. Can you pick a quiet conference room at work to study during lunchtime? Or maybe you need background noise to study, like in a coffee shop. Again, you know yourself the best. Consider your study habits and needs and ensure you are studying in an environment that is optimal for your learning.

The last component of your plan is making sure you are ready for exam day! Choose a date that you will stop studying and stick to it to give yourself a mental break. Just like you wouldn't want to run a 10-miler the day before a marathon, you want to make sure you're mentally refreshed before taking this exam. For my last attempt, I stopped studying early in the week and even took the day off before the exam to sleep in, work on a craft project, and relax.

For the day of the exam, do you know where the testing site is? Where parking is? Whether you are able to bring lunch on-site? What time you need to report to the exam site? These are all details that you should figure out well in advance of the test date to avoid any unnecessary surprises. Read the NCEES Examinee Guide carefully to ensure you're not bringing anything inside that may break the rules.

For my last attempt, I had my husband drop me off at the exam site. We had a hard time finding the parking lot since the gates all appeared to be closed, and based on how many cars we saw circling the site, we weren't the only ones. Finally, he dropped me near a group of confused examinees standing next to a fenced area. We may or may not have had to physically roll our suitcases and ourselves under a gap in the fence to get inside the testing center. You want to avoid these fun surprises on the day of the exam.

2. Don't take the exam during major life events (if you can help it).

While preparing for my second attempt in October 2017, I was six months away from my wedding and was busy with planning. We took our engagement photos three days before my exam. As you can expect, it was hard to focus on exam preparation while planning a wedding at the same time.

After I failed twice, I considered when to retake the exam. The next available exam date would be just a week after my wedding. I couldn't imagine juggling the final months of wedding planning and studying for the exam at the same time or sitting for the exam before I could even go on my honeymoon. Instead, I decided to put off my next attempt so I wouldn't even have to think about the exam until after I returned from my honeymoon.

I have no regrets with this decision-it allowed me to enjoy the final, frenetic stages of wedding planning with my husband and focus my efforts on decisions that really needed my undivided attention (Kelly or Moss Green napkins?) Once I returned from my honeymoon, I felt refreshed and ready to tackle the exam again.

I know life can throw us curveballs (pandemic, anyone?) and that you can't plan for everything. But if you already know that you have a big life event planned for a certain date (wedding, moving, etc.), really consider the timing of your exam.

3. Work problems, problems, and more problems.

I didn't work on many problems while preparing the first and second time. For my passing attempt, I scrapped what I had done before (reading engineering theory) and instead focused on practicing as many problems as I could-problems from textbooks, problems from the internet, I did them all. If a problem confused me, I'd consult my textbook to gain a better understanding of the material.

As my exam date crept closer, I started practicing my test-taking strategies while solving each problem and reworking problems until I could solve them easily. For example, I'd work through each problem as if I were taking the test using the resources available to me, instead of stopping to look up the answer. I practiced problems with my binder material. Now, though, since many of the exams are CBT, it will mean solving problems using solely the Reference Handbook. Make sure you have a good understanding of what formulas are included in this handbook and practice using it electronically while working through problems. You do not want to wait until exam day to review the Reference Handbook for the first time.

The more problems you do, the more you broaden your understanding of the topics. In fact, working through problems will increase your chances of passing. While taking my third exam, I encountered plenty of problems that I initially found confusing, but eventually felt comfortable answering due to the variety of problems I had prepared with.

If you've previously failed the exam, study your diagnostic report to determine your weaknesses. My personal career is in remediation, so I felt confident with that topic. But air and water? Not so much. I decided to focus my study on those two topics where I had been struggling.

4. Don't compare yourself to other people.

You surely have heard stories of examinees waiting until a week before the exam to study, skimming through their materials, and passing the first time. These people do exist and are infuriating, especially if you studied longer and still failed. I remember the smile I faked when one of my coworkers expressed how he had passed despite putting forth exceptionally little effort.

Remind yourself that everyone is different. Like I mentioned in Tip #1, craft a battle plan that is right for YOU. And if you're retaking the exam, don't be hard on yourself-many of us have had to retake this exam multiple times. Focus on strengthening your weaknesses and continue working actively towards your goal.

