Lou: We’ll get started right at the top of the hour. Until then, know that we’re here and ready to deliver an excellent, high-value presentation on the use of insulation coatings for burn protection. We’ll be right back.
Welcome everyone! It’s the top of the hour, and we’re excited to have you here. Good morning, good afternoon or good evening to everyone who has joined us worldwide for what we believe will be an excellent presentation on the use of insulation coatings for burn protection. I’m Lou Frank, publisher of the Corrosion Media Network. That includes Corrosionpedia, SpecSource Global and Coatster web-based platforms designed to help corrosion professionals globally.
We’re excited to have you here today. Clearly, each of you has a professional interest in coatings used in industry to mitigate burn and other personnel safety issues. Clearly, each of you has an interest in keeping your facilities as safe as possible. And I’m sure some of you already have questions or you’ll have questions arise during the presentation. At any time, please use the dialog box on the right side of your screen – right there down at the bottom – to pose those questions. We encourage them and we promise we’ll get to them immediately at the end of the presentation.
Over the past two decades, there has emerged a variety of coatings technologies that have addressed the need to provide insulation protection for personnel. Interestingly, what seems not to have emerged is industry consensus on measuring effectiveness. The Corrosion Media Network is honored to host today’s presentation featuring one of those rare individuals with keen experience in this area. Howard Mischke is uniquely qualified to speak on this topic. Howard, welcome!
Howard: Thanks, Lou! I’m delighted to be here.
Lou: Howard, you had quite a career. Let me share a bit about you and your background with our audience. May I?
Lou: Howard has a Bachelor of Science degree in Biology from the University of Houston and worked for Shell Oil for 32 years until his retirement in 2009. During his career, he worked in biochemistry, epoxy resins technology, material testing, but especially, was a coatings specialist for 17 years. In that role, he was responsible for R&D on many different coatings issues including technical support, writing coatings specifications and qualifying coatings products for a particular application.
Howard is a member of NACE and is a certified NACE Level 3 coatings inspector. He actively participates in committee meetings and has written several technical papers and has also been invited to give presentations. He’s also engaged in SSPC, having won an Outstanding Publication Award for his paper on the Effects of Chloride Contamination on the Performance of Tank and Lining Vessels. I’m sorry, Tank and Vessel Linings.
The research that Howard is currently working on is directly related to his work at Shell. While working there as a coatings specialist, he evaluated insulation coatings as a way to mitigate corrosion under insulation, CUI. That’s a hot topic today for a lot of us. In that research, one of the goals was to gain an understanding of the thermal characteristics of these coatings.
In discussions with coatings manufacturers, he realized that the thermal performance of these coatings was not well understood. In addition, the thermal properties on the product data sheets were not comparable between manufacturers. Oftentimes, they use different units or different test methods. At various meetings and forums, he found other end users with the same frustrations and many people questioned whether the claims for these coatings were real. So in his “retirement,” Howard has been working with numerous test methods designed to help explain the various claims made by coatings manufacturers.
We’re delighted to have you, Howard. And I’m impressed that you went all the way through with the NACE CIP Level 3 course work. I got a lot out of earning my CIP Level 1 a few years ago, but was never able to find the time to go beyond that. Good for you. And I think that brings real credibility here today. You not only know the theory from a high-level engineering perspective, but you’ve really lived it in the field as well as in the lab. Any experiences out there you want to share a quick story with our audience?
Howard: Well, Lou, I don’t really have any big stories to share, but I just wanted to say that my training in the NACE CIP courses was extremely valuable to me. It set the foundation for all my other duties as a coatings specialist, and it taught me a lot of little things that make the coatings and their application successful. In my duties that involved some sort of inspection, I did inspecting of coating processes, and numerous pipe coating facilities, inspections of coating applications inside large storage tanks and applications for general atmospheric pipe coatings and much, much more.
