Flame Retardance and the Regulatory Landscape
Would you like to know how flame retardant thermoplastics really work? Do all the complex flame retardant specifications and regulations have you wondering if your products comply?
Then join Derek LaRock, product development engineer at custom compounder RTP Company, for a one hour webinar during which he'll explain everything you need to know to better understand the constantly changing world of flame retardance.
Questions and Answers
Q: Has RTP considered the fluoropolymer for FR additives?
Q: Is there a difference in UV stabilizer for outdoor parts vs indoor constantly exposed to fluorescent ligthing for commercial applications?
Q: How are reach requirements different that ROHS for halogen requirements?
Q: does the FR performance of a part change over time?
Q: Is it a standard process to "trim" test bars before flame testing, and why?
Q: What are your internal testing capabilities, and how extensive is your network of external labs?
Q: Do additives like glass tend to increase or decrease flammability?
Q: If RoHS is an EU regulation, what impact does it have on materials for the US market?
Q: Why is lower the specific gravity in FR halogens free? Why a lower specific gravity involved an advantage?
Q: Why is flame retardance of a material dependent on sample thickness?
Q: Typically the flame retardant used suffocates the flame by producting smoke, which in turn will cause the calbe to fail smoke density testing.
Q: Does Mechanical property drop on additon of Halogen additives.
Q: Any specific tests for the automotive industry (iinteriors, exteriors, under the hood)?
Q: Where to F1 definition?
Q: Polypro with F1 and V-0 ratings appear to be going off the market due to EPA restrictions. Can you elaborate on the likelyhood of being able to develop a polypro that meets those requirements?
Q: Are there processing benifits in using FR PEEKs, one vs another? i.e. LF vs HF 2200
Q: Would you please elaborate on the RoHS compliance using halogenated materials.
Jake Godber, UL IDES: Today's webinar, Flame Retardants and Regulatory Landscape is being brought to you by Global Custom Engineers Thermoplastics Compounder RTP Company.
Your presenter today, Derek LaRock, Product Development Engineer at RTP Company. My name is Jake Godber. I'll be monitoring the event.
I'd now like to turn over the presentation to Derek LaRock.
Derek LaRock, RTP Company: Hello and welcome everyone. Again, my name is Derek LaRock. I'm the Product Development Engineer at RTP Company. Today, I'll be speaking to flame retardants and the evolving regulatory landscape. First I'll go over a little background. An overview. We'll talk to what flame retardants are, some of the goals, and we're flame retarding thermoplastic material. And then we'll get into thermoplastic flammability.
I'll talk to the inherent flammability of some thermoplastics, and we'll move into the additives and chemistries as well as the mechanisms that are involved in flame retarding thermoplastics.
We'll get into the regulatory landscape. I'll speak to some new regulations that have come out or some old ones to help to clarify any misconceptions that might be out there.
We'll move into some testing standards that are common in a few different markets that involve flame retardant thermoplastics. I'll wrap up with some case studies to help show, how do these regulatory concerns and test standards affect material selection.
What is a flame retardant exactly? By definition, it can be considered a material that does not ignite readily or propagate flames under small to moderate fire exposure. Thing to remember is that materials are combustible.
At the bottom of the slide here, you can see what is known as the fire triangle. It's made up of three main components. You have your heat source, fuel source, which is the thermoplastic material and oxygen. You need all three of these components to sustain combustion. What flame retardants are doing is trying to eliminate one of these legs of the triangle and either delay or stop the spread of flame.
Again, speaking to the goals, we're either trying to increase resistance to ignition. Maybe we want to reduce the rate of the flame spread of the material. We might want to reduce the rate of heat release, or the amount of smoke that's getting emitted.
These can be either accomplished separately or maybe you need a material that has a low rate of flame spread as well as a low amount of smoke emissions. But, at the end of the day what we're really trying to do is help you meet your flame specification. And, of course, we're all trying to make the world a safer place.
