by: Elizabeth Keller

 

Everyone is aware of the benefits of professional licensing for Fire Protection Engineers; however, few people consider the cost (time and money) for maintaining licensure.  Although the benefits far outweigh the costs, there is an opportunity for improvement in the licensing system that would greatly streamline license maintenance.

A professional engineer must meet the engineering licensure requirements in each state in which the professional engineer seeks to practice.  Most states allow licensure by comity if a professional engineer is already licensed in another state with requirements at least equal to those in the state in which licensure is being sought.  Fire Protection Engineers are always in demand and are increasingly crossing state lines and finding the need to be licensed not just in one state, but in many.  Sounds great, doesn’t it?

The issue is that most states require continuing education prior to the renewal of an engineering license.  Continuing education requirements are not uniform across the states and unlike the more streamlined comity application process, very few recognize the requirements for continuing education via comity.  Renewal periods range from annual to triennial, and the number of continuing education hours ranges from zero to thirty-six (36) or more per renewal period.  It is up to the licensee to keep track of their continuing education hours (also called professional development hours in some states) and to present a log of activities to the licensing board upon request.

Imagine being licensed in more than ten states.  No two of your licenses expire in the same month and different requirements must be satisfied for each.  How do you balance that?  Do you fulfill the requirements of the most demanding state and know that the others are then taken care of?  Unfortunately, it’s not that simple.

Not only do different states have different hour requirements, they also have specialty requirements, such as the need for “live” training, multiple categories for activities with specific limits on each category, and requirements for state specific courses in ethics and rules and regulations.  You could complete all of the continuing education activities required for one state, and still only be halfway to completion in another state.

So why are all of the requirements different?  Well, the simple answer is that’s just the way it is.  Professional licensing boards are all made up of representatives from the state they represent.  They are empowered by the laws of their state and they research, propose, and vote on amendments to their regulations on a state board basis.  Although one state may look at another’s process, there is no real crossover.

What about NCEES you ask?  The National Council of Examiners for Engineering and Surveying (NCEES) published model Continuing Professional Competency (CPC) Guidelines in 2008 for the use of state licensure boards in developing state specific requirements for continuing education.  Many pieces of the NCEES CPC guidelines can be found in state laws and regulation across the country, but boards can pick and choose the pieces that ultimately become incorporated.  If all states used the NCEES CPC guidelines, it would even the playing field and make complying with continuing education requirements a much simpler process.

One idea that could easily streamline this process is a national licensing board for engineers.  Currently, NCEES plays a large role in the licensing of engineers for every state and every prospective engineer generally follows the same four major steps:

  1. Earn a degree from an ABET accredited engineering program.
  2. Pass the Fundamentals of Engineering (FE) exam.
  3. Gain acceptable work experience (typically a minimum of four years).
  4. Pass the Professional Engineer (PE) exam in the appropriate discipline.

What is the benefit to having each state manage application approval when a national council is really managing the application process?  Perhaps the benefit is in the details, but this is not certain.  This is a debate that has many sides and deserves more research.

Overall, the professional engineering licensure system could be well served by a reset and reboot.  As more states adopt continuing education requirements and more engineers cross state lines in the name of business, a better and better case can be made for the development of national guidelines and somewhere in the future, perhaps even a national licensure board.

Video  —  Posted: January 21, 2016 in Fire Protection
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by: Jason A. Sutula

Hello and welcome to the Fire Science Blog! For those of you who are new visitors to this site, the genre of this blog is anything and everything related to fire and fire science. As a fire scientist, I consider it my mission to educate and inform on all topics related to fire, fire investigation, and fire protection. By education, I am a fire protection engineer with degrees from the University of Maryland and the University of Edinburgh in Scotland. By experience, I have been fortunate to research how fire behaves and the best method of putting it out (my favorite project was learning how fire operates in outer space!). By training, I am a Certified Fire and Explosion Investigator and have been conducting forensic analyses of fire and explosion incidents for over 16 years.

Today’s post is an opportunity like no other. The Fire Science Blog was selected for hosting Samarra Khaja (SK), author of her new book Sew Adorkable: 15 DIY Projects to Keep You Out of Trouble (C&T Publishing, $26.95) on her book blog tour.

