Interpretation Response #99-0260 ([Oklahoma LP Gas Administration] [Mr. Gary McDonald])

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date: 10/20/1999

Company Name: Oklahoma LP Gas Administration

Individual Name: Mr. Gary McDonald

Location State: OK Country: US

View the Interpretation Document

Response text:

October 20, 1999

Mr. Gary McDonald                     Ref No. 99-0260
Senior LP Gas Inspector
Oklahoma LP Gas Administration
Number B45
2101 N Lincoln Boulevard
Oklahoma City, OK 73105-4904

Dear Mr. McDonald:

This responds to your request for clarification of the requirements for cargo tanks in liquefied compressed gas service under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171­180).  Your request was forwarded to us by Bob Craig at the Transportation Safety Institute.  Your specific questions concern new requirements for cargo tanks recently adopted under Docket HM-225A.  Your questions are paraphrased and answered below.

Q1:       The final rule published on May 24, 1999, appears to suggest in § 173.315  (n)(5)(iii) that non-specification cargo tanks authorized under § 173.315 (k) may have a capacity over 3,500 gallons.  Does the requirement in § 173.315(k) limiting the capacity of non­specification tanks to 3,500 gallons or less still apply?

Al.:       Yes.  The inclusion of language in § 173.315(n)(5)(iii) concerning non-specification tanks authorized under § 173.315(k) was inadvertent.  We will correct this discrepancy in a future rulemaking.

Q2:       What marking and certification is required for non-specification tanks authorized under § 173.315(k)? If non-specification tanks are not equipped with internal self-closing stop valves, will they have to be so equipped to meet the thermal activation requirements of § 180.405(n)?

A2:    A non-specification cargo tank authorized under § 173.315(k) must be marked in conformance with the edition of the ASME Code in effect when it was manufactured.

A non-specification cargo tank must be equipped with an internal self-closing stop valve.  As you note in your letter, § 180.405(n) requires non-specification cargo tanks conforming to § 173.315(k) to be equipped with a means of thermal activation for the internal self­-closing stop valve as specified in § 178.337-8(a)(4). Section 178.337-8(a)(4) requires each vapor or liquid discharge outlet to be fitted with a primary discharge control system as defined in § 178.337-1(g). The definition in § 178.337-1(g) states that a primary discharge control system consists of an internal self-closing stop valve that may include an integral excess flow valve or excess flow feature, together with linkages that must be installed between the valve and remote actuator to provide manual and thermal on-truck remote means of closure.  Taken together, these sections require a non-specification cargo tank operating under the provisions of § 173.315(k) to be equipped with an internal self-­closing stop valve as part of a primary discharge control system.  Under the provisions of § 180.405(n), a non-specification cargo tank that does not currently conform to § 178.337­8(a)(4) must be retrofitted with a primary discharge control  system by the date of its first scheduled leakage test after July 1, 1999.

Q3:       The exceptions from the requirement that each liquid and vapor discharge opening in an MC 330 or MC 331 cargo tank must be protected with an internal self-closing stop valve that are listed in § 178.337-8(a)(5) do not appear in § 173.33(h). Does this mean that all liquid and vapor discharge openings on MC 330 and MC 331 cargo tanks must be equipped in conformance with § 173.33(h) and that the exceptions in § 178.337-8(a)(5) do not apply?

A3        No. Section 178.337 lists the requirements for DOT Specification MC 331 cargo tank motor vehicles.  The exceptions from the requirement for protecting each liquid and vapor discharge opening with an internal self-closing stop valve in § 178.337-8(a)(5) may be utilized even though they are not explicitly stated elsewhere in the HAM.  Further, Note 16 in § 173.315(a) requires MC 330 and MC 331 cargo tanks to be equipped in conformance with§178.337-11(c). Until publication of the HM4-225A final rule, §178.337-11(c)was the paragraph that listed the exceptions from the requirement for internal self-closing stop valves for liquid or vapor discharge openings of I 1/4 inch NPT or less and for engine fuel lines.  The final rule issued under HM-225A moved these exceptions from § 178.337­-11 (c) to § 178.337-8(a)(5). Unfortunately, we neglected to amend Note 16 to reference the new section number.  We will correct this in a future rulemaking.

