047 - Effective pressurization of compartments with Grzegorz Sypek

Wojciech Wegrzynski: [00:00:00] Hello and welcome to the Fire Science Show session forty-seven. Today, the podcast is taking a little twist into world of engineering, more than science, but actually it's, uh, science-based and, uh, factual-based engineering, so it's very welcome in, uh, the podcast lineup. Uh, we're gonna talk about pressurization systems or pressure difference systems, PDS, as they're going to be referred in the ex- episode a lot, and these types of solutions are used in d- different types of buildings, especially on evacuation routes and stairwells, lobbies, sometimes corridors, in order to create a pressure difference that prevents smoke from entering the space that's protected.

Very simple idea, very efficient potentially, and also an idea that is known to be quite difficult in employing in a real building. Many places of the world, people just do not believe these types of systems can work or there's a history of these systems not [00:01:00] giving the performance they were expected of.

And for that reason, there's a lot of happening in Europe. There's new standards that will be published very soon, EN 12101 Part 6 and 13, so this, this will be important step forward in creating a new future for pressurization systems. But it's not just standardization. We want to talk today more about the fundamentals of these systems and in a way, a Polish twist in their design, which led to creation of very successful applications, which have been used in practice in dozens, if not hundreds of buildings, also very tall buildings with, with great success.

And, uh, yeah, this is the story we want to share with you today. My guest for this topic is, uh, Grzegorz Sypek. He was an engineer at the company SME who developed, uh, one of the first adaptive, uh, pressurization systems in Poland, and now he's an independent consultant who also work with PDS systems. He has [00:02:00] worldwide experience, uh, from Middle East through Europe, and also he has been an active member of CEN committees that wrote the standards I've just mentioned.

So he's the definitely a good person to talk about the systems being used in Poland, how they different from the solutions around the world, and how can we actually provide safety through pressurization in very tall buildings. I hope this is an exciting topic. It's, it is for me, for sure, so I hope you'll enjoy it.

And yeah, let's not prolong this. Let's spin the intro and jump into the episode.

Grzegorz Sypek: Welcome to the Fire Science Show. My name is Wojciech Węgrzyński, and I will be your host.

Wojciech Wegrzynski: Hello and welcome to the Fire Science Show. [00:03:00] I'm here today with a good friend, Grzegorz Supek. Hello, Grzegorz. Great to have you in the podcast.

Grzegorz Sypek: Hi, Wojtek. Good to hear you. I'm glad to be here.

Wojciech Wegrzynski: Thanks. Uh, I'm glad to have you in the show. Today, we're gonna talk about important thing that is pressurizations of various compartments in, in fire as a means to protect spaces.

But before, uh, we start, I would like to say a few words. I would like to dedicate this episode and recording to our mutual friend, Michal Kozek, who unfortunately went missing a year ago on Madeira. Uh, Michal was very active in the pressurization community in Poland and in Europe, a member of CEN committee working on the pressurization standards, member of SFP and, and a good, good colleague.

So, uh, Michal, wherever you are, we're thinking about you and, uh, missing you, man. This is for you.

Grzegorz Sypek: Yep Exactly. This is for him

Wojciech Wegrzynski: This is for you. Okay, Grzegorz. S- so there is this funny thing, pressurization systems, and [00:04:00] in Poland, we routinely go into 200-meter-tall skyscrapers, install our PDS systems in there, commission them, and they just work, and whenever you step outside of Poland and tell that to someone, they go like, "It's impossible.

They don't work like that. It's not going to work." And yet here standing with, I think, 15 years of experience in applying these types of solutions, we seem to have built a national confidence in this field of protection. S- so I'm really wondering, what is the difference between the Polish way of pressurizing buildings and, and some things you observe outside of Poland?

It's the same pressure. I, I just feel we're in, like, completely two parallel universes, one of which technical solutions are really advanced and amazing, and that is Poland and in, uh, in the world when... where people just don't believe in these type of systems.

Grzegorz Sypek: Well, yeah, that's a very good question, and it's good to start from this particular question.

You know, from my [00:05:00] point of view, actually, PDS, we can discuss a lot whether PDS works or not. That depends on the project. That depends on the quality of, of different works, and that depends on the variety of different factors. However, from my point of view, we don't have alternatives for the time being, so we use such systems regardless whether we like it or not.

The only issue is that we can do it in the, in the right way or we can do it in a little bit-

Wojciech Wegrzynski: European way. Sorry.

Grzegorz Sypek: Well, in a global way- ... which is a little bit old school way- Yeah ... from, from today's perspective. You know, our world is changing continuously, so the, the same thing happens when, when we talk about the PDS.

So if we discuss systems, multiple injection system, multiple air s- multiple-point air supply systems, constant capacity fan, and a mechanical pressure relief damper at the top of the stairwell, it may be not sufficient for, for advanced buildings. You know, look at the modern buildings. They, they are getting taller.

Yeah. They are getting more advanced. We've... We [00:06:00] collect variety of different data out of those buildings. It is packed with e- electronical devices, so I don't see any particular reason that we shouldn't follow the same manner, I mean, th- go the same way when it comes to fire safety systems, especially since this is not something which is only fancy.

You know? Sometimes it is-

Wojciech Wegrzynski: Mm ...

Grzegorz Sypek: highly required to design fully functional PDS for given building.

Wojciech Wegrzynski: Okay. I- I'll give some background to our, um, our friends outside of Poland on w- what happens in here. So as Grzegorz mentioned, constant, uh, capacity inlet fan and a pressure relief damper would be a common way to pressurize different compartments in many buildings.

However, in Poland- We have more active systems. I mean, it's, it's funny when you think about it now, everyone is talking about Internet of Things and, uh-

Grzegorz Sypek: Smart buildings ...

Wojciech Wegrzynski: advanced m- smart buildings and everything, and in Poland, in terms of [00:07:00] pressurization systems, wow, that, that, that's exactly what we have.

