Chris Bradley 0:18 Okay. Ready? Yeah. Welcome back to the Sustainable Design Lab Podcast. I'm Chris Bradley.

Brodie Vander Dussen 0:26 And I'm Brodie Vander Dussen. This is the final episode in our cold chain master class series. In episode one, we lay the foundation, the physics, the materials, how cold chain systems work. In episode two, we examined where those systems break, especially in high stakes categories like biopharma and GLP one logistics. But today, my favorite, we're focused on design strategies, how to take everything we've discussed and turn it into cold chain systems that actually hold up in the real world.

Chris Bradley 0:55 And this episode is really about discipline, about moving from reacting to problems to engineering systems that tolerate reality.

Brodie Vander Dussen 1:03 So let's jump into it. Strategy one is design from failure. Most teams begin with reviewing insulation options or PCM catalogs. From your perspective, why is that the wrong starting point?

Chris Bradley 1:15 Because materials don't fail. Systems do. And when cold chain systems fail, it's rarely because insulation wasn't good enough on paper. Failures come from assumptions about lanes, about dwell time, about conditioning windows, about orientation, and how people actually pack boxes under time pressure. If you start with materials, you optimize in isolation. If you start with failure modes, design becomes grounded in reality. You stop the guessing and you start engineering against known risks.

Brodie Vander Dussen 1:46 And that brings us to strategy number two, stratify risk. You know, we often talk about designing for the worst case, and that sometimes sounds responsible. But you've said it's one of the biggest sources of inefficiency. Why is that?

Chris Bradley 2:00 Uh, I guess I would say because worst case is almost never defined and almost never probable. What usually happens is emotional design. Someone remembers one bad shipment and that experience becomes the new baseline. Suddenly, every box is built for one in a thousand event, And that drives excess insulation, excess PCM, oversized footprints, higher dim weight, higher freight cost, higher carbon emissions. So good design doesn't ignore risk. It stratifies it, And you design for normal lanes. You stress taste stress test for seasonal extremes, and you plan contingencies for true exceptions. You don't carry worst case weight on every shipment.

Brodie Vander Dussen 2:46 Which brings us to strategy three, design the system. You know, another common approach is upgrading individual components, better insulation, better PCM, so on. Why does that reliability not work? Let me

Chris Bradley 3:00 re sorry.

Brodie Vander Dussen 3:02 You know, another common approach is upgrading individual components, better insulation, better PCM, and so on. Why does that not work? Why is that why doesn't that reliably work? Okay. Sorry. You know, another common approach is upgrading individual components, better insulation, better PCM. Why doesn't that reliably work? now, another common approach is upgrading individual components, better insulation, better PCM, and so on. Why does that not work? Why is that why doesn't that reliably work? Okay. Sorry. You know, another common approach is upgrading individual components, better insulation, better PCM. Why doesn't that reliably work?

Chris Bradley 3:23 I would say because cold chain performance emerges from interaction. Payload thermal mass, insulation, PCM type and placement, internal geometry, air movement, and assembly execution. You can upgrade insulation and lose performance if airflow changes. You can add PCM and still fail if geometry creates voids. So systems don't behave addictively. They behave dynamically. So cold chain system design is really an exercise in systems engineering, not component shopping.

Brodie Vander Dussen 4:01 Strategy number four is engineering for repeat repeatability. Strategy number four is engineering for repeat why it's not working? Strategy number four is engineering for repeatability. You know, a lot of systems pass validation, but failures still happen later. What's missing?

Chris Bradley 4:21 Repeatability. So a system that works once is just a prototype. A system that works every time is engineered. So in the lab, we don't test one box. We test multiple identical builds side by side, same packout, same profile, same payload. That's because customers don't ship one box. They ship thousands or tens of thousands. So let me give you just, um, an an example from the lab. So we tested a refrigerated shipper that performed beautifully in a single box validation. Clean curve, plenty of margin. Then we went ahead and we ran six identical builds side by side, and two drifted early. Same insulation, same PCM, same profile. The difference turned out to be a small variation in how one panel seated at a coronal. So nothing you'd catch vis visually, nothing you'd see on a data sheet, but enough to create localized edge loss. So the design wasn't bad. It just wasn't very tolerant. And if performance depends on being, um, assembled perfectly, it won't survive at scale.