5. Use all available resources.

Take practice exams! Borrow prep materials from coworkers! Sign up for an exam prep course (and see whether your company will reimburse you for the expense)! Try studying with colleagues or friends!

During the preparation for my third attempt, I worked through practice exams and used old practice problems that colleagues had given me. I also frequented a forum called Engineer Boards when I needed help with questions that stumped me, test-taking advice, and/or general camaraderie. Knowing that I wasn't alone was a confidence booster!

With a strong battle plan and focused study, you too will see the green box that indicates your success in achieving this milestone. Good luck on your journey to becoming an Environmental PE!
About the Author: Jennifer Stark

Jennifer Stark is an environmental engineer and is licensed in the state of Texas. She works from home in Indiana, where she lives with her husband and feisty dachshund/canine coworker. In her free time, she enjoys craft projects, playing music, and complaining about the cold weather.


Friday 24 December 2021

What Is the Best Strategy to Pass the PE Civil Exam?

There's never been a better time to become a professional engineer (PE). The amount of information and resources for engineers available today are virtually endless, creating countless ways you can leverage an engineering license. The PE is a great tool to position yourself across many lines of business that require engineering services certified by a professional engineer.

What Is the Best Strategy to Pass the PE Civil Exam?

1. How hard is the PE exam?

After chatting with dozens of engineers and colleagues, this question is the one I hear most. I think that people ask this particular question because they're still not convinced about becoming a professional engineer. What people should be asking instead, in my opinion, is why should I become a PE? Many engineers are proficient and successful in their fields and no part of their job duties and/or expectations involve the use of a PE seal, so why even bother?

A PE career consists of more than certifying plans and specifications. I think that becoming a PE is a statement of experience and commitment to the engineering profession. It carries a degree of responsibility that motivates you to become a lifelong learner and acquire specialized knowledge to help others design critical engineering products. There are many applications of licensed engineering beyond the design of plans and specifications, like consulting, expert witness consultations, investigations, and reports that all play an important role in the contracts that secure our infrastructure.

The first step towards becoming a PE is to make a change in your mindset. Before starting any PE exam preparation, you want to start making engineering decisions within your work duties that can be documented to show relevant experience (this will be necessary when you go to apply for your exam). At the same time, you will want to apply your skills with a high level of competency. Taking on a leadership role might make you anxious at times, but people tend to turn to PEs when it comes to decision-making. The good news is that with most problems, you will typically have time to do enough research and calculation to find the answers you need. Remember, it's all about knowing where to find the appropriate references and data needed to solve engineering problems, and then just using that information to calculate and solve them.

2. How did I study for the exam?

When I began my exam prep, I asked myself, if I can't solve one question with enough time, the internet, and the Civil Engineering Reference Manual (CERM), then how am I going to solve 80 of them back-to-back on test day? The exam is even more centralized now that the NCEES transitioned to a computer-based testing (CBT) format with one single common reference manual. That means that you just need to know your way around one manual and how to utilize the equations and graphics in it. I decided that what I really needed was good, concentrated, and focused study time to get ready for the test, so leading into the exam, I requested two weeks of "vacation" from work and just focused on studying all day, every day. I minimized outside distractions and made my entire day about studying and being in a learning mindset. I purchased a bunch of exam practice problems and worked on them on a full-time basis to simulate the 8-hour testing environment, all while using the CERM as my main exam reference.

Since engineers like to have equations for everything, I created my own PE Study Time Equation to estimate the hours needed to study for the exam:


This equation includes time for efficiency losses and breaks. I figured that having an equation to follow would help me focus my concentration while preparing for the PE exam. After you calculate your estimated number of hours, you can spread those hours out to match your learning style. If you do better studying in smaller increments during the week and longer increments on the weekend, do so. Keep in mind that typical PE preparation courses are about 100 hours total spread over three to four months, and many of them can be accessed on-demand from anywhere, fitting into almost any schedule or work-life situation.

Once you have a schedule set up, the next thing you need to focus on is your exam prep strategy. If you rely on a proctored training course, I recommend you follow their carefully planned study schedule. If you want to take the independent approach like I did, I recommend trying to solve problems as if they were taking place in the real world. A can-do mentality and exam references will also help.