It's just we didn't call it like that 10 or 15 years ago when, uh, these things were born, and now, uh, you say that they're not only fancy, but they truly have better capabilities than solutions that were used for decades over the world. Maybe y- I, I know you were there when these systems were invented, uh, developed, uh, designed, engineered.

Uh, maybe you can tell us the, the story how you went from, uh Or maybe h-how you didn't even go to the route of, of pressure relief damper. What was the thing that pushed you into these smart systems, uh, and how this revolutionized the, the Polish market in the early 2010s? You were there, you've seen

Grzegorz Sypek: it- Yeah, yeah

on and off. I, I've been there, you know. I, I, I still remember it well. So it's, you know, basic idea was to really solve the problem, not to hide the problem. Yeah. Because, you know, what we do globally [00:08:00] in terms of personalization or PDS, let's call it PDS, it is more comprehensive because this is not only personalization, it-

Wojciech Wegrzynski: Yeah

Grzegorz Sypek: we wanted to solve the problem, and the problem was that in very tall buildings, especially in cold climate or very warm climatic zones, there were significant problems with stack effect, variety of different factors. I mean, vari- variety of different phenomenas which are not discussed at all actually at the moment for the time being.

For instance, airflow resistance of the stairwell, we supply quite huge amounts of air to the stairwell, and we've got one opening at the top of the stairwell, so the air has to flow through the stairwell, and we've, we've got some specific airflow resistance of the stairwell. And our objective... Let's start with the objectives.

Our objective is to have specific air, uh, pressure difference across the door or the, yeah, fire compartment at the fire floor. So we want to have positive pressure in the, in the protected space and some reference pressure, not necessarily negative pressure in the fire compartment or the fire floor.

Wojciech Wegrzynski: Sorry. W- With [00:09:00] pressure in the protected space being higher than on the other side- Exactly ... so making sure that, uh, uh-

Grzegorz Sypek: Exactly. To keep vertical or not necessarily vertical, but, but escape routes free of smoke, to prevent infiltration of smoke, and to have directed airflow from the protected space to somewhere else outside the protected space, again, to prevent smoke from coming into protected space.

And, uh, like, let's say standard PDS operates in two modes. One mode is pressure mode, where, where when we have all doors closed, I mean, the, the protected space is more or less airtight. And the other one is airflow mode when we open the door, and it strongly corresponds to the fire scenario or evacuation scenario from the building.

So there is a huge discussion on how many doors shall be open simultaneously at the same time, and it depends. It is not like we each and every time we can open three doors, for instance, into the stairwell. It, it depends. And so we have started... Let's say we have started from the scratch. We, we made sure that PDS [00:10:00] available at that time are not sufficiently advanced to be applied or to be installed, uh, in very tall buildings, and that was the starting point for the entire discussion.

Then we have decided to do some, uh, real scale tests, and we have carried out such tests in Kraków in 90-meter tall tower. It was actually a part of the high-rise building, which was like 30 years old at that time, but it was very useful because we were able to do the, the, to do the tests for over two years in the real scale, which is quite unique in the global scale because each and every time when I look at the PDS, I either see CFD or some ana- analytical calculations, you know?

There are very few-

Wojciech Wegrzynski: Or small, or small scale, uh, experiments-

Grzegorz Sypek: Exactly ... that was done as well. Exactly. Uh, and we went for the huge project, which was, it was very useful to, to develop and to design the final version or fi- [00:11:00] final shape of the PDS. So we wanted to solve few important problems. We wanted to solve the stack effect issue problem and we wanted to solve wind influence problem because both are very important and both are different because, you know, stack effect is rather static.

I mean, it results from temperature differences inside and outside the building, so, you know, the temperatures don't change that much. Whereas when we talk about wind, it is very dynamic, so we wanted to have a solution for both. So we went through the internet, we went through, you know, different design concepts or dif- different PDS concepts available at that time, and we didn't find anything which was, you know, sufficient from our point of view to, to, to be installed in the building.

So we developed system, let's say active control system, which, which is modular, that is very important. Very often it happens that, you know, PDS are being designed for specific projects. So we do- we, we take different components and integrate them on-site, [00:12:00] which is not a very reasonable approach because it is very important, the interactions between components are very important.

So we wanted to have the well-defined modular solution which would be suitable for different buildings, and the architecture of the PDS would vary depending on the height of the building. And the same system can be used to protect or to, to pressurize vertical escape routes, uh, lift shafts, and firefighting lobbies.

Because when we talk about PDS, it is very important to, to point it out that we are talking about huge part of the building. We are not talking about the stairwell only. Because when I, when-- I've been living in, in, in Dubai for two years, you know, and each and every time when I discussed PDS there, it was the stairwell Stair pressurization system.

That, that, that was w- uh, h-how they called it. So it's way more than that. So yeah, the system was developed based on real scale experiments, you know, supported by CFD analysis and then laboratory testing of, of the components of the kits. We, we'll talk it over a little bit [00:13:00] later.

Wojciech Wegrzynski: Yeah. Okay. Uh, let's go back to fundamentals.

You've mentioned it was designed to battle stack effect, and we know that many design guidelines, recommendations would say that you're ought to subdivide your vertical route into smaller-

Grzegorz Sypek: Sections ...

Wojciech Wegrzynski: say

Grzegorz Sypek: sections.

Wojciech Wegrzynski: Partitions. Yeah, 30 meter or something, uh, to prevent the stack effect. The... I, I think the underlying physics is that over 30 meters the stack effect will not develop into very huge pressure because in, in a very tall building you can have easily 100, 200 pascal from the stack effect only.

So if you sub... The, the idea was to cut it into subsections, but we also know that this is wishful thinking. If you have a stairwell and people are evacuating in it and someone opens doors to both of them, which are interconnected with some compartment, the stack effect will not, uh, wait patiently until the path is sealed, but it, it will just form.

And I think this is a major [00:14:00] problem in the systems that often wishful thinking is part of the design. You would omit some of the physics, omit some of the consequences because otherwise it's, it's very difficult to prove the system will be working. And now you're telling me you designed a system for 90 met- meters stairwell.

