Interpretation Response #03-0011 ([Mr. John L. Hoffer])
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name:
Individual Name: Mr. John L. Hoffer
Location State: WA Country: US
View the Interpretation Document
Response text:
Jun 20, 2003
Mr. John L. Hoffer Reference No. 03-0011
5104 - 97th Street, S.W.
Mukilteo, WA 98275
Dear Mr. Hoffer:
This is in reference to your inquiry concerning the requirements for marking a plus sign (+) on DOT 3A and 3AA cylinders as specified in § 173 .302a(b) of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). I apologize for the delay in responding.
A DOT cylinder 3A or 3AA may be marked with a plus sign (+) and filled with a listed gas to 10 percent above its marked service pressure if all requirements for testing and evaluation contained in § 173.302a(b) are met. The plus sign is required to be marked on any cylinder, including a new cylinder, when charged to 110 percent. Only a plus sign after the last (most recent) test or retest date applies. That is, as stated in your Interpretation A, the cylinder must have the plus sign stamped after each requalification retest if it is be filled to 110 percent. The requalification retest must be performed using the water jacket method.
With regard to the differences in wall stress limits, the wall stress limits prescribed in § 178.37(f)(2) for the DOT 3M cylinder must be met by the cylinder manufacturer at the time of construction. The wall stress limits prescribed in § 173.302a(b )(3) must be met at the time of each requalification retest. The HMR contain no limitations on the number of times a cylinder that meets the requirements in § 173.302a(b) may be marked with a plus sign.
I hope you find this information responsive and helpful If you have further questions, please do not hesitate to contact this office.
Sincerely,
Hattie L. Mitchell, Chief
Regulatory Review and Reinvention
Office of Hazardous Materials Standards
173.302a