{"operation":"document","citation":"09-0067","title":"Cabot Microelectronics — Hazardous Materials Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"2009-07-20","effective_on":null,"summary":"09-0067 response to Cabot Microelectronics concerning 173.24.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-09-0067.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-09-0067.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-09-0067","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretations/2009/090067.pdf","body":"<<<PAGE 1>>>\n\nU.S. Department of Transportation\nPipeline and Hazardous Materials\nSafety Administration\n1200 New Jersey Ave, S.E.\nWashington, D.C. 20590\nJUL 2 0 2009\nMr. Michael Trembley\nCabot Microelectronics\n870 N. Commons Drive\nAurora, IL 60504\nRef. No. 09-0067\nDear Mr. Trembley:\nThis responds to your March 19,2009 letter requesting clarification of requirements in the\nHazardous Materials Regulations (HMR; 49 CFR Parts 171- 180) applicable to intermediate\nbulk containers (IBCs). Specifically, you ask if it is permissible to use vented caps to prevent\nhydrogen gas build up in an IBC to meet the provisions concerning venting in 9 173.24(g)(2).\nAccording to your letter, you plan to use a vented cap (e.g., G2 Plug Silicone Vent #48 1645\nor equivalent) on an IBC containing a non-hazardous, water-based product to prevent the\nbuild up of hydrogen in the head space of the container. You state that hydrogen levels in\nexcess of the 4% Lower Explosive Limit (LEL) concentration can build up over time inside a\nclosed container such as an IBC and suggest that the use of a vented cap would prevent this\nfrom occurring.\nThe answer is yes. It is the opinion of this Office that the use of a vented cap as described\nabove to prevent hydrogen gas build up in the IBC is permissible, and does not constitute a\ndesign change that would necessitate retesting of the IBC. Please note that any change to the\noriginally produced packaging involving structural design, size, material of construction,\nwall thickness, or manner of construction would constitute a design change that would\nrequire completion of the tests set forth in Subpart 0 of Part 178 of the HMR.\nI hope this answers your inquiry.\nSincerely\nfl;d\n\n<<<PAGE 2>>>\n\nHeadquanew\n870 N. Cwnmm f)aive\nAurora, It 6WM\n630 375-@?i3 1\n806.&1,2756\n63ii 375,5539 fax\nW-CaWtomp wrn\nMar& lfP,ZFIE)!2\nG.5, Uepanmmt af Tmnspuftati~n\nPiyrlise and Nazlrrr%ous Mnteriab &fe't.ty Adnairt (3\"l.tJ\"i- 10)\nOffice of Hwmdozzs M ~ M B I s %fety\n1200 New Ja4sey Avenue, SF: Fast B~kitding. .2& Flcror\nWashington, BC' 20590\nAttn: Mt. Edward 3: R4anulfa, i3ireeior\nOt'tice of Hwrdeus h 5 c ~ i d 8 S~andwds\nSubject: ;Inre\"rl.neiadon Requeajt for 49 CFR 1 T,1.24(g)(2)\nDear Mr. k m l i o .\nPutsuaM to sn informal &lephrme c~nfauroe call eonducked m March 1 1.2009 befw een Roy\nMarshall. on behalf of C~bot Mirroelecaonics C2xparaapaa. and Sharu Kellry. we f a m l l y\nrqued y ~ u r tisistBRw 0t1 ri shippja&:mttfcrmlaked to the use of vented caps.\nSpeciRoslly. \\ate would like to know i r i l i ~ -5ssibJe to usc a vented cap (eg. (i2 Plug Silicone\nVent $481 645 pa equivaimtt) on u packgin& fa.&. an X~tem~ediillc BuLk Con~aiwr) co~~truninp a na-\nhWwdot.k, xvhh-ksed preduot to preyent ibe.buil6up of hwogen m the head @ace of the container\nif the venrpd ilydmp 8s Reaper reach %he L o w e Gxplabive Lh13r (LEL) of s 4% eoncmmtion\nwith Bir iif the mqOfl ve~clr\" ar fright onntairinq.\nQ ~ e ~ d y . hydrf>gea levels in m c e s of tk 4% LEL concentntion a t buildvp over ume inside a\ncJosed eonsner aoch sr an %mediate Bulk Canfaher. The use of a m t e d cap would prevent the\nbuijujld-up ofh$fdr~gcn ursfde such a untUnerthus preventing the 4% LEL conccnmtion $om king\nreitch&.\nWhile (he initis! guidance we ncceiMd fmm the US. DFp-ent gf Tranqonatim seems fay-ic\n(i*. a v&ed csp would be pcmirrible unda &q circumstnnrcs described in L e second paragritph\nabove). we respectfully requen a forms1 wriqefi inteqreration ofthe Wssibilixy of wnrrd caps (as\ndiscussed in pmgraph Ea.~.ab%~e) in sc~brdanee with 49 CFR 17?.24(g)(2).\nh addition. we have iti~luded a fopy ofthe-ini~ial inform~tion provided u, the L1.S. ~epsrtmenr of\nTranspoetion nnd cxsmplcr afrhc lntmnediatr Bulk Container ventilstion system oaps under\ncarasidwTi:on.\n'Kank pa^ fir p t t r blp in this matter.\nSbcerely,\nTe1- 630.375.5576\nFax- 630.375.2082\nEmail- rnichag3-rrcmb*iry@c~k~tc'1*1tp~~:om\n\n<<<PAGE 3>>>\n\nHydrogenPackaging Issue\nWe need help to determine what our options are in terms of eliminating the headspace build-up, proper\nclassification, interactions with the DOT, any exemption opportunities, etc.\nAssuming the containers are hazardous, we need to be able to ship by ground and water. Air is not required,\nbut if possible would be nice to have. Our internal policy is to ship Cargo Aircraft only. No passenger\naircraft even if legally allowed.\nPackaging specs: We typically use 5-gallon plastic jerricans (3H1), 55 gallon drums (1H1) or tote (3 1HAI)\n...........................................................................