Some of the markets that flame retardant thermoplastics are seen in, the electrical parts, electronic enclosures, better known as the E&E Market make up a large portion of this. As well as the wire and cable industry.
We're seeing a lot more flame retardant plastics. And both the appliance and transportation industry. We'll talk to these a little bit later, and as well as the building and construction industry.
As people are trying to replace metal, or any other type of material that was more common in the building industry. We're starting to see more and more thermoplastic materials wanting to be used.
I'll get into the flammability of thermoplastics. We'll talk about some of the differences here. There's two basic types of materials in terms of flammability. We have flammable thermoplastics. These are your engineering and commodity resins.
We have what are considered inherently flame resistant materials. Your more highly engineered, higher heat materials that aren't going to burn or increase flame spread alone.
The final materials here on the left require some type of flame retardant additive to make them flame retardant. I'll speak to some of the challenges that we face as formulators as far as trying to make a material flame retardant.
The Limiting Oxygen Index, or LOI, I'll show a good example of that. This line here at 28% is what can roughly be considered the line between a material being flammable and inherently flame resistant.
As you look toward the top, here, you can see that cotton is mixed in. That cotton is considered more or less flammable than acetyl. What that test is for the Limiting Oxygen Index, a bar is placed into a chamber, and there's the flame attached to it.
The amount of oxygen inside that chamber is increased until combustion is sustained on that material. The higher the LOI Index, the more oxygen that is required in that chamber to sustain combustion.
I'll speak to some of the different flammatory additives out there. Also the mechanisms by how these additives work. There are two common types of flame retardant types of flame retardant additives.
First the halogen flame retardants. This consists of brominated and chlorinated systems. These systems typically require some type of synergists as well. The halogen free flame retardants, your metal hydroxide, the phosphorus-based, and melamine-based.
As you can see here, a large portion of flame retardants that are used in the market, are the inorganics or metal hydroxides. I'm talking more towards injection molding specimens. The brominating chlorinated systems are the real drivers there and make up most of the market.
The phosphorus portion is starting to grow as more and more halogen free materials are coming out and there's becoming more interest in halogen free flame retardants. This portion is starting to expand. But we'll talk to that more later.
First looking at the halogenated FR mechanism, the halogenated technology works by inhibiting the chemical reaction in the gas and vapor phase. What it does is get molecules that efficiently get large amounts of free radicals to the gas phase and limit that combustion process.
There are two basic types. The additive type and polymeric. The additive type is exactly that. It's an additive that is going into your matrix.
Typically these additive type flame retardants have a higher halogen content. So, you're able to get away with lower loading levels in the material. And they typically have a higher thermal stability.
Polymeric type, how it sounds, is now blendable so it's actually melting and blending within the polymer matrix. It will have less of an effect on your physical properties than it is blending in. It can help to enhance your flow of your material.
The halogenated FR mechanism is compatible with most resin systems. Except, with the exception of [acetyl]. As far as different types of materials, you're going to have a halogenated option in just about every resin system.
Speaking to the non-halogenated mechanism, three main types again. Phosphorus based, hydrated minerals and melamine cyanurate. There are various forms and blends of the phosphorus based.
Halogen free flame retardants, how these works is they contribute to the condensed phase of the combustion and it's forming a char, an [inflative] char layer over the material, preventing that flame from spreading.
Typical resin systems that we see this type of material in mechanism used in is polyolefins, polyamides, polyesters, polycarbonates, and alloys between these materials.
Hydrated minerals, how this mechanism works is it actually produces water during the production process, which helps dilute flammable vapors and helps to cool the polymers well. This kind of works as a two part process, as it also forms an insulated char much like the phosphorus systems over in the material.
Typically, this type of mechanism is used in polyolefins, and polyamides. Speaking to the melamine cyanurate, this mechanism works as an endothermic decomposition. Where it's actually physically removing a flame from the surface of the material and has a dripping effect, again, pulling that flame away.
Typically we see this used in polyamides. It can also be used as a synergist for other phosphorus technologies within polyamide materials.