My approach mimicked what will be happening on exam day. I did batches of 10-20 problems at a time; even if I wasn't familiar with the question, I would still attempt to answer and then review all my answers against the solutions later. While working through the solutions, I would highlight and add color tabs to the reference manual marking the relevant information, and if I made a mistake, I would study the solution very carefully, re-writing it on another piece of paper to be reviewed later.

I stopped working on problems two days prior to the exam. My exam was on Friday morning, so I spent Wednesday reviewing all the problems I had worked on, organizing my notes and tabs, and just going over the main subjects that would be on the exam. The day before the exam I devoted entirely to relaxation and preparing my mind for the big day. I went to yoga in the morning and then went swimming in the afternoon. The day before your exam will also be the last chance you have to go to the store for water or snacks that you can have during the break.

3. What should I know on exam day?

One thing I noticed on test day is that after the morning session is complete-which is supposed to be the easier portion of the test, by the way-your mind is exhausted from all the high level problem-solving. By the time you're two hours into the afternoon session, you just want it to be over. You'll be physically tired, your mind will be fatigued, and you will be wanting to tap out. Remember to think about all it has taken to reach this point to incentivize yourself to finish strong.

If you come upon a question you're unfamiliar with, don't ever be afraid to follow your intuition and your common sense. Many exam questions go unanswered every year because people limit themselves and give up too early without trying. Try marking the questions you are unfamiliar with and revisiting them later if you have any free time. Trust yourself-you've already gone to college, worked for over four years, and were recommended by other PEs to reach this milestone in your life. You've got this.

I would 100% recommend becoming a PE and I wish someone would have told me about how beneficial obtaining a PE license is for your career. In fact, I can guarantee that you will encounter so many more opportunities beyond your field of experience and benefit in ways that you didn't know were possible with a PE license. Out of the gate, the investment of finance, time, and effort you put in usually pays for itself, whether through salary increases or company reimbursement. Ultimately, I found that the most important element to pass the exam is for you to connect with the field and realize that becoming a professional engineer is something you really want for yourself. When you apply that energy in your study efforts, you will surely be able to achieve your goal of passing the PE exam and becoming a licensed civil engineer! Good luck!
About the Author: Enrique Lairet

Professional Engineer with 7 years of continuing success in civil engineering roles. I genuinely enjoy creating engineering solutions that have generated millions of dollars in savings to customers. I thrive in fast-paced environments that require critical operational management and mastery of technical details. My goal is to join a growing team that is looking to scale their footprint and profitability.

Friday 17 December 2021

School of PE Podcast Season One Episode Summaries and Winter Break Update

We started the School of PE Podcast this year to provide our students and the engineering community with a new educational resource touching on hot topics in engineering, study tips, and more. Our host Chris Miller has thoroughly enjoyed the opportunity to communicate with various engineers and subject matter experts on such engaging and interesting topics. We have not only learned more about these fields, but also gained a new appreciation for the passion and commitment engineers have for their careers.

We just wanted to take a moment to inform you that we are taking a short break from podcast production and posting to give our staff and podcast guests the chance to enjoy themselves with their families this holiday season. But don't fret-season two of our podcast will be beginning in January!

School of PE Podcast Season One Episode Summaries and Winter Break Update

In case you're not up to date, here's a short summary of each that the episodes we have produced so far:


1. Pilot

In this pilot episode of the School of PE Podcast, host Chris Miller introduces himself, the podcast, and touches on the elephant in the room: the transition of the PE Civil exam from pencil-and-paper format to computer-based testing (CBT) format. Chris notes that there is no need to panic about this change, as most students have likely taken their FE exam in the CBT format already! Listen today and learn more about this transition!

2. Sidney May

Join host Chris Miller as he talks to School of PE student-turned School of PE instructor Sidney May. May is a civil engineer with a focus in transportation and owns her own engineering practice out of Birmingham, Alabama. In this episode, you will learn about May's joining the School of PE team as an instructor, her passion for engineering, and her experiences as a woman in engineering. Tune in today!

3. Mike Villarosa

In this episode of the School of PE Podcast, Chris Miller talks with Mike Villarosa, a civil engineer in New York who has been teaching with School of PE for three years. Villarosa is a civil engineer for the Orange County Department of Public Works as well as a Water Resources instructor for School of PE. You'll learn about the different experiences students have taking Onsite versus Live Online classes, the benefits of taking the FE exam right out of college, changes in engineering, and more!

