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Interpretation Response #PI-14-0010

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

Interpretation Response Details

Response Publish Date: 09-03-2014
Company Name: Technical Response Planning Corp    Individual Name: Mr. Greg Desmond
Location state: TX    Country: US

View the Interpretation Document

Response text:

Mr. Greg Desmond
Senior Project Manager
Technical Response Planning Corp
1610 Woodstead, Suite 355
The Woodlands, TX 77380

Dear Mr. Desmond:

In an email to the Pipeline and Hazardous Materials Safety Administration (PHMSA) dated November 4, 2013, you asked for an interpretation of the five percent reduction offered for tertiary containment of breakout tanks when determining a worst case discharge.

Under Title 49 Code of Federal Regulations § 194.105, operators of onshore pipeline facilities may claim prevention credits for breakout tanks that contain oil. These credits correspond to secondary containment and other specific spill prevention measures. One of the other specific spill prevention measures is tertiary containment. Under § 194.105(b)(4), operators can claim a five percent credit for a tertiary containment system.

The definition of the word "tertiary" is in the place or position counted as number three. The main purpose of a tertiary containment system is to prevent the release of oils from breakout tanks to the environment in the event of a failure of both the primary and secondary containment systems. Thus, it is the number three or third line of protection. Additionally, it would be employed to contain leakage, a product release, and drainage. In this case, it is intended to assure that the operator does not lose control of the petroleum product and drainage because of such an event. It also allows time for additional measures to be deployed if an incident escalates.

The tank, in these circumstances, would be the primary containment system, while a diked or remote impoundment would be the secondary. A remote or diked impoundment comprised of various combinations such as site drainage, sumps, diversion tanks, pits, ponding areas, lagoons, and/or impervious liners would be considered the tertiary containment.

Therefore, PHMSA's interpretation of a tertiary containment system is an impoundment (a National Fire Protection Association's (NFPA) term) that is installed in accordance with NFPA 30 and is outside of a secondary containment that complies with 49 CFR 194.105(b).

If we can be of further assistance, please contact Tewabe Asebe of my staff at (202) 366-5523.


John A. Gale
Director, Office of Standards
and Rulemaking

Regulation Sections

Section Subject
§ 194.105 Worst case discharge