Uh, I should be surprised, but I'm not because, uh, as a consultant on the Polish market, I, I've seen buildings twice that high, which had modern PDS systems in them. Uh, more than that, I've been doing CFD and commissioning of the systems, and they just worked. So, uh, if possible, maybe you can share the magic how stack was handled.

Grzegorz Sypek: Yeah, there is very... Actually, there is very little magic in, in the overall concept for the, for the PDS because it is strongly based on science and technology. And I hope you still remember that we had a chance to meet in Dubai in 2016 at the SFPE [00:15:00] conference and- For one of the projects over there and actually in Dubai, for a 220 meters tall tower, we did a design concept and carried out some CFD simulations to prove that, you know, for this very, let's say, for this extremely warm part of the world, the system will work as well because in, in Europe, in US, we mostly have problems, uh, during the wintertime where it's colder outside than inside.

So when the stairwell or the vertical escape routes operate more or less as chimneys in, in buildings, so the mo- the air moves from the bottom to the top of the building. But in the warm climate, we've got a reverse stack effect, and if you go to the hotel in Dubai and you take a look at the stairwell, you will see that there are swinging doors at the bottom of the stairwells, you know, and they are not closed All the time because they are partially open due to the stack effect.

So we know the system, the, the, the problem is clearly visible in the buildings. The issue is that [00:16:00] there is very little real scale tests and good commissioning of the, of the systems across the entire world, more or less because the knowledge about PDS is, is relatively low. But that, that's a different story.

You know, coming back to your, to your question, the magic, the magic, there is no magic, as I said. The overall idea is to lever or to supply air to the negative pressure zone and to exhaust it from the positive pressure. Because in, in each and every building we will have both zones where the-- there is a difference, uh, of air temperature outside and inside the building.

So we supply air at the bottom in the wintertime and exhaust it, uh, at the top, and we do opposite, uh, during the summertime when the temperature differences are opposite. So we wanted to create airflow, directed airflow resistance throughout the stairwell to produce specific pressure drop or airflow resistance throughout the stairwell, you know, to compensate the stack effect.

The structure and the architecture of the system is relatively [00:17:00] simple because you've got air supply, you've got reversible fans at the bottom and at the top of the stairwell, and you've got pressure differential sensors and, you know, some control panels to control the, the airflow inside the stairwell to produce specific pressure difference, overpressure in the protected space, and to create specific airflow resistance in the stairwell, where, uh, during the times where we've got pres- temperature differences outside and inside for, you know, isothermal conditions where there is no temperature difference, you just pressurize the stairwell in the, in the common way.

Uh, but you have to, to keep in mind, you have to remember that it, the, the system, the architecture capacity of the system strongly depends on air leakages rate of the protected space. It strongly depends on airtightness of the building facade, and it strongly depends on air release provided because, you know, air release it, it is critical in, in most of the cases, and sometimes it is highly underestimated because in Poland we mostly use mechanical [00:18:00] air release for PDS, right?

It, it, it, it results from our national regulations, whereas in different countries it is being done and carried out in different, in different manner. For, for instance, in Switzerland or in Germany, they mostly use na- natural air release. So you know, it, it is-- Therefore I, I'm talking about PDS, not only about pressurization because fr-from my point-

Wojciech Wegrzynski: Yeah

Grzegorz Sypek: point of view, pressurization is just air supply side.

Wojciech Wegrzynski: Yeah. I'll, I'll, I'll take you there just in a second. Uh, any Sufficiently advanced technology is indistinguishable from magic, and I'm sure what you just des- described, uh, as something you commonly use will be considered magic for many. And the realization that to create the necessary overpressure, you sometimes have to remove air, that's a kind of a brilliant thought and not one that you immediately get, but it, it really works to remove the air from the positive pressure zone in the part of the building where it is created.

Basically, [00:19:00] with this simple move, you reset the stack effect in the building, bringing it under control and ha- being able to provide The pressurization, the designed pressure over the, the whole height of the building. That- that's brilliant. And now you, you've brought me into very important subject, what do we do with the air that we supply?

And this is extremely interesting because as you mentioned, uh, some people would consider it stairwell protection system or stairwell pressurization systems. And for me, I always thought that the stairwell is, in a way, the most important thing we protect, and in the same time the most difficult thing to protect because during the evacuation and rescue operation processes, you cannot...

You just cannot be sure that it's going be sealed in a way you expect it to be, or the standards would expect it to be. And but this is not the end of the protection. In Poland, the common thing would be a lobby or [00:20:00] vestibule, however you call it, a small compartment next to your, next to your opening to the stairwell, to the elevator shafts, where you would have additional point of protection being a, a secondary PDS system or a secondary inlet designed in a, in a very special way to always make sure this lobby is positive pressure against the corridors.

So you s- you gain like an airlock, uh, part of your system, like in spaceships in movies. It's just you, you don't have to wear a space suit to enter that airlock. And, uh, now you open the doors to your fire room, and we know fires make a lot of products, a lot of hot air. If there is water, it is gonna evaporate, so these whole things are adding to pressure being, in a way, produced.

Goddammit, I, I'm a scientist, I shouldn't say it like that, but, uh, for the podcast, yeah. The pressure is being produced in there. So it, it's necessary to [00:21:00] make sure that the route the air flows is from the staircase, from the lobby, through the floor and somewhere. Now, you've said a po- a popular thing in Poland would be to provide mechanical outlets at the space that the fire is, so you basically suck the air from there in amounts that allows this flow path of air always form.

In other solutions, you can open the, the windows, uh, but what, what's the issue with that? Does the wind, uh, trouble you or w- Yeah ... why are you worried with the systems based on natural e- exhaust?

Grzegorz Sypek: As you, as you already said, we are each and every time in, in very tall buildings and even in relatively low buildings where we use the PDS We are dealing with phenomenas that influence our PDS dynamically, I mean, in an active way.