4. Sean Stuntz

This fourth episode of the School of PE Podcast features a conversation between Chris Miller and USAF Major Sean Stuntz. Stuntz is a civil engineer for the Air Force originally from Louisiana but based currently in Nevada. In this episode, you will find out about the mission for military civil engineers, differences between civilian and military engineers, and more!

5. Collin Sims

In this episode, Chris Miller talks with Collin Sims, School of PE's Program Administrator. Collin is from Zanesville, OH but lives in Columbus now. This conversation touches on taking the FE exam while you're in college/right out of college, the transition of the PE Mechanical exam from pencil-and-paper to CBT, and the importance of maintaining a positive attitude during exam preparation.

6. Dustin Douglas

This episode of the School of PE Podcast features a conversation between Chris and Dustin Douglas, a geotechnical engineer living and working in Texas. Douglas is currently a region engineer for a geotech firm called GeoPier, but originally began his education as a music major! In this episode, you will learn about why engineers would want to earn PE licenses in multiples states, the cold weather-induced power outages in Texas during early 2021, the compounding nature of engineering education, and more!

7. Erin Kelly

Join Chris as he talks to Erin Kelly, an instructor for School of PE and structural engineer in California. Kelly currently performs seismic risk assessments for commercial real estate with Blackstone Consulting. In this episode, you will find out about the California Seismic and Surveying exams and why they're intentionally difficult, as well as the importance of teachers and advisors in helping students recognize skills and strengths.

8. James Lindsey

On this episode of the School of PE Podcast, Chris interviews James Lindsey, a structural engineer currently working in the field of utilities. You'll learn about the effects of weather on transmission lines and structures, the pros and cons of certain assembly structures, when you would want to use underground versus overhead lines, and more!

9. Mike Villarosa

In this episode of the School of PE Podcast, we are joined by a repeat guest, Mr. Mike Villarosa, a New York State civil engineer and instructor for School of PE. This episode focuses on new information released by the NCEES about the PE Civil CBT exam, the pros and cons of having open book exams vs. exams where students can only use their reference handbook, and time management. You'll also learn about some of the engineering projects Villarosa has been working on in New York and the experiences he had while transitioning from working from an office to working from home during COVID.

10. James Avery

In this episode of the School of PE Podcast, join Chris as he puts fire protection engineer James Avery in the hot seat! Based in Memphis, Tennessee, Avery began his engineering adventure in the mechanical sector before receiving an opportunity to work for a sprinkler company. You'll learn about technological developments in fire protection like firefighting drones, active vs. passive fire protection systems, and Avery's goal of eventually putting firefighters out of business! Tune in to satisfy your burning curiosity about fire protection engineering.

11. James Lindsey

In this episode of the School of PE Podcast, we are joined by a returning guest, Mr. James Lindsey, a structural engineer. This episode focuses on Lindsey's personal experiences with and strategies for preparing to take both the FE and PE exams. Lindsey gives suggestions on how to overcome mental hurdles, how to improve content retention, and how to keep a positive attitude through this taxing exam prep process. Tune in today!

12. Collin Sims

This episode of the School of PE Podcast features a discussion between Chris and repeat guest, Collin Sims, School of PE's Program Administrator. You will learn more about how School of PE is a leader in professional education with innovative technology designed to improve learning experiences for students. Discover how and why we developed certain learning tools, the benefits of content retrieval and refreshing your memory, and the advantages of including augmented reality (AR) features in our publications! Tune in today!

13. Doug Smith

In this episode of the School of PE Podcast, Chris is joined by Mr. Doug Smith, the Learning Success Manager for HoloPundits, a leading augmented reality solutions provider that has been helping School of PE create AR/VR features for our publications. Discover the exponential growth of extended technology applications and the benefits of implementing these technologies within education, manufacturing, and engineering. Listen now to learn more about these exciting innovations and the numerous ways they can be applied in the real world!

