Feb. 4, 2026

237 - Fire Fundamentals pt. 18 - Explosions with Ali Rangwala and Lorenz Boeck

237 - Fire Fundamentals pt. 18 - Explosions with Ali Rangwala and Lorenz Boeck
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237 - Fire Fundamentals pt. 18 - Explosions with Ali Rangwala and Lorenz Boeck
237 - Fire Fundamentals pt. 18 - Explosions with Ali Rangwala and Lorenz Boeck
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Welcome back to Fire Fundamentals! Today with prof. Ali Rangwala from WPI and dr Lorenz Boeck from Rembe and WPI we take the world of explosion protection engineering. 

In this episode we touch:

• distinguishing fires and explosions by time scale and damage mode
• taxonomy of explosions by energy density and deposition time
• hybrid mixtures in coal mines and turbulent burning velocity
• severity metrics for gases and dust deflagration index for reactivity
• explosion sphere testing, ignition positioning, and model limits
• ignition sensitivity minimum ignition energy and hot surface risks
• prevention via ventilation, inerting, and ignition control
• protection through deflagration vents, isolation, and external hazards
• pressure vessel bursts, inspections, and rupture disks
• transport scenarios vapor clouds and BLEVEs with fireball correlations

We also delve into future directions for explosion research:

• emerging risks hydrogen, BESS, ammonia, and layered defenses
• space and microgravity impacts on dust and flammability

Check out the XPE programme at WPI, and find more informations on how to enroll at:  https://www.wpi.edu/academics/study/master-science-explosion-protection-engineering

I have also received some good listening material, that you could follow up with:

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The Fire Science Show is produced by the Fire Science Media in collaboration with OFR Consultants. Thank you to the podcast sponsor for their continuous support towards our mission.

00:00 - Setting The Stage: Why Explosions

02:57 - Meet The Experts And Their Paths

07:51 - Why A Master’s In Explosion Protection

10:44 - Fire Vs Explosion: Core Differences

14:22 - Types Of Explosions And Scales

21:05 - Hybrid Mixtures And Coal Mines

24:12 - Burning Velocity And Flame Speed

27:39 - Severity Measures And Dust Indices

31:15 - Testing Tools: Explosion Spheres

35:05 - Ignition Sources And Sensitivity

39:19 - Prevention: Ventilation, Inerting, Control

43:20 - Non-Combustion Blasts And Process Safety

47:19 - Deflagration Venting And External Hazards

52:06 - Fragments, Risk, And Protective Design

56:12 - Capstones And Industry Projects

01:00:13 - Transport Hazards: VCEs And BLEVEs

01:05:15 - Emerging Frontiers: Hydrogen And Batteries

01:09:16 - Ammonia, Toxicity, And CFD

WEBVTT

00:00:00.297 --> 00:00:00.928
Hello everybody.

00:00:00.928 --> 00:00:02.427
Welcome to the Fire Science Show.

00:00:02.427 --> 00:00:09.237
And here we are once again back, uh, to the Fire Fundamentals Series, or perhaps today it's explosion fundamentals.

00:00:09.237 --> 00:00:15.340
But on that in a second, fire Fundamentals is one of the audience favorite.

00:00:15.340 --> 00:00:30.652
And serves a role to introduce some aspects of fire safety engineering, perhaps in a little bit more structured way than the general podcast interviews, but still serve the same purpose, transferring knowledge in an easy way so we all learn from it.

00:00:30.652 --> 00:00:35.512
I also learn, uh, from doing those episodes, I learned a lot from doing those episodes anyway.

00:00:35.512 --> 00:00:39.412
Uh, for this episode, I thought we have never really covered explosions.

00:00:39.412 --> 00:00:43.716
Well in the fire science show, well, it's a fire science show, not the explosion, show.

00:00:43.716 --> 00:00:53.121
But, uh, I guess, uh, whether we like it or not, fire safety engineers are commonly exposed to some sort of explosion engineering in one way or another.

00:00:53.121 --> 00:01:01.893
At least I have been over the years of my career, continuously asked about some explosion related Analysis, commentary or consultations.

00:01:01.893 --> 00:01:07.135
Therefore, I think it's important to at least have the basics covered and to teach explosions.

00:01:07.135 --> 00:01:18.302
I, I went to people who teach explosions every day, and they actually have opened a whole master course on explosion, protection, engineering.

00:01:18.302 --> 00:01:21.966
Which is, I believe the first one around there, those great people?

00:01:21.966 --> 00:01:25.661
Are Professor Ali Rangwala and, uh, Lorenz Boeck.

00:01:25.661 --> 00:01:30.070
Ali is a professor at Worcester Polytechnic Institute, WPI and, uh.

00:01:30.070 --> 00:01:37.530
Lorenz is a chief uh, officer at the Rembe and also an adjunct professor at the WPI.

00:01:37.530 --> 00:01:41.819
And as I said, they teach a whole master course and explosion.

00:01:41.819 --> 00:01:46.507
I ask them to do a very difficult thing to give me a 1 0 1 version that com.

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Pressed version of stuff that they try to convey through the course.

00:01:51.152 --> 00:01:57.352
In one podcast episode, we also talk a lot about why it's important to learn about explosions.

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When that knowledge becomes important and useful, how it is used, what types of explosions are there, what are the severity measures, what are the sensitivity measures, All that in this compressed podcast episode.

00:02:10.455 --> 00:02:11.715
I hope you enjoy.

00:02:11.715 --> 00:02:15.164
I've learned a lot and I hope that you will as well.

00:02:15.164 --> 00:02:17.474
Let's spin intro and jump into the episode.

00:02:42.711 --> 00:02:46.941
The Fire Science Show podcast is brought to you in partnership with OFR Consultants.

00:02:46.941 --> 00:02:56.711
OFR is the UK's leading independent multi-award winning fire engineering consultancy with a reputation for delivering innovative safety driven solutions.

00:02:56.711 --> 00:03:05.939
we've been on this journey together for three years so far, and here it begins the fourth year of collaboration between the Fire Science Show and the OFR.

00:03:05.939 --> 00:03:23.366
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00:03:23.366 --> 00:03:30.356
This makes me very proud and I am super thankful to OFR for this long lasting partnership.

00:03:30.356 --> 00:03:46.236
I'm extremely happy that we've just started the year four, and I hope there will be many years after that to come So big thanks, OFR for your support to the Fire Science show and the support to the fire safety community at large that we can deliver together.

00:03:46.236 --> 00:03:53.794
And for you, the listener, if you would like to learn more or perhaps even become a part of OR, they always have opportunities awaiting.

00:03:53.794 --> 00:03:58.235
Check their website@orconsultants.com And now let's head back to the episode.

00:03:58.751 --> 00:03:59.381
Hello everybody.

00:03:59.381 --> 00:04:04.751
I am joined today by Ali Rangwala, professor at Worcester Protecting Institute, WPI.

00:04:04.751 --> 00:04:05.350
Hey Ali

00:04:05.361 --> 00:04:05.689
Hello.

00:04:05.895 --> 00:04:11.594
and Lorenz Boeck, chief, uh, scientific officer at Reba, and also an adjunct professor at WPI.

00:04:11.594 --> 00:04:13.106
Hey Lorenz, welcome back.

00:04:13.187 --> 00:04:14.141
Hey, thank you.

00:04:14.419 --> 00:04:15.080
Thank, thank you.

00:04:15.080 --> 00:04:16.430
Thank you for agreeing to this.

00:04:16.430 --> 00:04:22.420
Uh, we've previously tease that we need to do a explosion fundamental episode, and here we are.

00:04:22.420 --> 00:04:27.452
so before we start, maybe you guys would like to introduce, yourself and what you're doing.

00:04:27.452 --> 00:04:27.992
Where are you from,

00:04:28.053 --> 00:04:29.463
so yes, so thank you once again.

00:04:29.463 --> 00:04:39.170
Uh, uh, so my undergraduate degree is in, uh, electrical engineering from Pune, India, and then I got my master's in Fire Production Engineering from University of Maryland College Park,

00:04:39.605 --> 00:04:39.966
Hmm.

00:04:40.040 --> 00:04:43.613
worked on a problem of low ventilation compartment fires, with Professor Jim Quinter.

00:04:43.613 --> 00:04:50.211
Uh, then I got my PhD, at uc, San Diego, with Professor Steve Buckley, where I worked on flame spread on condensed fuels.

00:04:50.211 --> 00:04:53.696
so then I interviewed at WPI in 2006.

00:04:53.696 --> 00:04:57.608
and, uh, they liked me here and I, and I got a job as an assistant professor.

00:04:57.608 --> 00:04:59.586
so I've been here since then.

00:04:59.586 --> 00:05:11.071
along the way, I have graduated around 10, PhD students, uh, and around 10, around 20 master's thesis students, uh, working on different problems, mostly related to industrial fire and explosion safety.

00:05:11.071 --> 00:05:17.286
from an explosion research perspective, I've been working on dust explosion problems since 2006.

00:05:17.286 --> 00:05:22.475
uh, initially I was working on dust layer ignition with Tim Myers and Alfonso Berita from Exponent.

00:05:22.475 --> 00:05:32.875
what really got me into the problem of explosion of dust explosions especially was this five year research grant, from NSF on the topic of understanding dust explosions.

00:05:32.875 --> 00:05:45.209
So at WPI, uh, one of my PhD students, Scott Rockwell, uh, he developed a very unique experimental platform to measure laminar and tur and burning velocity of air and hybrid dust, air gas mixtures.

00:05:45.209 --> 00:05:50.009
And so this was a shift from the traditional explosion sphere apprentice.

00:05:50.009 --> 00:05:59.608
we later worked, on, experiments and modeling with Professor Sava Ackerman from the University of West Virginia, on dust explosions, especially in coal mines.

00:05:59.608 --> 00:06:03.170
I've also written a book on explosion dynamics, with Bob Zalo.

00:06:03.170 --> 00:06:06.290
And Bob was at WPI, uh, when I joined.

00:06:06.290 --> 00:06:10.281
And a lot of courses I teach were originally, were originally developed by him.

00:06:10.281 --> 00:06:20.139
we are currently working on building Bob's legacy at WPI by working towards creating one of the best curriculums related to the study of explosion safety in the world.

00:06:20.139 --> 00:06:26.302
And last year we launched a Nation's first Masters of Science Explosion program, in explosion production engineering.

00:06:26.607 --> 00:06:27.237
That, that's good.

00:06:27.237 --> 00:06:27.627
That's good.

00:06:27.627 --> 00:06:29.786
Well, I, I knew who I'm bringing to the show.

00:06:29.786 --> 00:06:32.694
You're definitely the explosion, person in my mind.

00:06:32.694 --> 00:06:33.983
Uh, how about you, Lawrence?

00:06:33.983 --> 00:06:35.184
What, what brought you to Explosion?

00:06:35.184 --> 00:06:35.738
What's your background?

00:06:36.074 --> 00:06:45.824
So I started in explosions during my PhD, which was a technical University of Munich, and I'm very thankful that my advisor, professor Meyer, brought me into this world.

00:06:45.824 --> 00:06:49.740
He offered me a research topic on the explosions in Fukushima.

00:06:49.740 --> 00:06:56.096
So nuclear reactors scenario where hydrogen release due to a loss of coolant led to hydrogen explosions.

00:06:56.096 --> 00:06:58.620
that started the journey for me.

00:06:58.620 --> 00:07:04.380
So ever since my PhD, I've been doing explosion research and then transitioned into industry.

00:07:04.380 --> 00:07:12.134
After PhD, I came to the us I worked at Caltech with Professor Shepherd, especially on explosion hazards in commercial aviation.