Lou: Hey, that’s excellent. Wow, you’ve really been out there. Thank you! Well, I think we’ve been in long enough to allow for any late arrivals. Let’s move on with the presentation for everybody. We’re here again today to talk not so much about you, Howard, but more about your current research. It’s really about personnel protection in hot environments and how new technologies can help prevent accidental burns and make a safer workplace. This is not about PPE, something all of us are keenly familiar with, but instead – well, a PPE is mandated in many environments, but there are a surprising number of areas with hot equipment in use where PPE is not required.
One thing, if I may, Howard, before we get started, today’s presentation is sponsored by Moscoat. Moscoat was founded in 1995 to provide insulation solutions in coatings technologies. Today, they have revolutionized how industries insulate and protect facilities, equipment, and people.
Oh, and if you will, one last reminder about the questions. Everyone, please, post your questions, post them now or as they arise during the presentation. Just use that dialog box down on the right side of your screen. We welcome those questions. Alright, Howard, it’s all you.
Howard: Okay, thank you again, Lou, and welcome everyone to this webinar on insulation coatings. I appreciate your interest in this topic, and I hope to share with you a number of things that we have learned and I hope that you find it informative and interesting.
Insulation coatings are primarily used as a coating on hot objects, so that if we accidentally touch a hot object with this coating on it, we won’t get burned. It’s one of the ways that we can protect workers who work around hot equipment. And so, this presentation is about validating that thermal insulation coatings can be used for personnel protection. And it’s also about the development of test methods to determine the coating’s safe-to-touch temperature limits.
This is an outline of the presentation. I will first give a little background on thermal insulation coatings. I’m going to call them TICs for short. Then I’m going to talk about the myth of the 140 °F rule. Then I’ll discuss the importance of taking accurate temperature measurements on the surface of a coating.
Many of us, like the fellow in the picture below, like to put our hands on the coating to tell how hot it is. But there are better ways to use the different instrumentations that are available and to get more accurate readings. I do see that the fellow also has an IR meter in his hand, too. So he’s got both ways to test the temperatures. I will also talk about two ASTM standards that deal with this subject on touching hot objects. And those standards are ASTM C1055 and 1057. Finally, I will discuss how to determine temperature limits of these TICs using an instrument called the thermesthesiometer. I will call that instrument TM for short. And one last thing, when I refer to temperature limits in this presentation, I’m referring to the limits for personnel protection purposes not for its surface temperature limit.
Insulation coatings have been around now for well over 20 years. And when applied properly, they can provide many good years of service. They are primarily used for personnel protection and for process stability. But since they are bonded directly to the steel substrate, they don’t have an annulus where water can enter underneath the insulation and initiate corrosion. So in this way, these TICs help to mitigate CUI. They can be also coated over irregular shapes such as in the photo below. They can also be used to minimize condensational cold equipment, and they can help to reflect solar radiation on tanks to keep them cool in the summer.
TICs are usually made with either a water-borne acrylic or water-borne epoxy type material. The coatings are – since the coatings are water-borne, it is highly recommended that you apply a corrosion protective primer such as an epoxy phenolic. TICs contain generally either ceramics, aerogels or hollow spheres and that gives them their insulation value. Thicknesses can range from 40-200 mils. Because TICs are thinner than conventional insulation, thus surface temperatures can range from warm to hot depending on how hot the metal is and how thick the coating is.
But the big question is, what coating thickness should we use for a given metal temperature to be compliant for personnel protection? And the second question would be, how do we determine this temperature limit? Unfortunately, we don’t have any standardized test methods to answer these questions.
Some owners in the past have been skeptical about the performance of these TICs for three reasons. In some cases, modeling predictions for the surface temperature would not agree with actual temperatures made in the field. There’s also a misconception that all surfaces must be less than 140 °F for personnel protection even if an insulation coating is used. That is an incorrect belief. And the third reason is that, as I mentioned before, there are no standardized test methods to validate these coatings. And on top of that, the one instrument that could provide such data, that TM instrument, it wasn’t commercially available until just recently.
