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Interpretation Response #09-0067 ([Cabot Microelectronics] [Mr. Michael Trembley])

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

Interpretation Response Details

Response Publish Date:

Company Name: Cabot Microelectronics

Individual Name: Mr. Michael Trembley

Location State: IL Country: US

View the Interpretation Document

Response text:

July 20, 2009




Mr. Michael Trembley

Cabot Microelectronics

870 N. Commons Drive

Aurora, IL 60504

Ref. No. 09-0067

Dear Mr. Trembley:

This responds to your March 19, 2009 letter requesting clarification of requirements in the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to intermediate bulk containers (IBCs). Specifically, you ask if it is permissible to use vented caps to prevent hydrogen gas build up in an IBC to meet the provisions concerning venting in §173.24(g)(2).

According to your letter, you plan to use a vented cap (e.g., G2 Plug Silicone Vent #481645 or equivalent) on an IBC containing a non-hazardous, water-based product to prevent the build up of hydrogen in the head space of the container. You state that hydrogen levels in excess of the 4% Lower Explosive Limit (LEL) concentration can build up over time inside a closed container such as an IBC and suggest that the use of a vented cap would prevent this from occurring.

The answer is yes. It is the opinion of this Office that the use of a vented cap as described above to prevent hydrogen gas build up in the IBC is permissible, and does not constitute a design change that would necessitate retesting of the IBC. Please note that any change to the originally produced packaging involving structural design, size, material of construction, wall thickness, or manner of construction would constitute a design change that would require completion of the tests set forth in Subpart O of Part 178 of the HMR.

I hope this answers your inquiry.


Charles E. Betts

Chief, Standards Development

Office of Hazardous Materials Standards

173.24(g)(2), Part 178 Subpart O

Regulation Sections

Section Subject
173.24 General requirements for packagings and packages