00:07:12.134 --> 00:07:13.862
Then I made the switch to industry.

00:07:13.862 --> 00:07:25.262
I joined fm, or at the time they were so called FM Global as a research scientist, where I was in charge of large scale explosion testing, as well as modeling and testing of explosion safety devices.

00:07:25.262 --> 00:07:33.437
After if I'm a joined Reba as Chief Scientific Officer, where I'm now in charge of our r and d efforts to push the boundaries of explosion protection.

00:07:33.437 --> 00:07:40.196
since last year, I'm lucky to involved in the explosion Master's program at WPI.

00:07:40.196 --> 00:07:41.365
Very thankful for that.

00:07:41.365 --> 00:07:50.805
It's a fantastic experience to be able to share, experience and our understanding from an industrial explosion protection standpoint with the next generation of engineers.

00:07:51.211 --> 00:07:56.771
Uh, you have started an Explosion protection engineer program, uh, at WPI.

00:07:56.771 --> 00:07:58.961
It's a fresh initiative.

00:07:58.961 --> 00:08:05.288
Perhaps you tell me why, why do you think this, field, needed a whole program related to it?

00:08:05.581 --> 00:08:12.886
so, uh, WPI has always been in the forefront o of teaching, developing and cutting edge research on, uh, engineering safety.

00:08:12.886 --> 00:08:22.725
Uh, we have a fire protection engineering program that is, uh, almost 45 years old and we have been teaching graduate level explosion protection related courses since 1980.

00:08:22.725 --> 00:08:33.510
Uh, when Professor Bob Zalo, after having a successful career at FM Global, decided to join WPI he developed some of the first courses, in this area.

00:08:33.510 --> 00:08:38.716
so in a way he was a pioneer in defining the explosion, production, engineering discipline.

00:08:38.716 --> 00:08:42.193
so, uh, why have we started, uh, this program?

00:08:42.193 --> 00:08:46.903
Um, the reason is the world is moving towards a direction of carbon neutral energy.

00:08:47.428 --> 00:08:47.788
hmm.

00:08:47.879 --> 00:08:56.366
so this means renewables, hydrogen biofuels, and any kind of storage of energy, uh, for example, in batteries as well.

00:08:56.366 --> 00:09:01.565
Um, all this is going towards a high energy density, storage solution.

00:09:01.565 --> 00:09:05.171
high energy density, storage, transport and handling.

00:09:05.171 --> 00:09:10.196
uh, and the fundamental problem with any of these solutions, is explosions.

00:09:10.196 --> 00:09:29.706
So as you start storing more and more amount of energy in lesser and lesser amount of volume, the hazard due to an explosion is much greater so keeping this changing, global environment, uh, the faculty at WPI from chemical engineering, civil engineering, mechanical engineering, uh, aerospace engineering.

00:09:29.706 --> 00:09:37.924
Fire production engineering, they all came together, uh, and decided to roll out this, uh, interdisciplinary explosion production engineering program.

00:09:37.924 --> 00:09:41.760
uh, it's the first program which is a master's program, in the us.

00:09:41.760 --> 00:09:50.520
and the idea was to bridge the knowledge across many engineering disciplines, uh, towards defining a curriculum for explosion protection engineering.

00:09:50.520 --> 00:09:55.048
Uh, so we have been internally working on this, for almost two years.

00:09:55.048 --> 00:10:07.652
Lawrence has been a part of this as well in kind of defining the curriculum, how it should look from an industry perspective, and, and I think we have some of the most unique and interesting courses, uh, in this subject area.

00:10:07.652 --> 00:10:11.339
and, the thing that you must remember is the practice of explosion.

00:10:11.339 --> 00:10:21.759
Production has existed for a very long time, but it basically lies in this, in these codes and standards, on one side and then on technical papers, on the other side.

00:10:22.374 --> 00:10:22.594
Mm

00:10:22.749 --> 00:10:29.104
makes it very fragmented, and this was an attempt to truly define this discipline for the first time.

00:10:29.104 --> 00:10:34.638
and also importantly, the, program is dedicated to, uh, Bob Zilo.

00:10:35.038 --> 00:10:35.639
Fantastic.

00:10:35.639 --> 00:10:44.756
And how do you think, how big is the overlap between the explosion prevention versus, uh, fire protection engineering?

00:10:44.756 --> 00:10:46.886
Does the overlap exist?

00:10:46.886 --> 00:10:52.886
Is it how, how much of it is, is common between the disciplines and how much divides them?

00:10:53.341 --> 00:11:02.667
well, there is a, uh, there is a big, uh, difference, uh, between fire, and explosion to start off with.

00:11:02.667 --> 00:11:09.379
so, your key distinction, between an explosion and a fire, uh, is the timescale and physics.

00:11:09.379 --> 00:11:14.537
So fires evolve over minutes, while explosions occur over a millisecond.

00:11:14.537 --> 00:11:17.961
secondly, fire is fundamentally about thermal damage.

00:11:17.961 --> 00:11:27.172
and explosion, are more about pressure, damage, uh, and damage from the fragments, uh, that are created from the pressure damage.

00:11:27.172 --> 00:11:36.077
so naturally you have some overlap of where, for example, core courses like combustion, fluid dynamics, ignition.

00:11:36.077 --> 00:11:44.580
in, are, are in sync, uh, but then you have to kind of have a completely different, uh, ideology.

00:11:44.580 --> 00:12:02.293
when it comes to explosion protection, engineering, where you have to go into the compressible flow world, have to go into explosion dynamics, which is very much different from, fire dynamics, explosion protection, engineering, again, because of the timescales, uh, in the problem, which are extremely small.

00:12:02.293 --> 00:12:16.743
and the fact that you are trying to study about pressure, uh, rise versus time compared to temperature rise versus time, uh, you have a, a different, course or a different, a different set of graduate courses towards that.

00:12:16.743 --> 00:12:19.206
Uh, and then finally you have your modeling as well.

00:12:19.206 --> 00:12:24.649
So explosion modeling and fire modeling are, are two different, altogether.

00:12:25.150 --> 00:12:29.260
But, uh, I, I guess, uh, some things must be very common.

00:12:29.260 --> 00:12:45.009
I think flammability lies in the heart of both disciplines, and I think to a large extent, there will, at least from the fire protection engineer perspective, there will be an overlap in assessing the hazards, you know, the fuels, uh, the potential scenarios, even trees.

00:12:45.009 --> 00:12:55.328
I, I think this is where a lot of, uh, fire protection engineers will have to deal because something can end with fire, can end with explosion in, in many cases.

00:12:56.004 --> 00:12:56.394
Yes.

00:12:56.394 --> 00:13:04.447
I think it's interesting also from a perspective of, you know, the folks, the students who are joining this program, quite a few of them come from the fire protection

00:13:04.726 --> 00:13:05.017
Okay.

00:13:05.557 --> 00:13:09.427
And, um, that's where this overlap, I think creates a great experience for the students.

00:13:09.427 --> 00:13:20.407
start to understand how these technical, uh, challenges, but the technical, also the technical knowledge they already bring from fire protection helps them understand concepts and explosion protection.

00:13:20.407 --> 00:13:21.907
It's just a different.

00:13:21.907 --> 00:13:24.996
Perspective and a different twist on similar physics.

00:13:24.996 --> 00:13:30.157
Like Ali said, you know, combustion physics, combustion science forms the foundation of all of this.

00:13:30.157 --> 00:13:37.206
But in explosions, we add on compressible flow, blast effects, structural response under dynamic conditions and so on.

00:13:37.206 --> 00:13:49.306
So especially if you go through both fields in your educational journey, fire protection and explosion protection, I think you can get a very comprehensive package that gets you ready for the safety industry and many problems out there.

00:13:49.306 --> 00:13:53.265
I have a student in my class right now, he wants to go in the oil and gas field.

00:13:53.265 --> 00:13:54.436
So guess what?

00:13:54.436 --> 00:13:56.025
Both are extremely relevant.

00:13:56.500 --> 00:14:01.740
And, also touching on our previous episode a few weeks ago on battery storage systems.

00:14:01.740 --> 00:14:05.160
I like, this is so fundamentally intertwined.

00:14:05.160 --> 00:14:10.140
The, the fire safety and explosion safety for those facilities requiring a holistic management.

00:14:10.140 --> 00:14:12.000
I think there's a big future.

00:14:12.000 --> 00:14:14.910
So congratulations on setting up this important program.

00:14:14.910 --> 00:14:19.458
And thanks, once again for coming to Fire Science Show because we have, you know, fire Protection engineers here.

00:14:19.458 --> 00:14:23.749
Let's hope they also have a nice entrance to explosion through this, uh, talk.

00:14:23.749 --> 00:14:35.190
perhaps we should clear out the types of explosions first because, uh, you know, explosion is, I, I guess a broad term that, uh, you can throw a lot of things into it.

00:14:35.190 --> 00:14:42.720
So how you, as, as experts in this field, how do you, I don't know, subdivide the, the, the world of explosion.

00:14:42.720 --> 00:14:46.230
What, what, what are your brackets that you divide the explosions into?

00:14:46.639 --> 00:14:49.360
Okay, so in terms of definition, let's start there.

00:14:49.360 --> 00:14:57.038
So, as I said, an explosion is a rapid release of energy, that generates a pressure wave, that is, uh, traveling away from the source.

00:14:57.038 --> 00:15:09.005
And, uh, a fire, uh, on the other hand is, can also release huge amounts of energy, but this energy is released relatively slowly, and you don't get that same kind of, blast type, pressure wave.

00:15:09.005 --> 00:15:24.721
so with that in mind, the, the way explosions are classified are usually based on these two, ideas that what is the quantity of energy, that is, uh, per unit volume, and what is the timescale.

00:15:24.721 --> 00:15:28.390
At which that energy, is deposited per unit volume.

00:15:28.390 --> 00:15:34.001
so these are the, two scales that you kind of now start classifying explosions, on.

00:15:34.001 --> 00:15:41.940
to give you an example, the highest amount of energy per unit volume, or, or the highest pressure comes from a nuclear, explosion.

00:15:41.940 --> 00:15:47.254
you have enormous amounts of energy that are deposited, around 10 to power of five.

00:15:47.254 --> 00:15:52.522
over pressure in a very, very small timescale of around one microsecond.

00:15:52.522 --> 00:16:02.745
in one microsecond, you are having an over pressure that's about 10 to four of five bars, So that, that forms like the, the strongest kinds of explosions.

00:16:02.745 --> 00:16:18.479
and then you can now start, uh, visualizing all the different kinds of explosions that take place, based on this idea, the simple idea of what is the over pressure that is created or what is the energy that is deposited per unit volume.

00:16:18.479 --> 00:16:22.318
If you see energy per unit, volume has the same, is is the same as pressure.

00:16:22.318 --> 00:16:24.433
Pressure is nothing but energy per unit volume.

00:16:24.433 --> 00:16:28.186
And so what is that, that pressure and how long?

00:16:28.186 --> 00:16:31.033
Time does it take for that pressure to be reached.

00:16:31.033 --> 00:16:38.071
So then you can go on to explosives, where you are one order of order magnitude less compared to nuclear explosion.

00:16:38.071 --> 00:16:47.135
So when you have, when you think of an explosive, you are looking at around 10 to bar of four, bar over pressure, and the timescale is about 0.1 millisecond.

00:16:47.135 --> 00:16:52.355
not the microsecond timescale like the in nuclear explosion, but 0.1 milliseconds.

00:16:52.395 --> 00:16:55.730
And I think, um, Ali, under explosives, it's actually interesting.

00:16:55.730 --> 00:17:01.880
There are engineered explosives, so materials that are designed to explode that are used for blasting, for example.