A common misconception with field personnel is that, what I call the “myths of the 140 °F rule for personnel protection.” It is commonly accepted that equipment will be insulated if it’s 140 °F and personnel protection is needed. Many field personnel still think, though, that materials other than metal must also have a temperature that’s less than 140 °F for personnel protection no matter what that material is made of. The rule is correct, of course, for metals, but it is not correct for insulation coatings. These TICs can have much higher surface temperature limits than 140 °F. As I mentioned before, TICs can feel hot to the touch because they are relatively thin. But because they have a low thermal conductivity, the TICs conduct heat at a much slower rate to the skin than metals do. And the slower it conducts heat, the higher you can go on its surface temperature or safe-to-touch temperature.
So let’s talk about surface temperature measurements. To me, it appears that there’s a general lack of knowledge on what thermal devices to use and how to use them correctly to get accurate measurements. If the surface temperatures are inaccurate, the temperature limits that we determine will be also inaccurate. And if we’re going to base temperature limits on surface temperatures of the coating, we need to be more accurate than we currently are. Personnel protection relates to safety and we definitely want to be accurate when it comes to safety. Furthermore, inaccurate temperature measurements will not agree with modeling predictions. And here again, that lowers our confidence in the TICs, and the users may begin to think that maybe the coating isn’t doing what it’s supposed to do.
In this slide, I’m going to discuss three commonly-used temperature measuring devices starting with the contact probe. It’s okay to take measurements with the contact probe on metals, but they are slow to come up to temperature. They need at least about two minutes to equilibrate. Most people don’t go that long. They think it’s equilibrated at one minute, but it does take a few minutes and it does slowly creep up over time. If you use the contact probe on TIC however, it may take as long as 10 minutes to equilibrate because of the slow conduction of the heat from the TIC to the sensor. And even after the 10 minutes, the readings will still be lower than actual readings. The other thing is that no one is going to hold a probe on the surface for 10 minutes. If they go past three, I’ll be amazed.
The thermocouple is fine in the lab, but it’s not practical in the field. It has to be attached or embedded in the surface such that it is not cooled by the surrounding air. You can use a conducting paste, but holding it in place in the field is a bit difficult.
The IR meter we found to be the best instrument to be used on TICs. The readings only take two or three seconds, but the IR meter must be able to have the feature to enter emissivity for the coating. And you also need to know what the emissivity of the coating is. You can get that kind of information from the manufacturer. However, a couple little details on that emissivity. You can determine the emissivity with an ASTM E408 test, but you have to use the same frequency range that is used by the IR meter. They are typically using about 8-14 microns on the frequency range. The standard E408 test for emissivity uses 2-43 microns. So you have to tell your test lab or the manufacturer that you want the emissivity for the same range that the IR meter is used.
The photo on the left is an example of a contact probe. There are dozens of different designs for them. They all have a thin thermocouple or wire that you see at the bottom, and that’s what contacts the surface. These type of thermocouples are very fragile. They’re easily damaged. And if they’re bent, they can give you lower readings than actual. The photo on the right is an example of an IR meter.
In the lab, we have experimented with different ways to measure surface temperatures because we wanted to make sure that we get it right. We want to know exactly what devices to use and how to use them.
In this table, we show the equilibrated readings for three different instruments. We measure temperatures on a non-insulated surface and on a surface that was coated with 80 mils of TIC. The metal substrate in both cases was 300 °F. Note that the temperatures in the center column here and in the right column are given in both Celsius and in Fahrenheit. The three devices that we tested were the thermocouple. We had it embedded in conductive phase. And we used an IR meter with an emissivity set at 0.95. And then the third was the contact probe.