So it's hard to imagine that we can, you know, fight those, those phenomenas and those, those interferences in, in a passive manner. You know, we have to react to [00:22:00] what's happening in the building. So if, if anything is passive by default, it is very hard to imagine that it could co-counteract some-something which is highly dynamic.

You know, when we talk about the, the air release, it has to be provided to have the airflow from the specific airflow, because each and every time we will have some airflow from the positive pressure zone into the fire, fire floor. But it has to be, you know, specific value of this airflow because it's also defined by the standard.

A-actually, we are talking about airflow velocities from 1.0 meters per sec up to-- minimum up to 2.0 meters per sec, depending on the fire scenario, I mean evacuation scenario and, and, you know, intended use of the PDS. Because we are talking about evacuation or we are talking about evacuation and firefighting on site.

So this is the phase of the, of the fire, depending on the phase of the fire. In the initial phase, we assume that it 1.0 meters per second is sufficient, whereas when the fire is fully developed, we need at least 2.0 meters per sec from the pressurized and, and [00:23:00] protected space into the fire floor to prevent smoke from coming in, into the protected space.

Uh, what troubles me is that every solution has some bright sides and dark sides, and it-- when we use the mechanical air release, it's more comfortable from design point of view because when we suck air from the, from the fire floor, from the fire compartment, from the air release path, it will flow from the positive pressure side to the air release mechanically supported.

But when we talk about natural air release, we have to keep in mind that the shafts would be significantly bigger There is no fan at the top of the, of the shaft to, you know, to suck smoke and suck air and smoke from the, from the fire floor. And it is even worse when we are opening the windows because PDS tend to work properly where the building facade is airtight.

Because, uh, if it's very tight, a- as for most of the modern buildings because [00:24:00] we are talking about different things that influences the airtightness of the facade. We... And the f- airtight facades are highly required at the, at the moment because of energy use and, and things like that. But wh- when we open the, the window with the given floor, we will equalize the pressures, you know, inside the building and outside the building, but only at this floor.

So this additional interference for our PDS because when the building is airtight, I mean, the entire facade is closed and tight, uh, then we, we will have stack effect because it is very important to understand that that stack effect happens and occurs not only in the vertical escape routes, it occurs in the entire building in...

I mean, inside the building. So when we are opening the, the, the facade to the ambient, we've got additional, uh, uncontrolled interference. So from my point of view, mechanical air release is, is, is very good option, robust and very reliable.

Wojciech Wegrzynski: I'm also in favor of controlling. However, [00:25:00] it, it sometimes is, is... I will admit, uh, with Grzegorz here, we only touch the pinnacle of the engineering that goes into PDS systems.

And even though, uh, we, we seem to make it quite easy that we have great solutions, we have great systems in Poland, we can manage that. It, it's not that you go into PDS shop, uh, pick a box from the shelf, drop it on your building and it works. There's a whole hell of design that goes along with that. And in here, it's not that, uh, we, uh, magically possess the knowledge, uh, to do that.

It's, as Grzegorz mentioned, they have spent years in a real building playing out, trying out solutions, testing what works, what does not work, and, and finding the correct combination of systems to finally create the first kit that went onto the market. Now, a decade later, we have multiple, uh, multiple companies that specialize in, in delivering these types of systems.

There's, um, a lot of engineers who [00:26:00] specialize in designing them in Poland. So by saying it's easy, I, I think in, in a way, it's like, uh, in mathematics, you know, if there's a... If the problem exists and it was solved, it's easy. If it was not solved, it's hard. Same here. You solved it, so it's easy. But in... for... to engineer it, it's a whole lot of work.

Grzegorz Sypek: Yeah.

Wojciech Wegrzynski: Now I wanted to switch a bit to the much more fun aspect of designing new technology, new system, and that is standardization I know you've been involved in, in, uh, writing the EN 12101 Part 6 and Part 13 standards for, like, probably one-third of your not very long life. Uh, th- uh, no, the standards was really- That was a

Grzegorz Sypek: compliment, yeah.

Thank you. Thank you.

Wojciech Wegrzynski: Uh, the, it's... You're welcome. But, but that's true that the standards have been written for more than last decade, and, uh, you've been there for, for a long time. So, so, and now, today, many friends from UK, many friends from other European countries are reaching out. They hear [00:27:00] that we have experience with the 12101, the, uh, Part, Part 6 and Part 13 already, because we have, in fact, for the last decade, thanks to espionage of you and your colleagues, we've been working with the principles in, of these standards, and we, we've put them into, into buildings already.

So people are reaching... Because the standards are about to be published- Yeah ... people are reaching to us to, to know, know our experience. So maybe you can tell us a few words about the standardization process of these standards, uh, what's changing, what, w- what's the, the key differences, and do you think if this standard can, uh, truly open a new era for pressurization systems in Europe?

And before you start, I will just think about your clever answer, and I, I'm just gonna briefly give introduction to why old 12101 Part 6 was horrible and created nothing but issues. So there was a standard, I think it was 2005 or '6, published, uh, certif- harmonized. It was a standard that allowed to give [00:28:00] CE-marking to kits.

The only issue is it did not give an answer how to do it, and that created a hell of a problems. It was more like a design standard on how to design a pressurization system to your building. By design, I mean calculate leakages and choose whatever performance criteria you want to achieve, not really how to design it.

And that was a source of very, very big problems because suddenly you have a harmonized standard. In EU, that means you can CE-mark with that, but you really could not And yeah, we, we had to find a way out. We found a way out through the projects of the new standards, through national, uh, assessments and building our own laboratory following the, the new procedures that were being born at the time.

And, uh, yeah, Grzegorz, tell us how, how were they born and w- w- what's, what's changing? What was the big fuss about?

Grzegorz Sypek: Yeah, actually, you've already touched the point. We used to have already with TRONI and 1211 Part 6 from 2005 based on BS, former [00:29:00] BS standard, and it was a, it was funny thing because it was a product, harmonized European product standard, which mostly dealt with the design of this PDS.