00:17:01.880 --> 00:17:08.721
But then there are also materials that are not really designed with the intention of an explosion, but that can explode with very similar physics.

00:17:08.721 --> 00:17:11.121
For example, fertilizer grade ammonium.

00:17:12.046 --> 00:17:12.405
Hmm.

00:17:12.560 --> 00:17:13.760
leads us to accidents.

00:17:13.760 --> 00:17:16.161
For example, the one in Beirut, right?

00:17:16.161 --> 00:17:22.611
Where that material can get sensitized and explode in a manner, very similar to actual engineered explosives.

00:17:23.284 --> 00:17:24.453
Yeah, exactly.

00:17:24.453 --> 00:17:39.044
so then, moving along on that same, idea, the next order of magnitude less, which is around 10 to four of three bars of over pressure, and slightly longer timescales that are about 10 to hundred, microseconds.

00:17:39.044 --> 00:17:41.188
you are looking at pressure vessel bursts.

00:17:41.188 --> 00:17:52.943
So these are explosions that necessarily don't even involve combustion, are just pressurized vessels that can break open and release over pressure in the form a blast wave.

00:17:52.943 --> 00:18:00.391
then, uh, again, look along the same, if you go again further down 10, around a hundred bars of lower pressure.

00:18:00.391 --> 00:18:03.929
These are typically steam explosions, so these.

00:18:03.929 --> 00:18:06.391
Over timescales of around one millisecond.

00:18:06.932 --> 00:18:07.051
I.

00:18:07.102 --> 00:18:13.826
further down, from a hundred bars to 10 bars of over pressure, and now you're looking into closed vessel deflations.

00:18:13.826 --> 00:18:22.708
so these are your, your classic explosions or, or deflations that take place when you have complete confinement.

00:18:22.708 --> 00:18:23.367
So let's

00:18:23.417 --> 00:18:23.498
Hmm.

00:18:23.518 --> 00:18:29.038
I'm having a, propane air or methane air mixture in a, in an enclosure and it's completely sealed.

00:18:29.038 --> 00:18:36.959
Uh, and if I ignite it, uh, I will get over pressures about 10 bars, uh, with timescales between one 200 milliseconds.

00:18:36.959 --> 00:18:56.484
So these closed vessel deflagration also form the standard for explosion safety, which is your classic 20 liter explosion or the one meter cube explosion vessel that's used in industry for all the flammability assessment associated with gases, with mist, with, with dusts.

00:18:56.484 --> 00:18:57.756
And so on.

00:18:58.009 --> 00:19:00.914
And Ali in explosion protection engineering.

00:19:00.914 --> 00:19:12.816
this is an extremely important category because this is where we protect, for example, industrial equipment using things like deflagration bands so that these closed volumes, uh, don't rupture.

00:19:12.816 --> 00:19:15.865
For example, under the internal over pressure of an explosion.

00:19:15.955 --> 00:19:25.635
yeah, so that's, so in terms of engineering contacts, these are like your standard equipment, deflations, explosions and dust collectors, explosions and electrolyzers.

00:19:25.635 --> 00:19:31.746
so now from the closed vessel deflations, uh, which are 10 bars, we can go further down the scale.

00:19:31.746 --> 00:19:37.026
So now we are looking at over pressures that are of the order of one bar or even less.

00:19:37.026 --> 00:19:40.185
so these are your classic, uh, building deflations.

00:19:40.185 --> 00:19:42.855
Uh, and these are the most common explosions.

00:19:42.855 --> 00:19:46.756
Like you have gas leaks in buildings, uh, you have dust explosions.

00:19:46.756 --> 00:19:55.442
and these are usually with over pressures between 0.1 to 0.5 bars, uh, with timescales of the order of 0.1 to one second.

00:19:55.442 --> 00:19:59.731
So we have gone from that, that microsecond in nuclear explosions, then the

00:20:00.122 --> 00:20:00.201
Hmm.

00:20:00.602 --> 00:20:08.703
in, uh, in these, uh, steam explosions and closed vessel, explosions to these building deflations that now start taking place in 0.1, second to one second.

00:20:08.703 --> 00:20:14.854
So these are slower and they are weaker in terms of the energy wise, uh, the energy deposition.

00:20:14.854 --> 00:20:17.674
But however, these are equally devastating.

00:20:17.674 --> 00:20:19.865
I mean, you can see this in in practice as well.

00:20:19.865 --> 00:20:22.472
When you have an explosion, you have a very high amount of damage.

00:20:22.472 --> 00:20:26.484
and the reason is because you don't need much in terms of a pressure load.

00:20:26.484 --> 00:20:30.670
To to break open walls of an enclosure.

00:20:30.670 --> 00:20:37.359
So typically walls in a building will start opening up or breaking at around 0.1 bar over pressure.

00:20:37.359 --> 00:20:44.549
that also comes to why explosions are so dangerous because, you don't need much, to, uh, create, damage.

00:20:44.766 --> 00:20:48.758
is the type of expl ties to the fuel to the circumstances?

00:20:48.758 --> 00:20:58.673
Can the same fuel be both, something that def flow rates and detonates, for example, or, or the type of dictates the, the type of hazard explosion that that can occur?

00:20:58.673 --> 00:21:01.223
Or, or, or there are any other factors into that?

00:21:01.605 --> 00:21:04.545
Well, there's an impact of scale, first of

00:21:04.694 --> 00:21:04.984
Okay.

00:21:05.055 --> 00:21:05.325
right?

00:21:05.325 --> 00:21:09.286
Some of these categories that just different, differ massively in scale.

00:21:09.286 --> 00:21:17.506
If you go, um, from a small enclosure all the way up to maybe a Vapor Cloud explosion, that is one of the largest events we see as far as

00:21:18.066 --> 00:21:18.145
Hmm.

00:21:18.195 --> 00:21:20.445
extent of, of Vapor Cloud, for example.

00:21:20.445 --> 00:21:23.056
So it takes a certain time to consume the fuel.

00:21:23.056 --> 00:21:24.453
That's the scale aspect.

00:21:24.453 --> 00:21:32.175
The other part is like you're saying, the rate of reaction, and you already mentioned Deflations and Detonations, so I think we can get into that in a little more detail.

00:21:32.175 --> 00:21:43.226
But Deflations burn a lot slower than Detonations, the two distinct categories of explosions and some fuels can undergo either deflagration or detonation, for example, flammable.

00:21:43.226 --> 00:21:47.576
Gas mixtures with air or with oxygen especially, that can be very reactive.

00:21:47.576 --> 00:21:51.385
So depending on what combustion phenomenon you have, I agree with you.

00:21:51.385 --> 00:21:53.486
Yeah, your timescales can be very different.

00:21:53.579 --> 00:22:01.349
in Poland, a big thing was always the, uh, coal mine explosions where you would have methane and, and some kind of dusts.

00:22:01.349 --> 00:22:05.670
Uh, and, and from what we've learned in here is local knowledge that, that we are exposed to.

00:22:05.670 --> 00:22:10.461
Those were very challenging to, to manage because they were in some way very powerful.

00:22:10.461 --> 00:22:12.932
Can you, can you also comment on, on those types of mixtures.

00:22:13.180 --> 00:22:20.291
Yeah, so those are your classic, uh, hybrid explosions, where you have both particles as well as, uh, a gas, and in coal.

00:22:20.291 --> 00:22:21.521
Mine is usually methane.

00:22:21.521 --> 00:22:27.281
Uh, so you have methane gas and, and these tiny particles of coal and they both are interacting.

00:22:27.281 --> 00:22:38.965
and, uh, from a fundamental point of view, it's a very, complex problem, uh, because you have particle air interaction, you have, the actual premixed flame as well that, that exists.

00:22:38.965 --> 00:22:42.236
And in that premixed flame, you now have these coal particles.

00:22:42.236 --> 00:22:46.970
and then when you add turbulence, which is what most of these explosions are, they're highly turbulent.

00:22:46.970 --> 00:22:49.692
You have additional effects.

00:22:49.692 --> 00:22:54.892
So you have mixing effects that are created because of the presence of the particles as well.

00:22:54.892 --> 00:23:02.484
the quantity that you usually use to, to quantify or model these explosions, uh, is your turbulent burning velocity.

00:23:02.484 --> 00:23:18.273
and that, and, uh, we have done experiments at WPI, uh, that show that your, turbulent burning velocity, can increase or decrease, uh, depending on the particle size, depending on the particle, concentration, and, and depending on the level of turbulence.

00:23:18.405 --> 00:23:20.506
what is the burning velocity exactly?

00:23:20.506 --> 00:23:24.286
Like w what, what kind of o of thing does it measure?

00:23:24.625 --> 00:23:28.974
So the simplest way to imagine the burning velocity is, let's start with a laminar.

00:23:28.974 --> 00:23:30.257
Context first.

00:23:30.257 --> 00:23:38.494
So imagine you have a premixed flame that's moving, and now imagine that, uh, you are on this flame and what do you see?

00:23:38.494 --> 00:23:41.875
You see this unburned gas that's approaching you.

00:23:41.875 --> 00:23:47.016
So the velocity at which this unburned gas is approaching you is the burning velocity.

00:23:47.016 --> 00:23:52.641
and then now again, you are, you, you are having this, this flame moving.

00:23:52.641 --> 00:23:57.827
And Lawrence is, for example, watching me while I'm on this pre flame.

00:23:57.827 --> 00:24:01.202
So the velocity at which I am moving is the flame speed.

00:24:01.202 --> 00:24:03.750
So those are the two main aspects.

00:24:03.750 --> 00:24:08.125
when it comes to, velocity, uh, when it, uh, with premixed, uh, combustion.

00:24:08.470 --> 00:24:18.781
like Ali was saying, um, often we use the fundamental laminar burning velocity as the quantity to characterize reactivity of a flammable gas mixture or vapor, for example.

00:24:18.781 --> 00:24:26.041
but then in reality that burning velocity gets modified through different effects that can lead to flame acceleration.

00:24:26.196 --> 00:24:26.416
Hmm.

00:24:26.882 --> 00:24:36.954
For example, flame instabilities, in the absence of turbulence, flame, uh, flames can be unstable, create flame surface area and therefore accelerate.

00:24:36.954 --> 00:24:57.742
then especially when turbulence comes into play, so when the flow that is generated by the explosion itself, for example, interacts with the confinement, so the walls of your coal mine, for example, or any obstacles that can generate turbulence that can strongly accelerate combustion, and going back to the types of explosions that would now lead you to a faster energy release.

00:24:57.742 --> 00:25:02.813
And therefore how we would see it, a more violent explosion that is also harder to mitigate.

00:25:03.012 --> 00:25:12.008
So, so there is like a direct link between how fast it occurs and uh, how severe the outcome in terms of pressure wave is.

00:25:12.008 --> 00:25:15.337
What, what's the link there between, between the timescale and damage?

00:25:15.506 --> 00:25:19.586
So for example, if you use a closed vessel explosion as an example, so you

00:25:19.750 --> 00:25:19.830
Hmm.

00:25:20.006 --> 00:25:21.086
say, a piece of equipment.

00:25:21.086 --> 00:25:22.736
There are two main questions.

00:25:22.736 --> 00:25:27.780
The first one is how much pressure would be built inside of the equipment if there's a deflagration.

00:25:27.780 --> 00:25:32.576
Let's say the enclosure remains intact, how much pressure would you build?

00:25:32.576 --> 00:25:36.415
And then the question is, does that pressure exceed the strength of the enclosure?

00:25:36.415 --> 00:25:38.576
That's one measure of severity, right?