On the epoxy primed steel, we see that the temperatures for the contact probe were about 10 °F lower than for the thermocouple and the IR meter which both agree very nicely. For the TIC temperatures, they also agreed very nicely for the thermocouple and the IR meter. But the contact probe was now 20 °F lower than for the TIC with the IR meter and the thermocouple. We also see this wide gap between the IR meter and the contact probe at two independent labs that were working on some similar projects. And the other thing is that the IR meter results also agree very closely with modeling predictions such as the 3E Plus that we’ve used. So, given all this, we feel very confident that the IR meter is the best instrument to use in both the lab and the field.
And I’m going to take a short break here, get a few sips of water and I’m going to let Lou get these few comments.
Lou: Hey, thanks, Howard. Thanks for powering through this first half. Your presentation is excellent. We already have a couple of questions that have come in that we’ll address right as this presentation ends. For all of you in the audience, keep those questions coming. We’re excited about being able to do that.
And just as a reminder, this presentation is sponsored by Moscoat. Moscoat provides insulation solutions in coatings technologies. They have revolutionized how our industries insulate, protect, facilities, equipment and people.
Howard, have you had enough there? Do you want me to keep going? Are you ready to get into the heart of your presentation here?
Howard: Sure, Lou, I’m ready to go.
Howard: Okay, let’s talk about those two ASTM standards that I’ve mentioned. The ASTM 1055, 1057 are the two standards that give us guidance on how to determine skin temperatures after contacting a hot object, and whether or not we’re going to – that contact is going to be safe or will cause us a burn.
ASTM 1055 makes two recommendations for us. The first is to allow a contact time of five seconds so that workers who accidentally fall against a hot object can reposition themselves and remove contact, and this is what the industry accepts. The second choice is to allow a first degree burn as the maximum injury level. This is also accepted in the industry. So, with those two criteria, the C1055 standard tells us that the skin temperature should not exceed 58 °C or 137 °F. Now, keep those two temperatures in mind because I will refer to them numerous times in other graphs that are coming up.
Here is a photo of... Oh, let me... I went to the wrong slide here first.
Now, there are three factors that affect how bad a burn will be. The thermal properties like thermal conductivity and specific heat are one; and then there’s the temperature of the surface and the contact time. The higher that you – these values are for these properties, the more severe will be the burn. And small changes in metal temperature can have a great effect on the skin. You can touch the metal, for example, with a surface temperature of 111 °F and you won’t burn yourself if you touch it for six hours. But you raise that surface temperature by only 29 °F and bring it to 140 °F, you will start to get a first-degree burn after only five seconds. So that’s how sensitive the skin is to small increases in temperature.
In the figure below, you see the three degrees of burns to the skin. Skin has two layers to it. There’s an outer epidermal layer and then an inner dermal layer. In a first-degree burn, some of the cells in the outer layer die, resulting in a reddening of the skin. You may have a lingering burning sensation, but there’s no permanent damage to the skin. In a second-degree burn, all of the cells die in the outer layer and you get some reddening of the skin and blistering. The burning sensation will last longer and healing will take days. In a third-degree burn, most of all the cells in the inner layer, the dermal layer, die and there is permanent damage to the skin. Healing takes much longer and requires significant medical attention. These burns can be life-threatening if it covers a pretty good percentage of your body.
So that was a quick background information that leads us now into the test program for the TM testing. I started consulting with Moscoat about four years ago and our first project was to do some tests with the thermesthesiometer instrument. And at that time, the only available test unit was at a third-party testing lab. There was only one lab in the US that I found that had this. But we did search around for an instrument company that could possibly make a unit for us – that turning out to be way too expensive. But we did have a surprise when we found out that some TM instruments were becoming commercially available, and that was around January 2013. So we purchased one and we began our own in-house testing, and now we’ve tested hundreds of these tests since then.
The testing is fairly simple. We use a 4”x8”x1/4” thick test panel. We have tested for coating thicknesses, five or six different thicknesses in the range of 40-200 mils. We’ve tested usually five different metal temperatures in the range of 150-375 °F. We’ve also tested three different ambient temperatures and three different wind speeds to see how they affect all these temperature – skin temperature simulations.