Q4:       Section 173.315(k)(4) says that non-specification cargo tanks must conform to NFPA 58 except to the extent that NFPA 58 is inconsistent with requirements in parts 178 and 180.  What is the intent of this section?

A4:       When § 173.315(k), authorizing continued use in liquefied petroleum gas service of non­specification cargo tanks, was adopted, such continued use was conditioned on the cargo tanks conformance with NFPA 58.  The new requirements for cargo tank inspection, testing, and emergency discharge control adopted under HM-225A differ in significant respects from NFPA 58.  Thus, we added the exception in § 173.315(k)(4) to assure that operators are aware that they must comply with the new HMR requirements in parts 178 and 180.

Q5:    Since most enforcement officers do not have ready access to NFPA 58, shouldn't the applicable sections be included in § 173.315?

A5:    Incorporations by reference of material developed by industry organizations, international agencies, and other groups permit Federal agencies to reduce the volume of material published in the Federal Register and the Code of Federal Regulations.  Materials incorporated by reference into the Code of Federal Regulations have the force and effect of law.  If all the incorporations by reference included in the HMR were republished and reprinted word-for-word, the HMR would fill many volumes and would be very difficult to follow and to enforce.

Q6:       NFPA 58 and the HMR do not include consistent requirements for pressure testing hoses and hose assemblies.  Which regulations apply to cargo tanks transporting liquefied compressed gases?

A6:       We recognize that NFPA 58 has been adopted as law by most states.  However, the requirements of NFPA 58 are not incorporated by reference in the HMR in their entirety.  Where the requirements of NFPA 58 conflict with or are inconsistent with the requirements in the HMR, the HMR apply.  A representative from NFPA participated as a member of the negotiated rulemaking committee that developed the new cargo tank requirements under HM-225A.  It is our understanding that the NFPA 58 Committee is considering revising NFPA 58 so that it is consistent with the new requirements.

Q7:       The National Petroleum Gas Association has prepared a chart that says that when a cargo tank is remounted on a chassis, it must have appropriate emergency discharge control equipment installed.  If the cargo tank is not due for its five-year pressure test at the time of the remount, am I correct in the conclusion that installation of emergency discharge control equipment is not required until the pressure test is due?

A7:       Your understanding is not correct.  A cargo tank that is subject to the retrofit requirements in the HM-225A final rule should be equipped with emergency discharge control equipment that conforms to the requirements in § 173.315(n) if it is rebarrelled or remounted on a new chassis, whether or not its five-year pressure test is due.

Q8:       Would it be possible to state a more easily understandable definition of the requirements for protecting valves, fittings, and accessories on a cargo tank than is included in § 178.337-10(a)?

A8:       We are currently engaged in a rulemaking project to make revisions and updates to the requirements for manufacture, maintenance, and use of cargo tanks.  We expect this rulemaking to clarify and simplify many of the current requirements, including those applicable to protecting valves, fittings, and accessories.

Q9:    If a non-specification cargo tank has been retrofitted and certified as an MC 331 cargo tank, am I correct that it may be operated in interstate commerce as long as it meets all of the new requirements?

A9:    Yes.  A non-specification cargo tank may be brought into conformance with and recertified to the MC 331 specification and operated in interstate commerce.  The cargo tank motor vehicle must conform in all respects to the MC 331 specification and must be equipped with an appropriate emergency discharge control system as specified in the Hm­225A final rule.  Further, the cargo tank must be inspected, tested and maintained in accordance with the applicable requirements of Subpart E of Part 180 of the HMR.

I hope this information is helpful.  If you have further questions, please do not hesitate to contact this office.

Sincerely,

Thomas G. Allan
Senior Transportation Regulations Specialist
Office of Hazardous Materials Standards

173.315

Regulation Sections