00:25:38.576 --> 00:25:42.655
Simply comparing that maximum pressure against the strength of the enclosure.

00:25:42.655 --> 00:25:59.737
if you use methods, for example, like deflagration venting, so you put openings in your, in your vessel that are initially covered with a lightweight membrane or a lightweight panel that are intended to blow open and relieve pressure, then the speed of the pressure rise comes into play.

00:25:59.737 --> 00:26:06.125
the faster you build pressure inside of the vessel due to the explosion, the more vent area you need, for example.

00:26:06.125 --> 00:26:17.165
So this becomes a very dynamic effect where, again, the faster you burn, the faster you generate volume, the faster you have to also be able to relieve that volume from the enclosure to protect the enclosure.

00:26:17.165 --> 00:26:20.526
So both matter of pressure and the speed.

00:26:20.921 --> 00:26:33.040
in practical engineering, you know that through some fundamental relationships, I know first principles or, or this is something, uh, validated experimentally for, uh, types of mixtures.

00:26:33.211 --> 00:26:34.056
Um, so,

00:26:34.256 --> 00:26:34.375
I,

00:26:34.385 --> 00:26:41.031
what Lawrence was talking is actually a very important aspect of explosion, and specifically explosion dynamics.

00:26:41.451 --> 00:26:41.571
Hmm,

00:26:42.142 --> 00:26:50.031
uh, the, so just like in fire dynamics, uh, fire dynamics evolved based on the need to model growth of a fire in a compartment.

00:26:50.031 --> 00:26:53.365
We have these one zone models, two zone models, et cetera.

00:26:53.365 --> 00:27:03.338
And the entire physics of fire growth, which coupled with a smoke layer, your, um, smoke layer growth, your doorway flows, temperature rise in enclosure.

00:27:03.338 --> 00:27:09.368
These are all developed using these very elegant models that were developed by Thomas, by and many others.

00:27:09.368 --> 00:27:17.644
um, in the world of explosions, uh, there's no universal model yet that kind of captures this growth of an explosion in an enclosure.

00:27:17.644 --> 00:27:49.173
And this again brings us back to why it's so important a discipline, towards explosion protection because, in explosions we are interested heavily on what is this pressure versus time as your premixed flame propagates in an enclosure, as that enclosure starts venting, and you now have hot exiting the enclosure, not at slow rates like you would see in a fire, but at very high speeds, you're looking at 200 meters per second of venting, uh, flows.

00:27:49.173 --> 00:28:00.486
so this is, uh, so that is something that forms this also the starting point, like, uh, even a zero dimension enclosure model can model the pressure rise in an enclosure as a function of time.

00:28:00.486 --> 00:28:05.935
And this was something that, Like, for example, Bob used to spend a lot of time, in teaching, uh, as well.

00:28:05.935 --> 00:28:10.976
Lawrence spends a lot of time in teaching this in his course on explosion collection engineering.

00:28:10.976 --> 00:28:15.175
I spent a lot of time teaching about this, uh, in explosion dynamics.

00:28:15.337 --> 00:28:28.384
And, and do we have like experiments or tests or standards that allow you to, to capture some of those characteristics that, you know, in, in, in, in, in fire protection engineering, you'd have the con calori matter, you'd have all the reaction to fire experiments.

00:28:28.384 --> 00:28:28.626
Uh uh.

00:28:28.626 --> 00:28:31.203
Ignition related experiments, et cetera.

00:28:31.203 --> 00:28:35.439
What do you use to to, to build knowledge on those, on those phenomena?

00:28:35.837 --> 00:28:40.836
Yes, I like the link with the cold colorimeter because that really is the workhorse of fire protection.

00:28:40.971 --> 00:28:41.260
Yeah.

00:28:41.766 --> 00:28:43.296
in, um, explosion protection.

00:28:43.296 --> 00:28:44.346
We have a workhorse too.

00:28:44.346 --> 00:28:45.786
That's the explosion sphere.

00:28:45.786 --> 00:28:49.644
think of an explosion sphere as a very, very simple test.

00:28:49.644 --> 00:28:50.994
It's simply a closed volume.

00:28:51.000 --> 00:28:51.275
Mm-hmm.

00:28:51.285 --> 00:28:54.644
Sometimes there's spherical, sometimes they're actually cylindrical vessels.

00:28:54.644 --> 00:29:01.934
But you have a, a, a sort of closed vessel that you can fill with a mixture of interest, and then you can ignite that mixture typically at the center.

00:29:01.934 --> 00:29:06.075
And you can observe, especially the pressurize as a function of time.

00:29:06.075 --> 00:29:15.075
a quantity that can inform, for example, the rate of pressure rise that can then be scaled to account for volume scaling effects, for example.

00:29:15.075 --> 00:29:19.104
So how would that behave at a larger scale like an at an industrial scale, for example?

00:29:19.104 --> 00:29:23.057
we can also use that test for many other safety characteristics.

00:29:23.057 --> 00:29:25.696
Learning about safety characteristics of mixtures.

00:29:25.696 --> 00:29:31.096
For example, test for minimum ignition energies, or a test for limiting oxygen concentrations.

00:29:31.096 --> 00:29:35.386
Or a test for, like I mentioned earlier, maximum explosion pressure.

00:29:35.386 --> 00:29:42.950
These are all relevant safety characteristics that are typically determined by test according to standards such as A STM standards.

00:29:43.107 --> 00:29:48.748
I really want to follow on characteristics or ignition, but I, I need to ask immediately one question.

00:29:48.748 --> 00:30:02.118
You said, uh, it's sometimes ignited at the center, how much the location plays a role and the follow up, immediate follow up to that question is how much the complexity of the space influence the explosion outcomes.

00:30:02.118 --> 00:30:17.828
Because I can imagine if you have an explosion in a large, I don't know, grain silo, which is like a round vessel, that's it, it's probably different than you have, explosion in a, I dunno, shopping mall filled with a lot of, shelves, et cetera.

00:30:17.828 --> 00:30:25.898
So, so how, how much the location of ignition and, and, uh, the, the, the type of enclosure in which you have the explosion, uh, plays a role in, in all of this.

00:30:26.095 --> 00:30:27.025
That's a great question.

00:30:27.025 --> 00:30:33.234
And that really goes into the link between these simple lab type experiments and then the reality, right?

00:30:33.234 --> 00:30:37.615
The types of explosions we see in, in residences or in industrial facilities.

00:30:37.615 --> 00:30:40.827
And of course we have much more complex geometries.

00:30:40.827 --> 00:30:44.097
In reality, we are not looking at spherical vessels.

00:30:44.097 --> 00:30:46.678
In reality, typically that experience explosions.

00:30:46.678 --> 00:30:55.113
one fact is also that we typically don't know the ignition location, or very often we don't know potential ignition locations.

00:30:55.113 --> 00:31:01.022
So in explosion protection engineering, we often have to understand worst case scenarios.

00:31:01.022 --> 00:31:02.913
we consider.

00:31:02.913 --> 00:31:04.326
For a certain structure.

00:31:04.326 --> 00:31:07.866
For example, there might be ignition taking place in different locations.

00:31:07.866 --> 00:31:15.817
There's a certain probability attached to every one of these ignition locations, but in general, there's maybe a host of ignition sources in a certain space.

00:31:15.817 --> 00:31:22.272
In our job, we need to understand what of these or which of these ignition location constitutes a worst case explosion scenario.

00:31:22.272 --> 00:31:31.564
So what leads to, for example, fastest rate of flame propagation or highest amount of pressure built to that ignition location, and then design for that worst case?

00:31:31.564 --> 00:31:36.933
Because again, in reality, we are not in charge, we are not deciding where ignition will happen.

00:31:36.933 --> 00:31:40.894
It will just happen at a possible location where an ignition source is present.

00:31:40.894 --> 00:31:46.624
That could be, for example, even a, a human who is walking and who is building electrostatic charge.

00:31:46.624 --> 00:31:50.163
So you're really not in control of where that ignition would happen.

00:31:50.334 --> 00:31:53.273
and just coming back to that question of the, the test.

00:31:53.273 --> 00:31:55.703
So whenever you have a standard test.

00:31:55.703 --> 00:31:59.532
you are basing the standard test on some kind of a model.

00:31:59.532 --> 00:32:11.749
Uh, so for example, when you're having a cone test, you're basing it on this idea that you have this uniform heat flux that's supplied by the cone kilometer you are applying, that at, uh, and you know exactly, you're quantify that.

00:32:11.749 --> 00:32:12.348
Exactly.

00:32:12.348 --> 00:32:17.307
and then you're trying to measure time to ignition or heat release rate, or heat of combustion or whatever.

00:32:17.307 --> 00:32:30.675
your boundary conditions and your initial conditions are very well prescribed in that standard test, so that when you are extracting parameters from that standard test, those parameters are quantified repeatable.

00:32:30.675 --> 00:32:45.006
The same idea exists with the, with the explosion, sphere as well, which Lawrence had said is the workhouse of explosion, protection, engineering, or the explosion world, where the actual test needs you to have ignition at the center.

00:32:45.006 --> 00:32:55.596
The, the model that correspondingly evolves, which is the flame propagating from the center, as a spherically expanding flame and going towards the walls of the explosion sphere.

00:32:55.596 --> 00:33:00.605
Uh, that, that, that model has a mathematical basis, that is known.

00:33:00.605 --> 00:33:05.135
And then, and then based on that basis, you are now extracting parameters.

00:33:05.135 --> 00:33:12.391
So as soon as you start changing the location of ignition, even in the standard test, you are going to get a different, flame movement.

00:33:12.391 --> 00:33:23.540
you will have different effects because of buoyancy, because of the wall, and these alter the mathematical model and therefore that test is no longer going to be valid in terms of extracting parameters.

00:33:23.540 --> 00:33:29.931
It just like you are having a cone kilometer and rather than applying a uniform heat flux, you start applying a heat flux that's variable.

00:33:29.931 --> 00:33:34.040
I mean, you can do that from a research exercise, but from a.

00:33:34.040 --> 00:33:38.893
of extracting parameters for, for a standard, you don't do that.

00:33:38.893 --> 00:33:40.468
So the same idea here as well.

00:33:41.036 --> 00:33:49.252
in terms of, igniting those mixtures, how do you quantify ignition and how easy it is to, to ignite, such a mixture?

00:33:49.252 --> 00:33:52.313
And what role does it play in, in, in explosion engineering?

00:33:52.531 --> 00:33:57.037
So, you know, but once we're talking about ignition, we can maybe take it a step back.

00:33:57.037 --> 00:34:00.247
What we talked about so far, we talked about flame speed, we talked about

00:34:00.301 --> 00:34:00.422
Hmm.

00:34:00.666 --> 00:34:01.207
pressure.

00:34:01.207 --> 00:34:04.560
Those are severity, parameters of explosions, right?

00:34:04.560 --> 00:34:07.576
How bad will it be Now we're switching toward ignition.

00:34:07.576 --> 00:34:10.313
Those are things we call sensitivity parameters.

00:34:10.313 --> 00:34:12.202
How sensitive is a mixture to ignition?

00:34:12.202 --> 00:34:14.512
How easy or how hard is it to ignite?

00:34:14.512 --> 00:34:18.927
And this is also strongly linked to probability of an explosion, right?

00:34:18.927 --> 00:34:24.538
Again, now how bad will it be, but how likely might it be that an explosion occurs in a certain mixture?

00:34:24.538 --> 00:34:25.947
So it's a bit of a different perspective.

00:34:25.947 --> 00:34:27.867
equally important, right?

00:34:27.867 --> 00:34:34.257
Because we need to understand what is the likelihood there will be an explosion in a certain mixture given a certain ignition source, for example.