One thing I do want to mention, too, NACE is now getting involved. They have a committee that’s working on this. The goal is to develop standard test methods so that we can have some uniformity within the industry on this. And I think a lot of people have that work in NACE have been presenting this question to NACE, too, or at least this concern. So that’s good that they’re doing that.
Here is a photo of this thermesthesiometer set up. The metal test sample on the left hand side here – I’m going to get my pointer out so I could show you. This is the test sample. Herein you see the white coating on top. That’s the TIC. There’s a thin silicone heater that you can barely see underneath the test sample. That’s like this one in the front here. It’s 4”x8” and same size dimension as the test panel. That’s the heater we use to bring the test panel to its desired temperature. The blue box in the center here is the temperature controller. The TM probe that’s being held on to the surface is the thermesthesiometer probe. The probe sends signals to the white box here. That’s the thermesthesiometer itself. The data from the thermesthesiometer is then sent over to a data logger – this little black and white box. And then after the run, we can download the data from this box, the data logger, to the PC and determine what the simulated skin temperature is.
And this is a photo of the wind tunnel we used. As I mentioned, we just did at different wind speeds. We tried 06 and 12 mph. The wind direction is coming in from the left side. And on the right side, we have a 26” diameter fan pulling air into the tunnel. And for a small unit like this, that was pretty much home-built here, it works very well. We get a smooth flow of air on that left side over the panel. So we’re overall happy with it.
Well, we did accumulate a lot of test data in all of this work, but I won’t be going into all of those details. For the test results, that would take another hour just to summarize that, but I do want to share one thing with you on what I feel is the most important data, and that’s this slide here. It actually validates that the TIC that we tested can be used for personnel protection. We are plotting the skin temperatures versus the surface temperature here of the TIC. The red line that you see, the horizontal line, is the skin temperature limit that I told you to remember. That’s 58 °C or 137 °F.
The blue line – let me get my pointer out here, too. The blue line represents the skin temperatures after touching a steel metal panel that was primed only with an epoxy coating. There was no insulation on this metal. Note that you have the start of a first-degree burn right here where the line intersects with the blue line. The other thing to note is that just a few degrees above that – remember we’re at 58 °C here – at 61 °F here, is the start of a second-degree burn. So here again, there’s a lot of sensitivity of the skin to just a few degrees change in temperature.
The green line near the bottom is the skin temperatures for a TIC coating that was 3 mm thick – that’s 120 mils. Note that the green line is below the red line all the way up to that approximately the 140 °F last data point. So that’s telling us that it can prevent us from having burns all the way up to that temperature, but we do have a temperature limit. When that green line intersects the red line, that’s where we start to get our first-degree burn, and that’s at 140 °C or 289 °F – a whopping 289 °F before we start to get a burn. At that temperature, though, the TIC will feel very uncomfortable for the touch and you may feel like you will want to pull your hand off.
But if you hold it there for 5 seconds contact and then you pull it off, you won’t have a serious burn on your hand. I have done this test numerous times out of curiosity, trying to see if the thermesthesiometer is how accurate it is. And yes, my hand did feel the uncomfortable-ness, but after pulling it off, I only had a slight redness but did not have any lingering sensations afterwards. So I felt like my hand was right at the edge of a first-degree burn there. And I feel that thermesthesiometer is probably giving us fairly accurate results, so I’m always glad to see that. So I think this graph clearly validates that the TICs can be used for personnel protection with surface temperatures that are well above that 140 °F rule.
We can determine the temperature limits then for personnel protection in two ways. For engineering designs, we would want to know what coating thickness is required for a given metal temperature and when it would be in compliance with ASTM 1055. So we can base the temperature limit on the metal substrate or on its surface temperature. If we want to validate and apply coating, we would want to determine what is the maximum surface temperature allowed. So we would base the temperature limit on the surface temperature. We could then check a recently applied coating that is in service and see if that surface temperature is below – that the surface temperature is below the maximum temperature for that coating.
