USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #15-0102 ([Mallinckrodt Pharmaceuticals, formally Ikaria, Inc.] [Mr. Juan Miró])

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

Interpretation Response Details

Response Publish Date:

Company Name: Mallinckrodt Pharmaceuticals, formally Ikaria, Inc.

Individual Name: Mr. Juan Miró

Location State: LA Country: US

View the Interpretation Document

Response text:

December 8, 2015

Mr. Juan Miró
Project Manager, Engineering Department
Mallinckrodt Pharmaceuticals, formally Ikaria, Inc.
1060 Allendale Dr.
Port Allen, LA 70767

Reference No. 15-0102

Dear Mr. Miró:

This is response to your May 22, 2015 e-mail requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to filling Department of Transportation (DOT) specification cylinders. In your e-mail, you ask whether it is permissible to overfill a cylinder by 350 psia during the filling process to compensate for losing 350 psia when detaching the cylinder from the gas transfer system. The final pressure after the cylinder is ejected from the filling nozzle is below the marked service pressure.

The filling of the cylinder must comply with the applicable requirements in Part 173 Subpart G of the HMR. This subpart does not address the variation in pressure during the filling process. Section 173.301a(c) states that when offered for transportation, the pressure in a cylinder at 21 °C (70 °F) must not exceed the service pressure for which the cylinder is marked or designated, except as provided in § 173.302a(b) of the HMR. Except as otherwise provided in § 173.301a(d), the pressure in a cylinder may not exceed 5/4 times the service pressure at 55 °C (131 °F) when the cylinder is offered for transportation. Therefore, your operating procedures must ensure that these requirements are met when the cylinder is offered for transportation.

I hope this satisfies your request.



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

173.301a(c), 173.302a(b), 173.301a(d)

Regulation Sections

Section Subject
173.301 General requirements for shipment of compressed gases and other hazardous materials in cylinders, UN pressure receptacles and spherical pressure vessels
173.302 Filling of cylinders with nonliquefied (permanent) compressed gases or adsorbed gases