00:34:34.608 --> 00:34:36.648
Is there any severity measure that we've missed?

00:34:36.648 --> 00:34:39.367
I would like to complete one before we jump to another.

00:34:39.630 --> 00:34:50.670
I think, um, what we can point out for dust explosions, the severity parameters are defined a little bit differently by necessity, actually, because dust explosions are very complicated, the physics

00:34:50.715 --> 00:34:50.835
Hmm.

00:34:50.909 --> 00:34:55.865
complicated, the material properties vary widely, and the application conditions vary widely.

00:34:55.865 --> 00:35:10.025
what we're doing there, we're not typically using fundamental burning velocities, but we're using the so-called deflagration index, and that is directly tied to the spherical bomb or spherical vessel experiment where we measure rate of pressurize.

00:35:10.405 --> 00:35:10.735
Hmm.

00:35:10.971 --> 00:35:19.757
to get a deflagration index, would measure the maximum rate of pressurized in a standardized vessel, and we would scale that with the test volume.

00:35:19.757 --> 00:35:25.728
So mathematically it's the maximum rate of pressurized, multiplied with the test volume to the power of one third.

00:35:25.728 --> 00:35:31.672
That's, so-called very important cubic law of explosion protection that scales over volume.

00:35:31.672 --> 00:35:36.139
And that allows us to define this index as a reactivity parameter of a certain dust.

00:35:36.139 --> 00:35:40.489
what's important there when you see these, defecation indices.

00:35:40.489 --> 00:35:45.135
So for example, a certain dust might have a defecation index of 200 bar meter per second.

00:35:45.135 --> 00:35:49.704
That is a quantity that gives you a relative comparison between different dusts.

00:35:49.704 --> 00:35:54.085
So you can tell, well, this dust is 100 bar meter per second, that dust is 200.

00:35:54.085 --> 00:35:56.425
So the one with 200 is more reactive.

00:35:56.425 --> 00:35:58.554
Yep, that's a fair relative comparison.

00:35:58.554 --> 00:36:10.795
But that number is not a fundamental parameter of the dust itself, and that's what differentiates this approach from the fundamental laminar burning velocity, which is a fundamental property of the mixture.

00:36:10.795 --> 00:36:25.445
the deflagration index is a function of the material, so the dust material as well as the test conditions, for example, initial turbulence, but again, by necessity, that's the parameter we're using for combustible dust to quantify reactivity.

00:36:25.797 --> 00:36:29.063
Also, when you talk about explosives, there's also different metrics, right?

00:36:29.063 --> 00:36:31.617
Like TNTN, equivalent, et cetera.

00:36:31.617 --> 00:36:33.507
That that's what I've seen.

00:36:33.788 --> 00:36:34.358
Absolutely.

00:36:34.358 --> 00:36:41.407
So when you have explosives, you're interested primarily in the amount of energy that gets released from a certain mass of that explosive.

00:36:41.682 --> 00:36:42.043
Yeah.

00:36:42.043 --> 00:36:42.103
Okay.

00:36:42.217 --> 00:36:48.938
one of the conventional ways of scaling that or making different explosives comparable is using a TT equivalent mass.

00:36:48.938 --> 00:36:58.027
So you're essentially comparing a certain mass of an arbitrary explosive with a certain mass of t and t that would release the exact same amount of energy.

00:36:58.483 --> 00:36:58.813
Hmm,

00:36:58.958 --> 00:36:59.887
a scaling idea.

00:36:59.887 --> 00:37:06.398
There are different variations of this, uh, less focused on energy, for example, but maybe more focused on blast impact.

00:37:06.398 --> 00:37:12.829
generally we like to tie it back to t and t because it's such a well understood and extensively researched material.

00:37:13.257 --> 00:37:15.387
So, okay, let's move to, to sensitivity then.

00:37:15.387 --> 00:37:18.382
Uh, talk, talk about ignition in, in, in those mixtures, please.

00:37:18.655 --> 00:37:18.894
Right.

00:37:18.894 --> 00:37:22.195
So how easy or, or hard is it to ignite a certain mixture?

00:37:22.195 --> 00:37:29.074
Um, generally, for example, when you talk about flammable gases or vapors, those are actually very easy to ignite and.

00:37:29.074 --> 00:37:30.291
How can I say that?

00:37:30.291 --> 00:37:50.527
Well, by comparing the minimum ignition energy of these mixtures with ignition energies by common ignition sources or of common ignition sources, for example, when you test these mixtures for ignition, for minimum ignition energy, you might find that hydrocarbons, for example, in air, have minimum ignition energies on the order of 0.25 millijoules.

00:37:50.527 --> 00:38:01.927
a very small amount of energy that is needed to ignite that mixture to put that into context, electrostatic energy that is accumulated when I walk, um, for

00:38:01.981 --> 00:38:02.202
Hmm,

00:38:02.382 --> 00:38:10.719
especi, when it's very dry out and I walk over flooring that is not, uh, dissipating, then I might accumulate maybe around 10 millijoules of energy.

00:38:10.719 --> 00:38:18.909
So that's already well above actually orders of magnitude above what I need to ignite a flammable gas or vapor mixture typically.

00:38:19.181 --> 00:38:20.710
any, any open combustion.

00:38:20.710 --> 00:38:23.170
I guess that's already way, way more than enough, right?

00:38:23.349 --> 00:38:24.250
So open flame.

00:38:24.250 --> 00:38:31.090
Yes, open flame is a very strong ignition source in that context that provides plenty of energy to ignite one of these mixtures.

00:38:31.090 --> 00:38:39.043
in fact, there's a whole variety of ignition sources that we need to be aware of, that we need to understand in terms of their ignition energy potential.

00:38:39.043 --> 00:38:44.226
but then also outside of sources that can, for example, provide a spark.

00:38:44.226 --> 00:38:50.436
So electrical sources, we need to consider things like thermal sources, hot surfaces, for example, right?

00:38:50.436 --> 00:38:53.387
How hot a surface need to be to ignite a certain mixture?

00:38:53.387 --> 00:39:01.217
And there's a metric for that too describes the sensitivity of a mixture that would be the minimum ignition temperature for closed vessels.

00:39:01.217 --> 00:39:03.228
For example, the auto ignition temperature.

00:39:03.599 --> 00:39:05.753
And, in terms of turning this.

00:39:05.753 --> 00:39:07.840
Into protection strategies.

00:39:07.840 --> 00:39:16.860
I, I guess here the, the flammability limits play an important role do you have more tools than, than ventilation and flammability limits really in, in preventing, or,

00:39:16.992 --> 00:39:18.012
So you're right.

00:39:18.012 --> 00:39:21.911
Flammability limits, that's the other component of answering a question.

00:39:21.911 --> 00:39:23.351
Will a certain mixture ignite?

00:39:23.351 --> 00:39:23.862
Right?

00:39:23.862 --> 00:39:29.351
The one part is, is that mixture within the flammable range as far as is composition.

00:39:29.351 --> 00:39:34.362
So how much fuel, oxygen, and inert has, do I have, and is that mixture flammable?

00:39:34.362 --> 00:39:39.945
And the other part is, do I have an effective ignition source that has enough energy to ignite that mixture?

00:39:39.945 --> 00:39:48.137
And to prevention, you can attack any of these components that can lead to successful ignition, right?

00:39:48.137 --> 00:39:51.648
You can prevent any of these aspects individually or together.

00:39:51.648 --> 00:39:53.958
For example, you can prevent.

00:39:53.958 --> 00:39:55.938
A flammable mixture from forming.

00:39:55.938 --> 00:39:58.443
where things like ventilation come into play.

00:39:58.443 --> 00:40:02.288
So you remove fuel from an enclosure, for example, or inert.

00:40:02.288 --> 00:40:08.706
You supply an inert gas to the mixture to a place outside of the flammability zone.

00:40:08.706 --> 00:40:13.177
It's very common using nitrogen inert, for example, very common practice.

00:40:13.177 --> 00:40:22.302
you can attack the ignition aspect so you can make sure you don't have possible ignition sources in the space where you know that a flammable mixture might be present.

00:40:22.302 --> 00:40:24.702
That's called ignition source control.

00:40:24.702 --> 00:40:33.373
There are many methods around that, how you can make sure that, for example, equipment like electrical equipment cannot present a possible ignition source in practice.

00:40:33.742 --> 00:40:34.041
yeah.

00:40:34.041 --> 00:40:35.572
You mentioned coal mines,

00:40:35.632 --> 00:40:36.052
Mm-hmm.

00:40:36.052 --> 00:40:36.251
Yes.

00:40:36.382 --> 00:40:40.045
mines typically use, inerts like sand, dust.

00:40:40.045 --> 00:40:54.911
or rock dust to, and they, they, they put all this rock dust on the coal mine, surface so that when, uh, when there is a disruption and the coal dust lifts up due to any kind of, disruption, and, and creates, uh, a cloud of coal dust.

00:40:54.911 --> 00:40:57.161
And that coal dust is also mixed with rock dust.

00:40:57.161 --> 00:41:02.822
And so that essentially inerts the mixture and it's, it, it's more difficult to ignite it.

00:41:03.706 --> 00:41:03.927
Hmm.

00:41:04.501 --> 00:41:22.701
we have also done studies, in the laboratory where, where, again, you have, because it's such a complex problem where even if you have inerts like rock dust in a premixed gas mixture, what the rock dust does is it locally enhances the turbulence because.

00:41:22.701 --> 00:41:24.300
Of the, the particles.

00:41:24.300 --> 00:41:30.530
So you have that, that local enhancement of turbulence now, increases the turbulent burning velocity in some

00:41:30.865 --> 00:41:30.985
Hmm.

00:41:31.257 --> 00:41:32.967
it's a function of the size of the rock dust.

00:41:32.967 --> 00:41:38.983
And if the concentrations are not high enough, then that rock dust essentially more dangerous because it

00:41:39.079 --> 00:41:39.199
Hmm.

00:41:39.253 --> 00:41:41.114
it increases the levels of turbulence.

00:41:41.114 --> 00:41:47.061
And now the, the flame is able to consume a lot more, of the fuel because the, the flow of turbulence has increased.

00:41:47.619 --> 00:41:52.659
I immediately know ev every, all the time we, we talk, I, I immediately jumped into fire.

00:41:52.659 --> 00:41:59.739
But you mentioned there are a lot of interesting explosions that are perhaps not fire related, like you mentioned steam explosions.

00:41:59.739 --> 00:42:02.608
You've mentioned vessel ruptures, use of explosives.

00:42:02.608 --> 00:42:10.077
Is there any, uh, thing comparable to ignition, like in, in those explosions that you can prevent?

00:42:10.077 --> 00:42:13.617
H how, how, how does an engineer deal with such hazards?

00:42:13.617 --> 00:42:15.447
What are the approaches there?

00:42:15.447 --> 00:42:20.731
'cause obviously you don't ignite steam, but, uh, it, it's still like something must lead to a steam explosion.

00:42:20.731 --> 00:42:23.431
How does it look in, in that kind of, of, of explosions?

00:42:23.726 --> 00:42:30.434
so, so I'll, I'll let Lawrence answer that from industry perspective, but I'll answer it purely from an academic perspective.

00:42:30.434 --> 00:42:36.106
From an academic perspective, the way an engineer deals about with that is by education.

00:42:36.106 --> 00:42:42.922
that is why programs like explosion protection engineering are so important, because unless you don't educate.

00:42:42.922 --> 00:42:59.980
who are in the field, faced with these problems and now even newer problems because of hydrogen, because of batteries, because of, uh, all these high energy density energy solutions, it becomes, uh, very difficult, to address, uh, the safety, uh, of these.