In order to determine these temperature limits, we can’t run just one TM run, or TM test. We must run several tests over the whole surface temperature range of the TIC and with several coating thicknesses. I recommend that we use five different substrate temperatures and five coating thicknesses, and that test protocol would give us about 25 thermesthesiometer runs. They’re not too difficult to run. They only take about 30 minutes a run, so very doable test, wouldn’t be very expensive either.
This slide shows an example of six thermesthesiometer runs, all with the same coating thickness of 2 mm or 80 mils, but we ran them with six different metal temperatures. The six dotted lines that you see here are a data taken from the TM probe and represent the simulated skin temperatures while that TM probe was held onto the test surface. The substrate temperature for the bottom green line is 190 °F, and for all the other examples, we incremented the temperatures up by 40 °F and so forth. So the highest temperature up at the top with the red coating is 375 °F for a metal temperature on that panel.
The red horizontal line here again refers to that temperature limit that I told you to remember – 137 °F or 58 °C. The vertical blue dash line is the 5-second end point and wherever the data from the thermesthesiometer run intersects with that point, we call that the TM/5S result, and the 5S refers to 5 seconds. So that’s the number that we want from this test. So when these six runs are completed, we will pull that test panel off, put a new one on with a new coating thickness, or a thicker coating thickness, and we’ll repeat this test all over again.
So for each of these coating thicknesses then, we can take the six intersecting data points and plot them on another graph such as this one that we see here. This first plot at the top was for the 40 mil coating, and the one that we saw in the previous graph was this 80 mil coating here. Those six intersecting data points aren’t shown here but they do fit on this curve, the green curve. And as you see, the maximum substrate temperature for each coating thickness is shifted to the right as you increase the coating thickness. And of course, the intersection of these lines with that 137 °F line is the maximum substrate temperature for each coating thickness.
And finally, if you take these five data points, at the intersection with the red line and plot them on one more graph, you will get this graph here. This is the graph that – the final graph that we want. This graph shows one line that gives the minimum coating thickness that you would need for any substrate temperature within the service range of the coating. Any combination of coating thickness and substrate temperature that is below that line would then not be acceptable for personnel protection. If you’re above the line, it is acceptable. This graph is the type of graph that we would like to see all the coating manufacturers include on their product data sheets. This is what the end users have been asking for a long time – something simple, a simple graph like this showing minimum coating thickness required for the surface temperatures. This type of graph would be very helpful to standardize this information for all to understand, then we can compare apples and apples for various different products.
The second way to define a coating limit is to correlate these TM/5S values with the surface temperature of the coating. The plots in this case are linear, and you do need a single value for the temperature limit which is at the intersection of the red line with the plotted line. It’s a little interesting on this particular TIC that we tested. We have two separate plots that kind of pull out from each other. We have a blue line at 40 mils and it has its own separate temperature limit. And then, the other thicknesses between 2 and 5 mm seem to clump together on one line, and they have their own temperature limit up there, too.
So, let’s talk about top coats added over the TICs. Sometimes top coats are applied usually in thicknesses of 2-3 mms – I’m sorry, mils – to improve aesthetics or for safety colors or just to protect in some types of aggressive surfaces. We have found, however, that they can lower the temperature limit of the TIC, the maximum temperature limit, by about 30-50 °F depending on the substrate temperature.
The good news is that you can neutralize that effect by adding an additional coat of your TIC. But sometimes, you may need to have two coats of top coat. Maybe the first coat isn’t hiding the TIC very well. Or maybe there’s hollow … in the coatings and you have to go to two top coats. In that case, you may need an even greater thickness of TIC to neutralize having to go two coats of top coat.
It gets even a little more complicated here, too, because there may be local areas where the applicator applied may be two or three times the desired thickness. No applicator is perfect and he’s not going to get 4-6 mils exactly on an application, so there may be areas that are thicker than we desire. And unfortunately, it’s very difficult to tell where those thicker areas are even with the DFT …. So just be aware that if you do apply a top coat, you need to add one or two coats of the TIC to negate the effect of that top coat.
