Flame Retardance and the Regulatory Landscape

flameRecorded April 9th, 2013
Presented by RTP Company

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.

Download the slides | Questions and Answers

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Questions and Answers

Q: Has RTP considered the fluoropolymer for FR additives?
A: RTP Company does not currently use flouropolymers as a primary FR, however, PTFE is widely used in the industry at a small percentage as a drip suppressant.

Q: Is there a difference in UV stabilizer for outdoor parts vs indoor constantly exposed to fluorescent ligthing for commercial applications?
A: The use of UV stabalizers is still important for indoor applications with constant light exposure. The amount of UV stabalizer and the type/make up of UV additive package may differ dependant upon the application and types of exposures. When selecting a material it is best to let us know up front what type of light the material will be exposed to so we can ensure that it will perform well in your application.

Q: How are reach requirements different that ROHS for halogen requirements?
A: Reach references RoHS and therefor has the same restrictions in terms of substances allowed. Halogenated products are still considered acceptable to both Reach and RoHS

Q: does the FR performance of a part change over time?
A: Once a material is compounded with an FR additive the flammability performance is concidered permanent unless the extremes of the operating temperature of the material are exceeded

Q: Is it a standard process to “trim” test bars before flame testing, and why?
A: Not typically. Each FR specification has a required specimen size and allowable tolerances highlighted within the document. If the molded specimen is not to the required size the test bar or molded sample may need to be trimmed or cut to be in compliance. For example mold cavities are available to be able to mold UL 94 test bars to specification and the only modification may involve removing a sprue.

Q: What are your internal testing capabilities, and how extensive is your network of external labs?
A: RTP Company’s Internal capabilities for flammability testing include: UL 94 VB, HB 5V, Glow Wire, FAR 25.853 VB, FMVSS302. We have an extensive network of oustide testing labs available for virtually any flammability test out there.

Q: Do additives like glass tend to increase or decrease flammability?
A: Both! Dependant upon the resin system and the FR technology being used glass fibers can either aid in increasing a flammability rating for example; an unfilled material may only be capable of obtaining V-0 @ 1/16″ (1.5 mm) however if 20% glass fiber is added to the formulation it will then be capable of V-0 @ 1/32″ (0.8 mm). on the other end there are some instances where the addition of glass fibers can interrupt the mechanism and prevent it from being effective.

Q: If RoHS is an EU regulation, what impact does it have on materials for the US market?
A: RoHS does not have a direct impact on the US market, where it becomes important is if this same application is going to be sold or potentially sold in the EU

Q: Why is lower the specific gravity in FR halogens free? Why a lower specific gravity involved an advantage?
A: Halogens are inherently high in specific gravity due to the fact that they are heavy elements. A lower specific gravity material provides an economic advantage due to more parts per pound of material.

Q: Why is flame retardance of a material dependent on sample thickness?
A: Typically the thinner the cross-section of the material it become more difficult to make it flame retardant. This is because the sample becomes easier to ignite at thinner cross-sections and allows for the flame to spread at a more rapid rate.

Q: Typically the flame retardant used suffocates the flame by producting smoke, which in turn will cause the calbe to fail smoke density testing.
A: Halogen Free additives are recommended when low smoke production is a design criteria. You are correct the mechanism by which halogenated flame retardants work inherently produces large amounts of smoke, making it difficult to pass such standards.

Q: Does Mechanical property drop on additon of Halogen additives.
A: All flame retardant technologies will have some type of negative effect on the host polymer in terms of mechanical properties.

Q: Any specific tests for the automotive industry (iinteriors, exteriors, under the hood)?
A: The typical flammability standard in the automotive industry is FMVSS302, which measures the burn rate of a material.

Q: Where to F1 definition?
A: F1 is a UL outdoor weatherability rating comprised of a period of UV exposure and water immersion, comparing mechanical properties and flammability retention.

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?
A: RTP Company has Polypropylene grades available that use FR technologies that are not under restriction by the EPA and fully comply with both UL94 V-0 and F1 requirements.

Q: Are there processing benifits in using FR PEEKs, one vs another? i.e. LF vs HF 2200
A: PEEK is considered an inherently flame retardant material and typically does not require any type of FR additive to meet any flame standard in the industry.

Q: Would you please elaborate on the RoHS compliance using halogenated materials.
A: The RoHS Directive only restricts the use of One specific type of halogenated flame retardant. There are multiple halogenated flame retardant chemistries/technologies available in the market that fully comply with RoHS.


The views, opinions and technical analyses presented here are those of the author, and are not necessarily those of UL, ULProspector.com or Knowledge.ULProspector.com. While the editors of this site make every effort to verify the accuracy of its content, we assume no responsibility for errors made by the author, editorial staff or any other contributor. All content is subject to copyright and may not be reproduced without prior authorization from Prospector.

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