Wojciech Wegrzynski: Fantastic.

Grzegorz Sypek: So-

Wojciech Wegrzynski: Thank you so much, as-

Grzegorz Sypek: It, it, it, it, it should have never been published, actually. So there, there was a decision and it is very com- Amen ... it was very common in Europe, it is still very common in Europe that we talk a lot about different things, and we, we do it very slowly. So now we've got a new European EN revised EN 12101 Part 6, which will be a pure product standard, which probably it, it's, it depends, but I'm not sure if it's gonna be harmonized European standard or not, but this is a different story.

We need reliable and decent products to be installed in buildings when we are talking about fire safety, so it is clear for me, and we've got this set of European EN 1.101 standards. We build our [00:30:00] PDS, and not only PDS, different fire ventilation systems out of those components, so there is a huge discussion whether we can use this product or not, and we need harmonized European standards for different products.

And the idea of EN 101 is very good, so it gives us clear recommendations and requirements for products installed in buildings. Uh, when we talk about design, it is, uh, new European standard EN 12101 Part 13 which will cover design, acceptance testing, commissioning, different things for the PDS in buildings.

But, um- There are some significant changes. It, it, uh, the idea was it should be simpler, I mean, easier to apply, easier to use for designers because we had... we used to have different classes. I mean, six classes of PDS in the previous EN 12441 Part 6. Uh, now there are only two classes, A and B, and there are some changes.

I'm not sure if it's revolution, but it's definitely easier to be used and to be understood from designer's point of view, and it is actually the most important thing for the standard to be successful on the, on the [00:31:00] market. I have f-for years, I've, I've heard that you don't have to use this standard because it is not obligatory to use this standard because it is not possible to harmonize or, or to standardize the, the design process.

However, when I look, you know, across the world, I mean, in different countries where I had the chance to work, I see that designers strongly prefer to use some standard, some design standard because it's easier for them, it is safer for them, it is simply better. So I think this is very important that we have the standard in Europe, which is way more detailed than, for example, NFPA standard, which deals with PDS over there in, in, in America, in the US.

So I think this is the step ahead. It is not perfect. It, it is to be developed for over a decade, as you, as you already mentioned. So I think in many cases, I mean, in many ways, it's already outdated So I'm, I'm expecting that, you know, the, the revision of the standard will start soon. So this is the problem of [00:32:00] Europe, you know, it is quite passive and we need a lot of time to introduce important changes and updates.

But, but ne- nevertheless, I think it is a step ahead and I think it's gonna be useful because there are some problems mentioned and listed, and there are some solutions for those problems as well. So I think it is, it's, it's gonna be, it's gonna be a step ahead once published, and it's gonna happen soon.

Wojciech Wegrzynski: That's great. I, I certainly appreciate the changes to 12-1/6 where it gives, uh, testing methodology. A- as I've mentioned before, in the time where there was no good regulation, meaning that, that the existing standard was useless and we had to pursue the national general assessment pathways to put these fire safety solutions on the market safely, we were heavily inspired by the work ongoing in, in your committees.

And in, in fact, we, back then, we've already implemented all the electromagnetic, all the environmental compatibility [00:33:00] tests for the parts of the kit to make sure from this perspective they are safe, and we have built a hydraulic laboratory to test the, the hydraulics aspects of these, of these devices, where we test its reliability and the, the capabilities of the system to achieve their performance points in terms of pressure or flow within a certain, uh, time from opening, closing the doors between the protected and, and the fire compartments.

So there, there is quite advanced laboratory base already existing, very ready to- Yeah,

Grzegorz Sypek: the second, uh, second oldest in the world- Yeah ... actually, so congrats on that. You know, it's, it's a huge achievement.

Wojciech Wegrzynski: Thank you.

Grzegorz Sypek: Yeah.

Wojciech Wegrzynski: Thank you very much. And, and it, it has been extensively used already. I think we've went through at least 10 manufacturers of PDS systems in Poland and in Europe, in fact, and this also gives us a good basis, uh, of experience on how to, how to deal with this, uh, with these systems.

And, uh, if any of your [00:34:00] listeners are interested in testing your PDS, uh, I... you're very welcome to send me an email, and we are very ready for you- ... uh, to test this for the new standard. Not yet accredited, because the standard does not exist, but I can promise you that day one, when it's possible, we're gonna opt in for accreditation-

Grzegorz Sypek: Yeah

Wojciech Wegrzynski: for that test, test streak. Uh, so a little, a little insert of my marketing in, in, in the podcast episode, but I think it's important that there is a basis of knowledge that, that exists based on experience.

Grzegorz Sypek: Actually, there is... It is, again, very important to mention that we've got components, we've got kits, and we've got systems Um, we very rarely test real scale PDS in the lab, but we have to clarify what is the intended use and what is the intention of the lab tests.

It is to assess and validate whether specific combination of predefined components is capable To meet some design objectives. [00:35:00] If it's not capable to do that in the lab, in the smaller scale, we can really doubt that, you know, it's gonna work out in the, in the real building. It's not

Wojciech Wegrzynski: gonna work.

Grzegorz Sypek: So this is, this is, this is, this is...

That was one of the most complex and long-lasting discussions in the, in the committee because people tend to not to understand what's the difference between kit component and system. Once it is tested in the lab and it passes the tests, it can be installed in the building more or less, you know, right?

And then if, once it's installed in the building, it's ha- it has to be tested again. This is not instead, this is additional test to, to provide and to guarantee-

Wojciech Wegrzynski: Oh, I, I, I will tell you something funny that will not surprise you at all because you were involved in that. But we already have been testing kits that were designed for particular buildings undergoing refurbishment.

When you have a new building, it's very, let's say, easy to engineer the system based on the existing [00:36:00] market solutions for it. But when you have a 50-year-old skyscraper or a 30-year-old skyscraper, you work with what's available in the building. It's, uh... You cannot go to the owner and tell them, "Okay, I need five new shafts in the core of the building."