11114D

Gifted and schooled in the fine arts, Samarra Khaja is a designer, photographer, art director, and illustrator. Her work can be found in The New York Times, The Guggenheim, Time magazine, and Cirque du Soleil to name a few.

SK came to the Fire Science Blog with many questions from herself and her main audience regarding the fire safety and flammability of various fabrics and materials used in fabric design, sewing, and the equipment used. It is my great honor to present SK as the host of this question and answer session.

Jason Sutula (JS), thanks so much for fielding my fire-related questions. As you know, aside from my book being filled with fun projects, it’s also full of fun facts. So on this blog tour I thought it only appropriate to continue to provide my audience with fun facts and you, JS, are my living, breathing anthropomorphized fun fact section for this event. Sound good? Great, let’s get to it!

 SK- Sewing, crafting and DIY projects are really hot right now. That said, should I fear that my book will spontaneously combust? What’s the real world risk of that?

JS- One of the first books I remember reading in high school was Fahrenheit 451 by Ray Bradbury. The premise was a dystopian society where books were outlawed and burned by “Firemen.” 451 degrees Fahrenheit was the temperature that Mr. Bradbury decided on for the ignition temperature of paper in his story. I learned over my schooling and career that the type of paper, whether it is tissue, newsprint, glossy, or engineering paper, determines the fundamental material properties of the paper that control the ignition temperature. Mr. Bradbury was not far off though, as “book” paper has an establish ignition range between 437 °F and 464 °F. The good news then is that a single one of your books sitting out on a coffee table has no chance of spontaneously bursting into flame.

SK- The materials for the projects have been left to the discretion of the maker. From a fire-safety stand point, what are the safest and least safe fabrics to use?

 JS- When scanning the internet, I came across a great article in the Fall 2011 edition of On Track! magazine, which you may have some familiarity with. The article is titled, “Safe Batting Choices for Baby and Invalid Quilts,” by Beth Kurzava. The article does a great job of demonstrating how easy or hard it is to spread flame over different batting materials. Cotton, wool, silk, cotton-poly blends, polyester, bamboo-cotton blends, cotton-corn blends, and fire retardant cotton fabrics were all tested following an ad hoc procedure based on the code of federal regulations (CFR) clothing fabric flammability test. The test was simple, expose an 8” square of each fabric on a 45 degree incline to a three second fire exposure at the corner of the sample, then sit back and observe the fire spread. Pictures were provided in the article and show that wool and fire resistant cotton are the best performers and polyester is the worst performer. These results are very consistent with the science of fabric flammability. Natural fibers will burn or smolder, but are naturally resistant to rapid fire spread over a surface. Polyester, on the other hand, is a petroleum-based, plastic synthetic fiber. Like all petroleum-based plastic products, it tends to melt and liquefy upon heating, but once ignition has occurred, it will sustain vigorous flame spread over a surface.

SK- In terms of fire risk, what tool(s) used to make my projects are the most dangerous?

JS- Every year, the National Fire Protection Association (NFPA) compiles statistics gathered by fire departments for the U.S. Fire Administration on the suspected cause of ignition of a fire. The one that jumped out at me from your book is the use of a clothes iron for your projects. Most recently produced clothes irons have built-in safety features such as automatic timers for shutoff and, on some models, automatic shutoff if the iron is tipped on its side or soleplate for longer than one minute. Even with these safety features, an average of 318 clothes iron fires occur every year, resulting in over $10 million in damages. My recommendation, then, is to continue to follow safe practice by never leaving unattended a clothes iron that is on.

SK- Finally, would you mind going through my book’s projects and pointing out some fun fire facts relating to them?

11114, Khaja,FA15

JS- I would love to! Since I have yet to conduct a fire scene investigation in a lighthouse, your Lighthouse Dress project inspired me to research famous lighthouse fires. Some of the first lighthouses were built with a “core” of brick and concrete. Wood was used to build up the exterior of the lighthouse and provide for a means to access the top of the lighthouse where the light was located. One of these lighthouses was built on Eddystone Rocks, south of England. This particular lighthouse was named Rudyard’s lighthouse, which was actually the second lighthouse built as the first was washed away in a large storm. The second lighthouse was constructed in 1709 and lasted until 1755 when the lantern at the top caught fire and spread through the wooden walls of the structure. The three keepers of the lighthouse fought the fire with buckets of water, but were unsuccessful at saving the structure. Luckily, they were rescued by boat and survived the fire.

