Hi Ted, Thanks for your further explanation. I have clarified it with the test lab who seems to have explained unclearly about the requirements of UL 723 for flame spread rating and the flame retardant on polymeric material that encloses the internal ignition sources.
During the conversation, I mentioned the medium size fridges or under counter fridges may be exempted from the condition of size but the lab said that the condition of size "material longer than 6 feet (2 meters) or greater than 10 square feet (1 square meter) in area" no longer exists in the latest standards UL 250 and UL 60335-2-14. As I have no such latest versions in hand, may check it later. Regards, Scott On 26 June 2017 at 23:30, Ted Eckert <[email protected]> wrote: > Hello Scott, > > > > UL 723 requirements are far more strict than a UL 94 5VA rating. The UL 94 > 5VA test uses a single high-energy flame applied to a sheet sample of the > plastic. The test determines how the material burns. 5VB and 5VA are the > same test except that 5VB allows the flame to burn a hole through the > material and 5VA does not. Both have strict prohibitions against dripping > flaming particles and the material must self-extinguish quickly. > > > > UL 723 has a large burner at one end of the tunnel and forces the flame > along the length of a large sample. The UL 723 test simulates how materials > would behave in a moderately large structure fire. It determines whether > the materials would help the spread of the fire and whether the materials > would generate enough smoke to cause problems for occupants of the > building. > > > > Ted Eckert > > Microsoft Corporation > > > > The opinions expressed are my own and do not necessarily reflect those of > my employer. > > > > *From:* Scott Xe [mailto:[email protected]] > *Sent:* Sunday, June 25, 2017 11:03 PM > *To:* Ted Eckert <[email protected]> > > *Cc:* [email protected] > *Subject:* Re: [PSES] Metal back of US fridge - Grenfell Tower Fire > > > > Hi Ted, > > > > Very appreciate your useful information! It tells me why I could not find > it in the product specific safety requirement in UL 250 & UL 60335-2-14. > > > > According to testing laboratories, they claim the plastic back, HIPS is > allowed but must meet fire retardant UL-94 5VA rating, otherwise metal back > is a must. Is it equivalent characteristics of ASTM E84 and UL 723? > > > > Regards, > > > > Scott > > > > > > On 26 June 2017 at 04:59, Ted Eckert <000007cf6ebeab9d-dmarc- > [email protected]> wrote: > > The United States has significant national differences. > > > > Many U.S. national standards have very strict flammability requirement for > larger areas of materials used indoors. The basic requirement applies when > you have a piece of material longer than 6 feet (2 meters) or greater than > 10 square feet (1 square meter) in area. This material must pass the > Steiner Fire Tunnel test, covered in ASTM E84 and UL 723. This video > gives a basic outline of the test > <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Ftime_continue%3D1%26v%3DiEe5dQ7LPhM&data=02%7C01%7CTed.Eckert%40microsoft.com%7C9505044e827341c9898508d4bc58f46d%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636340537621918986&sdata=XKXuwtGektgHn4HzOzgf46vprAIC9UX%2BuOeGbHmynQ4%3D&reserved=0>. > Interior building surfaces must meet fairly strict requirements and this > would include a large sheet of plastic on the back of a refrigerator. There > are even stricter requirements for materials used in air plenums, such as > above a suspended ceiling. > > > > The linked video references the “International Building Code”, or the IBC. > The same requirements are in the Uniform Building Code, or UBC. Most > municipalities in the United States adopt either the IBC or UBC. > > > > Here is a sample UL Listing for a material commonly used for kitchen > countertops > <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdatabase.ul.com%2Fcgi-bin%2FXYV%2Ftemplate%2FLISEXT%2F1FRAME%2Fshowpage.html%3Fname%3DBTAT.R11986%26ccnshorttitle%3DMolded%2BPlastic%26objid%3D1074291935%26cfgid%3D1073741824%26version%3Dversionless%26parent_id%3D1073984739%26sequence%3D1&data=02%7C01%7CTed.Eckert%40microsoft.com%7C9505044e827341c9898508d4bc58f46d%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636340537621918986&sdata=IZTAcCl8jyrXSmxB4mRFkEy225Q%2BNQ3q7As4P870ExY%3D&reserved=0>. > Similar requirements apply to drywall, flooring materials, plastic glazing > materials, ceiling tiles and other construction products. > > > > Many U.S. national standards do not specifically call out this > requirement, largely because few products that fall under those standards > have enough surface area. For example, I had a large piece of computer > equipment certified to UL 60950-1. UL applied the UL 723 requirements to > the plastics used for large air plenums on the structure. It was probably > one of the few pieces of