Or

Grzegorz Sypek: I need to, uh- Or I need to, you know, test it for two weeks or, or a month in your, in your building, you know?

Wojciech Wegrzynski: Or I need to close the building- Yeah ... and test it for two weeks. Yeah, exactly. S- so, so we've done that. We have been modifying the, the testing, uh, station to, as closely as possible, mock up the existing building and test the capabilities of the system as close to what's gonna be in, in the real building in terms of leakages and stuff like that.

The only thing that is very hard is the stack effect, obviously. But, but still outside of stack effect, everything can be pretty much, uh, modeled on the, on the rig. So it's, it's funny, we, we don't even have a standard published and we've already went into performance-based engineering pathways w- with, with that.

And I, I think this segues me to one of the questions I really wanted to ask you. From the... In the beginning of the talk, you said [00:37:00] that, uh, it's a kit, it, it contains pieces that you can use at buildings as necessary. I wondered, how did you... how do you determine what's gonna be needed on the building? What type of engineering analysis did you pursue to design a system for a building?

Or you just go to a catalog and pick a system for 170-meter, uh, tall building? That, that would be cool, actually.

Grzegorz Sypek: No. Y- y- yeah, it's, it's not that easy, but pretty much, it works pretty much like this. We, each and every time we have to start with design objectives, right? Ar- architecture of the building, I mean, the to- height, height of the building and, and, and building parameters are just one group of input parameters for the, for designing the PDS.

We start with the design objectives and- We also defined design pressure differences, desired airflows, and, you know, all the parameters which actually describe the PDS. So, and basing on this database, we design PDS, but what I wanted to say is that [00:38:00] we don't experiment with combinations of different components from one project to another.

So today I'm, I'm working as an i- independent consultant for over two years. So, you know, I mostly base mostly on my experience 'cause we, we had a chance to work on some tallest buildings in Poland and also I, I had a chance to, to work on some projects in, in the Middle East. But so I, I, I, I, I, I work using my experience, uh, practical experience, but it has to be calculated by the design stage.

You have to prove, and this w- also one of the requirements of the new EN 12101 Part 13, that for buildings taller than 60 meters you have to prove at the design or at the design concept stage, you have to prove that the system is capable or your PDS is capable to meet some specific design parameters.

So there is a door open for CFD analysis, which are still not very common when we talk about PDS because we model fire, we, we model spread of smoke, temperature differences, but we don't [00:39:00] most... In m- most of the cases we don't do CFD for PDS. And I think this is very good tool to, to prove at the design stage that the system works properly because the parameters of assessment of the PDS are very clearly defined.

There is a pressure, specific pressure difference, there is specific airflow, and that's more or less it. Uh, and this pressure difference corresponds to door opening force, which is, which is actually critical in most of the cases when we talk about PDS because we don't-- we, we are not allowed actually to exceed 100 newtons in, in Europe and 133 newtons in US.

Maybe US guys are stronger than Europeans are. I don't know what, what's the reason for the difference, but we don't want to have pressure differences that result in, in exceeding 100 newtons of door opening force. And this is really the most important parameter. So just to put it all together, we want to have some specific pressure difference across the door at the fire floor We want to have direct airflow from the protected space into the fire compartment to prevent smoke from coming [00:40:00] in to the protected space, and we want to have the possibility to evacuate from the building, so we don't want to have any doors closed due to the exceeded door opening force.

Wojciech Wegrzynski: And with the CFD, I, I assume that you don't model just the compartment where the fire is taking place or the floor. It's more like a simulation of the whole building to model the, the stack effects and, and other effects, um, involved, uh,

Grzegorz Sypek: in fire, right? Yeah, exactly, exactly, exactly. The best option would be to model entire building.

This is not always possible because the models are getting bigger and bigger, and it's very time-consuming. So it depends how much potential and how much time you can spend. But, um, at least we need to model vertical escape route, which is protected, and representative floors in, in the building. And this is when we talk about the building, this is more or less it.

Wojciech Wegrzynski: And what about shafts like... What about like elevator shafts and stuff as

Grzegorz Sypek: well? Sure. Definitely. You know, we, we, we need to model all, all parts of the building which strongly influence the pressure distribution across the building.

Wojciech Wegrzynski: [00:41:00] So like all, all, all the possible paths

Grzegorz Sypek: of the, of the airflow. Exactly, exactly, exactly.

You know, when we- Okay ... talk about outside of the building, it is even more complex because we are dealing with dynamic changes of, of wind speed and also the location of the building is important. If it's located in downtown, we've got a variety of different tall buildings around the building. You know, it also influences the, the pressure distribution on building facade.

But what is, from my point of view, what would be the most important thing, I'm not talking about the wind tunnel testing of the... some specific part of the city. Rather talking about pressure distribution on the building facade because what is important for me, for, for me, from my point of view, is the pressure difference between protected space and some reference space in the building And to the outside where there is an air release, for instance, at the building facade.

Because when the, the facade is, is airtight- Yeah ... and I don't open it for the means of PDS, so there is n- no particular need to model the outside of the building. So I can only limit the model to, to the building [00:42:00] inside.

Wojciech Wegrzynski: Yeah. He- here is an- another point why mechanical e- exhaust would be maybe, uh, better than natural openings on the facade because you would have the outlets at the roof level usually, or at the technical floor, which hopefully would be the same floor when you have inlets, just maybe opposite side of the building.

But this simplifies both wind and both stack effect because these effects will, uh, often even cancel out or, or, or- And can be compensated ... not have that, that... Yeah. Yeah. That they can be compensated, so, so, a, a good point. And have you considered... I, I know, uh, for American audience, they are pretty much going like, "What the hell?

These guys are doing CFD for pressures. We have content for that." And have you considered, like, simplified models to model that?

Grzegorz Sypek: They... Well, actually, they do more or less the same in Switzerland. It's even more-

Wojciech Wegrzynski: Yeah ...

