DEPARTMENT OF TRANSPORTATION
Research and Special Programs Administration
Potential Failure of Check Valves Following Remanufacturing
AGENCY: Research and Special Programs Administration (RSPA), DOT.
ACTION: Notice; issuance of advisory bulletin.
SUMMARY: RSPA is issuing an advisory bulletin to owners and operators of Hazardous Liquid and Natural Gas Pipelines. The bulletin advises the industry about potential failure of check valves following remanufacture.
ADDRESSES: This document can be viewed on our home page at: http//ops.dot.gov.
FOR FURTHER INFORMATION CONTACT: Linda Daugherty, (202) 366-4577.
SUPPLEMENTARY INFORMATION:
I. Background:
In a recent accident, a hazardous liquid pipeline cleaning pig was late arriving at a pump station. The pig was thought to be lodged in the check valve due to the noise level at the valve. The valve was equipped with a lock open device and the wrench was locked in the open position by a bolt intended for that function. An attempt was made to remove the bolt from the operating handle on the check valve in order to exercise the valve and dislodge the cleaning pig. The wrench locking bolt was moved about one-half of a turn and the shaft unexpectedly blew out of the valve releasing liquefied petroleum gas into the environment. The on-site valve inspection indicated that the valve stem was held in place only by the locking bolt. The clapper and hinge were detached and the set screws were missing.
II. Advisory Bulletin (97-05)
To: Owners and Operators of Hazardous Liquid and Natural Gas Pipelines.
Subject: Potential Failure of Check Valves Following Remanufacturing.
Purpose: Inform system owners and operators of the need to inspect/ test remanufactured check valves.
Advisory: Recent information discovered during the course of an Office of Pipeline Safety (OPS) accident investigation indicates certain older check valves were not remanufactured within specified tolerances. Significant differences were found in several of the same type of re-manufactured check valves. All of the shafts were different and none of the valves appear to match the description given in the check valve remanufacture procedure. Additionally, the valves were assembled differently. Evaluation of other remanufactured check valves also shows evidence of improper reassembly.
Remanufactured check valves should undergo a thorough quality assessment to assure tolerances are within design parameters, particularly valves where the shaft is retained inside the valve by set screws. Operators should consider including testing or inspection as part of the quality assessment. Remanufactured check valves currently in service are included in this advisory because damage to a pipeline and release of pressurized product may occur as a result of improper remanufacturing of check valves.
OPS recommends operators also be aware of an October 20, 1997, Environmental Protection Agency (EPA) and Occupational Safety and Health Administration Joint Safety Alert (Alert) concerning a similar but unrelated problem with certain types of check and butterfly valves. According to the Alert, certain types of check and butterfly valves can undergo shaft-disk separation and fail catastrophically or "blow-out''. For more information on the Alert, visit the EPA CEPPO home page at http://www.epa.gov/swercepp/ or contact the Emergency Planning and Community Right-to-Know Hotline at 1-800-424-9346 or 703-412-9810.
(49 U.S.C. Chapter 601; 49 CFR 1.53)
Issued in Washington, D.C. on November 5, 1997.
Stacey L. Gerard,
Acting Director for Program Development.