Rod Ammon: So, welcome to the CFITrainer.Net podcast. We've got something new and pretty interesting for you today. A closer look at the role of metallurgical and material science in fire origin and cause determination. Our guide into this world is Larry Hanke. Larry Hanke of Materials Evaluation and Engineering, Inc. is a registered professional metallurgical and materials engineer with over 40 years of experience in failure analysis, materials characterization, product evaluation, and research and development. He specializes in engineering evaluation of failures in metallic and nonmetallic material by deformation, fracture, corrosion, and wear. Larry is skilled in a wide variety of materials evaluation, laboratory methods and instruments. He has testified as an expert witness many times, contributed to numerous scientific publications and held multiple leadership positions at ASM International and other professionals associations. Larry, it's great to have you with us today.

Larry Hanke: Thank you very much.

Rod Ammon: So, I'm going to start out real basic. We've never done this before on CFITrainer. So, I'd like to start out just having you tell us about what material science is and what is metallurgical science.

Larry Hanke: Okay. Material science is a general term and a general field, and that's involved with the science of materials and what they're made of and what properties they have. So, metallurgy then is a subset of that, and that's a focus on metallic materials. So, steels or copper. Copper being very important in the world of fire and electricity, steel being more popular in other fields for structural materials.

Rod Ammon: Yeah, I get how copper could affect us greatly. So, tell me a little bit about how metallurgy and material science is used in fire investigation.

Larry Hanke: First of all, many fire investigations, they are complex and we have multiple failed components. So, part of what I do is figure out what has failed and why it's failed. So, what is the mechanism that has caused that component to failure? Did it corrode, does that put a hole in it or did it break because of stress? By figuring that out and whether it's a single stress or a multiple stress applications can be important to understanding why a particular component has failed.

Rod Ammon: So, when do you typically get involved in a case?

Larry Hanke: In a fire case, I'll get involved usually after the initial investigation. So, there'll be the fire investigator, the origin and cause person has been on the scene and has picked out an area that's important and components that have been involved in the fire and realized that he needs to know more about those things, he or she, I should say.

Rod Ammon: Okay. So, what can the examination of these metals and materials tell the fire investigator? What types of questions are you asked to examine?

Larry Hanke: The basic things that I can tell is if it's failed, how it's failed or if it's damaged, what the damage mechanism is. So, if I look at something that it has a hole in it, if it's a gas line, for example, it has a hole in it, is that hole a mechanical damage or is it a fracture or is it corrosion? What's caused the perforation that has let the gas leak out? I can also get involved many times in looking at things that are from the fire scene and looking at damage that has resulted in alteration of the component somehow, so I can look at things and figure out whether it's caused by... The damages been caused by the fire or whether it's been electrical arc that might have initiated the fire.

Rod Ammon: All right. So, I'm wondering, just thinking about you getting involved in the case and wanting to make sure that others are aware how to get someone like you involved, who else gives you a call? I'm thinking sometimes it might not be just the fire investigator.

Larry Hanke: No, sometimes it is. I mean, there are certain fire investigators that know me that will call me when they get into a scene to figure out what they should be saving and what we can do with that. But most of the time I'm getting called by either the insurance company that covers the property or the insurance company that is defending what is being blamed as the cause of the fire. So, normally I get hired by either the insurance company or a law firm that's representing the insurance company.

Rod Ammon: Okay. So, what's the typical day look like for you? What kind of things do you do as an engineer?

Larry Hanke: A typical day for me is probably not going to be involving a fire investigation. So, we look at all sorts of broken things and do all sorts of consulting for manufacturers of different products. So I may be looking at a medical device one day, car the next day, and then artifacts from a fire scene the following day. So, that may be just looking at them, making measurements of a part or doing research on the material that the part's made out of, or I could be in the laboratory doing something, taking pictures with the microscope, either a light microscope or a scanning electron microscope or analyzing the microstructure of a metal, for example. That's very key to the work that we do here. Basically just looking at the part and characterizing the damage and trying to figure out what has caused that damage to get that back to the root, to the root cause of the incident.

Rod Ammon: So, what's it like in your lab? I mean, describe it to me.

