Understanding the Temperature Ratings of Your Cold Storage Thermal Gear

Al:
We're here in a cold storage facility to unpack temperature ratings in thermal gear. Okay, so what goes into a temperature rating? Well, it's really an equation of three variables, right? You have your insulation, which is measured by something called CLO. You have your activity levels, which is measured by something called MET Activity Level.

And then you have the time factor. That's how much time you are out in the cold, right? So you put insulation plus activity level plus time and that equals your temperature rating. So when we're talking about CLO, again, that is really measuring the effectiveness of your insulation and how warm it is. Very simple math there, the higher the CLO, the warmer the insulation.

Okay, so one CLO is equal to the amount of insulation that allows a person to rest comfortably at 70 degrees Fahrenheit. For context, your typical flannel shirt measures about 0.30 CLO, while the average down jacket measures about 0.55 CLO. Cold storage gear like Ergodyne’s new freezer jacket and bibs features a toasty 2.59 CLO. So CLO values are tested and determined in controlled environments, right?

So they're using thermal mannequins equipped with sensors that actually simulate human heat production and sweat patterns. Now, when it comes to activity level, that is measured again by something called MET Activity Level, and you can either be light, moderate or high, very active. MET stands for Metabolic Equivalent of Task that's defined as the ratio of your working metabolic rate relative to your resting metabolic rate.

It's really one way to describe the intensity of an exercise or activity. So again, MET levels are classified as either light, moderate or vigorous. So on the light end, that's measuring less than 3 METs and that would include jobs like forklift drivers or, say, equipment operator. The moderate MET levels are measured between three and six METS. On the moderate side you would have your pickers and packers and maybe delivery folks. And then on the vigorous side of things, which is more than six METs, you have people doing high activity work, right? So think about concrete demo or tower climbers. And then the third variable is, of course, how much time you are in the cold and exposed to the cold.

The longer you're in the cold, your temperature rating is going to dip. Okay, so there you have it, Insulation plus activity, plus time put them all together and you've got your comfort equation, right? Good basis for temperature ratings, but it's not that easy. There's a whole host of other variables that go into affecting the thermal performance of any sort of garment.

And to sort of help parse out those variables, we brought in our expert, Claudia Weber. She is part of the Ergodyne Innovation Team charged with designing and testing our thermal work gear. Welcome, Claudia.

Claudia:
Hi. Thanks for having me.

Al:
It's a pleasure to have you. So why isn't it that easy, right? If something is rated to -50, why can't we just bank on that?

Claudia:
Yeah, because everybody is a little bit different. You and I could go into the same cold storage environment wearing the same gear, and we're two different people, and we might feel a different sensation when we're in there. So there's a few factors that I like to think about. One is, how old are you? So somebody who is older is actually more at risk for having a cold related illness.

Somebody who is overweight is also actually at a higher risk. Something to think about. If you have a medical condition. So just giving an example, Hypothyroidism, diabetes, sometimes those types of medical conditions can actually lower your circulation rate. And so in turn, you might have a harder time staying warm in the same exact environment that another person would be in.

Another thing to think about is hydration levels. So it's so easy in the summer when it's hot to be chugging water, but when it's cold or you're working in a cold storage environment, you might not be drinking enough water. Our body actually kind of fakes us out and tells us that we don't need as much when we get cold because all the blood vessels are kind of getting thinner towards the extremities of our body and the blood is rushing to the core of your system.

So it's protecting your heart, your lungs, your brain. So sometimes back to what I'm saying is we often don't think that we need water when we do. So that's important to think about.

Al:
So a lot of different physical factors. One example that that comes up a lot is like sleeping bags. Right? Sleeping bags are like, well, those are rated to -30 Fahrenheit, and, you know, that is a pretty stable rating. People can count on that. But there are a bunch of environmental factors too that go into thermal ratings, right?

Whereas if you're in a sleeping bag, you're likely in a tent. You're not moving around. There's not any wind. What can you tell us about maybe some environmental factors that are mixed in with those physical factors you were just talking about?

Claudia:
Yeah. So I think the environmental factors are a bit more obvious. So if you're working in damp air, if there's a lot of wind. So I never thought there would be wind in a cold storage environment, but they have those stands running. It is cold. And then you stand in front of the wind and it's even colder.

So that's a big factor. Of course, just the temperature that you know, that it's set to if you're outside or inside. Those are some big ones. If you're also working on machinery, that is cold itself. So metal, think of that. Those are just some environmental factors. So you kind of need to combine the personal as well as the environmental.

When considering, how is it going to affect you as a person?

Al:
Yeah, absolutely. That makes a lot of sense.

Claudia:
And I don't want to forget too. Also, if you don't get enough sleep or you're drinking, you're boozing hard the night before you took drugs, that can definitely affect how you feel the next day as well.

Al:
Okay. All right. So then, all that in mind, what advice would you give to workers that are looking for the proper thermal gear to wear?

Claudia:
So a few things that I personally would look for is you want to look at the temperature rating. We have it there for a reason, but it is a guideline, it is a benchmark. It is not the end all be all for every single person. So look at it. See if it fits in the environment that you're working in.

Two is use this garment and try to test it, bring it to your facility, see if it works for you. Every facility is a little bit different and every person is different as well as don't use this garment as the only garment you're wearing. You are wearing something underneath it. So consider layering wear your base layer, your mid-layer, wear insulated boots, etc. maybe wear the hand warmers if you know your fingers get colder during the day or wear foot warmers if your feet naturally get colder.

I also would make sure you're wearing properly fitted PPE. So let's say you're the last worker. You grab the jacket and it's three sizes too big. Well, it's going to be baggy. You're going to get a ton of wind and air going through your garment. And in turn, you're probably going to be colder than the rest of the workers.

So make sure it fits properly.

Al:
All right. I think that's some pretty good advice for the folks out there. Once again, I want to thank you all for watching. Listening. If you're listening to this on Spotify or Apple, please do remember that you can catch a video version of this on YouTube or ergodyne.com. Thanks again, everybody, for watching, listening and stay safe out there people.