Why halogenated versus halogen free? Looking back to the past, some of the conceptions as far as these two different types of flame retardant technologies. Your halogenated technology was thought of as the lower cost way to go.
Typically got better processing, better efficiency out of the flame retardant, and better physical properties. And halogen free flame retardants were thought of as a material that was limited as far as availability goes. Has a reputation of having a lower smoke, lower toxic byproducts in terms of combustion.
Halogen free flame retardants are less corrosive on the tooling. Some of the acids from in the halogenated can have an adverse affect on tooling. Your halogen free flame retardants are going to have a lower specific gravity making your overall material have a lower specific gravity in turn giving you more parts per pound.
This is kind of thought of as a niche material. The halogen free flame retardants typically a little more expensive and again used to serve or fill one of these niches I just mentioned.
Moving to today, as far as halogenated systems, pretty much the same. Not much has changed there.
Moving to the halogen free systems, the economics that really involved, as more and more companies and suppliers are coming out with halogen free flame retardants, it's creating more competition, which is helping to make these more cost competitive solutions.
They're also being able to process these more economically themselves. We're starting to see this become more on a better level, or terms of comparable to halogenated flame retardants.
Again, with that processability is improving greatly, as a supplier, they're getting to know their material more, they're able to work through those kinks that might have been there in the past and have a material that's going to have better processability.
Again, the wider variety of products are coming up to market. Which really helps us as formulators have better options and pick a material or a flame retardant that's going to meet your need the best.
They're still the go to as far as low smoke, low toxicity. Still considered less corrosive than the halogenated counterparts. Again, a big advantage here is in the lower specific gravity which I'll also talk to later.
Going back, how do we decide which flame retardant mechanism to use? Resin system plays a big role. Not all halogen free flame retardants are compatible in a specific resin system. Styrenics more specifically. Halogen free systems are not able to flame retard those materials.
That's something to keep in mind from the get go, picking a resin system or having a resin system in mind will already limit the amount of flame retardants or the type of flame retardant that we can use.
A big one is the FR specification. Maybe you're trying to meet a low small glow heat release specification. We're going to want to go the halogen free route there. Maybe you just need a UL94V0 and there is no specification towards having low small or low heat.
We can use a halogenated or a non hal system. Part function plays a key as well, as they're unique colored. You need UV. Some different types of fillers and additives can have adverse effects on flame retardants and make them incompatible.
Something to keep in mind, and that helps us to know if there's other fillers or additives that need to go into material. We can make that decision as what routers going to be the best to take.
Also regulatory concerns. Is there halogen restrictions? RoHS, etcetera.
Now we'll get into the regulatory landscape. I'll go through RoHS. What it is. I'll also speak to some halogen restrictions that are out there. And then we'll get into how this can have an affect on material selection.
The RoHS directive, the directive out of the European union, and went into effect July 2006. And what this was doing was eliminating the use, or banning the use of these five substances here. Some of these effect pigments.
The one that we're focusing on here are flame retardants. That last one there, the PBBs and the PBDEs, are a specific type of flame retardant. And a big misconception here that we see a lot is some people think that in order to comply to RoHS, that we need a material that is halogen free, which is not the case.
There are options out there in halogenated systems that will allow you to comply with RoHS, and not need to be halogen free.
How does RoHS compliance affect material selection? There's two different routes you can take if you have a material that is not RoHS compliant and you want to move to a material that is. That will be the halogen free route.
All those materials are going to comply with RoHS. Or, there are drop in replacements available. These drop in replacements offer identical properties in terms of flow, physical properties, heat resistance, the processability of the material.
However. there is a slight cost premium, when moving from material that is not RoHS compliant to one that is. Here is an example. Just showing a 25% glass filled polypropylene. Just, again, highlighting that these really are drop in replacements
The only major difference here being the cost. How is halogen free technologies involved? What we're seeing is a lot more self policing in the industry. Internal regulations. Banning the use of halogenated materials or halogenated technologies.