Larry Hanke: It's pretty clean. A lot of our work for the industrial part of it is for medical device companies. So, it's very important that we keep the laboratory clean and have areas that we can put things that we know that they're not going to be contaminated. So, that's important for a fire investigation as well. Although at the end of the day, if we're doing a fire investigation at the end of the day, the laboratory isn't nearly as clean as it was in the morning. So, that's going to be the end of the day is going to be cleaning up the laboratory to make it available for the next day. But we'll start off usually with a visual exam of the components that are at the issue and gradually work our way up in magnification and different levels of destructive evaluation. So, at first we'll probably look at a part, take some measurements, take photographs with the regular digital camera, a single lens reflex camera probably, and then we would look at it at higher and higher magnification. So, we'll start off with a stereo microscope and we'll take photographs with a stereo microscope and eventually we'll decide which parts of that component need to be more closely evaluated. So we'll make drawings and sketches with marks on them to show where it's going to be cut and cut out different pieces to look at in a scanned electron microscope, for example, or to do microstructural evaluation of that part.

Rod Ammon: Okay. So, let's say you get done with a portion of, or let's say you're done with a specific fire investigation. What should the fire investigator expect from a materials examination report?

Larry Hanke: For the rewritten report, it would be more detailed, but obviously we're available for more informal consultations before the written report is done. So, at the end of the day, we'll sit down with a fire investigator and describe what we've done, what we've seen, what the significance of those features are, and how they could be related to the fire and then answer any questions that the investigator has, specific questions that he may have regarding the artifacts at issue. But in the end, what we'll really be able to do, what's really important is going to be, say, what's the component? What's it made out of? How is that material going to behave in a normal manner? How did it behave? Was it affected by the fire? In other words, how hot did it get is often question that I have about a particular part and we can tell that based on the hardness, the mechanical properties and the microstructure, for example, when we're done to see where it was when it started and how it's been changed by the fire, for example, perhaps.

Rod Ammon: So, do you ever get involved in creating visuals or explanations that would help make a case either describe to, I don't know, the insured or a jury for instance?

Larry Hanke: Oh, definitely. Definitely. What we do do is very visual. So, I've had many cases in trial and we've made some pretty spectacular graphics to show the jury to be able to help them understand the technical part of the material behavior. In other words, because what we do is even the microscopic work is documented with images and some of them can be very colorful and graphic, which can really help a jury understand what the circumstances of the failure were.

Rod Ammon: Okay. So, I'm thinking of one thing. It's in the back of my mind. Often when I talk to folks like you that are in a supporting role to an investigation or part of a team, they have things that they wish they could communicate to fire investigators. So, this is your chance. I was thinking, I wish I could have told them this. I wish they would've done this. Do you have any messages you'd like to pass on?

Larry Hanke: Not really. I think I'm pretty clear with what I think I need to do. So, if I have an artifact, I ask questions, if I need to know about what that artifact was, how it was handled, in other words, and taken out of the fire scene to make sure that whatever I'm seeing is a real evidence and not an artifact of the extraction from the fire scene. And certainly most of the investigators that I work with know that when they come to me, I'm going to ask questions. So, they're prepared and they've got those already at the tip of their tongue when we start.

Rod Ammon: That's really great to hear. I'm thinking now maybe you could give us some examples for some of the people in the audience who might not be as aware of what you do, some examples of your casework.

Larry Hanke: Most of the cases that I work, the parts that I work with are very simple. For example, I'll get the wiring, electrical wiring from a building going now the investigator is maybe using something like arc mapping trying to define the origin area, and he wants to know what we've got, how much of this is melting from the fire, and how much of it could be electrical. So, by doing the metallurgical evaluation, I can determine that quite conclusively because the physical morphology and the microstructure of the metal of the electrical conductors will be very different if it's electrical arcing versus ambient temperature of fact. There may be components that are otherwise damaged, not related to the fire, and an investigator will want to know about that. So, for example, years ago I did a number of investigations, assisted with a number of investigations where overhead radiant heaters installed in open spaces like warehouses or fire stations where there's a big tube in the ceiling. I don't know if anybody that's listening knows what that is, but basically you've got a fire at one end and it heats up the tube and the tube then radiates the heat out into the open space and those were very popular and are still popular, I think. But there were a number of failures several years ago that were related to fractures of the incoming gas line where the gas line comes in to feed the burner on the end of the tube and by looking at the fractures, I could tell right away that those were fatigue failures. In other words, they were caused by the growth and the shrinking of the radiant heating tube that put a bend on the gas line, multiple bends until it had fractured, then that of course released gas into the ambient space and when you've got a burner right there, once you have the right amount of gas in the air, it doesn't take long to have a big boom.

Rod Ammon: Yeah. Well, glad you figured out what it was and hope that it avoided a couple of the situations in the future. I'm sure there's a lot of things that you do where you are able to prevent future events.

Larry Hanke: I hope so. That's the whole point of this job. I think the rules have changed about those heaters and they've changed the codes, I think for the most part to change the way that the gas line comes into the burner. So, it doesn't bend at a highly focused area. In fact, one of the fire investigators that I worked with was very active in the community, in the regulation community called me up and wanted to know more about what we'd seen and take some of my photographs that he could take to the code group and just so that they could change the rules for the heaters.

