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Interpretation Response #14-0147 ([Gayston Corporation] [Mr. Christopher A. Cornelius])

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

Interpretation Response Details

Response Publish Date:

Company Name: Gayston Corporation

Individual Name: Mr. Christopher A. Cornelius

Location State: OH Country: US

View the Interpretation Document

Response text:

March 25, 2015

Christopher A. Cornelius
Gayston Corporation
Director of Quality
200 Advance Drive
Springboro, OH 45066

Reference No. 14-0147

Dear Dr. Cornelius:

This is in response to your July 21, 2014 letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the calculation of the tare weight of cylinders. Specifically, you seek an interpretation of § 178.35(c)(3)(vii) as it pertains to the process by which you report the tare weight and volumetric capacity of a specification cylinder during the manufacturing process.

In your incoming letter, you propose to determine the tare weight of the cylinder prior to conducting the hydrostatic testing. This information is collected and summarized by a lot code and the highest tare weight (i.e. the heaviest part) would then be used to determine the volumetric capacity for the entire lot of cylinders. You ask if it is permissible to gather the tare weight prior to hydrostatic testing.

The answer is yes. The HMR does not specify when in the manufacturing process the tare weight of the cylinder must be determined. Determining the tare weight of the cylinder prior to conducting the hydrostatic test is not prohibited. In addition, using the maximum tare weight in a specific lot as the marked tare weight is not forbidden provided that the tare weight and volumetric capacity measured under § 178.35(c)(3)(vii) are accurate and not affected by any other test conducted on the cylinder. However, caution is advised since marking the cylinder with the maximum tare weight instead of the actual weight could result in cylinder underfilling, errors during requalification, or other recordkeeping issues.

I hope this satisfies your request.


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


Regulation Sections

Section Subject
178.35 General requirements for specification cylinders