11114, Khaja,FA15

Your typewriter project was of interest as well, as I have yet to come across a fire investigation case where a typewriter was deemed to be the cause. The best I could come up with was this video I found on Youtube:

 

I am still not completely certain as to why you would ever want to burn a typewriter.

11114, Khaja,FA15

I couldn’t help but notice your references to the classic movie, Office Space, in your red Swingline stapler project. Swingline staplers are made from plastic and can burn, but a single stapler on your desk or in your home office is not considered a great fire hazard due to the significant amount of metal in the construction and when loaded full with staples. If we stored 1,000’s of them in a warehouse… well that is a different story. While we are on the topic of Office Space and if you are interested, the machine that gets taken to a field and destroyed by the office employees would burn nicely (i.e., it is made from plastic) whether you believe it was a fax machine, printer, or fax machine/printer combo.

11114, Khaja, FA15

My children have always been interested in learning about dinosaurs, maybe even more so than when I was their age. Your prehistoric portrait project begs the question that my children would ask. Did the dinosaurs have to worry about fire? The answer is a resounding yes, and, unfortunately, they were not well prepared to fight fire. Dinosaurs would have had to deal with fires as a result of volcanic activity, lightning, and earthquakes. Any of those mechanisms would have had the potential to initiate wildfires in the prehistoric world. Dinosaur skin may have been slightly more resistant to burn injury than our skin, but without advanced warning of an approaching wildfire, the dinosaurs were at a distinct disadvantage.

11114, Khaja, FA15

My final thought was about your 8-bit bird project. Believe it or not, one of the world’s most renowned arsonists was a bird. I came across the story of this bird a few years into my career. According to the story, a bird was accused of bringing a smoldering cigarette back to her nest, which just so happened to be in the post of a wooden front porch of a house. The cigarette started a smoldering fire in the straw of the nest, which broke out into the connecting space between the porch and the house. Fortunately, the house had minimal damage, and no one was hurt. What happened to the arsonist bird you ask? Well, she remains unidentified and is still at large to this day. Hopefully, she has learned not to use materials that can start a fire to build her nest!

SK- Well, my brain is officially smoldering from all this amazingness that you’ve now fueled it with. I have to say, you really do know how to set a blog post ablaze with flare. Plus, I know these were hot topics that I was simply burning to ask, so I’m thoroughly stoked that you’ve taken this time to shed some much needed light on the situation. You have really sparked some great ideas here. Really and truly, you’ve made my tour more scintillating. Searing perspective. It’s really warmed my hearth. I’m sure you’re scorched from all my puns. Am I getting hot yet? No rapid fire response needed, I’ll stop with the third degree. And also the puns. Maybe. Okay, never.

JS- Thank you for the opportunity to answer your and your audience’s questions SK. It has been a great pleasure having you on the Fire Science Blog.

And, now for the contest! The rules are simple. To be entered into the random drawing to win a copy of SK’s new book for yourself or as an awesome gift for friend or family, simply answer this question in the comment section of this post: What fire hazards related to sewing and fabrics do you experience in your home or place of work? (If we did not touch on it in this interview, it could be the topic of a future post.)

Fine Print: Only one entry will be given for each individual so please only submit one comment per person. One book per winner. Open internationally, however if winner lives outside of the US, they will receive a promo code to purchase the ebook version free of charge. US winner will receive a hard copy. Winner will be chosen from all entries at the close of the tour on Monday, October 26, 2015.

Good luck in the contest and please check out the rest of the blogs on the Sew Adorkable book blog tour!