Rod Ammon: Yeah. Well, I'm glad to know you were there because that does sound like a scary situation. Any others that are, even some things that are basic, I can imagine that there's times when you've gotten something as simple as an outlet.

Larry Hanke: Exactly. So, the simplest one I've ever done is an investigator came to me and wanted to make sure of what was on the polarized outlet on which was the hot side and which was the neutral side. If you've worked with outlet before, you know that where the wires come in and they're attached, that one of the two screws that hold the wires to the outlet is brass, and the other one is a silver finish. So, we were able to analyze the two screws in the scan electron microscope using something called energy dispersive x-ray spectroscopy, and verified that one of them had a coating, which was the hot side and let it lay out the wiring and they were able to solve the mystery then and trace the fire back to a stain rags that were in the area and it wasn't a failure of the outlet at all, but it was a victim. The damage to the outlet was a victim of the fire.

Rod Ammon: So, I'm guessing that the rags were left out to dry?

Larry Hanke: I assume so.

Rod Ammon: Okay. Well, you started it, you said, I'm going to give the easiest one I did. So, you want to talk about the hardest.

Larry Hanke: I can tell you about the more most complicated one, which was an area where we had laid out the entire underground heating system from a driveway that had snow melt on it. So, that was the case where we had rebuilt the entire system down on my farm in Iowa inside a Quonset hut, if you know what that is.

Rod Ammon: Yeah, wow.

Larry Hanke: We couldn't put it in the barn, obviously, we didn't want to burn the barn down, but that was a tough one.

Rod Ammon: Yeah. So, you're talking about one of these radiant driveway heating systems?

Larry Hanke: Correct.

Rod Ammon: Wow.

Larry Hanke: An extensive one. So, there was many, many feet of cable under the ground.

Rod Ammon: It's funny, I always thought that there was fluid running through those.

Larry Hanke: Oh, I think that's one style. But this happens to be the electrical resistance heating system.

Rod Ammon: So, what did you find out?

Larry Hanke: Well, we found out that the heating system worked, it seemed to work okay. So we don't think that it was the cause of the failure, so it had to do with the way that the owners were operating it.

Rod Ammon: Wow. So, you mean to tell me they actually took up the heating system from underneath the driveway so that you could move it to another location to test it?

Larry Hanke: Yes.

Rod Ammon: I've heard of hard digs, but that sounds pretty brutal.

Larry Hanke: It was a big job. It was a big job

Rod Ammon: And a gentle job, I would think. A lot of work that you have to do carefully. Wow. Yeah. Any other idea or any other examples that you care to share?

Larry Hanke: Well, the other one that I really like is the work that we did on the cruise control for Ford trucks years ago. There was a problem with the speed control deactivation switches that were causing fires. So we did the metallurgical evaluation of those and that was fun because I actually got to testify in that case, eventually. But they were pretty dangerous because they could start fires when the truck wasn't running. So if the owner put the truck in their garage, left in the garage and went to bed, they could start a fire overnight so it is a very dangerous situation.

Rod Ammon: What was actually happening?

Larry Hanke: What was happening was that the way that the switch was sealed off from the brake fluid, because what it says was the switch that shut down the cruise control when you touch the brakes. So, it reacted to the press pressure in the brake system and the brake fluid and they used a Kapton seal to keep the brake fluid away from the electrical part of the switch. But the Kapton eventually broke down because it had to survive the full pressure of the brake pedal but it also had to react to a very, very small amount of pressure on the brake pedal to turn off. So the bottom line is that the kapton seal that was in the switch body itself would crack and leaked brake fluid, which happens to be flammable into the electrical components and it caused a short between the positive and the negative inside the switch and that started the brake fluid on fire. The switch is mounted on the master cylinder. So that's where there's a lot of fluid, there's a lot of oil on the engine in that area. So it's tended to be a pretty big fire.

Rod Ammon: I'm thinking somebody had to do a real good job, or there had to be a repeated failure, I mean what tipped you off or what tipped off the investigators?

Larry Hanke: Well, before I got involved, a number of investigators that looked at these had done the location of the failure origin, the fire origin to the area of the master cylinder, and of course, after the fire, the master cylinder is melted and collapsed and the switch is a lot of times ended up on the ground. But different investigators were smart enough to realize that there was an electrical potential within that switch that was always on. So I think someone probably looked at it and went, "Hey, these switch components don't look right, something else is happening here." This is charred brake fluid or melted plastic, something in that area. So that's when they brought them into me and said, what can you see here? What we could see was that there was very high temperature for the switch component, the metallic switch components, and some of them actually had arcing between the contacts of the switch.