Grzegorz Sypek: w- more common in Switzerland. Because especially around Zurich, there is a canton Zurich, they require the, they've got some local regulation.

Uh, th- these are not even national regulations. These are just [00:43:00] canton regulations for some part of Switzerland where they require to do CFD to do numerical analysis Not necessarily CFD for the PDS, uh, for buildings taller than 60 meters and they are quite, quite advanced. Uh, and they mostly use CONTAM for that.

But this is not that the eq- th- th- this is not, this is definitely not the equivalent for the full scale, I mean, fully advanced CFD because this is like about, uh, kind of simpl- simplification of the, of the nature of the, the real world, so-

Wojciech Wegrzynski: Yeah ...

Grzegorz Sypek: I think it, it is somewhere in between. We do analytical calculations- Yeah

hand calculations for the, for the PDS all over the world. And the most of the cases, unfortunately, tho- those, uh, hand calculations are limited to the capacity of the fan only and to, you know, sizing the, the mechanical pressure relief damper rate of the building, and that's it, which is way too less. I mean, which is way too little to- Yeah

to assess the PDS in the real building. So we do it commonly like this. On the other hand, we've got CFD, [00:44:00] advanced C- CFD simulations, which is the perfect way to... Once it is carried out properly, this is, uh, another issue- Mm-hmm ... but let's not go into too many details on that. The CFD is very good to, to, uh, analyze the processes when it comes to PDS in, in, in various buildings.

Somewhere in between, we've got this CONTAM, the zone node models, right? So it is way better than s- than hand calculations, but it, it is definitely not the CFD.

Wojciech Wegrzynski: I, I, I think I have to ask some expert on CONTAM for the podcast. I have a few people in mind maybe. Look forward to- towards the East. There will be an episode one day coming.

Grzegorz Sypek: What would be- That could be actually pretty cool ... Wojciech, what would be the difference? What's the advantage is that even if you don't have very powerful computers, like you do, you've got hu- huge number of licenses- Thank you ... you've got big computers and stuff like that, so you've got in, uh, all the required infrastructure to carry out advanced, big scale, large scale, uh, CFD simulations.

In most of the cases, we have to limit the size of the model because [00:45:00] we are not able to do the, to perform the- Mm ... the, the fully advanced CFD simulation. So CONTAM gives you the advantage that you can model entire building Even outside the building you can do some, some, you know, calculations. So you, you don't need to have, you know, that much advanced computers for that, so.

Wojciech Wegrzynski: You, you can always outsource it to us, we'll handle it. We're cheap, like

Grzegorz Sypek: I, I, I, I don't- Just kidding ... actually I don't use Concan much.

Wojciech Wegrzynski: We're, we're not

Grzegorz Sypek: cheap.

Wojciech Wegrzynski: So,

Grzegorz Sypek: you know, I do ha- If, if anyone- I, I do hand, I do hand calculations, so no worries. I will not outsource

Wojciech Wegrzynski: it to you. Yeah, uh, the thing to take out of this episode, if you need help in engineering a system, call Grzegorz and he will CFD for that.

And I will call Wojciech to do

Grzegorz Sypek: CFD for that, you know.

Wojciech Wegrzynski: A- and we'll, we'll do CFD for you, so you have a full, y- you have a full package there.

Grzegorz Sypek: Yeah.

Wojciech Wegrzynski: One last thing I wanted to ask you because, uh, we, we've touched a little when talking about laboratory. So y- you've said that laboratory tests are, like, prerequisite for that the system will work on the building.

We know that, uh, i- if it... Well, the fact [00:46:00] that it works in lab does not mean it works in a building, but there's a good chance it will. If it doesn't work in the lab, then I'm sorry, it's not gonna work anywhere. But when you go into a building, you've designed all this system, how do you prove it works?

Grzegorz Sypek: Yeah, actually, there is a, um, let's say, testing procedure, real scale testing procedure, commissioning of the PDS procedure described in EN 12101 Part 13, which gives you clear requirements on how to test it, you know, and what has to be measured and what is the required accuracy of the measuring equipment.

So it's relatively well described, and it is quite easy to be carried out in the building. It-- The only thing it may be time consuming. Therefore, I'm 100% for active controlled systems, active controlled PDS, because I, I've got a chance, even if it's installed in the building, I've got-- we've got, got a chance to recalibrate it, to reset it, to, to, to introduce different settings for different components.

Yeah. When we talk about mechanical [00:47:00] solutions, which are, you know, predefined and pre-configured, for instance, on the production side, there is very little chance to, to change and to adjust anything- Yeah ... in, in building. And additionally, you touched a point that I want to mention again that in the lab we do tests in relatively small scale.

But what is the major problem in most of the cases when we talk about PDS? This is not necessarily the stairwell, because the pressure distribution inside the building strongly depends on the, uh, on the temperature differences outside and inside. But the most important part of the-- I mean, the most critical part of the PDS turns out to be the firefighting lobby, because we've got relatively small, uh, small room, I mean small space, right?

Where we supply quite huge amount of air, right? And we open and close the door, and that this is our interface between the air release path and the protected space, as you said at, at the beginning. So- The airlock, yes ... the airlock. So it is, it is the, the smaller the space is and the more airtight the space is, and the more air we [00:48:00] supply into this specific space, the harder to control pressure differences in this, in this specific space.

Because we've got huge pressure jumps when we close the door and we... Then we, we open the door and we have to increase capacity of the fan very fast. So it has to be very well controlled and very stable on the other hand.

Wojciech Wegrzynski: Yeah. You, you, you can literally have, uh, hydraulic hits in the system, like the waves of pressure formed by, by closing the, the system.

And we, we've seen that in lab that we, we, we've seen in lab kits that were jumping from this actually, like literally jumping into air because of the, of the force that was in there. And that was not due to, uh, the, some miscalculations or wrong design. It was just because you're trying to put a lot of air into very small space, which is very airtight.

And,

Grzegorz Sypek: and this-

Wojciech Wegrzynski: This is critical.