Another thing that we’ve seen, initial tests indicate so far that the high gloss top coats seem to have a greater effect on lowering the temperature limit than for flat and satin type finishes. More work is being done in this area, so maybe at some point we could share more data at a later time on all of this.
In summary, then, the surface temperatures of TICs can be higher than that 140 °F rule that I mentioned, and they could still be acceptable for personnel protection. It’s also very important to use accurate temperature measurements for the coating surface. The IR meter is recommended for these measurements on TICs but it must have the emissivity function to be properly accurate. Contact probes should not be measured, or used – I’m sorry – for measuring surface temperatures on TICs. With this thermesthesiometer test instrument, TICs can be validated for personnel protection and we now have the capability of determining the coating’s maximum temperature limits are for basing it either on metals or – I’m sorry – the metal temperature or the surface temperature. We have seen that top coats can significantly reduce the temperature limit of these coatings for personnel protection. Hopefully, in the near future, NACE will have some standard procedures for us all to go by, so that we could determine these limits and validate the insulation coating. And like I said before, we can compare apples and apples when we want to compare the coating performance between manufacturers.
So this concludes my presentation. And once again, thank all of you for your interest in this topic. And I’ll turn it over to Lou.
Lou: Howard, thank you! Excellent job! Very, very informative presentation. Thank you also to the interested men and women in our audience for joining us today. Thanks as well to Moscoat, our sponsor, for making this presentation possible. Moscoat provides insulation solutions and coatings technologies to insulate and protect facilities, equipment and people.
Howard, let’s get right into some questions. We have a pretty engaged audience. I see a few questions here. Let’s take as many as we’ve got time for. I mean, launch with this first one. Kind of interesting. In your testing, did you find that the lower thermal conductivity of the TIC, the better it performs for safe-to-touch at equivalent thickness?
Howard: Yes, that’s true, and that’s also in the models, it will give you that, too. The lower the thermal conductivity, the better will be your performance.
Lou: Excellent! James P, thank you for presenting that. Michael M. asks something about OSHA and regulations. This is a good question here, Howard. Are there any OSHA regulations that need to be taken into account when using these TIC materials?
Howard: First of all, OSHA is an organization, the Occupational Safety and Health Administration. They do deal with a lot of safety issues in the industry. But when it comes to these thermal type questions and what is okay to use or not for personnel protection, they don’t get into that. They merely say or state in their regulations that personnel protection must be used. They do give guidance on this by saying that they refer to the two ASTM methods 1055 and 1057. So they just give general guidelines only but no specific ones that I’m aware of.
Lou: Gotcha, thank you! Okay, Jim S. asks, does this work mean that all commercially available TICs have all the same benefits and performance?
Howard: Well, you would think they should have similar characteristics, but the fact is, we don’t know how good they are until we produce these test data from them. So, it’s incumbent on each coating manufacturer that they test their coatings with some tests that are similar to these and to tell their clients what those results are.
Lou: Interesting. Thank you! Alright, looks like we got one last one here. How do you calibrate or check that TM unit? I’m not even going to try to pronounce it. You’ve got practice at that. How do you calibrate or check that unit and make sure that it’s giving you correct numbers after months of use?
Howard: Yes, the thermesthesiometer can be calibrated each year. You just send the unit in to the instrument manufacturer, but you really do need to have some checks on it in the meantime. Say, periodically, maybe once a month you would check the unit with a new probe that hasn’t seen much service. In that way, if there is any significant difference from the new one to the old one based on what you did at the very beginning, you can maybe change out the probes. Another alternative way to do that is to use a test sample just for doing calibration checks. You use that test sample and pull it out initially to get the differences between two probes. And then you can pull it out, say, a month later and do another test and see if you still get that same difference on that same test panel. If they don’t agree, you need to check out your thermesthesiometer.
