Interpretation Response #23-0106
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: ATECH Engineering
Individual Name: Edward Mansell
Location State: MO Country: US
View the Interpretation Document
Response text:
May 31, 2024
Edward Mansell
ATECH Engineering
116 W. Wakefield Ave.
Sikeston, MO 63801
Reference No. 23-0106
Dear Mr. Mansell:
This letter is in response to your December 18, 2023, letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to cylinder specifications. Specifically, you ask questions about the requirements for the heads on Department of Transportation (DOT) 4BW welded steel cylinders with electric-arc welded seams found in § 178.61(b)(2).
We have paraphrased and answered your questions as follows:
Q1. You ask whether the heads on DOT 4BW welded steel cylinders with electric-arc welded seams need to meet the specification requirements in Table 1 of Appendix A to Part 178—Specifications for Steel.
A1. Per the requirements of § 178.61(b)(2), the heads for DOT 4BW welded steel cylinders with electric-arc welded seams must conform to the specifications in Table 1 of Appendix A to Part 178—Specifications for Steel, or the alternative specification requirements for heads as provided in § 178.61(b)(2).
Q2. You ask for confirmation that the composition limit for "Carbon" indicated in Table 1 of Appendix A to Part 178—Specifications for Steel, is a maximum limit for each grade. You also ask whether there is any relation to the requirements in § 178.61(b)(2).
A2. Table 1 of Appendix A to Part 178—Specifications for Steel, lists three grades for steel, with ranges or maximum composition limits of "Carbon" for each grade. Grade 1 lists a minimum and a maximum composition limit for "Carbon", while grade 2 and grade 3 list only the maximum composition limit for "Carbon". The steel requirements in § 178.61(b)(1) apply to all parts (shell and heads) of the cylinders whereas § 178.61(b)(2) provides alternative steel composition for the construction of heads on DOT 4BW cylinders.
Q3. You ask whether the low carbon steel for the heads of DOT 4BW cylinders referenced in § 178.61(b)(2) is the same steel referenced in Table 1 of Appendix A to Part 178—Specifications for Steel.
A3. The answer is no. The term "low carbon steel" listed in § 178.61(b)(2) is not a reference to the steel in Table 1 of Appendix A. If low carbon steel, as referenced in § 178.61(b)(2), is used to make DOT 4BW cylinder heads, it must comply with the alternative steel composition requirements as detailed in the same subparagraph. Additionally, the thickness of such heads must be determined by using a maximum wall stress of 24,000 psi in the formula described in § 178.61(f)(2).
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
Steven Andrews
Acting Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division
178.61(b)(2), 178.61(b)(1), 178.61(f)(2)