There's new FR standards that are out there written around low smoke, low heat release and again going back talking to the mechanisms, the halogen free technologies are the route we want to choose as far as the low heat, low smoke, low tox material.
I'm sure everyone's aware of the Green Movement. As this has taken off, a lot of interest is in place, and coming up with a more Green solution. If that's something that you're interested in, a halogen free flame retardant technology is definitely the route to go there.
As we're seeing more and more suppliers come out with materials that are halogen free, again, we're getting more effective flame retardants. We're also getting more economical flame retardants.
Again, help increase the performance of the material and the competition in the market has really been key in helping to drive these materials to be developed and come up with better solutions.
Speaking of some of the halogen restrictions, there are some molian driven bans out there. HP Dell, IBM, that have internal restrictions on the use of halogens and their materials. You can go on their websites. You can read about it.
There's also eco-labels. These are out of the European Union. Again, something to highlight here, these restrictions are all voluntary. There's no government regulations saying that you cannot use a halogenated flame retardant voluntary bans.
The eco-label thing works where you have a material that complies that does not use halogens. You can place this label or sticker on your part to prove that you comply.
What is the impact of choosing a halogen free solution? Again, resin limitations, if you would like to use a styrenic material, AVS for example, there's not a halogen free technology available on the market that is going to allow you to have a halogen free flame retardant AVS. Sometimes there can be effects on physical properties. Slight down ticks can be seen in strength and impact at times. Might have a little less heat resistance. You might have increased flow. Again, these are all resin dependant. Not every material is going to act the same. The differences might be seen greater in one material versus the other.
Speaking to flammability, sometimes it's typical to get a halogen free flame retardant material to be flame retardant at really thin cross sections. There are some challenges there in terms of trying to choose a halogen free solution that's going to be flame retardant at a thin cross section. Again, this is resin dependant as well.
And again, the cost, there's a slight cost increase going to halogen free solutions. But where this can start to level the playing field is the reduction that's seen in specific gravity. This can help absorb some of that increased cost of the material.
Here's an example of a 30% glass fill Nylon 6/6. We have the halogenated RTP tool five the far, and on the right the halogen free. As you can see here, slight downtick in the strengths. Modulus impact's relatively the same.
We get the same type of heat resistance. where you see the biggest gain here is in the specific gravity. You have a 1.66 material to 1.41 in the halogen free. This again is really where you can hope to see savings in getting more parts per pound.
Even if the material might be more expensive. In this case, we're able to have solutions that are both easier and a lot thin cross section.
Again, just comparing these two materials and the blue is the halogenated solution. The red is the halogen free solution. They're pretty close in terms of properties. Again, the biggest savings you'll see here is in the specific gravity.
I'm going to go over some test standards in a few different markets. I'll talk to these markets, and some of the bigger standards that we see come across our desk and what people are trying to get materials to meet.
First, I'll talk to the electrical and electronics or E and E Industry. This is the, this industry is driven by UL94V-0 via 5BHB rating. This is seen in appliances, the connector industry, the housings. And also with that is UL746, short term electrical properties, HAI, HWI, CTI.
Let's take a closer look at UL94.
I'll go through the horizontal burn, describe what it is, show a schematic of how the test is done. And then I'll get into the vertical burn test. And then give an example of a material that would be considered a no rating, and a material that would be considered V0.
Here we have V-O94HB. As you can see here, there is a horizontally placed specimen. The flame is applied to the end. What this test is doing, is it's measuring the burn rate of the material
Once the flame reaches that first line here at 25 millimeters, the test is started. It's timed. And we're measuring how fast this flame spreads across the material. The bottom here you can see the different criteria for ratings.
In general, most thermoplastics are going to meet this specification without the use of flame retardant additives.
Now, speaking to UL94, the vertical burn, it's a little more stringent test as you can see on the right here. You have a vertically placed specimen. A flame is applied to the bottom. And we're having two 10 second applications of the flame applied.
The standard is written around after flame time, one said flame is removed, how long does the specimen keep burning for? As well as it pays attention to whether or not the specimen drifts and if that's igniting the cotton.
