Interpretation Response #PI-80-002

Interpretation Response Details

Office of Pipeline Safety
911 Walnut Street
Room 1802
Kansas City, MO 64106

Gentlemen:

This letter is in reference to DOT Regulations for the Transportation on Liquids by Pipeline - Part 195, Section 195, Section 195.416(c) concerning inspection of cathodic protection rectifiers.

We are currently studying the feasibility of monitoring the status of our mainline rectifiers by installing a receiver in our weekly patrol plane in conjunction with a transmitter in each rectifier. The transmitter would be preset to turn off if the current output to the groundbed fell below a predetermined acceptable value. The receiver would emit an audible tone if the transmitter were operating. Should a rectifier transmitter be off, its number would be logged on the line flyer report and a man would be dispatched to investigate the problem.

We would like to know whether this type of surveillance could be used to satisfy the two month inspection criteria outlined in Section 195.416(c). This type of inspection would greatly reduce the manhours spent in rectifier monitoring.

Your prompt response to this inquiry would be appreciated since we would like to implement this program as soon as possible.

Your very truly,

E. Hobson
Electrical Engineer

Mr. E. Hobson
Dome Pipeline Corporation
District Office
P.O. Box 1430
Plaza Centre One
Iowa City, Iowa 52240

Dear Mr. Hobson:

This is in reply to your letter dated June 14, 1979. We regret the delay in responding to your letter which we inadvertently mislaid for a period of time. You requested a finding concerning section 195.416(c); specifically, whether equipping rectifiers with transmitters to indicate current flow above a certain level and detecting this operation by a receiver in a patrol aircraft constitutes compliance with this subsection. Please be advised that the intent of section 195.416(c) is to ensure that the rectifiers are functioning and that your proposal meets this intent.

We commend you on your resourcefulness in developing methods to monitor cathodic protections.

Sincerely,

/signed/

Cesar De Leon
Associate Director for
Pipeline Safety Regulation
Materials Transportation Bureau

Regulation Sections