Lou: That makes a lot of sense. Quickly, we have a couple of people who’ve asked whether the files would be available. Yes, each one of you who registered for this will get an email with a link to be able to see this presentation again. It will also be decoded into a text form so you can have it graphically as well. We did have one more question. Density was one of the properties mentioned in the heat flow. How is the density of a material related to heat flow – the higher the density, the higher the heat flow, or is it the reverse, Howard?
Howard: Well, I’m not an engineer in thermal science, so I probably would defer that question to one of our engineers for that. But I do know that as far as with the thermesthesiometer, there’s three factors that affect it. There’s density, specific heat and thermal conductivity. And according to the textbooks, if any of those three members do increase, then you will have greater heat transfer. So I think what you’re asking is the same. With higher densities, you’re going to have higher heat transfers. Would that answer your question?
Lou: Yes, for now I think so. And maybe in our transcription online, we can be able to do a more thorough treatment of that answer. We actually have one more. Let me throw this at you, Howard. With respect to corrosion under insulation, how well does the product, this TIC product, retard the spread of corrosion?
Howard: Okay, we do use a two-coat system. I’ve mentioned early on in the presentation that it’s highly recommended that you use a corrosion protective primer under the TIC. That’s what really provides us our corrosion protection. The insulation coating is there for providing the insulation value. Together, both of those coatings work as a system. And we have very good protection there. They both act together. You’ve got the corrosion protection there. You don’t have any kind of gaps where water can get in, so the system works very well. And if there ever was a damage to, let’s say, the coating itself, and you’re now exposing the metal substrate, you will be able to see that you have a defect there and that can be corrected or repaired. That’s as opposed to where you might have damage underneath traditional insulation where you can’t see it because of the … and such.
Lou: I appreciate that. Wow, good answer. Well, this is fun because we’ve got several more questions that have been popping in. So we’ll just keep it going here for just a couple more minutes, let everybody go and we will for sure be done at the top of the hour, or maybe just a few minutes prior. But hang in there everybody, these are some good things. How do you know, Howard, what emissivity value to use for a particular coating?
Howard: That was ...
Lou: …I’m sorry. And there’s a follow on. Should that emissivity coating be listed on their data sheet?
Howard: Yeah. Emissivity has served us for two purposes and we’ve found this out kind of with roundabout ways of asking questions and we finally realize this. Okay, emissivity is used for two purposes. The ASTM E408 is used generally to get an emissivity number, and that number would then be used in modeling calculation software. Okay? That number used as the emissivity that’s determined in the frequency range. I think it was 2-43 microns. I mentioned that in the presentation. For purposes of measuring the surface temperature with an IR meter, you need to modify that test method, tell the test lab to give you data that is in the range of about 8-14 microns frequency. That’s typically the range that these meters use. Not all are the same, though. You need to check the data sheet from the manufacturer and tell the third party lab or the coating manufacturer to give you that data for that range of, in the emissivity calculation.
I hope I said that correctly. I hope you were able to understand all that. It is a little bit confusing sometimes.
Lou: You know, that’s another one perhaps we’d want to do a little follow up on during our …. Alright, one last question and we’re going to let everybody go here. And this is from Martin Q. Martin, thanks for tossing us a good question here. If the coating has the same thermal conductivity as other insulation materials, does this mean that the thermal spray coating has to be sprayed at the same thickness to achieve that required heat retention?
Howard: You would have to have this... Yes, given that if you had the same thermal conductivity for two different materials, you would have to spray the same thickness on for both of them to – and they would then have both the same insulation properties given that they were, there’s no other factors affecting it.
Howard: You would need the same thickness.
Lou: Excellent. Howard, thank you so much. Thanks also to Moscoat for making this presentation possible. Moscoat provides insulation solutions in coatings technologies. They have revolutionized how industries insulate and protect facilities, equipment and people. Howard, thank you so much! I appreciate it.
Howard: Thank you, Lou!
Lou: Alright. Thanks and goodbye to everybody.