14. Isaac Oakeson

Join Chris as he talks with Isaac Oakeson, the founder of Civil Engineering Academy. In this episode, dive into the new PE Civil CBT exam format-learn about the different alternative item type (AIT) questions, the pros and cons of the exam going digital, and some of the best strategies to ace the exam. This episode is particularly applicable for examinees with questions or concerns about the new CBT exam format beginning in January.

15. James Avery

Join Chris as he talks to repeat guest Mr. James Avery, a fire protection engineer based out of Memphis, TN. In this episode, you will learn about the safety tools Avery uses on a day-to-day basis, the fire protection equipment individuals should have to protect themselves and their homes, and the rigorous testing done on commercial fire protection systems to make sure they will function properly when needed.

16. Erin Kelly

In this episode of the School of PE Podcast, Chris chats with repeat guest and structural engineer Erin Kelly! During this episode, you will learn more about the different paths that civil structural engineers can take, including design engineering, forensics engineering, risk assessment, and in-house engineering support. Kelly explains how there's no right way to be an engineer and that there is value in experimenting in different fields of engineering before you make your decision on which to choose as a career. She also notes that there is often overlap in engineering careers, so even if you feel like you might not be qualified for a position, you likely are due to previous engineering experience and training. You will also discover the common instruments a structural engineer would have in his or her daily toolkit!

Our podcast is now live on Spotify and Google Podcasts as well as on our website and YouTube and has been listened to across the globe! These podcast episodes are complete with fun facts and exam hacks in addition to intriguing information on the guests themselves. Thank you for joining us as a listener-enjoy your winter break and tune in to season two of the School of PE Podcast beginning in January!
About the Author: Martha Hunsucker

Martha Hunsucker is a content writer for EduMind. She received her BA in English from Stetson University and has experience marketing, copywriting, editing, and blogging. In her spare time, she enjoys reading books by Jon Krakauer (her current favorite author), hiking with her two dogs, and sleeping in on weekends.

Thursday 9 December 2021

What Happens During an NCEES Exam Development Experience?

After taking two PE exams for mechanical and fire protection engineering, I thought I was done with those eight-hour exams and NCEES in general. However, in 2017, I was approved to volunteer on the NCEES PE Mechanical engineering exam development committee. The committee is responsible for writing and reviewing the items and developing the exams to meet all established guidelines for administration. Meetings are held at NCEES' headquarters in Greenville, South Carolina (previously Clemson, South Carolina before relocating). Volunteers in attendance had their expenses paid in accordance with the NCEES travel policy, and I simply could not pass up this golden opportunity to volunteer and help guide the future of professional engineering.

What Happens During an NCEES Exam Development Experience?

Professional mechanical engineers from all over the country attended this meeting, and I estimated there to be at least 80 of us there. We provided our feedback to NCEES after a multi-day meeting and many of the discussions were enlightening-I was able to learn what other engineers, companies, and governments around the US were doing and how licensure affected them. It drove home the importance of having a robust and relevant PE exam. I was familiarized with the exam development process and had the chance to meet some incredible NCEES staff, most of whom were professional engineers themselves. (Sidenote: Throughout the meeting, I felt woefully inadequate compared to my peers who were all incredibly talented and intelligent, but this has only served to push me harder in my own pursuits of professional development).

Overall, this experience with NCEES was eye-opening for me and I was glad I participated. I was impressed with the professionalism of my fellow engineers as well as the drive of the NCEES organization. As a test-taker, I always grumbled at the expense and difficulty of the exam without understanding or even considering the work that goes into developing, administering, and scoring the exams. I was glad to see that NCEES valued not only our exam experience but also our experience in the industry. They stressed that they relied on engineers like us to give accurate feedback because we know what is going on with the engineering profession across the country. The benefits of attending this meeting cannot be understated, and I even received a complimentary official NCEES coffee mug!

Another positive of attending this meeting was the ability to network with other like-minded engineers who were just as passionate about advancing the profession. Years later, I still keep in contact with engineers that I met there across the country, including Alaska and Texas. They have provided me with valuable advice, especially as it relates to sustainability and energy usage for HVAC systems.

After the meeting was over, and at my own expense, I spent a day in Greenville and Myrtle Beach, two beautiful places that I'm glad I was able to visit. I enjoyed my stay there as a tourist and it was nice to see some of the fun things there. Also, the food was delicious! I certainly hope I get another chance to participate in NCEES exam development and look forward to my next trip to South Carolina.