9/14/15 C&T Blog
9/16/15 Generation Q Magazine
9/18/15 Sew Timeless
9/21/15 Fire Science Blog (Thank you for visiting!)
9/23/15 Art School Dropout
9/25/15 Craft Buds
9/28/15 Pellon
9/30/15 Crafty Planner
10/2/15 Modern Handcraft
10/5/15 Imagine Gnats
10/7/15 May Chappell
10/9/15 Nancy Zieman
10/12/15 Dritz
10/14/15 Spoonflower
10/16/15 Sew Sweetness
10/19/15 Aurifil
10/21/15 Accuquilt
10/23/15 Schmancy Toys
10/26/15 Samarra Khaja

by: Jason A. Sutula

 

According to the 2014 Edition of NFPA 921 – Guide for Fire and Explosion Investigations, “The boiling liquid expanding vapor explosion (BLEVE) is the type of mechanical explosion that will be encountered most frequently by the fire investigator.” NPFA 921 provides a good basic description of how a BLEVE occurs. In general, a BLEVE event will begin when a container that is filled with a liquid undergoes an insult that results in the rupture of the container. The rupture can be caused either thermally or mechanically. In the thermal case, the heating of the container is responsible for the mode of failure. In the mechanical case, the container rupture is due to an impact or other event that causes a portion of the container to be breached. When the container is breached, the vapor of the liquid expands while the liquid becomes superheated. The superheating of the liquid results in the boiling of the liquid. Additionally, a pressure wave will be generated at the time of rupture and release, which can lead to the fragmentation of the container and the production of missiles. If the liquid in the container is flammable, a premixed system of fuel and air will develop and result in a fireball [Abbasi and Abbasi, 2007]. The Youtube video shown above is one that I show to my students to demonstrate the awesome power of the BLEVE.

One of the most famous BLEVE events took place in Crescent City, Illinois on Father’s Day, June 21, 1970. A freight train with 109 cars derailed. Ten of the rail cars were tank storage cars each carrying 34,000 gallons of liquefied propane gas. At the start of the derailment, one of the liquefied propane gas cars collided with another, tearing a large rupture into one of the other tanks. The result was a large initial fireball and subsequent sustained fire. Five of the liquefied propane gas cars achieved a BLEVE in the first four hours.

According to an excellent article by Robert Burke that was published by Firehouse in 2010 (http://www.firehouse.com/article/10467137/crescent-city-train-derailment-40-years-later), twenty-five homes and sixteen businesses were destroyed by fire. Three homes were destroyed by “flying” tank cars and numerous other homes received damage. More than $2 million in property damage occurred as a result of the derailment, fires and explosions along with six fire trucks [Burke, 2010].

It can be hard to put into perspective this amount of damage and how massive the fire and fireballs from the explosion were. After digging around on Youtube, I found the following video that shows actual footage of the Crescent City event. This particular video is narrated in Russian, but still clearly shows the magnitude of the event and the dangers of a BLEVE to both citizens and fire service personnel.

 

References

Abbasi and S. Abbasi, “The boiling liquid expanding vapour explosion (BLEVE): Mechanism, consequence assessment, management,” Journal of Hazardous Materials, no. 141, pp. 489-519, 2007.

Burke, 2010, http://www.firehouse.com/article/10467137/crescent-city-train-derailment-40-years-later

Video  —  Posted: September 1, 2015 in Fire Investigation, Fire Science
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by: Nathan Pascale

 

When analyzing the effect of toxicants, there are a few trains of thought that we must consider. First, there are the biological effects. How does the human body process the harmful byproducts that are be produced during a fire and how effectively can it do so? This perspective looks exclusively from an organic point of view, only taking into account functions within the body. The second consideration is for behavioral influences. At a micro scale level, this could be linked to the biological effects as far as how the toxicants can debilitate the brain’s capacity to function normally. However, in taking a big picture point of view this can simply be defined as changes in an individual’s decision making and the actions they take as a result of the toxicants. Finally, in the grand scheme of a fire scenario, we can look at how these biological and behavioral variations can affect the overall tenability analysis of a particular building.