Rod Ammon: That's really interesting. I'm often amazed at the level of detail and the intelligence, the thought process that goes through to find something like that when you're dealing with, in many cases, this massive hunk of char.

Larry Hanke: Oh, right, right. If you think about it, if you think about a car to find this little thing that'll fit in your hand, the palm of your hand out of all of the mess that's around on the car. Yeah, that's right.

Rod Ammon: I see a lot of classes and I've been to a few of them for vehicle fire investigations, and it still amazes me after I sit there and look at what they're doing, and I'm just like, "Man, you got to be a dedicated person to want to dig in there."

Larry Hanke: Right. No, that's very true. Fortunately for me, I'm not the guy that's out there digging 99% of the time. I wait till those people, those investigators are out there that they've found what they think are the key parts and they bring them back to me and all I do is maybe sort out a few of the key parts and say, "Well, it could be this one or it could be this one, or it's none of these."

Rod Ammon: You just made me think of, we've done a lot of things about spoilation and I was thinking about, "Oh, he's the lucky guy who gets the silver can after all that digging." But what's the biggest piece of evidence that you ever had to work on?

Larry Hanke: Oh man. I think the biggest thing that I ever had to work on was a mineral terminal on Lake Michigan. What did they, a stacker reclaimer, I think they called it.

Rod Ammon: Okay.

Larry Hanke: I can't remember, but it was huge.

Rod Ammon: Like for taconite, that kind of-

Larry Hanke: Yeah, this was actually at the steel mill. So, yeah, they scooped up. I think they probably did scoop up taconite with it, but they also scooped up whatever the coke and whatever they would use in the steel mill.

Rod Ammon: So, how big was this thing? Was this like a shovel?

Larry Hanke: No, I'm trying to remember. The shovel on the end was big enough to fill up a truck, a semi-truck, and that was the shovel on the end and I don't remember the size of it, but it was...

Rod Ammon: Well, that's big enough.

Larry Hanke: Yeah, no.

Rod Ammon: Filled the back of a truck

Larry Hanke: And you had to actually climb a ladder or use an elevator to get up to where we could go to look at the evidence.

Rod Ammon: As far as communicating some other things to fire investigators, how do they know, and you sound pretty confident in the investigators you work with, but maybe there's some other folks out there around the globe that haven't worked with you, that aren't as aware. How does the fire investigator know if a case needs a metallurgical or a materials analysis?

Larry Hanke: Well, I think that the good fire investigator will put a team together initially and look at the big scene and see where he think it's thinks it's going to go. But I think the reality is, what it boils down to is that if the investigator is looking at a piece that he thinks is important to the investigation and he doesn't understand what happened to it, that's when we can get come in and try to help him to understand what the history is, the history of that part might be. But I think, like you said, I think most of the investigators are aware before the investigation is over or at some point they know what's important and all they have to do is realize what they understand and what they don't understand about the important artifacts and if it appears to be a materials issue, that's where I can get involved.

Rod Ammon: All right. So, give me some tips for fire investigators, how they can take advantage of what material analysis provides.

Larry Hanke: Well, I think the one thing that we can provide that almost all structure fires get involved with is knowing what's the difference between the fire melting and arc melting. So, we can do that. They can look at what the source of the fire is, if it's a gas related fire, where's the leak? What component has the leak, and what has caused the leak, because we can look at that and try to figure that out.

Rod Ammon: And what should fire investigators do to build up their awareness of what your capabilities are?

Larry Hanke: Well, I think listening to this podcast is probably one thing that shows that they're on the right track. But going to conferences, the IAAI International Training Conferences are good to learn about the techniques about the different sciences that are involved in fire.

Rod Ammon: Anything else I'm missing? I just feel like there must be a myriad of cases that are out there, but I know sometimes you can and cannot get into the details of those. But anything I'm missing that you'd like to get across? I have one other question, but I'd rather hear what you're thinking first, if anything.

Larry Hanke: No, I think we've pretty much covered it because you're right. What you have to do is just talk to your colleagues and ask them who they use and how they would recommend, because it's important that you put that team together early on, because a lot of the stuff that we do can be really messed up if it's not handled correctly during the breakdown. So, that's important to get us involved in a timely manner, but otherwise collect the evidence and collect it right and find someone that you like to work with.

Rod Ammon: All right. I was reading the paper this morning, well, the paper on my phone, and I saw that they're starting to do an investigation on the ship fire that happened in Newark at the Newark port in New Jersey. I thought of you and I thought, man, if there's a place with a lot of metal and a lot of fire, unfortunately that was, we had two fatalities there, but any thoughts you want to share or what did you think of when you saw that from your perspective?

