Conoco Inc. — Pipeline Safety Interpretation

Page 1PI-92-0100 February 7, 1992 Mr. Lyman Toews Director, Regulatory Compliance Conoco Inc. P.O. Box 2197 Houston, TX 77252 Dear Mr. Toews: This responds to your letter of August 19, 1991, concerning inspections of underwater pipeline crossings of navigable waterways. You asked whether the use of divers to probe with rods to detect the depth of cover over these crossings is an acceptable method of inspection under § 195.412. Of particular concern were pipelines buried so deeply that their depth of cover exceeds the length of the rod. Section 195.412 (b) provides: "Except for offshore pipelines, each operator shall, at intervals not exceeding 5 years, inspect each crossing under a navigable waterway to determine the condition of the crossing." Since this rule does not specify the method of inspection, any method is acceptable if it enables the operator to learn with reasonable reliability the condition of the crossing. We consider the use of divers to probe with rods along the length of the crossing to be an acceptable method of inspection for all underwater crossings. The divers can visually check any uncovered portions of the crossing for damage or for potential damage from drifting debris, such as logs or rocks. For covered portions, the divers can note the depth of burial or that the depth exceeds the rod length. From this information, an operator can decide if the crossing needs repair, or if it needs additional protection against reasonably anticipated external forces. I am sorry we were not able to answer your letter sooner. However, please let me know if you have further questions on this topic. Sincerely, Original signed by Cesar De Leon Director, Regulatory Programs Office of Pipeline Safety#

Page 2Conoco Inc. P.O. Box 2197 Houston, TX 77252 August 19, 1991 Mr. Cesar De Leon Research and Special Programs Administration Department of Transportation Room 8417 400 Seventh Street, S.W. Washington D.C. 20590 Dear Mr. De Leon: This letter is to request an interpretation of the DOT regulations concerning the inspection of crossings under navigable waters per DOT 195.412. The usual practice for inspection of crossings under navigable waters is to dispatch divers to identify the depth of the pipeline in relation to the water bottom by using pipe probes or rods. The diver will push the pipe probe into the soil until the pipe is felt. The depth of the pipeline below the soil surface is then noted. This inspection practice is to identify any pipe that does not have adequate soil cover to prevent damage by any vessels or other reasonably predictable erosion activity. Recently several river crossings have been installed using a directional drilling method as opposed to the trench-and-lay method. The directional drilling method allows the pipe to be installed at much greater depths under the bed of the river. These depths can exceed the ability of divers to locate the pipeline using probes. Therefore probing for the pipeline can only verify the pipeline depth within the probe's length or that the pipe is deeper than the pipe probe. It is our interpretation that the use of divers and pipe probes is an adequate inspection method for all navigable water crossings. Whenever the pipeline cannot be detected by probes due to the pipeline's depth, the pipeline has adequate cover and no further inspection activities are required until the next scheduled inspection or unless other evidence indicates that an intermediate inspection is required (such as evidence of excessive erosion). Please review our interpretation of inspection of crossings under navigable water and indicate whether or not this is an acceptable practice and interpretation of the regulations. Should you have any questions, please call me at (713) 293-4864. Thank you for your consideration of this matter. Lyman Toews Director Regulatory Compliance#