ITE equipment I’ve ever seen with pieces of > plastic large enough to warrant UL 723 testing. > > > > The back of a refrigerator would be close to the limits where a U.S. > Nationally Recognized Test Laboratory (NRTL) might apply UL 723. The > refrigerator manufacturer could come up with ways of reducing the panel > size below the limit to avoid this challenging test. > > > > The Steiner Tunnel Test is also used for wiring that could be hidden in > walls or air plenums, such as above a suspended ceiling. There is another > U.S. national difference that affects wires over 10 feet (3.05 meters) in > length. This is in UL 60950-1 and UL 62368-1. If your computer’s external > cable is less than 3.05 m, it only needs to be VW-1, FT-1 or better. If the > cable is longer, there is a concern that it could carry flame from where > the computer is located to another occupied space. Finding an Ethernet > cable that meets this requirement, often called plenum rated, is easy. > Finding a USB cable that meets the requirement is hard. > > > > Ted Eckert > > Microsoft Corporation > > The opinions expressed are my own and do not necessarily reflect those of > my employer, any NRTL or the code authorities behind the IBC and UBC. > > > > > > > > *From:* Scott Xe [mailto:[email protected]] > *Sent:* Sunday, June 25, 2017 7:01 AM > > > *To:* [email protected] > *Subject:* Re: [PSES] Metal back of US fridge - Grenfell Tower Fire > > > > Adam, > > > > It is a good statistics! > > > > Actually US now also adopts UL EN 60335-2-24 as their safety standard. > Does UL have deviation for US in this standard as suggested by John? > > > > Thanks and regards, > > > > Scott > > > > *From: *Adam Dixon <[email protected]> > *Reply-To: *Adam Dixon <[email protected]> > *Date: *Sunday, 25 June 2017 at 7:52 PM > *To: *<[email protected]> > *Subject: *Re: [PSES] Metal back of US fridge - Grenfell Tower Fire > > > > Here's another good UK data source for incidents, not recalls: > > https://www.gov.uk/government/statistical-data-sets/fire- > statistics-data-tables > <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.gov.uk%2Fgovernment%2Fstatistical-data-sets%2Ffire-statistics-data-tables&data=02%7C01%7Cted.eckert%40microsoft.com%7C17744cf20f834e2c7cfd08d4bbd2bc15%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636339961165781837&sdata=FwqZC6%2BVF27OkRORXGTemSPoSXe5YpSxkdHu9FarxkU%3D&reserved=0> > > The "Domestic appliance fires dataset" file near the bottom can be parsed > by appliance type. > > Cheers, > > Adam > > [email protected] > > > > > > On Sun, Jun 25, 2017 at 7:42 AM, John Allen <000009cc677f395b-dmarc- > [email protected]> wrote: > > Scott > > > > Look on the EU Commission RAPEX site: > > http://ec.europa.eu/consumers/consumers_safety/safety_ > products/rapex/alerts/ > <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fec.europa.eu%2Fconsumers%2Fconsumers_safety%2Fsafety_products%2Frapex%2Falerts%2F&data=02%7C01%7Cted.eckert%40microsoft.com%7C17744cf20f834e2c7cfd08d4bbd2bc15%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636339961165791839&sdata=B%2BpZYmERccXhKqUrO3Y9ZaRzTspq9nj7Y6xqrhJ9mJs%3D&reserved=0> > > > > Actually, don’t if you want to sleep tonight! > > > > John E Allen > > W.London, UK > > > > *From:* Scott Xe [mailto:[email protected]] > *Sent:* 25 June 2017 12:34 > *To:* [email protected] > *Subject:* Re: [PSES] Metal back of US fridge - Grenfell Tower Fire > > > > Hi Adam, > > > > The info supplied is interesting! Yes, it aligns with John’s thought. > However, the recalled units are quite different – 5,200 vs 1.2 m. In the > UK, there are a few million recalls of clothes dryers in last few years – > that is quite different from US data. Is there similar data of UK and/or > EU? > > > > Cheers, > > > > Scott > > > > > > *From: *Adam Dixon <[email protected]> > *Date: *Sunday, 25 June 2017 at 7:06 PM > *To: *Scott Xe <[email protected]>, <[email protected]> > *Cc: *<[email protected]> > *Subject: *Re: [PSES] Metal back of US fridge - Grenfell Tower Fire > > > > Here's a slightly dated but popular US magazine article with a table near > the end that supports John's closing thought about rarity of fridge fires > compared to tumble-dryer fires (1:9 ratio). > > http://www.consumerreports.org/cro/magazine/2012/03/ > appliance-fires-is-your-home-safe/index.htm > <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.consumerreports.org%2Fcro%2Fmagazine%2F2012%2F03%2Fappliance-fires-is-your-home-safe%2Findex.htm&data=02%7C01%7Cted.eckert%40microsoft.com%7C17744cf20f834e2c7cfd08d4bbd2bc15%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636339961165791839&sdata=aEnwHYkLu9GrByivxXoHMtluDF3ExAoDloWIrPrhtT0%3D&reserved=0> > > Cheers, > > Adam > > [email protected] > > > > > > On Sun, Jun 25, 2017 at 6:52 AM, Scott Xe <[email protected]> wrote: > > John, thanks for background info! > > LFB said one fire every day in London is