PSA Promotes Better Mooring

For the past year, the Petroleum Safety Authority Norway (PSA) has noted several improvements in the area of mooring. However, there are still many incidents that could have been averted through better systems for training and sharing experience.

On Monday, the PSA organized an industry seminar to exchange experience and promote a debate regarding incidents and measures implemented over the past two years.

The number of chain deployments, breakage in chains, couplings and fiber lines remains high. The PSA sees a need for better securing of necessary holding power in the anchors, and takes a positive view of the fact that the industry has now started to test the use of preinstalled anchors. The Safety Forum has adopted safer mooring as a new high-profile issue.

The Norwegian Shipowners Association is responsible for this issue and has prepared concrete goals intended to reduce the number of incidents. The PSA is monitoring the effectiveness of this program with great interest.

The contribution made by management in the various companies is among the PSA's priority commitment areas. Management involvement in preventing major accidents must also include shipping companies that operate mobile facilities and vessels. Management's responsibility for organizational factors, training of personnel and technical factors must be emphasized.

Important work is also being done in the vessel industry to improve working conditions for groups at risk. The use of new technology means that the crew is less exposed to risky work operations on the deck of the vessel. The industry has developed and is in the process of implementing various types of remote-controlled equipment and tools that enable crews to stay in safe areas.

In the same manner as the drilling industry has largely succeeded in automating operations on the drill floor, a comparable effort is needed for crews exposed to risk on the deck of the vessel.

The comprehensive effort to replace older chains in the past year is a positive development, in the opinion of the PSA. Fatigue breaks in anchor chains are caused by the chain being used too long, or that it has been exposed to damage, such as loose stud links.

As regards the latter, there have also been breaks in newer chains. The inspections and repairs in connection with certification and recertification are essential for the chain to meet the applicable quality requirements. This year, the PSA has intensified requirements for inspection of chains that are more than 20 years old.

Before an anchor is used at a location, the anchor is subjected to a test load. For a number of years, this test load has been too light, which drags the anchor. Experience has shown that anchor dragging can lead to breakage in the neighboring line. Drilling facilities are often moored in areas where there are many subsea facilities, so that dragging could damage other facilities.

The test loads have increased, and no anchor dragging incidents have been recorded in the past year. It is positive that analyses are being made of the consequences of dragging so that this risk can be managed. Checks to ensure that the anchor has been properly set have improved significantly.

Many of the mooring incidents on the shelf have occurred when the facility was connected to the well, or moored alongside another facility. The shipowner is responsible for the equipment on the facilities, and this is followed up through the AoC system. The operator is responsible for the site-specific evaluation, and this is followed up through the consent process.