00:43:00.215 --> 00:43:02.976
I can take an example of a pressure vessel burst.

00:43:02.976 --> 00:43:10.842
these are actually fairly common, whether we're talking about low pressure vessels or higher pressure vessels, they happen more often than you would think.

00:43:10.842 --> 00:43:15.012
There's a great video from the CSB, the Chemical Safety Board that elaborates on these.

00:43:15.012 --> 00:43:19.922
And, um, there are different ways you can get to a condition where a pressure vessel can burst.

00:43:19.922 --> 00:43:24.092
One of them is simply that it gets over pressurized, so beyond what it is designed for.

00:43:24.092 --> 00:43:28.771
there are actually ways to, to manage that situation, right?

00:43:28.771 --> 00:43:33.661
For whatever reason, if a vessel gets over pressurized, we can provide over pressure protection.

00:43:33.661 --> 00:43:41.222
This has nothing to do with what we would call explosion protection as such, but we would see this as a part of process safety.

00:43:41.797 --> 00:43:41.916
Hmm.

00:43:42.242 --> 00:43:45.128
over pressure protection, for example, in the form of a rupture disc.

00:43:45.128 --> 00:43:51.420
So very simply, a device that opens at a set pressure that relieves pressure from the vessel before it conversed.

00:43:51.420 --> 00:43:52.530
um.

00:43:52.530 --> 00:43:58.061
What's interesting here also from the educational standpoint, these devices, they look very simple.

00:43:58.061 --> 00:43:59.052
They seem very simple.

00:43:59.052 --> 00:44:00.641
The functioning principle is simple, right?

00:44:00.641 --> 00:44:03.161
You over pressurize it, it opens, it relieves pressure.

00:44:03.161 --> 00:44:14.271
we need thorough engineering when we bring these devices to a certain application because we need to understand, for example, how large of an area we need to provide for pressure relief.

00:44:14.271 --> 00:44:25.952
can get quite involved actually, especially when you might have materials inside of a vessel that are reactive when during the relief you might be relieving, not just gas, but maybe a multi-phase flow.

00:44:25.952 --> 00:44:27.155
even these.

00:44:27.155 --> 00:44:33.943
Seemingly simple things like over pressure protection are uh, various engineering disciplines that need to be involved there.

00:44:33.943 --> 00:44:35.773
They, they require rigorous engineering.

00:44:35.773 --> 00:44:37.452
It's part of what we teach in the program.

00:44:37.452 --> 00:44:42.505
And um, the other part if we talk about pressure vessels, for example, is inspections.

00:44:42.505 --> 00:44:48.085
So not just engineered solutions for protection, but also inspections to make sure we understand.

00:44:48.085 --> 00:44:54.175
Is there, for example, corrosion ongoing on a vessel that might thin out the walls and weaken the walls at some point?

00:44:54.175 --> 00:45:01.795
So even though a vessel is designed for a certain over pressure, it might not be as pressure resistant once it's been in service for 10 years.

00:45:01.795 --> 00:45:06.661
We need to properly maintain, test and inspect these types of equipment.

00:45:06.909 --> 00:45:18.914
as we are on technical, uh, stuff, uh, to, to prevent, can you talk more about deflagration uh, panels, the way we've touched them on the, uh, energy storage episode, but I think it's, it's highly relatable to what you've just described.

00:45:19.063 --> 00:45:19.483
for sure.

00:45:19.483 --> 00:45:23.443
So what I've just described is pressure venting over pressure protection, right?

00:45:23.443 --> 00:45:27.762
So those were these scenarios that are non-reactive typically, right?

00:45:27.762 --> 00:45:28.811
You just relieve pressure.

00:45:28.811 --> 00:45:39.657
difference for explosion, venting, or defecation venting is now we're dealing with a scenario where there is combustion going on inside of an enclosure, and we need to protect that enclosure.

00:45:39.657 --> 00:45:44.668
the fact that there's combustion going on means that we can have a very rapid pressure rise.

00:45:44.668 --> 00:45:45.083
So we're not.

00:45:45.083 --> 00:45:52.393
Talking about a deep depressurization of a storage vessel, for example, from a certain pressure down to ambient.

00:45:52.393 --> 00:45:56.623
But we have a vessel whose internal pressure is actually increasing very quickly.

00:45:56.623 --> 00:46:07.965
And what that means for venting is that you need to provide typically much larger vent areas to overcome or to combat that pressurize and keep pressure as low as needed.

00:46:07.965 --> 00:46:11.751
the idea behind rupture disc for process safety and.

00:46:11.751 --> 00:46:13.311
Vent panels for explosion.

00:46:13.311 --> 00:46:14.360
Safety is similar.

00:46:14.360 --> 00:46:17.150
The implementation is different because of the hazard.

00:46:17.150 --> 00:46:19.760
Now the panels are extremely simple.

00:46:19.760 --> 00:46:24.550
They're one of the simplest method of over pressure or explosion protection.

00:46:24.550 --> 00:46:36.985
It's simply a lightweight panel applied to the enclosure that is precut around the circumference, leaving only small so-called burst tabs that are designed such that the panel opens at a set pressure.

00:46:36.985 --> 00:46:48.161
So there's a predefined pressure, a very low pressure, typically 0.1 bar, for example, at which that panel will yield, it will open and will start relieving pressure and protecting enclosure.

00:46:48.496 --> 00:46:53.682
in engineering those types of, solutions, how much do you care what happens outside of that panel?

00:46:53.682 --> 00:46:56.862
You know, the propagation outside is, is, is that important?

00:46:56.862 --> 00:46:59.682
Or just getting the pressure wave out of your container?

00:46:59.682 --> 00:47:02.047
That's goal achieved, uh, time to go home.

00:47:02.422 --> 00:47:03.246
Uh, good point.

00:47:03.246 --> 00:47:17.856
Uh, we can absolutely not forget about what's going on outside the vent because we might actually, by doing this, by doing defecation venting, create external hazard, In the case of an explosion, we are relieving not just pressure, we're relieving a flame.

00:47:17.856 --> 00:47:23.677
We're sending a flame through these deflagration vents to the outside, we can generate external pressures.

00:47:23.677 --> 00:47:33.697
Now, the external pressures are typically by far not as high as the internal pressures might be, but still they can be damaging, they can be hazardous, can injure people can damage property.

00:47:33.697 --> 00:47:42.186
there is specific engineering methods that we also exercise when we design the fabrication vents to predict these external effects.

00:47:42.186 --> 00:47:43.552
one part of it.

00:47:43.552 --> 00:47:51.836
generally, we like to direct these vented explosions away from any hazard, away from any exposures, right?

00:47:51.836 --> 00:48:00.505
So away from people, away from driveways, for example, away from property that might ignite or that might get damaged by over pressure.

00:48:00.681 --> 00:48:03.231
What about the debris that you shoot with the explosion?

00:48:03.231 --> 00:48:05.990
Is there any way you can control for that?

00:48:05.990 --> 00:48:07.880
Is that an element of the design?

00:48:07.880 --> 00:48:13.730
To minimize the collateral damage caused by, objects that that can be taken by the explosion.

00:48:13.880 --> 00:48:18.951
So ideally when you protect an enclosure, for example, the goal is not to generate any fragments,

00:48:19.260 --> 00:48:19.340
Hmm.

00:48:19.581 --> 00:48:21.681
That's a very, very important design goal.

00:48:21.681 --> 00:48:25.496
but sometimes there are certain explosions that will generate fragments.

00:48:25.496 --> 00:48:27.327
For example, the pressure vessel burst.

00:48:27.327 --> 00:48:30.990
the typical approach is first of all to understand the hazard.

00:48:30.990 --> 00:48:48.050
So understand, for example, the types of fragments that might develop sizes, the weights then determine what velocity these fragments might have, then infer from that, how far could they reach and what impact forces or impact energy might degenerate.

00:48:48.050 --> 00:48:56.425
Attached to that is often a probabilistic analysis to understand what's the chance that a certain target gets hit by a fragment, It spread out over distance.

00:48:56.425 --> 00:49:01.525
So as you go farther away from the source, the likelihood that you actually get hit by a fragment goes down.

00:49:01.525 --> 00:49:26.039
So putting that all together gives you an informed basis for, for determining the risk that, comes with these fragments in terms of protection, when you are in a zone, for example, that is prone to fragment impact you might want to use, um, not just blast resistant construction, but also fragmentation resistant construction or fragment resistant construction protects, for example, people from potential fragments.

00:49:26.039 --> 00:49:30.298
And on an industrial site, that could be a reinforced control room, for example.

00:49:30.574 --> 00:49:36.739
are things like that something that, uh, you'd expect the explosion protection engineer to know, uh, after your course?

00:49:36.739 --> 00:49:42.590
is, is it common to, to design like this, uh, outside of, I dunno, petrochemical industry?

00:49:42.721 --> 00:49:51.490
so an interesting thing that Lawrence did, uh, in his course, uh, which was very, well received, was he had these capstone projects for the students.

00:49:51.490 --> 00:49:55.150
And the capstone projects were basically given by industry,

00:49:55.501 --> 00:49:55.880
Hm hmm.

00:49:56.141 --> 00:50:06.128
part of the class, the graduate course, uh, which were actual industry problems, like designer dust went uh, for a green silo or design, explosion.

00:50:06.128 --> 00:50:10.684
Went for a coal fired power plant, conveyor belt, design.

00:50:10.684 --> 00:50:13.204
An explosion went for a battery energy storage.

00:50:13.204 --> 00:50:22.657
So, so these were problems that were, that had, that had, were given by industry that, uh, were given to the students as final capstone projects for the class.

00:50:22.657 --> 00:50:36.014
And I think that was a great mechanism for the students to kind of do an actual problem that's faced by industry, apply what is being taught in the class and connected to, an industrial problem.

00:50:36.014 --> 00:50:44.369
just to give you a sense of history, uh, WPI was started with the moto of, in German, which is called Le and Kunst.

00:50:44.369 --> 00:50:47.353
And what that means is theory, and practice.

00:50:47.353 --> 00:50:56.480
So all WPI students are essentially, Trained and taught to learn in, but not just learn theory, but also to apply it.

00:50:56.480 --> 00:51:02.545
And, and, and this is, why, uh, Lawrence introduced in the form of the capstone project was like this amazing thing.

00:51:02.545 --> 00:51:03.684
Very well received.

00:51:03.684 --> 00:51:19.860
And the best part was that the, the industry was so happy with what Lawrence did, that they actually came and judged the capstone projects themselves, so that there was this, this judging panel that was created for the graduate class, which was industry people judging the, the capstones.

00:51:20.099 --> 00:51:20.699
think you

00:51:20.719 --> 00:51:20.900
Yes.

00:51:21.000 --> 00:51:23.400
just gave me a great idea for this year's capstone.

00:51:23.588 --> 00:51:24.518
Well, uh, thank you.

00:51:24.518 --> 00:51:33.440
I, I hope we don't, uh, you don't torture the students too much with it, but no, I, I think, uh, such a, such a nice, chance to, to, you know, apply this in, in practice.

00:51:33.440 --> 00:51:37.820
I, I, I think it's, it's very important for people to develop a, a specific skillset.

00:51:37.820 --> 00:51:41.780
And, you know, the more I listen to you guys, the more I understand how.

00:51:41.780 --> 00:52:03.099
Specific this field is and how many things go into it because it's like at the same time, you know, the reactivity of the ingredients for explosion, but also the circumstances in which it happens, the environment in which it happens, the collateral damage that's possible and can spin off into some sort of domino effect, which you would like to prevent.