As you can see here, if the specimen drifts and ignites the cotton, it's automatically a V-2 rating regardless of the after flame times. This test is really dependant on thickness as well. You may have a material that's V-0 at 3 millimeters. Press that material down to 1.5 or 0.75 millimeters, and you might not get the same rating.
That's something to keep in mind as well. Typically, the thinner the cross section, the more flame retardant additive required to meet that V-0 rating.
I'll show an example here. On the right, we have an unmodified polypropylene going through the vertical burn test. As you can see here, the first flame application is applied. So, after 10 seconds, the burner is pulled away.
As you can see here, this material is starting to burn pretty much out of control. We're getting flaming drips, so it would certainly ignite the cotton below. As this test goes on, it starts to consume the whole bar. This results in a null rating.
On the left here, we have a V-0 product polypropylene as well. We'll apply the first 10 second flame application. This is pulled away. You can see the specimen immediately goes out. The second 10 second flame is applied. Again, it immediately goes out.
You can see the big difference here in the material that is considered a null rating to one that is V-0 and puts that flame out immediately.
As we're developing products, it's always nice to see that V-0 come out when you go to test your products.
Now, getting into the aerospace industry. FAR 25.853 is a big standard here. A lot of these aerospace specifications are geared towards low smoke, low toxic byproducts, low heat release. the goal of all these is really to help increase escape time.
If a plane goes up in flames, they want these materials to burn slow, or help eliminate the spread of the flame or reduce the amount of smoke so that more people can get out.
All these specifications, the requirements that are needed for a certain material really varies on part size and location. We might not know specifically what you need. The governing bodies for these will dictate, you know, this part needs to have this rating and that.
We do have experience with materials that do pass each of these ratings and can certainly help to recommend it to your material that will.
The building industrial market, the big focus here is on products that have low smoke, low heat release, a low burn rate and flame spread. Again, what these are really geared towards is helping people escape in a fire situation.
There are various standards here. I'll hide a few UL2043. That was just for plum applications. I'll speak more to this later in the case study portion.
UL723 or ASTM E84, this is a pretty popular one a lot of you might have heard of. This is a Stiner Tunnel Test. A 24-foot chamber and a very large heat source is applied. And it's measuring flames spread.
The ASTM E1354 is a cone calorimetry test. Pretty standard in terms of flame retardant materials.
NFPA 701 is written around curtains and drapes. The FM 4910 has to do with flame retardant pallets or pallet testing and the CAL TB133 is a standard that's any furniture that is sold in California will need to pass this specification.
All of these are written around either some type of low smoke, low heat release, or helping to eliminate the spread of the flame.
Now, I'll get into some end product applications. We can see how all this really ties together. I'll go over an LED lens, where a highly transparent material is needed, as well as flame retardancy. I'll go through an outdoor connector. Talking about FRUV material or parts that are going to be in the outdoors.
I'll go over an overhead speaker unit in the plenum area. This is the UL2043 application. And then we'll get into a consumer electronic cover.
This first application here, a customer needed material, that is going to meet their regulatory needs, all while successfully defusing a powerful LED light located behind it. From a regulatory standpoint, RoHS compliance is needed as well as UL94V-0 compliance.
The difficulty with this material is meeting those needs while having a highly transparent base material. The highly transparent base material is something that is needed for the specialty pigment package that is used to diffuse these powerful LED lights.
We're able to develop a material that met not only their RoHS concern, but their UL94 V-0 rating. And was able to diffuse the LED lights successfully.
This next application required flame retardancy as well as high UV resistance. And this is something that requires special attention. Sometimes there can be incompatibility issues with the flame retardants and the standard UV stabilizers available. So, specialty UV stabilizers is required to be compatible and work within a flame retardant material.
For this marine connector, that has a lot of exposure to the elements, UL41 compliance is needed. This is their weather ability test which tests the performance of a material after exposure to UV as well as water emergents.