As mentioned previously, the main concerns when determining the tenability of the building are the time to impair one’s ability to escape in a timely manner and the time to incapacitation. The time to impair can be correlated to the behavioral consequences of toxicants in a fire. While the panic theory has been largely debunked, a normal individual is still expected to require time to perceive, recognize, respond, and move to a safe area, and this is all without the effect of toxicants. When we introduce that extra layer of complexity, the question of how much time is enough time becomes much harder to answer. There are many factors that vary on an individual basis that can affect the way they react to the problem at hand, one of them being age.

While irritant gases are important to consider in any fire scenario, their effect is very difficult to quantify due to differing opinions in the field and overall lack of data. Thus, for the sake of this argument, I will focus on narcotic gases. Unlike irritant gases, the lethal and incapacitating effects of narcotic gases are much more accessible and quantifiable through research on animal exposure as well as posthumous studies of fatal fires. Narcotic gases act primarily by attacking the nervous system and to a lesser extent the cardiovascular system. The result is a lethargic state, coupled with headache, nausea, or poor physical coordination, followed quickly by incapacitation or death once the body can no longer compensate for the lack of oxygen being supplied to the brain.

Carbon monoxide (CO) is a toxicant present as a byproduct of all fires. Many deaths have occurred due to CO inhalation where the victims are asleep or inactive for a duration of time before becoming aware of the danger. A model developed by Professor David Purser in 2008 showed that active subjects with greater respiratory minute volume (RMV) rates were much more susceptible to the effects of CO than subjects at rest. When an individual is remote from a room of origin that has undergone flashover, toxicants are inhaled while in a sedentary state until the danger is recognized. At this moment, the exposed individual tries to escape, at which point the effects of the increased respirations an environment laden with CO begin to cause severe impairment or incapacitation.

Elderly individuals are also more likely than the average adult or child to have conditions such as asthma or coronary artery disease. A study conducted by the EPA in 2000 determined that the tenability limit of carboxyhemoglobin (the amount of CO in your blood) for an individual with coronary artery disease is only 5%, while the limit for an average adult is 30% (Purser 2008) and 25% for a child (Klees 1985). Additionally, according to an SEFS report, elderly individuals are expected to spend more time in their bedroom then adults and children. The fact that elderly people are more vulnerable due to physical condition, preexisting health concerns, and that they spend more time in the bedroom environment when exposed to fire conditions, we can conclude that elderly individuals comprise the age group at the greatest risk of death and injury when faced with narcotic gases.

In conclusion, there is evidence to prove a correlation between the effects of toxicity and age, but not enough to reliably quantify what those effects are. Preexisting illnesses, physical conditions, familiarity with the building, and susceptibility to toxicants are just a few of the factors that have to be taken into account during a tenability analysis. Unfortunately, due to the harmful nature of toxicants, experimental studies on humans are considered unethical and there is not a large pool of data to analyze for effects on past fire victims. Thus, with the information currently available, the elderly population can be considered most at-risk in a toxicant exposure event, followed by children, and then adults. Consequently, it is my hope that code committees and the fire protection community as a whole takes a closer look at these factors and evaluates the possibility of increasing the required safe egress time, whether it be by decreasing the walking speed, increasing recognition time, or otherwise, for those occupancies and buildings that shelter a large number of elderly people or children.

References

Purser, D.A., “The Effects of Fire Products on Escape Capability in Primates and Human Fire Victims,” International Association for Fire Safety Science, 2008.

Klees, M., Heremans, M., and Dougan, S. “Psychological sequelae to carbon monoxide intoxication in the child,” Sci. Tot. Environ., 1985.

Gann, R.G., J.D. Averill, K.M. Butler, W.W. Jones, G.W. Mulholland, J.L. Neviaser, T.J. Ohlemiller, R.D. Peacock, P.A. Reneke, and J.R. Hall Jr., “International Study of the Sublethal Effects of Fire Smoke on Survivability and Health (SEFS): Phase I Final Report,” National Institute of Standards and Technology, August 2001.

