PDFWAC 480-75-640

Depth-of-cover survey.

For pipelines constructed after April 1, 1970, each pipeline company must conduct a depth-of-cover survey in its pipeline rights of way every five years to ensure the minimum depth-of-cover as required by subsections (1) and (2) of this section has been maintained for the entire pipeline. In areas subject to erosion and subsoiling, the survey must be conducted every three years.
(1) Unless specifically exempted in this section, each pipeline company must bury all pipe so that it is below the level of cultivation. Except as provided in subsection (2) of this section, the pipe must be installed so that the cover between the top of the pipe and the ground level, road bed, river bottom, or sea bottom, as applicable, complies with the following table:
Location
Cover
(inches)
For normal excavation
Cover
(inches)
For rock excavation
Industrial, commercial, and residential areas
36
30
Crossings of inland bodies of water
with a width of at least 100 ft. from high water mark to high water mark
48
18
Drainage ditches at public roads and railroads
36
36
Deepwater port safety zone
48
24
Any other area
30
18
Note:
Rock excavation is any excavation that requires blasting or removal by equivalent means.
(2) Cover less than the minimum required by subsection (1) of this section may be used if:
(a) It is impracticable for the pipeline company to comply with the minimum cover requirements; and
(b) The pipeline company provides additional protection equivalent to the minimum required cover.
[Statutory Authority: RCW 80.01.040, 80.04.060, 81.88.040. WSR 08-12-045 (Docket PL-070974, General Order R-548), § 480-75-640, filed 5/30/08, effective 6/30/08. Statutory Authority: RCW 80.01.040 and 80.04.160. WSR 02-18-032 (Docket No. TO-000712, General Order No. R-500), § 480-75-640, filed 8/26/02, effective 9/26/02.]