Along with that, so we have our UV concerns, our flame retardant concerns. But also the specialty color, this bright safety orange. I required a special pigment package as well to be able to get this nice, bright orange.
All while being UV resistant and having this flame retardant technology still, or mechanism still work within the system. That was the biggest challenge here is having all those different additives work together to get a material that's going to meet their need as well as have a high end strength and impact resistance. This material or this end product went through a drop impact and strength testing.
Something to be aware of when designing or using material that might be outdoors, it's good to bring those or bring that up ahead of time so that we know that we need to use a specific combination of flame retardants and UV stabilizers that will be compatible with each other.
This next application, thinking back to what we learned about the building industry and regulations surrounding it, we know we need to have low smoke production and low heat release rates in order for a material to be successful in passing a certain test in a building industry.
We also learned that DFR technology that will give us the best performance in terms of low smoke and low heat release is the halogen free FR mechanism. Right away we have to narrow this down to using halogen free technology.
In choosing a resin system, we know that some are not compatible with halogen free technologies as well. This housing is located in the Plenum area.
This UL43 test end part here what the test is is placed on a wire mesh and torched. The whole part came completely burned. What they're measuring is the heat release rate and the smoke emission. So, again, a halogen free material was the route of choice or the way to go here.
Also being located up in the ceiling in the Plenum area, this material needed to have good rigidity, nice strength. What we ended up with was using a glass fiber reinforced halogen free flame retardant polypropylene. And we were able to meet not only the application demands, but the regulatory concerns as well.
I talked before about the Green Movement. And this is really starting to drive developments and new products into the market. One area where there are a lot of opportunities for this is in replacing standard PCAVS and consumer electronics housings.
A majority of the volume that is, that PCAVS is used in, goes into different types of housings for consumer electronics. So, there is a lot of interest in finding a greener solution for all this material out there. And the situation was no different, a customer looking for a green alternative to a typical PCAV, or flame retardant PCAVS.
Naturally with this halogen free technology was the path chosen. Wouldn't make much sense to have a bio based resin and a halogen technology here in terms of flame retardants. So, that was the easy part.
Some of the concerns when moving to some of these bio based materials that people have are they're not as good as the neat petroleum based resins. As something to be aware of, and that might be of concern, but in this case, we're able to meet not only the heat requirements that this material needed but was able to meet the strength impact and have good dimensional stability.
All while meeting the regulatory halogen restrictions and passing the test standards of the UL94 V-0. Being able to encompass all that with the bio based resin is really something that's, was difficult, and we were able to achieve.
So, a recap here. When designing for a flame retardant application, some things to keep in mind is a regulatory landscape. Are there going to be RoHS restrictions? Is there a halogen restriction for the LAM? Maybe internally.
Your cells have a housing restriction in terms of the types of materials that can be used. The biggest driver for this is probably the specification. Are you trying to meet UL94 V-0? Is there an ASTM spec? Are you trying to meet a low smoke, low tox standard?
This is the basis really for what material, what flame retardant technology we're going to choose. This is what's driving that. The part function is also something to be aware of.
Your performance requirements, do we need a high strength flame retardant material? Does it need to be conducted as well? Maybe you need a specialty color in UV much like that marine application earlier.
All these are things to be aware of and things that need to be addressed at the beginning. Because it does require special attention when developing or designing with flame retardant materials.
The environment that the application is in is very important as well. Is it going to be exposed outdoors? Is this going to be in high temperature areas all the time? All things to keep in mind as well. Of course, the economic portion, prices of property, and it's important to know that flame retardants are expensive additives.
It's always something to keep in mind that when moving to a flame retardant material, price is always something that's going to be important and needs to be addressed.
Thank you all for listening in. Are there any questions out there?
Jake: Yeah. Thank you, Derek. This is Jake with ULIDES. If you do have a question, now is the time to type that into your question box.
Derek, I'm going to go ahead and turn it over to you for questions.
Derek: All right. First question here is can you define halogen free? And in terms of halogen free by definition, the material has to have less than a thousand parts per million. In terms of halogen content typically.
