Pipeline and Hazardous Materials Safety Administration (PHMSA); DOT.
Notice; Issuance of Advisory Bulletin.
The Pipeline and Hazardous Materials Safety Administration (PHMSA) reminds pipeline owners and operators of the importance of installing weldable compression couplings in accordance with manufacturer procedures and following appropriate safety and start-up procedures. The failure to install weldable compression couplings correctly, or the failure to implement and follow appropriate safety and start-up procedures, could result in a catastrophic pipeline failure. PHMSA strongly urges operators to review, and incorporate where appropriate into operators' written procedures, the manufacturer's installation procedures and take any other necessary safety measures for safe and reliable operation of pipeline systems.Start Further Info
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In 2007, a crude oil release occurred during maintenance activities on a major oil pipeline. The escaping crude oil ignited and resulting in two fatalities. When this incident occurred the operator was performing a pipe replacement using pre-tested pipe and weldable compression couplings. The failure occurred during start-up operations when the forces associated with pipeline operations exceeded the restraining capability of the unfinished replacement assembly. As pressure increased, movement of the piping occurred resulting in the eventual separation of the pipe from the weldable compression coupling. There was sufficient mechanical breakdown and the escaping crude oil created a flammable vapor-air mixture which ignited a few seconds after the release began. The pipeline was being re-started to allow for welding of the compression couplings to the pipe when the release occurred. The failure occurred while pressure and flow were increasing.
The weldable compression couplings use radial bolts (clamp screws) to attach the compression coupling to the surface of the pipeline. Once attached, longitudinal bolts apply pressure to a steel ring and neoprene seal which expands, providing a compressive seal between the weldable compression coupling and exterior surface of the pipe. The compression couplings are designed to be fillet welded to the pipe surface after bolting and sealing, making them a permanent welded repair.
In the above referenced incident, the weldable compression couplings had been modified prior to the installation by cutting off approximately half of the clamping bolts which reduced the restraining capability of the replacement assembly. The manufacturer's installation procedures did not authorize this modification. In addition, operators' procedures specific to the installation of compression couplings must provide sufficient guidance for their employees to determine whether a pipeline is fully anchored prior to welding. In the above referenced incident, the manufacturer's literature described a pipeline in the anchored condition as being “restricted from movement in all directions” and the operating pressure chosen by the operator to be sustained for welding was based on the manufacturer's recommendation for a fully anchored installation. However, the physical Start Printed Page 50273characteristics of the installation indicated that it was not fully anchored and that it needed to be limited to a much lower maximum safe working pressure. Operator personnel must be specifically trained and qualified for the installation of weldable compression couplings including ensuring that the extent to which the pipeline is not fully anchored is taken into account when determining the maximum safe working pressure.
To ensure safety, pipeline operators using weldable compression couplings must ensure personnel are trained and qualified to perform the installation. Also, operators must ensure their procedures accurately incorporate manufacturers' procedures and limitations on the use of weldable compression couplings and ensure that the procedures are available, understood and followed by personnel. PHMSA believes that the risk of compromising safety posed by unauthorized modifications to weldable compression couplings is unacceptable. PHMSA strongly recommends that any field changes in the installation process (i.e., modifications allowed by a component manufacturer) that could affect component performance and safety be subject to a documented authorization process, communicated to appropriate personnel, and be reflected by allowable working pressures. Allowable working pressures vary greatly between anchored and un-anchored installations. In order to use the pressure rating for an anchored installation, the operator must verify the pipeline is anchored in all directions in accordance with company and manufacturer procedures prior to pipeline start-up. To ensure safety for personnel, property and the environment, pipeline start-up procedures must be available and followed. Finally, any failure to identify and restrict access to hazard zones during pressurization of exposed pipeline sections could compromise safety.
II. Advisory Bulletin ADB-09-02
To: Owners and Operators of Hazardous Liquid and Natural Gas Pipelines.
Subject: Weldable Compression Couplings.
Advisory: The Pipeline and Hazardous Materials Safety Administration (PHMSA) advises operators of hazardous liquid and natural gas pipelines installing or planning to install weldable compression couplings and similar repair devices to follow manufacturer procedures to ensure correct installation. In addition, PHMSA also advises these operators to follow the appropriate safety and start-up procedures to ensure the safety of personnel and property and protect the environment. The failure to install a weldable compression coupling correctly, or the failure to implement and follow appropriate safety and start-up procedures, could result in a catastrophic pipeline failure. PHMSA strongly urges operators to review, and incorporate where appropriate into operators' written procedures, the manufacturer's installation procedures and any other necessary safety measures for safe and reliable operation of pipeline systems.Start Signature
Issued in Washington, DC September 23, 2009.
Jeffrey D. Wiese,
Associate Administrator for Pipeline Safety.
[FR Doc. E9-23527 Filed 9-29-09; 8:45 am]
BILLING CODE 4910-60-P