\nWe have a product that is non-hazardous. This is a water-based product that is not flammable, corrosive,\noxidizing, etc. Essentially it is used as part of a wire saw process to cut silicon ingots into thin wafers. As a\nresult of this process, small bits of the silicon mix with the product. This material is re-used a number of\ntimes until the product becomes 'saturated' with enough silicon that it no longer can effectively cut the ingots\nvia the wire saw process. This spent material is collected as it has the potential to be recycled and re-used.\nThis material is also water based, not flammable, corrosive, oxidizing, etc. and is considered in itself non-\nhazardous. However, there is a reaction occurring between the silicon particles and the water. The silicon\nreacts with the water to form silicon dioxide and hydrogen gas. The hydrogen gas accumulates over time in\nthe headspace of the containers- drums, jerricans and IBC type totes. The levels of concentration of H2\nmeasure in the closed containers varies based on time, headspace volume and amount of silicon present in\nthis spent material, and have been measured from 34%-75%. Once the cap is removed from the container,\nthe H2 disperses quickly to atmosphere to levels below the LEL. Some initial measurements on drums that\nwere initially stored using vented caps and then re-sealed for subsequent measurements:\nDrum\n1\nDrum\n2\nDrum\n3 3\nSlurry Height in /Immediate\nDrum :Hydrogen\nVery Full 34%\n2\" from top I\nFull 75%\n6 from top\nAbout 54%\nHalf full\n'i2hw- W. %%L.irS&'W&& m* iB X * 6 & u QI %\"tW% 4 P, \" b W * l N * l A .\n:Hydrogen after 1\n*minute\nHydrogen after 30 Hydrogen after 60 \"\n$\nminutes minutes\n6.3%\nAs you probably know, H2 has an LEL of 4%. From our measurements, we have determined that the\nreaction of the silicon with the water is generating H2 in levels above the LEL and creating a flammable\nheadspace.\nWe need help to determine what our options are in terms of eliminating the headspace build-up, proper\nclassification, interactions with the DOT, any exemption opportunities, etc.\nOne of the options we are interested in exploring is the use of a vented cap that allows an 'air exchange'\nbetween the headspace and the atmosphere. The thought that if this reaction were allowed to vent, then the\nLEL would not be reached in the headspace and thus it would be non-hazardous. We are not sure if this is\npermitted by the DOT or would require an exemption of some sort by the DOT and would like your\nassistance on that question as well.\nWe were able to obtain a Letter of Interpretation from the DOT that is almost spot on to our situation. The L\nof I relates to rail cars, but the H2 reaction issue is exactly the type of scenario we have. This has given us\nsome guidance, but takes us down a path that essentially prohibits from using jerricans, drums and totes if I\n\n<<<PAGE 4>>>\n\nHydrogenIPackaging Issue\nam understanding the packaging instructions correctly. I have attached for your review.\nPossible solutions to consider:\n1 . Vented Caps- is a vented cap that allows for pressure release and air exchange permitted that prevents the\nbuild-up of hydrogen above the LEL in the headspace of the container.\nAlso, can you look at the attached photos related to 2-way vented caps. It appears these are UN approved\nand allow for air exchange. These would allow the H2 reaction to vent and disperse to air thus potentially\neliminating the H2 generation in the headspace creating a flammable atmosphere. These are used with the\ntotes. Markings on the caps: UN31 HAlNIUSA/+AA2503 Leak Proof Inspection. Is this type of cap in\ngeneral an option for us?\n2. Overpack- can a jerrican of material be placed inside a larger overpack (85 gal) drum that could contain\nany released hydrogen from the jerrican within the overpack headspace. Also would prevent any potential\nspillage from jerrican depending on type of cap used.\n3. Freezing- could freezing of material which would prevent hydrogen reaction from occurring be used.\nMaterial would be shipped as a non-haz solid in jerrican, drum or tote.\nTo confirm, mode of transportation within the U.S. would be ground. Internationally, would need to be able\nto ship by water. No air shipping expected at this time.\nFrom our perspective, the use of an appropriate cap that allows air exchange and venting is the preferred\nchoice. It looks like there may be some options based on some cap information I had sent to you last week.\nAlso, looking at any suggestions you might have that we are missing. Basically, we are looking for ways to\nget the hydrogen out of the container so that the LEL is not reached while still in compliance with DOT.\nWe are also looking at reformulation options but are somewhat limited right now because we cannot move\nthe material where it needs to go for evaluation and more testing. Namely, from our customer site back to\nour site. Thanks.\n\n<<<PAGE 5>>>\n\nGoreDURAVENT\nSSSchuetz -40 D38 black SSSchuetz-100\n3-4277 1 #481645 3-8172 1 WOO4534 34277 1 a86876 3-8891 / #I270729 4-5039 1 L1199099 4-4121 1#9l3197 3-8861 1 IYJD06747 4-3754 1 #852430\nfor strong gahing material discharging without (e.g. hydrogene-pemxide) opening of screwcap discharging without\nopening of screw cap","truncated":false,"body_characters":9754}