Larry Hanke: Well, I haven't seen enough of the details to really know what's going on. I do know someone that's been out there, so I guess I'll find out sooner or later what the key issues are. But something that size, those are really tough to sort out and get down to that screw or that wire or whatever it needs to get into the laboratory to be looked at.

Rod Ammon: Yeah, I mean, thinking about that starts to make the cruise control switch look a little bit more simple. So Larry, any other examples of some of the work that you've done?

Larry Hanke: I think the one thing that we didn't cover that I've done a lot of is corrugated stainless steel tubing as gas supplies a mechanism. CSST tubing is fantastic because obviously it can be installed quickly and it's much safer in areas that have earthquakes and whatnot. But there is a problem with it here in the Midwest that hasn't been solved as far as I know, and that's that lightning in the area can perforate the tubing and cause gas leaks. So, we can take a look at the tubing out of a fire and do a pressure test and verify the location of a leak and separate the leaks that have been caused by the fire from leaks that were preexisting in the fire, which had probably been caused by lightning.

Rod Ammon: This is very interesting to me. So, how, I mean, one I guess is from, you can see from melting and well, I'm asking you, so.

Larry Hanke: So, right. Well, the holes can actually look very similar. I've spent, I don't know how much time, I don't want to think about how much time I've spent in laboratories where we've had 40 feet of CSST with a hundred holes in it going through and looking and saying, "Okay, that one's fire, that one's fire, that one's fire. Oh, there, what's that one?" But basically what we've got is that the holes that have been resulting from the fire in the stainless steel have been caused by corrosion in general and those have very jagged undercut material loss that has perforated the tubing. But the lightning and electrical activity that has caused holes in the CSST have very rounded edges and that they're very, very characteristic in terms of their morphology versus the corrosion or mechanical damage.

Rod Ammon: No. So, I don't know this is just one of these crazy things where I've got a smart engineer on the phone and I want to ask him a question, and it relates to lightning. I mean, I remember my mother telling me, you got to close the windows on both sides of the room, and you don't want to be in drafty areas and lightning can be huge and then recently, I just heard most lightning is, I don't know, something like a quarter inch wide. Any thoughts on this? Just because I find it interesting. I've seen some of the results in different fire investigation, fire investigation evidence that I've seen as photographs, and I was like, "Wow, that doesn't really look like much." And then I look at a tree and I go like, "Oh, wow, it looks like it was..." What are your thoughts?

Larry Hanke: Well, I think the lightning in as far as the CSST goes can be in areas that are remote from the house. There could be a lightning strike, can be in a tree that's out on the yard away from the house, but the electrical fields from the lightning can be so varied that they can cause damage a long way away from where they've hit. So even though the lightning bolt itself is only small, the field that is generated from the lightning can be huge.

Rod Ammon: Wow.

Larry Hanke: So, it gets into the system, gets into the electrical system of the building, and in this case it gets into the gas lines and propagates through the gas lines until it can be transferred to another ground and it's that point where it goes from one material to another, that it can cause the melting and the perforation of the tubing.

Rod Ammon: I thought that type of tubing was discontinued. Am I mistaken or did they just upgrade the way it's made or...

Larry Hanke: I think there has been an upgrade.

Rod Ammon: Okay.

Larry Hanke: I don't follow this stuff closely, and I haven't worked on a CSST failure for a couple of years.

Rod Ammon: I just remember when I... God, a long time ago, putting in a stove trying to find this stuff, and they're like, "Oh no, they don't make that anymore."

Larry Hanke: Okay.

Rod Ammon: All right. Well, again, I appreciate your time and anything else I'm missing?

Larry Hanke: Nope, I think we got it.

Rod Ammon: All right. I'll say goodbye this time, Larry. I appreciate again, your contribution to us here at CFITrainer.

Larry Hanke: My pleasure. Glad to do it.

Rod Ammon: All right, you be well.

Larry Hanke: You too, Rod. Bye bye.

Rod Ammon: This podcast and CFITrainer.Net are made possible by funding from a fire prevention and safety grant from the Assistance to Firefighters Grant Program administered by FEMA and the US Department of Homeland Security, with support from the Bureau of Alcohol Tobacco Firearms and Explosives, and voluntary online donations from CFITrainer.Net users and podcast listeners.

Thanks for joining us today on the podcast. Stay safe out there. We'll see you next month for the IAAI and CFITrainer.Net. I'm Rod Ammon.

Materials Evaluation and Engineering, Inc.