Mr. Thomas Lee Bartlett — Hazardous Materials Safety Interpretation

Page 1! U.S. Department 400 Seventh St., S.W. of Transportation Washington, D.C. 20590 Research and APR 21 2004 Special Programs Administration Mr. Thomas Lee Bartlett Ref. No. 03-0304 Attorney at Law Suite 3 North 402 Main at Preston Houston, TX 77002 Dear Mr. Bartlett: This is in response to your letter requesting clarification concerning requirements under the Hazardous Materials Regulations (HMR), 49 CFR Parts 171-180, applicable to DOT Specification an MC-312 cargo tank offloading 32% hydrochloric acid from the tank motor vehicles. You state that your request concerns product ball valve located in the discharge piping on top of the top of the cargo tank using pressure above 15 psig. A PVC manual cargo tank failed. the outlet nozzle blanked off for the customer to install the dip This cargo tank was manufactured in 1994 with pipe, valve and piping. I am answering your questions in the order as they appear in your letter. Q1. In 1994, were polyvinyl chloride (PVC) valves authorized on MC-312 cargo tank motor vehicles? Al. In 1994, a PVC (non-metallic) manually operated ball valve tank motor vehicle provided the material was capable of located in the product discharge could be used on an MC 312 cargo withstanding the pressures specified in the MC 312 specification. of the HMR, although new cargo tank constructions were authorized The MC 312 specification was last published in The 1990 edition to be marked and certified to the MC 312 specification until October 31, 1995 (See current $ 180.405 (c) (1)). The applicable requirements in the 1990 49 CFR, at § 178.340-8 (d) (3), state in part: piping and fittings for tanks to be unloaded by pressure Strength of piping, fittings, hose and hose couplings: Hose, shall be designed for a bursting pressure of Presure to which, in and not 1ebe than four times che in service by the action, of any vehicle mounted pump or it may be subjected §180.405 3180.407 030304#

Page 2action of which may be to subject certain portions of other device (not including safety relief valves), the the tank piping and hose to pressures greater than the design pressure of the tank. Q2. Are MC-412 cargo tank motor vehicles authorized to use PVC valves? A2. Yes. Section 178.345-9 (h) metallic pipe, valve or connection line that is not as strong and authorizes the use of a non- heat resistant as the cargo tank material only when the attachment is located outside of the lading retention system. 03. In January 2001, was a PVC valve installed as a replacement on an MC-312 cargo tank motor vehicle authorized? A3. Yes (see A2). cargo tank motor vehicle that was unloaded from the top using air 24. In 2002, was a remote closure device required on an MC-312 pressure? A4. Yes, see § 180.405 (f) (1) . Sincerely, Hothe z. Mithell Hattie I. Mitchell Chief, Regulatory Review and Reinvention office of Hazardous Materials Standards#

Page 3M'Intyre $180.405 THOMAS LEE BARTLETT @180.407 ATTORNEY AT LAW Tanks 713-225-6902 TELEPHONE 402 MAIN at PRESTON, SUITE 3 NORTH HOUSTON, TEXAS 77002 TELECOPIER 03-0304 713-225-0264 November 18, 2003 03 NOV 26 DOT/RSPA. Robert A. McGuire Ph 2: 47 UNIT /OHMS Associate Administrator for Hazardous Materials 400 7" Street S.W. Washington, D.C. 20590-0001 Re: Cause No. 2002-46963; Wilson A. Andrade v. L & B Transport, Tex.C., et al; In the 190" Judicial District Court of Harris County, Dear Mr. McGuire: This is a request for interpretation. It concerns an MC-312 Cargo Tank offloading 32% hydrochloric acid from the top, using pressure above 15 psig. A PVC manual product ball valve located in the discharge piping on top of the cargo tank failed. This cargo tank was manufactured in 1994 with the outlet nozzle blanked off for the customer to install the dip pipe, valve and piping. Questions: 1. In 1994, were PVC valves authorized on an MC-312? 2. Are MC-412 cargo tanks authorized to use PVC valves? 3. Is a PVC valve installed as a replacement on an MC-312 cargo tank in January of 2001 authorized? 4. Was a remote closure device required on an MC-312 during 2002, which unloaded from the top using air pressure?#

Page 4Your timely response would be greatly appreciated Sincerely yours, Phomas Lee Bartlett C:lAndradelmeguire1ltr.wpd#