Brodie Vander Dussen 5:34 Strategy number five is control the interfaces. You know, people often assume that if a material hello? You know, people often assume that if material density is consistent, system performance will also be consistent. Is that true? g, um, assembled perfectly, it won't survive at scale. Strategy number five is control the interfaces. You know, people often assume that if a material hello? You know, people often assume that if material density is consistent, system performance will also be consistent. Is that true?

Chris Bradley 5:52 Um, I'd say only partially. So density consistency is absolutely necessary, but it's not sufficient. In panelized insulation systems like cellulose or starch, geometry becomes just as important as the material itself. So panel length, squareness, edge compression, small dimensional differences can create these micro gaps at the seams and at the corners. And those gaps don't always cause immediate failure. They quietly reduce margin, especially under vibration and thermal cycling. So let me give you, um, another, I'll call it, anecdote of how this kind of dimensional tolerance, uh, really comes into play. So we've seen systems where insulation density was extremely consistent. We have a heat flow meter, and so we tested from one batch to the next. And the r value was consistent across batches, but performance still varied. So the issue turned out to not be the material. It was actually the geometry of the panels. Panels that were a few millimeter short created seam gaps. And so what was happening is there is a guillotine was cutting off the edge of the insulation, and that created this tolerance that was a few millimeters within between different panels. So nothing dramatic, nothing visible. You couldn't tell by looking at it. But under vibration, those gaps shaved hours off of hold time. So consistency isn't just what something is made of. It's how precisely it fits.

Brodie Vander Dussen 7:33 And our sixth strategy is removing orientation dependence. You know, another assumption another assumption teams rely on is orientation, that the box stays upright. How risky is it to rely on that?

Chris Bradley 7:46 Very risky. So orientation labels communicate intent, not control. So you can put right on the box this side up. It doesn't mean that that's what's gonna happen in transit. Boxes get flipped. They get rolled. They get stacked sideways. They get palletized upside down. So and they get reoriented repeatedly throughout shipments. And so in the lab, if you're just putting it gently into a thermal chamber and testing it, you're gonna get one result, but it's not gonna be the same as what you get out in the field. So let me give you an example. We tested a shipper that was designed with PCM concentrated at the top. Um, and that makes a lot of sense of to to put it there. So upright, it had a very strong hold time. But when we ran the same system on its side, um, or upside down, it still passed, but it lost nearly 20% of its thermal margin. No alarm, no excursion, just less buffer. And that's dangerous because you don't know it happened. So robust systems tolerate mishandling. So when we're designing products in the lab, we're thinking about what's gonna happen in logistics, and fragile systems really require obedience. t nearly 20% of its thermal margin. No alarm, no excursion, just less buffer. And that's dangerous because you don't know it happened. So robust systems tolerate mishandling. So when we're designing products in the lab, we're thinking about what's gonna happen in logistics, and fragile systems really require obedience.

Brodie Vander Dussen 9:02 Which brings us to strategy number seven, stabilized phase change. PCM specs focus heavily on energy, but you emphasize mechanics. Why why why that?

Chris Bradley 9:16 Because phase change is mechanical as well as thermal. So some PCM gel packs expand when they're frozen. They can get this almost, um, curvature on them, and then they soften when they melt, and they can change shape as they go through these cycles. So when a PCM changes shape, the whole packout changes. So if you take a a box and, you know, at the beginning, you can shake it and it's really tight, Oftentimes, after it's gone through the change and the the gel packs have softened, you can shake it. You can hear the product moving around its side. So we've seen this clearly with PCM gel packs. On paper, the energy was there. In practice, after the phase change, the pack softened and shifted. This packout loosened, air gaps formed, and that's when internal convection increased. And so the payload center stayed within the range, but edge sensors warmed faster than expected. So when we switched to PCM bricks, we didn't add energy. We added structure. Now PCM bricks are what we exclusively use on our Tempsafe line, and, um, a brick is basically built around a rigid or semi rigid foam core with the PCM encapsulated inside. And so when the material freezes and melts, the geometry doesn't stay the same I mean, doesn't change, and so the packout stays tight. What improved wasn't peak temperature. It was predictability. And so another analogy I would I would use is as it relates to panelized insulation in interfaces. So panelized systems perform well when dimensions are precise and edges stay engaged. But when tolerances drift even slightly, seams become thermal shortcuts. The insulation didn't fail. The interface did. So in cold chain, materials insulate, but geometry decides whether the insulation actually works.

