Interpretation Response #12-0121
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
AUG 16 2012
The Honorable Deborah A.P. Hersman
National Transportation Safety Board
490 L"Enfant Plaza, SW
Washington, DC 20594
Ref. No.: 12-0121
Dear Chairman Hersman:
Thank you for your May 4, 2012 letter requesting clarification of the inspection and maintenance requirements for the discharge system on a cargo tank motor vehicle in liquefied compressed gas service under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). Specifically, you request clarification of the meaning of "in service" as it applies to the monthly inspection of a delivery hose assembly (i.e., "a cargo transfer hose assembly") under § 180.416(d)(1).
As part of an investigation of an accident involving the rupture of a hose used to transfer anhydrous ammonia, the National Transportation Safety Board (NTSB) included among its findings the belief that lack of clarity of § 180.416(d)(1) regarding monthly inspections of each "in service" hose assembly can lead a cargo tank motor vehicle operator to mistakenly defer monthly inspections. The NTSB concluded that "if a motor carrier does not believe that [a hose assembly] will be used, it will not necessarily consider it to be "in service" and as a result, the hose assembly may not be inspected, as was the case in this accident." It is the understanding of NTSB that a hose assembly carried on a cargo tank motor vehicle has the potential to be used on any given day, and consequently, is "in service." Therefore, in order to provide greater clarity of the monthly inspection requirement of a hose assembly installed or carried on a cargo tank, in its Safety Recommendation H-12-5, the NTSB requests that PHMSA provide an interpretation of when a hose assembly is "in service."
Your understanding is correct. A hose assembly installed or (to be) carried on a cargo tank motor vehicle in liquefied compressed gas service must be inspected monthly regardless of whether it is used in any given month. Although a hose assembly must be checked prior to each unloading operation, this check involves only those components readily visible (see § 177.840(m)). The requirement of § 180.416(d)(1) ensures that at least once a month each hose assembly assigned to a cargo tank motor vehicle in liquefied compressed gas service will undergo a thorough visual inspection whether or not it has been used. "In service" as used in § 180.416, is associated with qualification and maintenance for purposes of hazardous materials transportation and should not be misconstrued as "in use." Just as a cargo tank in liquefied compressed gas service is subject to inspection and testing requirements and must be removed from hazardous materials service (i.e., placed out of service) if it fails a test or inspection, a hose assembly must be inspected and tested, and removed from service according to rejection criteria found in § 180.416. A repaired hose assembly successfully retested in accordance with § 180.416(f) may be placed back in service and then must again be inspected monthly regardless of whether it is used in any given month.
If I can provide further information or assistance, please feel free to contact me.
Charles E. Betts
Director, Standards and Rulemaking Division
|§ 177.840||Class 2 (gases) materials|