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Interpretation Response #19-0051

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

Interpretation Response Details

Response Publish Date: 10-15-2019
Company Name: The Hartford Steam Boiler Inspection and Insurance Co.    Individual Name: Oberst Mulet
Location state: CT    Country: US

View the Interpretation Document

Response text:

October 15, 2019

Oberst Mulet
CT Engineer II
The Hartford Steam Boiler Inspection and Insurance Co.
1 State Street
P.O. Box 5024
Hartford, CT  06102-5024

Reference No. 19-0051

Dear Mr. Mulet:

This letter is in response to your April 16, 2019, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to DOT 3AL seamless aluminum cylinders. Specifically, you ask whether the words "significant change" as used in § 178.46(c)(6) means an increase or decrease of the given criteria or just an increase in water capacity or base thickness, or the number of openings.

Section 178.46(c)(6) defines "significant change" applicable to DOT 3AL seamless aluminum cylinders as a 10% or greater change in cylinder wall thickness, service pressure, or diameter; a 30% or greater change in water capacity or base thickness; any change in material; over 100% increase in size of openings; or any change in the number of openings. The word "change" in the above paragraph means either an increase or decrease, meaning a "30% or greater change in water capacity" could be a 30% increase or a 30% decrease. Any of the above conditions would result in the change being considered significant for the purposes of § 178.46(c)(6).

I hope this information is helpful. Please contact us if we can be of further assistance.


T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division


Regulation Sections

Section Subject
§ 178.46 Specification 3AL seamless aluminum cylinders