caused by white goods. It is a > horrible figure! > > Grenfell Tower Fire is a bit different from previous ones and had another > risk of non-approved insulation and cladding tiles on the outer wall of > building. It is still unclear how the fire spreads from the fridge to the > cladding titles. Was the fridge close to the windows? > > From the video, the metal back seems to work delaying the fire spread. It > may trigger the standard body to think it again. The capacitor incident > prevention has been incorporated into the safety standard, why not this > one? LFB may take this case to reinforce their warning alert in 2015. > > Scott > > On 25/6/2017, 5:25 PM, "John Woodgate" <[email protected]> wrote: > > It's not quite 'resistance', it's more a matter of different > priorities. US safety standards major on protection against fire because > they were originated by the insurance industry (Underwriters Laboratory) > for obvious financial reasons, while European safety standards major on > prevention of electric shock, because 230 V is more dangerous than 120 V > (but of course not more dangerous than 240 V!), and timber-framed buildings > are relatively rare in Europe. > > I guess that the applicable safety standard (IEC/EN 60335-2-xxx) > isn't strongly influenced by US experts (US may even have voted for it) and > thus doesn’t require a metal back panel, whereas the UL standard (which may > be the IEC standard with a modification or several) does require one. > > All the Sections of IEC 60335-2 are under continuous review as > technologies change, and the recent incidence of fires may well result in > significant changes. > > However, unlike the tumble dryer case, where numerous fires were > reported, this fridge-freezer fire is just one incident, and may be due to > a 'one-off' fault' or obstruction of the ventilation. Even the enquiry that > is being held may not be able to assign a definite cause. I suspect that > fridge fires are very much rarer than tumble-dryer fires, even if, to be > fair, the epidemic dryer fires are excluded. > > With best wishes DESIGN IT IN! OOO – Own Opinions Only > www.jmwa.demon.co.uk > <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.jmwa.demon.co.uk&data=02%7C01%7Cted.eckert%40microsoft.com%7C17744cf20f834e2c7cfd08d4bbd2bc15%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636339961165791839&sdata=ewI3pMv%2B%2FSyeNkkneh8bgtWX9oIKUIFhhvmVkXHD3hs%3D&reserved=0> > J M Woodgate and Associates Rayleigh England > > Sylvae in aeternum manent. > > -----Original Message----- > From: Scott Xe [mailto:[email protected] > <scott.xe@G-%3cBR%3e----------------------------------------------------------------%3cBR%3e%3cp%3eThis%20message%20is%20from%20the%20IEEE%20Product%20Safety%20Engineering%20Society%20emc-pstc%20discussion%20list.%20To%20post%20a%20message%20to%20the%20list,%20send%20your%20e-mail%20to%20%3c%3cA%20HREF=> > > > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.ieee-pses.org%2Femc-pstc.html&data=02%7C01%7Cted.eckert%40microsoft.com%7C17744cf20f834e2c7cfd08d4bbd2bc15%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636339961165791839&sdata=l1RnVJPaZ6DrDl8Sre2WZZHPWJ8bntqXq6SyKancp5k%3D&reserved=0> > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ > <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fproduct-compliance.oc.ieee.org%2F&data=02%7C01%7Cted.eckert%40microsoft.com%7C17744cf20f834e2c7cfd08d4bbd2bc15%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636339961165791839&sdata=euJOUZgEen4mFMgZVsDDNGMyjeHtbPB0NszZObsL8Ls%3D&reserved=0> > can be used for graphics (in well-used formats), large files, etc. > > Website: http://www.ieee-pses.org/ > <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.ieee-pses.org%2F&data=02%7C01%7Cted.eckert%40microsoft.com%7C17744cf20f834e2c7cfd08d4bbd2bc15%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636339961165791839&sdata=7OJQKHvMsmpDz2nii0JICMCFmQ5Mw5TJuekMdXrg6bk%3D&reserved=0> > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) > <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.ieee-pses.org%2Flist.html&data=02%7C01%7Cted.eckert%40microsoft.com%7C17744cf20f834e2c7cfd08d4bbd2bc15%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636339961165791839&sdata=Oh0VetogpAIPGPGSFZZq19mOJoWM0vh1EqUOel56%2B4I%3D&reserved=0> > List rules: http://www.ieee-pses.org/listrules.html > <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.ieee-pses.org%2Flistrules.html&data=02%7C01%7Cted.eckert%40microsoft.com%7C17744cf20f834e2c7cfd08d4bbd2bc15%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636339961165791839&sdata=ebZpPH8QshSN1PJtrWBf83RxlRCXUx1lSYqSQzJ2N%2Fw%3D&reserved=0> > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> > > - > ---------------------------------------------------------------- > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. 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