Pipeline safety; waiver petitions: Chevron Pipe Line Co.,

[Federal Register: August 10, 1999 (Volume 64, Number 153)]

[Notices]

[Page 43422-43423]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr10au99-123]

DEPARTMENT OF TRANSPORTATION

Research and Special Programs Administration

[Docket No. RSPA-99-5442; Notice 2]

Chevron Pipe Line Company; Grant of Waiver

AGENCY: Research and Special Programs Administration, DOT.

ACTION: Notice.

Chevron Pipe Line Company (CPL) petitioned the Research and Special Programs Administration (RSPA) for a waiver from compliance with 49 CFR 19.612(b)(3), which requires that gas pipeline facilities in the Gulf of Mexico found to be exposed on the seabed or constituting a hazard to navigation be reburied so that the top of the pipe is 36 inches below the seabed.

CPL proposed to install concrete mesh blanket units to protect the pipeline from damage in lieu of the 36 inches of cover required by (192.612(b)(3)). Each concrete mesh blanket unit is a 20-foot by 8-foot by 9-inch section constructed from 160 individually cast 17-inch by 17- inch by 9-inch beveled concrete briquettes inter-connected with \3/4\- inch polypropylene UV stabilized line.

On May 27, 1999 we published a notice of petition for waver with request for comments in the Federal Register (60 FR 27809 May 25, 1995). We received two comments. The first commenter opined that the alternative to cover the line with a 9'' concrete mat did not appear to provide equal protection to the pipeline to that of 36'' of natural cover. The commenter further stated that the mat would produce a hump on the gulf floor which may create further safety risk. The second commenter expressed interest in the proposal to require a rock shield. The commenter believed that a pipe of the diameter would have been concrete coated before installation thus negating the need for any further protection of the pipe from the concrete mesh blanket units.

We have considered the concerns expressed by the commenter and agree that the concrete mat could under some circumstances pose a hazard to navigation by reducing the water depth by 9-inches. However, the potential for adverse consequences of a vessel striking the mat is less than the potential for adverse consequence for a vessel striking and rupturing a high pressure natural gas pipeline. As evidenced by repeated surveys in this area, the gulf floor consists of sugar sands which are highly susceptible to erosion. Although the concrete mats

[[Page 43423]]

would reduce the depth of water by 9-inches, the mats provide consistent penetration resistance and are designed to promote the collection of bottom silt and vegetative growth. This silt-in process is achieved by particulates dropping out of the water column as a result of reduced current flow across the mesh blankets and will add stability to the installation while building cover over the pipeline. The concrete blanket will consistently protect the line to an equal or greater degree as will 36-inches of soft, unstable natural cover.

We agree with the second commenter that the rock shield would be unnecessary if the pipeline is concrete coated. CPL confirms that the pipeline was concrete coated. Therefore we will not require a rock shield to be installed.

In consideration of the forgoing we find that the requested waiver of compliance with Sec. 192.612(c)(3) is not inconsistent with pipeline safety. Therefore the request for waiver is granted.

FOR FURTHER INFORMATION CONTACT: L.E. Herrick by telephone at 202-366- 5523, by fax at 202-366-4566, by mail at U.S. Department of Transportation, RSPA, DPS-10, 400 Seventh Street, SW, Washington, DC 20590, or via e-mail to le.herrick@rspa.dot.gov regarding the subject matter of this notice.

Authority: 49 U.S.C. 60118(c); 49 CFR 1.53.

Issued in Washington, DC, on August 5, 1999. Richard B. Felder, Associate Administrator for Pipeline Safety.

[FR Doc. 99-20539Filed8-9-99; 8:45 am]

BILLING CODE 4910-60-P