Video  —  Posted: August 20, 2015 in Fire Protection, Fire Science
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by: Matthew Gentzel

Mass Notification by Gentzel

Having spent my first semester of college at the United States Air Force Academy, I have been exposed to a lot of mass notification during drills. In general, by using the same systems to communicate information for fire evacuations, as well as other events, organizations have the opportunity to save money, streamline reaction times, and to frequently check that their emergency systems work. On the other hand, they also face the risks of causing confusion if alarms are not paired with specific information and direction (e.g., at the Academy there were many different alarm sounds for different types of threats, but not everyone knew the difference between the tones). Despite these and other possible problems, integrated mass notification systems are likely to be very beneficial, especially when paired with voice notification.

Although technological developments and improvements have affected mass notification systems, much of their implementation has been primarily affected by historical incidents and trends:

“The motivation to expand NFPA 72 to include mass notification and emergency communications systems beyond just fire events was driven by a number of fatal events such as the Khobar Towers bombing in 1996 and the Virginia Tech massacre in 2007. The Department of Defense (DOD), through the United States Air Force, first petitioned NFPA to develop a standard on mass notification in 2003.” [1]

With increases in the trending frequency of mass shooting in the recent years [2], a corresponding increase in mass notification is likely to continue, and to be beneficial to life safety. In a recent 2014 NFPA workshop, a panelist from the Federal Bureau of Investigation (FBI) described the scope of active shooter incidents, and more specifically how they affect schools. In 14 out of 16 studied school shootings, the shooters were students, which indicates a need for mass notification systems that cannot be abused by insiders.

Similarly, a problem was discussed by the panel about the issue of having too much communication. Due to the presence of social media, there is a high likelihood that during an emergency there may be reduced phone service from the high use of personal mobile devices. To prevent this, mass notification to mobile devices should be able to instruct message recipients to only send vital messages so that first responders can communicate situation updates.

Among other data considered, there was discussion of the effectiveness of lockdowns. Lockdowns are security measures taken during emergencies to prevent people from leaving or entering an area, and often involve taking shelter in place. Mass notification provides a rapid means of implementing a lockdown policy throughout a building or area, and can harden potential targets against harm, giving emergency responders more time to react to such situations. Although the median police response time to an active shooter incident is approximately three minutes, having building occupants seek shelter before this amount of time is likely to make a significant difference. According to the FBI, “The five highest casualty events since 2000 happened despite police arriving on scene in about 3 minutes.” [2] Because most of the damage inflicted in an active shooter incident is often early on, reducing the reaction times of potential victims is likely to be one of the highest leverage areas for reducing deaths. Though pre-training methods such as the “Run, Hide, Fight” technique are likely to be most effective, mass notification may play a future role in preventing bystanders from unknowingly entering an area that they are likely to be harmed.

Another type of potential problem for mass notification in the event of direct attack is that an attacker could deliberately send false information. Emergency responders have already dealt with the problem of false alarms and potential traps for years. The new complication of having mass notification is the potential for false information to be rapidly distributed to others. Systems should be designed so attackers cannot access voice notification systems, and so that fire alarms do not give access to secure areas during a lockdown.

Despite the benefits of emergency text alert tones in instances where there is a direct attack, there is the chance that this type of notification could be abused. Since part of the point of a lockdown in an active shooter incident is to make it harder for a gunman to find targets, loud emergency tones could assist such a person in differentiating between empty and occupied rooms. Ultimately, it is up to phone service providers to create the software so alerts can be sent with or without tones.

With over 160 mass shooting incidents recorded by the FBI, there is still a great deal of analysis left to tackle this specific type of problem. Security from an attack is very expensive, so good solutions to these sorts of problems will be dependent upon risk assessment as well as cost effectiveness. Based on the threats that are the most likely and the most harmful, reasonable measures can be taken to increase the resilience of mass notification systems and to streamline their integration with fire alarm systems.

 

  1. “How NFPA 72 Defines Mass Notification.” Facilitiesnet. N.p., n.d. Web. 07 Dec. 2014.<http://www.facilitiesnet.com/firesafety/article/How-NFPA-72-Defines-Mass-Notification–14311>
  2. “Active Shooter Events from 2000 to 2012.” FBI. Web. 7 Dec. 2014. <http://leb.fbi.gov/2014/january/active-shooter-events-from-2000-to-2012>

by: Jason A. Sutula

The (cliché?) saying, “It’s not what you know, it’s who you know,” comes to mind as I write this short blog post. Mostly because I have the good fortune to know Samarra Khaja. Besides being family and a friend of mine, she is a highly talented and creative individual. While having her husband and family over for a visit recently, she spent some time working with me on a new branding image for the blog. The final result is below. If anyone who reads this blog has a need for logo & branding work, illustration, or photography (and several other creative services), I hope you will consider contacting SK. You can check out her work at smarrakhaja.com.