Brodie Vander Dussen 11:20 Which brings us to strategy number eight, stabilize before scaling margin. You know, when systems show variability, teams often respond by adding more PCM or thicker walls. Does that work?

Chris Bradley 11:32 Sometimes. But often, it just hides the problem. More mass delays failure. It doesn't fix that underlying instability. So if components are moving, adding energy won't stop that. Stability reduces the need for margin. Mass just mass design flaws. So if you want, like, um, a lowest cost of ownership, you need to remove that instability. Good design fixes geometry and movement first and then adds margin intentionally.

Brodie Vander Dussen 12:02 Strategy number nine is to test to learn. Most testing is treated as pass fail. How should teams really use it? . So if you want, like, um, a lowest cost of ownership, you need to remove that instability. Good design fixes geometry and movement first and then adds margin intentionally. Strategy number nine is to test to learn. Most testing is treated as pass fail. How should teams really use it?

Chris Bradley 12:10 I would say testing should expose weakness, not certify success. So we test, we adjust, we tweak, we iterate, and then we retest. And ask how the system behaves when orientation changes, assembly isn't perfing, stress stacks. And so when we're going through these tests, we're thinking and we're we're playing with imagine somebody was, like, looking on their phone or they were when they were packing this out, and let's not make sure that everyone is just, like, this perfect scenario. If you don't trust your build after five tests, you shouldn't trust it after 5,000 shipments.

Brodie Vander Dussen 12:51 Totally agree. Which brings us to our tenth strategy, right size the system. This final strategy pulls many of the others together. What does it really mean to right size a cold chain system?

Chris Bradley 13:03 Rightsizing is about removing excess without removing protection. Oversized systems ship error. Overbuilt systems ship fear. When you design from failure, you stratify risk, you control your interfaces, you stabilize the system, something very interesting happens. You need less material. You need less PCM. You need less volume. So rightsizing reduces dim weight, freight costs, carbon intensity, and handling complexity, not because performance is compromised, but because waste is eliminated. So it's the underlying idea behind behind sustainability. It's the underlying idea behind cost containment. Rightsizing is a signal that the system is truly engineered. And so I would say this really kind of un is the underlying component of our core idea. If you step back, all of the strategies that we just went through point to the same truth. Cold chain excellence starts with failure, not materials. Consistency is dimensional, mechanical, and operational. It's not just thermal, and the best systems are designed to tolerate reality. So what happens when you're in a in a crazy pack out in a hectic Christmas season or something else? Cold chain excellence isn't heroic. It's engineered.

Brodie Vander Dussen 14:26 So if someone was listening to this that wants help applying these strategies to their own cold chain programs, where should they start?

Chris Bradley 14:33 Well, I would say they should start by not doing it alone. We have the cold chain labs. We have the thermal engineers, and we design systems like this that we're talking about every day around your parameters, not our preferences. We are material agnostic. We're test driven, obsessive, really, on testing, and, uh, we really design systems that are built to hold.

Brodie Vander Dussen 14:58 And, you know, that wraps up our cold chain master class. tems like this that we're talking about every day around your parameters, not our preferences. We are material agnostic. We're test driven, obsessive, really, on testing, and, uh, we really design systems that are built to hold. And, you know, that wraps up our cold chain master class.

Chris Bradley 15:01 If you found this class valuable, subscribe to the Sustainable Design Lab podcast. And And if you wanna go deeper, reach out. We're always happy to help and collaborate.

Brodie Vander Dussen 15:10 Thanks for listening. We'll see you next time.

Chris Bradley 15:16 What do you think?

Brodie Vander Dussen 15:18 Way better.