Grzegorz Sypek: This is

Wojciech Wegrzynski: critical ... I, I agree. This is a challenge. This is a challenge.

Grzegorz Sypek: Therefore, you know, the, the, the, the, let's say standard PID controllers Or perfect, uh, when we talk about maybe perfect, when we [00:49:00] talk about the stairwells and when, when we talk about firefighting lifts, which are relatively big and the airtightness of those spaces is, uh, relatively low.

But when we talk about, uh, the lobbies, which are small, fairly small, uh, I would even say tiny, so we need to have something more advanced when we talk about controls. The PID controller has this characteristic that the faster it operates, the less stable it becomes and opposite, right? So it's, it is not possible- Yeah

to configure it properly. So for firefighting purposes we've got the op- option to use, to, to use a more advanced control systems and actuators for the sy- for the system, I mean the, the control devices. Or to go for, let's say more or less constant capacity PBS ir- regardless of the position of the evacuation door, whether it's open or closed.

So I, I, I'd like to say that, uh, from my point of view, basing on my experience, if when something is advanced, it doesn't necessarily have to be very complex [00:50:00] It also can be relatively simple. The, the, the architecture of the system can be r- can be relatively simple and u-understandable from my point of view.

But for instance, when we use electronically controlled components, it is a, a matter of reliability of the system, right? So in the systems I recommend and design, all electronic components are continuously monitored. We cannot be sure that the system will work properly or not unless we don't monitor the entire system cont-continuously.

This is not like we will start the system once per year during the periodic testing of the, of the PDS. We need to be sure that it op- will operate, uh, more or less throughout the... Not more or less, throughout the entire year. So in the systems we developed, for instance, it, it normally goes through routine testing.

It is a self-testing system. So for instance, air supply fan is being started once per day with a very little, with very low capacity, not to interfere with the [00:51:00] use of the building, and we also open and close mechanical shutter dampers.

Wojciech Wegrzynski: Test procedure we do at laboratory also forces our clients to think about some sort of leakage compensation, uh, approach.

What I mean is that during the tests, we sometimes change the leakages a little bit, not a whole lot, but a little bit because in the, in the building it's enough that someone puts a carpet in a, in a corridor to change the leakages. And we don't want- Mm-hmm ... to have a system that works only fine-tuned to particular leakage, and when the leakages change a little bit, it goes into oscillations or something.

So usually clients have to develop some sort of systems that every now and then test the leakages and adjust the parameters of the PID controllers to match the thing they, they see in the building. Uh, and Grzegorz, well- Mm-hmm ... time flies great when you're having fun. You said it's, it's a boring topic, and we're gonna wrap it in 30 minutes, and an hour has passed and we could- All right

talk for [00:52:00] another one, but I will stop you there. But I, I will give you a chance for, like, a, a final statement. If you have a message to our friends outside of the Poland who want to design safe PDS systems, outside of calling, uh, you and me, what should they do?

Grzegorz Sypek: I do. You know, please do not believe that PDS In general, don't work because they are PDS.

Uh, they don't work because it's our fault when they don't work, actually, you know? Because this is... In most of the cases, this is a result of bad design or bad quality of components, so the, the overall idea is good from my point of view, and if it's properly designed, it, it has a chance to be very useful in terms of saving people's life and s- supporting firefighters on site.

So besides, I don't see any alternative for the time being to replace PDS with anything else. We've got two ways, to design good PDS or to design bad PDS, so I, I'm [00:53:00] definitely for designing good ones, and I think it, it doesn't have to be very, very complex and very hard task to do. And we have to keep in mind that we've got different buildings, and each and every time PDS has to be ta- tailor-made to the building.

So when we talk about simple projects, let's don't go into CFD analysis. Let's don't go into some advanced, some complex systems. Let's use- Mm ... what we normally use. But when we talk about buildings taller than, let's say 100 meters, in harsh climate, I mean climatic zones in, in parts of the world when it's cold outside and when it can be very warm outside, let's don't underestimate problems with, with PDS, and let's not copy...

We- if we have a b- building which is 30 meters tall, let's say, let's not multiply PDS into 150 meters by simply copy-paste because it will not work. So each and every time we have to think reasonably, and we have to behave in a, in a, in a, let's say, smart way to pre... to use and to, to, [00:54:00] to design and to use the smart PDS.

And, and the PDS will never be smarter than us, so it is our responsibility.

Wojciech Wegrzynski: Yeah. The PDS cannot compensate for the stupidity of its creator.

Grzegorz Sypek: Exactly.

Wojciech Wegrzynski: That's a brutal final remark. But yeah, we, we are engineers. Let, let's engineer. Um, thank you, Grzegorz, for this talk, and let's stay in touch, and I, I hope to work with you on many, many PDS projects around the world, uh-

Grzegorz Sypek: Thank you very much

thanks, man. Thank you very much for it, and, uh, for invitation, for your time, and I hope it's gonna be useful for you guys. And in h- in case you have any questions on, on the PDS related issues, do not hesitate to contact me. I'm, I'm, I'm for you.

Wojciech Wegrzynski: All the contact details in the show notes. Thank you, guys. See you around.

Thanks, Grzegorz.

Grzegorz Sypek: Great. Yeah. Bye-bye. Take care.

Wojciech Wegrzynski: And that's it. Thank you for listening. I hope the world of pressure resistant systems is, uh, more accessible to you now, and you believe a little more in that they can work actually and provide safety in, uh, the applications they are used for. If, [00:55:00] uh, you have any questions related to the systems, the implementations, or just the standards, you are very free to email Grzegorz.

He allowed me to give his contact details, so they're all in the episode show notes. And if you wonder about how to test your own system, how to make sure that the system you design, uh, will work in the application you need, or maybe you need help in modeling that, we're very happy to help you at the ITB, so you can also contact me.

I hope this episode was u- useful to you and, well, more useful stuff coming your way next Wednesday. So I hope to see you there. Cheers. Bye.

This was the Fire Science Show. Thank you for listening and see you soon