And now, the reveal:

Logo low res

Feel free to chime in on the design in the comment section. If there is enough interest, maybe I will make up some t-shirts and give them away in a contest!

by: Michael Harris

There are many methods that fire protection engineers can use to calculate egress time. One popular method taught is hand calculations that are based off of fluid dynamics (these can be done on a computer also). Unfortunately, this method does not take into account human behavior. There are many factors in a fire that can affect human behavior and egress time. One big factor is the toxic smoke produced by a fire.

Tadahisa Jin and Tokiyoshi Yamada (Jin and Yamada, conducted an experiment in Tokyo, Japan on the effects of human behavior in smoked filled corridors. This study attempted to produce as accurate results as possible by using 31 human subjects, aged 20 to 51, as oppose to animal subjects that previous smoke inhalation studies had used. The experiment was done in a straight corridor that was 11 m long, 2.5 m wide, and 1.2 m high. Certain stopping points were arranged in the corridor where the occupants were meant to stop and answer a simple arithmetic question. While in the corridor, the subjects were exposed to different levels of smoke and radiated heat. The inside of the corridor was also illuminated with fluorescent lamps.

To protect the subjects, a 16 layered towel was positioned on their nose and mouth. This provided a filtration of approximately 90% of the smoke from the environment. Additionally, the subjects had no prior knowledge of the corridor before, but were told it was a straight corridor with an end and that they could turn around at any point.

The study resulted in 17 of the subjects reaching the end of the corridor. Fourteen of the subjects had to turn around before reaching the end. An additional finding was that the subjects answered the arithmetic question incorrectly at a higher rate when the smoke density was higher. This correlation was almost linear. Finally, the subjects’ correct answer rate increased as they walked farther into the corridor. The experimenters concluded that this effect was due to the subjects becoming more emotionally stable as they acclimated to the controlled environment.

Jin and Yamada’s study resulted in valuable information that helped to better understand human behavior in a toxic gas environment. Close to half of the occupants decided the emotional toll was too high and decided to reverse direction and retreat out of the smoke filled corridor. It is worth noting that none of the subjects were exposed to a true fire scenario, considering that they only had to walk through a straight corridor and were protected from the toxicity of the smoke. A reasonable inference would be to assume that more of the subjects would have turned around in the corridor if they experienced pain due to breathing in the toxic smoke.

One of the most important findings of the study is that occupants will change their path due to the presence of smoke. This action of changing path can greatly increase egress time, and put the occupants at higher risk of injury or even fatality. Furthermore, the subjects’ cognitive ability decreased with heavier smoke. This decrease was strictly due to the emotional stress of the scenario. In an actual fire, occupants of the structure may lose cognitive ability to the point of not being able to find a safe path out.

The silver lining in this experiment is that the subjects’ cognitive ability was found to increase over time as they acclimated to the environmental conditions. Unfortunately, this observation may be inaccurate due to the limitations of the experiment. The possibility exists in an actual fire that the occupants will be exposed to an increasing dose of toxicants. Furthermore, in many structures, an occupant will not have as direct of an egress path as utilized in the experiment.

It is clear from the Jin and Yamada study that simply using fluid dynamics to calculate the egress time is not enough. Fortunately, many fire protection engineers will add a safety factor to help account for limitations such as human behavior. My hope is that future research will eventually give our community better insight into human behavior in fire, and allow for a more quantitative approach to the design of fire safe egress.

Jin, Tadahisa, and Tokiyoshi Yamada, “Experimental Study of Human Behavior in Smoke Filled Corridors.” Fire Safety Science-Proceedings of The Second International Symposium, pp. 511-519, 1989.

Video  —  Posted: July 16, 2015 in Fire Protection, Fire Science
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