Another question out here. What if a product has variable wall thickness? What thickness is the UL flame rating required at?
Typically, in this your nominal wall, your average wall thickness is what's required. The majority of your part is three millimeters in terms of thickness.
Maybe you have something sticking out or a reinforcing aspect that might be slightly thinner. Typically we're taking the average wall thickness of the entire part.
Another question. Can you elaborate on the possibility of using RoHS compliant halogenated materials?
As far as a glass fiber reinforced flame retardant Nylon 6/6, I would say there's not a whole lot of challenges in the material.
It's a pretty standard material in the market. And it's pretty robust in terms of what it's been through. And it's been used in quite a few applications out there. I would say it's a material that will and can perform well in your application.
Another question out here. Typical loading level of FR additives. This is something that is resin dependent and also somewhat of a proprietary thing but going back to the slide on the LOI.
Typically as you move up that ladder, and the material, the lower, the LOI, typically the more flame retardant additives that are required to make that material flame retardant.
This again can be resin dependent. Typically, if you're going to see a drop in mechanical properties when adding flame retardant additives. What the flame retardant additive is, more or less a contaminate in your material. So, there will be a slight deficiency in your mechanical properties in moving to a flame retardant product.
There are some flame retardant additives that do leech out or it's referred to as blooming. And will rise to the surface of the material over time. But there are additives out there to address those issues.
If there is a product you have that is leeching, or blooming, that's kind of like a white chalky surface on the material. There are different additives out there that do not leech or do not bloom.
I have a couple questions on the LOI or Limiting Oxygen Index test. I'll go through that again.
We're taking a specimen much like, you saw on the videos, and placing it into a chamber. There's a flame applied to the top of the specimen. As the test goes on, the level of pure oxygen inside that chamber is being increased.
Once that gets to a point where the material is able to sustain combustion at a given oxygen level, it's considered it's LOI index.
Going back to that screen, something like PBTS which has a high LOI index require almost pure oxygen within that chamber to be able to sustain flame. Where at a given room, where at ambient air, we're probably looking at 21% oxygen in the air.
Some of those materials like polypropylene are actually below that level. So, it would require some type of flame retardant to push it above that LOI index of about 28. So that material will not burn or burn too fast at room or air temp, normal air conditions.
How long does it take to develop a flame retardant material once you understand the requirements?
We have a lot of standard products around that. Really, it depends on the different requirements. Typically the more stringent or the more requirements, it might take slightly longer.
We can usually develop the material pretty fast in terms of getting something developed, tested and returned to you to sample or try.
Next question here. What is the minimum thickness available for a flame retardant material? I'll speak to this in terms of UL94 standard. The UL94 standard test, the vertical standard test material down to 25 hundredths of an inch.
There are material that are available that can be flame retardant down to that thickness. Again, it depends on the resin system.
Something like an AVS material might be more difficult to be flame retardant out of extremely thin cross section compared to, let's say, a flame retardant glass sealed nylon, where typically you see extremely thin cross sections in that material.
If there's a specific thickness or question, feel free to contact me and we can discuss and work through that.
Another question. Does RTP provide testing and certification to FR standards?
In terms of UL2043, we have materials that are known to pass this test. We have quite a bit of experience in terms of knowing what will pass.
This test is more of an end part test. This would be a situation where we would need to review the specific application, the size, and working with the specific material. We have a high level confidence going on.
What should be able to pass but ultimately, it would have to go through the testing. And we do work with labs that do test the UL2043 as well.
Another question here. Do you provide testing to FAR standards?
We can test in house to FAR standards. We have the capability to do the vertical burns. Some of the tests we do not have in house, but we do have contacts and we do have testing labs that we work with regularly to test materials too to see if they meet these standards.
That's all the time we have for questions. Some of the more specific questions I'll respond to personally through email or telephone. You can also contact me and I'll be more than happy to provide you answers to each of your questions.
Jake Godber: Thank you very much, Derek. Thank you all for attending today's webinar. Have a great day!
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