Jim -- Yes. My shorthand for for V rated materials is self-extinguishing once igniting flame is removed, and for HB is simply rate of flame propagation limited once igniting flame is removed. Total aside: up here in the north land, you can buy alcohol based windshield washer fluid than easily ignites and burns with a flame that I can't see in daylight. I've wondered since that experiment if this is why all the windshield washer reservoirs I see in cars are not in the engine compartment, but tucked inside the metal fender. Mike Sherman Sherman PSC LLC
> On 11/23/2024 1:21 PM CST Jim Bacher, WB8VSU <[email protected]> wrote: > > > Mike, I remember the same HB requirement by an NRTL. Although most of the > internal parts I dealt with were typically V1 or better. > > If you get bored someday, take a match to an HB material part and watch what > happens. I did that once (outside) and it turned into what looked like a pool > of wax, with what was an invisible flame. Once it turned into a pool of > plastic, we extinguished the flame. As a result of that test in my mind, HB > means slow burn. > > > Jim Bacher, WB8VSU > [email protected] > JBRC Consulting LLC > Product EMC & Regulatory Consultant > https://www.trc.guru/ https://trc.guru/ business email:[email protected] > mailto:jim%40trc.guru > IEEE Life Senior Member > > > On November 23, 2024 1:56:36 PM MIKE SHERMAN > <[email protected]> wrote: > > > John -- > > > > My recollection from working with one NRTL was that they wanted all > > nonenclosure polymerics on equipment to be HB minimum, even though I could > > not find this requirement in the related standard. > > > > Stated reason, as I recall, was to not provide any additional fuel for a > > fire, even an external fire. > > > > I also had a similar experience as Jim Bacher reports, where different > > shrinkage rates meant a new injection mold if changing from an HB to a > > V-rated material. > > > > Mike Sherman > > Sherman PSC LLC > > > > > On 11/22/2024 8:35 AM CST John Allen <[email protected]> wrote: > > > > > > > > > > > > Hello everyone, > > > > > > > > > > > > I’m trying to determine if a flame rating is required for polymeric > > > materials in a Limited Energy circuit. Per Clause 9 - > > > > > > > > > > > > 1 – Test to prove no ignition can occur (9.1). If ignition occurs, see > > > item 3 below. > > > > > > 2 – Eliminate or reduce the source (9.2). > > > > > > 3 – Contain the fire with appropriate materials (9.3). > > > > > > * Metal > > > * Polymeric V-1 minimum per 9.3.2c)2. > > > > > > > > > > > > I find it interesting when searching for “propagate” it only refers to > > > insulated wire and cables shall retard propagation (9.3.2b)). I believe > > > propagation of flame should also be a requirement of polymeric materials > > > near ignition sources. > > > > > > > > > > > > All that said, although we can argue items 1 and 2 above do not need a > > > flame rated enclosure, I feel 94HB should be the minimum and guessing a > > > NRTL/Certification Body would feel the same. > > > > > > > > > > > > Thoughts?? > > > > > > > > > > > > Best Regards and Be Safe, > > > > > > > > > > > > John > > > > > > > > > > > > John Allen | President & CEO | Product Safety Consulting, Inc. > > > > > > Your Outsourced Compliance Department® > > > > > > 630-238-0188, Cell: 630-330-3145 > > > > > > [social_facebook_box_blue for signature] > > > http://www.facebook.com/pages/Product-Safety-Consulting-Inc/97306850917[social_twitter_box_blue > > > for signature] http://twitter.com/SafetyTesting[social_linkedin_box_blue > > > for signature] http://www.linkedin.com/in/productsafetyconsultinginc > > > https://www.youtube.com/channel/UCVSzENmSoWeNFSBQcOYN7-A > > > https://www.youtube.com/channel/UCVSzENmSoWeNFSBQcOYN7-A > > > www.productsafetyinc.com http://www.productsafetyinc.com/ > > > > > > > > > > > > IEEE Product Safety Engineering Society > > > > > > President 2024-2025 > > > > > > Compliance 101 Technical Committee Chairman > > > > > > IEEE Senior Member > > > > > > > > > > > > Keeping our members informed and educated on Product Safety and > > > Certifications > > > > > > > > > > > > https://ewh.ieee.org/soc/pses/index.html > > > https://ewh.ieee.org/soc/pses/index.html > > > > > > > > > > > > Although PSC maintains the highest level of virus protection, this e-mail > > > and any attachments should be scanned by your virus protection software. > > > It is the responsibility of the recipient to check that it is virus free. > > > PSC does not accept any responsibility for data loss or systems damage > > > arising in any way from its use. 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To post a message to the list, send your e-mail to > > > [email protected] > > > > > > All emc-pstc postings are archived and searchable on the web at: > > > https://www.mail-archive.com/[email protected]/ > > > > > > > > > > > > Website: https://ewh.ieee.org/soc/pses/ https://ewh.ieee.org/soc/pses/ > > > Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to > > > unsubscribe) https://ewh.ieee.org/soc/pses/list.html > > > List rules: https://ewh.ieee.org/soc/pses/listrules.html > > > > > > For help, send mail to the list administrators: > > > Mike Sherman at: [email protected] mailto:[email protected] > > > Rick Linford at: [email protected] mailto:[email protected] > > > > > > For policy questions, send mail to: > > > Jim Bacher at: [email protected] mailto:[email protected] > > > > > > > > > --------------------------------------------- > > > > > > To unsubscribe from the EMC-PSTC list, click the following link: > > > https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 > > > > > --------------------------------------------- > > > > This message is from the IEEE Product Safety Engineering Society emc-pstc > > discussion list. 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To post a message to the list, send your e-mail to [email protected] All emc-pstc postings are archived and searchable on the web at: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://ewh.ieee.org/soc/pses/listrules.html For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher: <[email protected]> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