I highly recommend any professional engineer to volunteer with NCEES to help with their exam development. A link with more information can be found here:
About the Author: Nick Tran

Nick Tran is a licensed Mechanical and Fire Protection Engineer in California. He has an Associates degree in Computer Aided Design from De Anza College, a Bachelor of Science degree in Mechanical Engineering from San Jose State, and a Master of Science degree in Fire Protection Engineering from Cal Poly SLO. He is currently on the UL Standards Technical Panel for UL 38 and was president of the Alameda County Fire Prevention Officers Association.

Friday 3 December 2021

What Are the Basics of Fire Dynamics?

The first step in fighting fire is to understand exactly what a fire is. Simply put, a fire is a rapid chemical reaction, oxidation to be specific, that produces heat, light, and smoke as part of combustion. The processes that start a fire can be graphically explained through the fire tetrahedron, which shows that for a fire to start, it needs four items: fuel, heat (energy), an oxidizer, and an uninterrupted chemical reaction. If any one if these items is taken away, a fire will not start. As an example, water extinguishes a fire by efficiently absorbing the heat. Another example would be a carbon dioxide system that replaces the oxygen around a fire thereby removing the oxidizer. A unique fire suppression system known as clean agents will interrupt the chemical reaction of a fire.


What Are the Basics of Fire Dynamics?

1. The Four Stages of Fire Development

There are four stages of fire development: ignition, growth, fully developed, and decay. The ignition stage is when all four elements of the fire tetrahedron coalesce, the fuels reach their ignition temperature, and the fire begins. During the growth stage, the fire increases fuel consumption and creates more heat and smoke. The fully developed stage occurs when the maximum amount of fuel and oxidizers are consumed, and the highest heat release rate is produced. The temperature decreases and intensity is reduced during the decay stage, which happens when the available fuel has been consumed.

2. Determining a Fire's Intensity

Generally, the intensity of a fire is defined by its heat release rate, measured in kilowatts or BTU/second, and the higher the heat release rate, the more intense the fire is. Heat release rate can be modeled as a power law growth model, the most common of which is known as the t2-model (t-squared). Within the t2-model, fire growth is classified as slow, medium, fast, or ultrafast, where the heat release rate is dependent on the time of the fire. Choosing the correct fire intensity is paramount when designing a fire protection system. For instance, a slow growth fire might be appropriate for an office building with a limited fuel load and the fire suppression system would be relatively light and simple. However, a tire storage warehouse might have an ultrafast fire and the suppression system would need to be designed accordingly. Modeling a slow growth fire in that tire warehouse would be a poor basis of design.

3. Heat Transference

A major aspect of fire dynamics is to understand how heat is transferred to and from a fire. There are three main methods of heat transfer: conduction, convection, and radiation. Conduction is when heat travels through a medium via direct contact and transfers energy from a higher state to a lower state. Another way to understand conduction is the way that if a metal spoon is heated on one end, the heat will move to the other end of the spoon, burning the hand that is holding it. Convection occurs when heat energy is transferred via air. An example of convection is when a cake is being baked in the oven; the energy from the heating elements is transferred to the flour through the air. Radiative energy does not need a medium (air or direct contact) to transfer energy. Radiation involves electromagnetic waves that excite target molecules, such as microwave energy.

Many of the fire codes are based on studies of fire dynamics. For instance, the separation of buildings is driven by the heat release rate and radiative energy that would be produced by a theoretical fire. If buildings are too close to each other and one catches fire, there is a good chance the fire will spread to other buildings. The study of fire dynamics has immediate real-world applications to how the built environment is constructed.

Interested in learning more about fire protection engineering? Check out these other blogs from School of PE:
About the Author: Nick Tran

Nick Tran is a licensed Mechanical and Fire Protection Engineer in California. He has an Associates degree in Computer Aided Design from De Anza College, a Bachelor of Science degree in Mechanical Engineering from San Jose State, and a Master of Science degree in Fire Protection Engineering from Cal Poly SLO. He is currently on the UL Standards Technical Panel for UL 38 and was president of the Alameda County Fire Prevention Officers Association.