00:52:03.099 --> 00:52:10.030
You know, my personal, you know, exposure to explosions is when I design road tunnels because we designed them for all kinds of traffic.

00:52:10.030 --> 00:52:15.010
And I have to, you know, consider vapor cloud explosions, uh, you know, boiling liquid explosions.

00:52:15.010 --> 00:52:19.420
Maybe you could talk about those, uh, transportation scenario explosions.

00:52:19.420 --> 00:52:21.039
Actually, I would love to listen about them.

00:52:21.039 --> 00:52:24.280
So, and BLE perhaps?

00:52:24.581 --> 00:52:24.880
Yeah.

00:52:24.880 --> 00:52:30.597
So, a a levy is essentially a, pressure vessel burst in, uh, in some way.

00:52:30.597 --> 00:52:33.855
So the pressure vessel burst is you have a pressurized vessel.

00:52:33.855 --> 00:52:41.411
and, uh, what Laurens described is, uh, a fracture of that pressurized vessel that causes it to fragment because it's pressurized.

00:52:41.411 --> 00:52:46.036
a levy is just that pressurized vessel is damaged because of a fire.

00:52:46.036 --> 00:52:52.001
the structural failure of the vessel occurs because usually because of an external fire.

00:52:52.001 --> 00:52:56.452
That heats up this vessel, uh, that is pressurized and weakens it.

00:52:56.452 --> 00:53:01.860
Uh, and because of that weakening, that internal pressure causes that, that that vessel to burst.

00:53:01.860 --> 00:53:10.576
And it's fairly common in transportation because you have these road T tanks, for example, that transport, fuel liquid fuels, on, on the highways.

00:53:10.576 --> 00:53:13.356
And, uh, in some cases they have accidents.

00:53:13.356 --> 00:53:16.175
They, they collapse some of the liquid leaks.

00:53:16.175 --> 00:53:21.496
and you have a fire underneath the, the huge tanker, you have, a possibility of a ble.

00:53:21.496 --> 00:53:31.255
So, the, the main guidance with the B levy essentially is the, the time to B levy, or the time at which this tanker or the pressurized vessel.

00:53:31.255 --> 00:53:33.690
disintegrates is very important.

00:53:34.081 --> 00:53:34.161
Hmm,

00:53:34.260 --> 00:53:38.914
Uh, and, and there are all these correlations available in literature based on empirical, data.

00:53:38.914 --> 00:53:50.181
NASA had done this huge statistical analysis, comprised of like, I think around, uh, 300 different levy accidents and had come up with a number that, you know, when you have a ble, this is the distance.

00:53:50.181 --> 00:53:56.983
Uh, you need to stand away from the site such that you don't have the blast wave or fragment fragments, uh, hitting you.

00:53:57.092 --> 00:53:57.811
in open space.

00:53:57.811 --> 00:54:00.632
Also, the thermal damage from the fireball is important, right?

00:54:00.632 --> 00:54:02.007
Uh, or, or you don't care.

00:54:02.192 --> 00:54:02.202
Yes.

00:54:02.202 --> 00:54:04.456
So that is a big component as well.

00:54:04.456 --> 00:54:23.333
In fact, there was a very classic paper written, in the fire safety journal where there were these experiments that were done on, um, Uh, these tankers that were filled with, fuel, and there was a ble and, and the, the time it takes for the fireball to rise, uh, and then the time it takes for the fireball to stay there or linger in the air.

00:54:23.333 --> 00:54:28.673
And then the diameter of the fireball, which is how you calculate the radiative, uh, thermal damage.

00:54:28.673 --> 00:54:30.536
Uh, they were all kind of, measured.

00:54:30.536 --> 00:54:33.927
I believe the paper was by Rob Roberts, if I'm not mistaken.

00:54:33.927 --> 00:54:38.746
But there are these correlations, uh, that are again, available in, in literature about this.

00:54:38.746 --> 00:54:50.184
I mean, this is, a lot of this is also coming from the process safety engineering world, where the process safety engineers, which were predominantly chemical engineers, kind of wanted this problem really solved.

00:54:50.184 --> 00:55:00.606
so they kind of entered the fire protection engineering world and did work And then many of these researchers again, left, left, and went back to the process safety world again.

00:55:00.606 --> 00:55:00.927
Yeah.

00:55:01.226 --> 00:55:06.351
Oh, well, it's, it's a good pollination of ideas by, you know, changing disciplines.

00:55:06.351 --> 00:55:07.431
I, I highly support that.

00:55:07.431 --> 00:55:10.402
And for BLEs, I, I need to check the NASA study.

00:55:10.402 --> 00:55:17.391
I hope the time to BLE is not as short as in Hollywood movies where you basic barely touch a, a truck and it explodes.

00:55:17.391 --> 00:55:18.621
I open my tunnels.

00:55:18.621 --> 00:55:21.862
We have a little bit more time until, uh, a leva.

00:55:21.862 --> 00:55:22.552
Um.

00:55:22.552 --> 00:55:25.192
One final question I wanted to ask to you guys.

00:55:25.192 --> 00:55:28.282
What are the frontiers explosion research?

00:55:28.282 --> 00:55:31.612
What, what is the current, like topics being studied?

00:55:31.612 --> 00:55:34.521
Where, where are you guys going in in your research right now?

00:55:35.041 --> 00:55:40.454
Well, I can take some of the applied things that I see happening in the explosion protection industry right now.

00:55:40.454 --> 00:55:49.744
of this, as in many other disciplines, is driven by new applications, and we already touched on some of these, so new and alternative fuels or energy carriers.

00:55:49.744 --> 00:55:52.389
It's a big topic, an ongoing topic.

00:55:52.389 --> 00:55:59.534
For example, we are asked to protect more and more hydrogen systems the hydrogen economy is, is building globally.

00:55:59.534 --> 00:56:13.244
There are applications such as electrolyzers, such as fuel cells that need to be protected they present hazards that, you know, fundamentally we do understand from an explosion dynamic standpoint, from a combustion standpoint and so on.

00:56:13.244 --> 00:56:20.114
But we are definitely still in a process of developing engineering best practice to safeguard these applications.

00:56:20.114 --> 00:56:33.873
And there are very, very interesting, projects, for example, uh, electrolyzers where you can have potential of hydrogen oxygen crossover and you can generate mixtures that are very, very reactive and that could potentially detonate, right?

00:56:33.873 --> 00:56:37.739
So there goes your entire knowledge of explosion dynamics to understand.

00:56:37.739 --> 00:56:44.456
only how that scenario comes about, but then really what happens if there's an ignition in that atmosphere and what are the consequences?

00:56:44.456 --> 00:56:49.503
Um, another application, and we talked about this, is battery energy storage systems.

00:56:49.657 --> 00:56:49.878
Yep.

00:56:49.983 --> 00:57:02.601
one that's really pushing the explosion protection community very fast because it's such a fast growing industry to come up with best practice solutions, and there are many parties involved in this, obviously globally.

00:57:02.601 --> 00:57:08.721
And we're all trying to work toward a, what I would say could be a standard way of protecting these.

00:57:08.721 --> 00:57:12.501
There's been great progress made even o over the past five years.

00:57:12.501 --> 00:57:21.798
progress has transitioned into codes and standards to some extent, such as NFPA 8 55, but there is still ongoing debate on how we should be doing this.

00:57:21.798 --> 00:57:23.989
Should we be relying on deflagration venting?

00:57:23.989 --> 00:57:27.780
Should we be combining this with ventilation, for example?

00:57:27.780 --> 00:57:37.949
And something that we propose, for example, is that a layered protection concept would be adequate or would be very, very, uh, would lead to good way of safeguarding these systems.

00:57:37.949 --> 00:57:41.699
So combining ventilation and deflagration venting, for example.

00:57:41.699 --> 00:57:44.416
ongoing discussions in the expert community.

00:57:44.530 --> 00:57:52.994
how about the ammonia economy With, a lot of, agricultural industry moving to use of ammonia, source of fuel in, in their processing.

00:57:53.351 --> 00:57:53.681
Right.

00:57:53.681 --> 00:57:54.012
Yeah.

00:57:54.012 --> 00:57:58.751
That's another one of these hazards that we need to understand better and deal with more and more.

00:57:58.751 --> 00:58:03.461
And what I see, for example, is development of advanced CFD tools.

00:58:03.461 --> 00:58:09.942
So computational fluid, dynamic tools to model ammonia releases, dispersion and explosions.

00:58:09.942 --> 00:58:15.976
That needs to be done very carefully because of special properties of ammonia and um, also connects the world.

00:58:15.976 --> 00:58:20.356
Again, we often cannot simply focus on explosion hazards.

00:58:20.356 --> 00:58:22.396
We need to consider toxicity hazards.

00:58:22.396 --> 00:58:24.016
We need to consider the fire hazard.

00:58:24.016 --> 00:58:34.431
So very often we end up in a multiphysics hazard scenario where we need to pull in all that expertise from the explosion field, the fire field, and health and safety.

00:58:34.623 --> 00:58:43.367
An extremely interesting aspect of using water to, you know, actually control the, the, the leakages and, and everything because you can actually, uh, do that.

00:58:43.367 --> 00:58:45.077
How about, how about space industry?

00:58:45.077 --> 00:58:47.628
Is that then interesting direction?

00:58:47.628 --> 00:58:47.867
Uh,

00:58:48.181 --> 00:58:49.172
space is huge.

00:58:49.172 --> 00:58:52.889
I mean, that's like, uh, close to $40 billion of just a private sector.

00:58:52.889 --> 00:58:55.168
Uh, so it's, it's a huge industry.

00:58:55.168 --> 00:58:59.893
Uh, and if you think of microgravity, I mean, everybody wants to, uh, wants to do something on the moon.

00:58:59.893 --> 00:59:03.268
Uh, they wanna start manufacturing stuff on the moon.

00:59:03.268 --> 00:59:05.518
They wanna start manufacturing in space.

00:59:05.518 --> 00:59:12.907
Uh, uh, now just thinking of dust, like the way dust settles on earth, gravity, it won't do that in space.

00:59:12.907 --> 00:59:27.831
you would have a completely different dust explosion hazard if you're dealing in a, a with a dust cloud in a space station, which is likely if you're starting to start manufacturing on a large scale in space.

00:59:27.831 --> 00:59:47.108
so I think the whole field of process safety as it exists right now will completely evolve when you are taking the gravity out of the picture and going to these different gravities, I mean, flammability, uh, ignition, minimum explosion concentrations, all the things that that we discussed, they all will be different.

00:59:47.108 --> 00:59:49.864
And even the method of you trying to.

00:59:49.864 --> 00:59:55.728
Calculate those uh, in, in, uh, zero gravity or a microgravity environment will have to change.

00:59:55.728 --> 00:59:58.278
So the experimental standards will also have to change.

00:59:58.278 --> 01:00:00.346
so to me it's a huge focus.

01:00:00.346 --> 01:00:13.246
And, and the main, parameter or the main hazard is an explosion because you can, you will be able to manage a fire but if you have an explosion, that's something that is just, that's it.

01:00:13.246 --> 01:00:14.987
That, that's the end of the story.

01:00:14.987 --> 01:00:32.797
and if you look at space accidents as well, I mean, many of the major accidents have essentially been explosions the, where there was a space station, the space station mayor, the first fire recorded was actually an explosion in the gas canister that then that, that basically triggered the fire.

01:00:32.797 --> 01:00:37.581
so there, uh, the, the explosion is usually the trigger for the fire.

01:00:37.581 --> 01:00:42.530
And therefore to be able to understand explosions in space, I think is a very important step.

01:00:42.530 --> 01:00:45.561
and, and especially with dust as well.

01:00:45.561 --> 01:00:47.376
I think it's a huge, uh, problem.

