Custom Metalcraft, Inc — Hazardous Materials Safety Interpretation

Page 1U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Avenue, SE Washington, D.C. 20590 SEP 2 4 2013 Mr. Eric Larson Custom Metalcraft, Inc. 2332 E. Division, P.O. Box 10587 Springfield, Missouri 65808 Ref. No.: 13-0116 Dear Mr. Larson: This responds to your May 16, 2013 letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the manufacturing and design of portable tanks. In your letter, you describe the calculations you use for the testing of a specification United Nations (UN) portable tank, under § 178.275, for the transportation of liquid and solid hazardous materials. You ask this Office to verify whether the calculations as presented in your letter are correct and would meet the design requirements prescribed in § 178.275. This Office does not perform the function of certifying whether a portable tank design meets the UN specification as prescribed in Part 6 ofthe UN Model Regulations. However, the HMR provide an application process for approval of a Specification UN portable tank design as specified in§ 178.273. Such applications are submitted to a designated approval agency authorized to approve portable tank designs in accordance with the procedures specified in Subpart E, Part 107, of 49 CFR Volume II, chapter I, subchapter A. I hope this satisfies your inquiry. Please contact us if we can be of further assistance. Sincerely, T. Glenn Foster Chief, Regulatory Review and Reinvention Branch Standards and Rulemaking Division#

Page 2Drakeford, Carolyn (PHMSA) From: Sent: To: Subject: Attachments: INFOCNTR (PHMSA) Tuesday, May 28, 2013 12:17 PM Drakeford, Carolyn (PHMSA) FW: requesting a letter of interpretation 20130524104316272.pdf PtJr-!rJJ?I e_ Tan k5 /'3-0II~ Hi Carolyn, This caller requested we submit this e-mail as a formal letter of interpretation. Thanks, Victoria From: Eric Larson [mailto:ericl@custom-metalcraft.com] Sent: Friday, May 24, 2013 12:10 PM To: INFOCNTR (PHMSA); Majors, Leonard (PHMSA) Cc: Steve Allred; Jeff Nelson; Mike Bither Subject: requesting a letter of interpretation I am requesting a letter of interpretation on the information contained in the attached pdf. If this is the improper format to request a letter of interpretation please let me know. In the mean time please respond to the information contained in the pdf via email. If I get no response to the information contained in the pdf I will assume my statements in the pdf are correct and will proceed with vessel design and fabrication under that assumption. ;· From: Eric Larson Sent: Monday, May 13, 2013 10:13 AM To: 'leonard.majors@dot.gov' Subject: Questions Please submit a response as we discussed on the phone: 1) 2) Special provisions 814 & TP38 specify a thermal conductance of no more than .075 8tu/(Hr Ft/\2 F) which take as the thermal conductivity k per inch of thickness. We have a "repeat" job that was originally DOT 51 that had essentially 2" thick insulation. I don't know of any insulation that will satisfy the maximum of .075 8tu/(Hr FtA2 F) with a 2" thickness along with maximum insulation temperature requirements. Am I reading this correct? I am taking k and dividing it by the insulation thickness which must be less than or equal to .075 8tu/(Hr FtA2 F). k/t<=.075 8tu/(Hr Ft/\2 F)? If that is the case we are looking at 3" to 6" of insulation depending on what insulation material is used (see pdf). We use 2" of insulation on vessels unless there is some reason to go thicker and in this case we have an existing design we want to try and keep. In addition, what parts of the vessel need to be insulated (see pdf of original tank)? I would assume any parts that need to be insulated would have to have a minimum thickness measured perpendicular to the shell surface per the thermal conductance criteria? Per 178.275(8) "The partial pressure (in bar) of air or other gases in the ullage space, resulting from their compression during filling without pressure relief by a maximum ullage temperature of 65 oc (149 oF) and a liquid expansion due to an increase in mean bulk temperature of 35 oc (95 oF); and" Does this mean that we are starting with an empty tank that is totally closed off, no pressure relief valve or venting of any kind, with air at atmospheric pressure and temperature inside the tank and then filling to the maximum fill level with the hazardous material, the resulting pressure due to the compression of the air would then be calculated at the maximum fill level at 149 oF and the design pressure must not, in part, be less than this? 1#

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Page 4Andrews $172.102 3178.275 (B) Portable Tanks 13-0116 178.275 (6)(1) (B): VEu Full Volume Of Vessel (uncorreded). VN = Nominal Volume of Vessel (Max. Product Volume) de = density of Product @ 2/C 470°f) 2350° das" density or product 265° (149°F) _Istrease TA = Atmoseneric Temperature 294 K(*22)(*70€, PA = Absolute Atmostneria Pressure I bar (ISPS=) Choose ine fui volume of vessel VFU steP 2) calculate: Pe= max uncorroded poure pressure of the ullage Spare LAir). Tu= mat unerraded lage Temperature (Air) Start with EmPty vessel at Atmospheri 70°f OPSIG Pressue and Temperature Disable a venting ded Frassure relier, Fill the vessel to the Nominal volume of vessel the dir in the uage ifs. Will Now be at Ps and Tue#

Page 5PRIATIONS OND A CONSTANT vale for air of l.4 Pe and Tu can be calculatel. 1.4 PE= PA VFu 1 PA d050:u+2 VEU - VN (d65)) (/4-1) Ty= TA VFu VE.. VN đos)) STeP 3) recalculate Per step 1) and Stef 2) UNtil Tu is Less thon or Based on SteP i), Step? and iteP 3), The vessel now complies with 178.275 (6)(1)(B) and VEd is the full volume of the vessel that will be Built and i addition • the Vessel car IF VM. IS this Statement correct? If Not Please ExPlain.#

Page 6P83 172.102 TPZ: Per 178.275 (6)(1) (B) a maximum Degree of Filling is Determines. ... This is VF1 For the specific cose where all resting and Pressure relieF removes Disted 2.055 TRE is for the case where all Venting and Pressure relief is working Properly as specifies and Designed. The matimum Degree of Eling is the besser of that Determined Per 178:275 (k) (11) (B) ano 172102 TPE IS this statement Correct? IF Not PLese ExPIRiN.#