Tennessee Public Service Commission — Pipeline Safety Interpretation

Page 1PI-74-0119 May 30, 1974 Mr. John Searcy Tennessee Public Service Commission Engineering Division Cordell Hull Building Nashville, TN 37219 Dear Mr. Searcy: Thank you for your letter of May 8, 1974, asking if the requirements in sections 192.619(b) and 192.621(b) that pressure relief and limiting devices installed under those sections be installed in accordance with section 192.195 apply to pipelines constructed before November 12, 1970, since otherwise section 192.195 does not apply to pipelines constructed before that date. Sections 192.619 and 192.621 govern the operation of pipelines used in the transportation of gas. Under the Natural Gas Pipeline Safety Act of 1968 (Act), standards governing the operation of pipelines apply to pipelines existing when the standards are adopted as well was to pipelines constructed thereafter. Sections 192.619 and 192.621 were adopted on November 12, 1970, and apply to pipelines existing on that date. You are correct that section 192.195 does not apply to pipelines constructed before November 12, 1970. This section is a design requirement which under the Act may not apply to pipelines existing when the standard was adopted on November 12, 1970. However, as referenced in sections 192.619(b) and 192.621(b), the provisions of section 192.195 govern the operation of pipelines rather than design and are, therefore, a permissible regulation of existing pipelines. We trust this satisfactorily responds to your inquiry. Sincerely, Joseph C. Caldwell Director Office of Pipeline Safety#

Page 2May 8, 1974 Mr. Joseph C. Caldwell, Director Office of Pipeline Safety Department of Transportation 2100 2nd Street, SW Washington, D. C. 20590 Dear Mr. Caldwell: 192.195(a) requires pressure relieving or limiting devices to prevent a maximum allowable operating pressure from being exceeded. 192.195, however, is not retroactive to existing pipelines installed prior to November 12, 1970, unless changes have been made after that date. 192.619(b) and 192.621(b) refer to 192.195, and are retroactive. Can it be concluded therefore that, where 192.619(b) and 192.621(b) apply, 192.195 is retroactive and pressure relief or limiting devices can be required on pipelines installed prior to November 12, 1970. If 192.195 is not retroactive as described above, is there another section in the Minimum Safety Standards which is retroactive and requires pressure relief or limiting devices on pipelines installed prior to November 12, 1970? Sincerely, John Searcy Engineering Division#