01:00:47.885 --> 01:00:52.521
Yeah, I, I, I expose the audience of, uh, fire science show to a lot of space stuff.

01:00:52.521 --> 01:01:08.815
Uh, perhaps people may think it's a little bit weird, but I truly believe that we will very soon move from, you know, science fiction into space fire explosion, engineering as a thing because, uh, this observing how this industry is exponentially growing is,

01:01:08.896 --> 01:01:09.186
Yeah.

01:01:09.237 --> 01:01:09.686
insane.

01:01:10.161 --> 01:01:25.264
Yeah, because the first thing you'd have to do if you want to do interplanetary travel is have a gas station or a fuel station that's revolving the think of a, of a patrol station or a gas station that's orbiting, and is fueling.

01:01:25.264 --> 01:01:30.190
uh, the, uh, uh, the, the space shuttles to go to Mars or to go to other planets.

01:01:30.190 --> 01:01:36.766
So the logistics involved with setting up that gas station are all related to explosion protection, essentially.

01:01:36.842 --> 01:01:37.371
Fantastic.

01:01:37.371 --> 01:01:44.434
the, the feature, the feature looks, uh, really interesting for all, all types of, uh, safety engineers.

01:01:44.434 --> 01:01:46.054
Uh, it's like.

01:01:46.054 --> 01:01:50.376
I always say that human creates problems faster, that we can solve them.

01:01:50.376 --> 01:01:56.753
Therefore, our job security is unfortunately, pretty good from, from that, um, perspective.

01:01:56.753 --> 01:01:58.838
guys, we'll be wrapping up.

01:01:58.838 --> 01:02:05.532
Perhaps, uh, you would like to share with people, uh, how to enroll in that, protection engineering program.

01:02:05.532 --> 01:02:19.813
And if someone, uh, already, uh, has a master degree and they, they don't look for a master's degree perhaps, where they could, uh, you know, improve their knowledge and explosions in maybe some shorter forms, like courses or, or something.

01:02:19.987 --> 01:02:24.996
Yeah, so, so the program as is as currently comprises of 10 graduate courses

01:02:25.536 --> 01:02:25.657
Hmm.

01:02:25.717 --> 01:02:27.396
we have divided them into three areas.

01:02:27.396 --> 01:02:32.976
Uh, the fundamentals, uh, where learn about combustion, compressible, flow dynamics, transport phenomena.

01:02:32.976 --> 01:02:34.461
And explosion dynamics.

01:02:34.461 --> 01:02:44.275
Uh, and then we have these, uh, applied engineering focus courses, that translate theory to application, which is, uh, for example, the one that Lawrence is teaching explosion, production engineering.

01:02:44.275 --> 01:02:52.615
Uh, we also have courses in this category like quantitative risk assessment, which is a translation to chemical engineering focused jobs.

01:02:52.615 --> 01:02:59.815
And then we have these CFD courses, uh, which are explosion modeling applications and explosion modeling fundamentals.

01:02:59.815 --> 01:03:08.226
so these are courses that I think have never been taught in a graduate program ever before, like a course on explosion modeling only CFDA of explosion modeling.

01:03:08.226 --> 01:03:13.797
so we have worked quite extensively to kind of get the best, instructors, the guest, the best professors to teach this.

01:03:13.797 --> 01:03:19.286
Uh, the explosion modeling application course is gonna be taught in summer, uh, by wiper blast.

01:03:19.286 --> 01:03:24.597
And Peter McDonald and, and Andrew Nicholson from Wiper Blast in the UK are teaching it online.

01:03:24.597 --> 01:03:28.344
uh, we also have courses that are very specialized.

01:03:28.344 --> 01:03:36.324
Like we have this amazing course, uh, that was taught by Vito Browski, who is the author of Electrical Fires and Explosions Handbook, ignition Handbook.

01:03:36.324 --> 01:03:38.273
Also the inventor of the Cone Kilometer.

01:03:38.273 --> 01:03:44.880
he taught this course on case studies and explosion, and this was one of the, very, very well received course.

01:03:44.880 --> 01:03:48.498
I think every single engineer out there should be taking a course like this.

01:03:48.498 --> 01:03:52.635
so the, the, the program enrollments, as I said, have already started.

01:03:52.635 --> 01:04:01.838
it's an online degree and so it offers very high flexibility for someone already working in industry and who wants to improve their credentials or learn something new.

01:04:01.838 --> 01:04:04.195
and, uh, we have a website.

01:04:04.195 --> 01:04:14.672
Uh, you can also, uh, send an email, uh, to and, and yes, and we are also very proud of the strong industry support, uh, for the program.

01:04:14.672 --> 01:04:20.161
So, for example, Lawrence teaching this course, while he's still working with Rebe is a very big deal.

01:04:20.161 --> 01:04:25.021
So we have, we, we have similar instructors who have years of experience.

01:04:25.021 --> 01:04:31.534
Like for example, the QRA course is taught by professor Steve Kumo, has around 30 years of experience at, uh, at Dubon.

01:04:31.534 --> 01:04:38.650
So, so very, practically oriented, uh, courses are also part of this, uh, this program.

01:04:38.650 --> 01:04:46.346
and like I said, I mean the, the, this, this, the need for explosion protection, uh, is truly global and urgent.

01:04:46.346 --> 01:04:49.702
we have significant in incidents across various countries.

01:04:49.702 --> 01:05:00.269
there is, uh, you know, hydrogen battery storage systems, new fuel blends, space exploration, all these areas that we already discussed, but even traditional industries.

01:05:00.269 --> 01:05:06.780
So for example, if you consider a simple product like paint, it has pigment, it has fine powder that can be combustible.

01:05:06.780 --> 01:05:11.628
And so this, adding this to all an already flammable hydrocarbon liquid.

01:05:11.628 --> 01:05:16.030
entire process of manufacturing storage, of it is an explosion hazard.

01:05:16.030 --> 01:05:24.190
Uh, so any product that you see in a store when you walk down a supermarket, for example, think of all the chemicals you have, dry powder, that may have gone into this.

01:05:24.190 --> 01:05:25.090
Its manufacturing.

01:05:25.090 --> 01:05:29.949
When you buy lipstick, it contains flammable particles, a deodorant stick.

01:05:29.949 --> 01:05:31.570
Again, it contains flammable particles.

01:05:31.570 --> 01:05:37.329
If you look at medicine, vitamin B, vitamin C, they're all explosive energy drinks.

01:05:37.329 --> 01:05:45.396
Fine powder, explosive cereal, coffee, creamer, all these products, they're, they're manufacturing, they're transport storage.

01:05:45.396 --> 01:05:48.601
It's all fundamentally coupled to an explosion hazard.

01:05:48.601 --> 01:05:52.072
look, that's what our program is structured to address these risks.

01:05:52.139 --> 01:06:04.500
so besides enrolling for the whole program, uh, what I find interesting is also possible to take individual classes without actually fully enrolling at WPI, and that's especially interesting if you have a specific interest.

01:06:04.500 --> 01:06:08.010
Let's say you wanted to take a class on QRA, right?

01:06:08.010 --> 01:06:11.039
You could enroll in, I believe, up to two classes.

01:06:11.309 --> 01:06:11.760
Exactly.

01:06:11.980 --> 01:06:15.250
normally enrolling at WPI and take those.

01:06:15.250 --> 01:06:24.820
And then what we've seen in the past, which I find fantastic, is that sometimes, you know, after taking those two classes, folks sometimes decide they want to do the whole program.

01:06:24.820 --> 01:06:32.893
So those two classes could be your entry point to the whole program, or you could just take them individually and and see it as professional development.

01:06:33.190 --> 01:06:33.730
Fantastic.

01:06:33.730 --> 01:06:34.360
That, that's a great,

01:06:34.599 --> 01:06:34.780
Yeah.

01:06:34.869 --> 01:06:35.847
that's a great opportunity.

01:06:35.847 --> 01:06:44.773
And, if the listener, if you prefer some reading, I can also recommend a good reading resources explosion, dynamics, fundamentals and practical Applications.

01:06:44.773 --> 01:06:49.494
Uh, a Handbook by Ali Ran and Robert Zilo, which is a, a good, uh.

01:06:49.494 --> 01:06:53.619
Starting point, uh, to this, uh, field of knowledge as well.

01:06:53.619 --> 01:06:55.778
It just gave me an idea for another episode.

01:06:55.778 --> 01:07:15.800
Ali, I, I probably need to, do some atex, uh, engineers, from Europe, uh, on, on how do we perform Atex protection in, in, in here, because as you said, it's, it's a part of nearly every industry, nearly every facility has a lot of those, you know, explosion zones and, and prevention of those explosion hazards.

01:07:15.800 --> 01:07:20.690
And it's, it's a whole field of industry that that could be, uh, discussed.

01:07:20.690 --> 01:07:27.710
So, so definitely there will be more explosion related episodes in, in the Fire Science Show, and for this Fire Fundamentals.

01:07:27.710 --> 01:07:29.510
I would like to thank you Ali and Lawrence.

01:07:29.510 --> 01:07:31.010
This was a great chat.

01:07:31.010 --> 01:07:38.240
Uh, huge thanks for coming to the Fire Shine Show and sharing your knowledge with, with the listeners, and I hope to see you somewhere around.

01:07:38.364 --> 01:07:38.784
Thanks.

01:07:38.784 --> 01:07:39.143
Thanks.

01:07:40.447 --> 01:07:40.833
Thanks so much.

01:07:41.777 --> 01:07:42.436
And that's it.

01:07:42.436 --> 01:07:43.456
Thank you for listening.

01:07:43.456 --> 01:07:46.126
Uh, world of Explosion is definitely quite vast.

01:07:46.126 --> 01:07:49.516
If you want to do it well, you have to build up your knowledge.

01:07:49.516 --> 01:07:59.413
I think participating in those courses by WPI or uh, or other educational opportunities that pop around out there is, uh, highly appreciated.

01:07:59.413 --> 01:08:05.980
And, if you are actually dealing a lot with, uh, those types of hazards, you probably would like to, to get up.

01:08:05.980 --> 01:08:07.510
I, I feel, uh.

01:08:07.510 --> 01:08:15.972
I feel that this is a field of competency that I could build up a little bit more and I'll consider in improving that on my end.

01:08:15.972 --> 01:08:19.992
For me, it was very interesting to learn the explosions.

01:08:19.992 --> 01:08:24.216
So far, I've considered them only through the lens of DEF Declaration detonation.

01:08:24.216 --> 01:08:32.672
I knew about the vapor cloud, explosions, ble, et cetera, because of transportation, of course, but uh, not at a level where I could, for example, model in with cd.

01:08:32.672 --> 01:08:36.837
probably that's also something that could be very, very interesting.

01:08:36.837 --> 01:08:41.908
I hope that you've got your knowledge, you got your resources to move forward.

01:08:41.908 --> 01:08:46.587
I think we've done a good job in this episode of Fire Fundamentals.

01:08:46.587 --> 01:08:50.823
So, uh, what's left to me is to thank you for being here with me.

01:08:50.823 --> 01:08:54.738
Today, thanks to Ali and Lawrence for sharing their knowledge.

01:08:54.738 --> 01:09:00.329
I hope you have great success with your master's program at WPI and to you, listener.

01:09:00.329 --> 01:09:09.779
I hope, uh, you will be thriving for more fire science and you'll come back here next Wednesday because next Wednesday we will have another pack of fire science coming your way.

01:09:09.779 --> 01:09:10.770
Thank you very much.

01:09:10.770 --> 01:09:11.640
See you round.

01:09:11.640 --> 01:09:11.970
Bye.