As you may have noticed, our last Prusament announcements have been generally quite big news: they were not about mere new colors but about non-standard and specialized materials (PVB, PC Blend Carbon Fiber, PA11 Carbon Fiber, PETG Tungsten 75%). Though it may not look like it at first, this time it’s even bigger! We’re launching the one-in-the-world UL-certified self-extinguishing PETG filament. So why is it such a big deal and what is it good for?

Self-extinguishing vs. fire-resistant

First, let’s take a look at what the term “self-extinguishing” means. The self-extinguishing material has usually mechanisms that slow down and eventually stop the flame after it starts burning in the first place. When our Prusament PETG V0 starts burning, it creates a carbonized crust on the surface that prevents the oxygen from getting in and fueling the flame and eventually extinguishes the fire. On the other hand, fire-resistant materials are hard to set on fire in the first place.

The UL certification meaning

In short: the fact that we obtained the UL certification for our filament is a big achievement and a testament to the skills of our Prusament team. The UL is a global safety company that tests various products (materials and mostly electrical equipment) for different levels of safety certifications that are useful in both practical and legal implementations. Almost any product manufacturer can ask them to test their product. The UL company serves as an independent element that guarantees unbiased results for every tested product. Their staff selects the proper testing method (ASTM, IEC, ISO, or other) and accordingly asks the product manufacturer to provide a complete set of test objects. Then, they run the tests in their laboratories and finally provide the certificate of compliance that serves worldwide as legal proof for the product.

We asked the UL to test the flammability of the self-extinguishing PETG marked as Prusament PETG V0. The test method was made according to the IEC 60695-11-10 standard and resulted in a class UL94 V0 (for both our colors, see below). Here’s the Blue Card that serves as a certificate issued by the UL company.

Blue card issued by the UL

What does the UL94 V0 flammability category mean?

The UL94 method applies to various plastic materials. It helps to determine whether the material extinguishes or spreads the flame after ignition. This method is harmonized with IEC 60695-11-10, IEC 60695-11-20, ISO 9772, and ISO 9773.

There are several subcategories for the UL94 method. Our Prusament PETG V0 follows the Test criteria for Flammability UL94 V – 50 W, 20 mm Vertical. In this subcategory, it got the best result possible, which is marked as V0.

The test was conducted on a set of 600 pieces of 127×12.7 mm specimen with various thicknesses (minimum is 0.75 mm for Prusament PETG V0). The specimen included samples printed in all orientations (xy, yz, xz) with both minimal and maximal speeds.

During the test, the specimen was set on fire hanging vertically. It was observed how long it takes for the flame to extinguish and whether the material drips and spreads the fire. The flame in this test was 20 mm high and the exposition during this test took 2x 10s (the second exposition starts right after extinguishing).

As for the criteria, the V-0 means that our test objects burned less than 10s after both expositions. The total burning time was less than 50 s after 10 flame applications, burning and afterglow after second flame applications were less than 30s, there was no dripping (and igniting cotton pad) and no total burnout of the specimen.

All of the criteria are described on the UL website.

What was the purpose of the certification?

Making the material certified as self-extinguishing means not only practical implications (simply by greatly reducing fire hazard) but also legal implications. In other words: If you want your part (product) certified as self-extinguishing, it gets a lot easier and requires much less testing when the material itself has the proper certification. However, even with us making it one step easier for you, you still have to follow some rules set by us and the UL company. This means that you need to print the models with the MK3S+, MK4, or XL printer with a 0.4 mm nozzle (0.2 mm layer height), slice it in PrusaSlicer, and use the prepared profile. Also, keep in mind that the certification applies only to objects thicker than 0.75 mm (2 perimeters). Not following the rules leads to the risk of losing the desired properties!

What else makes the Prusament PETG V0 unique?

There are other self-extinguishing filaments on the market. Some of them even claim that they can fulfill the same UL standard as our PETG V0. However, their manufacturers don’t offer any legal note saying that the UL truly tested it. The Prusament PETG V0, on the other hand, is properly certified and the final result is published on the UL’s website.

And there’s more. Not only the other self-extinguishing filaments are not certified properly but they may also contain some toxic substances that are released into the air when burning. We’re talking about halogens. The Prusament PETG V0 is halogen-free.


Who is it good for?

There are two main reasons why we’ve decided to go on a long and challenging journey to make a self-extinguishing filament with proper certification. At first, there is a large business sector, where the companies need to have everything legally right and require certified products. Our filament allows them to make rapid prototypes with the legal (and practical) requirements around fire safety.

Second, we strongly recommend using this filament for making homemade electronic appliances. After all, accidents tend to happen even with relatively safe electronic products and if you’re a maker who crafts things by hand, you really want to make the products as safe as possible.

Colors, price, and printability

So far, we offer the PETG V0 in two colors – natural (white) and jet black. The 1 kg spool costs 54.99 USD/54.99 EUR (VAT incl.).

Compared to the Original Prusament PETG, the PETG V0 comes with slightly lower tenacity, and layer-to-layer adhesion. This filament needs to be kept as dry as possible as it’s more hygroscopic, compared to regular PETG. If you can’t keep the filament dry, we suggest drying it before use for 6 hours at 55 °C.

The Prusament PETG V0 is UL-certified only for printing with the Original Prusa MK3S+, MK4, and XL. Don’t forget to follow these three simple rules to get the best results, according to the certification:

  1. Use Prusament PETG V0 only.
  2. Print it with MK3S+, MK4, or XL 0.4 mm nozzle and 0.2mm layer height.
  3. For slicing, use PrusaSlicer with PETG V0 profile.

Examples of use

That’s all for now, we hope you’ll like this new PETG and as always, we’re looking forward to seeing your cool creations.

Happy printing!