Equinor’s internal investigations following the fires at Hammerfest LNG and Tjeldbergodden have now been concluded and the results submitted to the Petroleum Safety Authority.
The fire at Hammerfest LNG occurred on 28 September2020, while the fire at Tjeldbergodden took place on 2 December 2020. “Both fires at the onshore facilities in 2020 were very serious. These incidents have made a deep impression on everyone who was involved or affected. The emergency response effort helped ensure that no-one was injured. I want to commend the efforts and commitment exhibited by our employees, suppliers, and the local communities to return the facilities to safe operation,” says Irene Rummelhoff, Equinor’s Executive Vice President, Marketing, Midstream & Processing.
The incidents in 2020 triggered a comprehensive improvement effort within safety at the onshore facilities.
- 175 different departments at the onshore facilities have conducted time-outs for safety to reflect on improvement items and weak signals.
- The OPL Next Step project involves continued work on initiatives from time-out for safety, as well as improvement areas identified following audits, investigations, and internal verifications.
- A project has also been set up to capture lessons learned and establish measures linked to underlying causes related to organisation, management, and control.
- We are implementing new management training programmes for more than 180 managers at the onshore facilities.
- Analyses of the entire onshore facility organisation are in progress to identify measures within the areas of capacity and competence that can strengthen safety.
- The company is bolstering its recruitment of engineering resources within electrical disciplines and up to 50 skilled workers are bound for the onshore facilities. Additional efforts aimed at other recruitment in general will be assessed as needed.
“The safety delegate service at Equinor’s onshore facilities takes a very serious view of the incidents last year, and is ready to contribute as a constructive collaboration partner to further enhance safety. Generally speaking, the safety delegate service in the company’s onshore organisation is well-equipped to carry out its role in relation to a fully prudent working environment. We take a positive view of the work now initiated with a focus on the root causes of our challenges. This takes place in a joint effort via working groups composed of the various parties, where we look forward to contributing with a particular focus on the framework conditions for safe operations and safe work,” says co-ordinating Senior Safety Delegate in the Equinor ASA Onshore Organisation, Lars Christian Kronstadt, on behalf of the safety delegate service at the onshore facilities in Equinor ASA.
The fire at Tjeldbergodden – 2 December 2020:
During a routine job at Tjeldbergodden on 2 December, a steam turbine failed to shut down as expected and instead increased its speed. This led to a breakdown in a coupling between the steam turbine and a gear, which resulted in heavy metal parts being flung out. One of these made a hole in a pipe carrying lube oil to the turbine generator. The lube oil ignited and caused the fire. No one was injured in the incident.
The investigation group confirms that, under slightly altered circumstances, the outcome of the Tjeldbergodden incident could have been very serious, such as leakage and explosion of syngas. The potential included multiple fatalities, as several people were near the building where the fire occurred, at that particular time.
Equinor’s internal investigation group has concluded that the steam turbine sped up due to a fault in connection with a shut-off valve in the turbine.
The valve is supposed to close automatically if the flow changes direction, thus stopping the turbine. If that does not happen, an extra safety device will close the valve. However, on 2 December, both of these solutions failed, causing a continued supply of steam to the steam turbine after all connected equipment was stopped.
The shut-off valve was classified as non-safety-critical in 2004, as it was a valve for steam and not hydrocarbons. Based on this, a maintenance programme was prepared in accordance with this classification. It was not discovered during operations or in connection with third-party verification that the criticality assessment should have been higher. The maintenance programme has been followed up in accordance with the criticality assessments that were made.
A repair of the shut-off valve was conducted a month and a half prior to the incident. Since the shut-off valve was incorrectly classified in 2004 with low criticality as regards safety, the shut-off valve was repaired at Tjeldbergodden rather than keeping the turbine generator shut down.
The investigation also indicates a weakness as regards design. When the facility was planned in the 1990s, the steam turbine was located in the same building as the syngas unit.
All shut-off valves on steam turbines are now defined as safety-critical, and will be inspected after the incident at Tjeldbergodden. The investigation group proposes the following learning needs following this incident:
- Increase and maintain steam turbine expertise in Equinor.
- Reduce risk of breakdown of steam turbines by e.g. ensuring that sufficient preventive maintenance is carried out on critical valves.
- Evaluation of measures to prevent fragments, resulting from the breakdown of rotating equipment, from causing escalation in their surroundings, including the syngas compressor.
- The methanol plant at Tjeldbergodden resumed production on 20 February 2021, without operation of the steam turbine.
The fire at Hammerfest LNG – 28 September 2020:
During start-up of the facility, a fire occurred in the filter housing on gas turbine generator 4 at Hammerfest LNG. The investigation group notes that the cause of the fire was spontaneous ignition in the filters in the turbine’s air inlets, caused by excessively high temperature over a long period of time.
The anti-icing heat exchanger in the air inlet was used outside of its intended area of application, thus causing the high temperature that triggered the fire. The investigation group does not believe that the maintenance interval for exchanging the filters that self-ignited is a contributing cause.
No-one was injured in the incident. The fire was restricted to the filter housing on gas turbine generator 4 and the investigation group concludes that there was no major accident potential as regards personal injuries. Both the PSA report and Equinor’s own investigation confirm that the fire was unlikely to spread to other parts of the facility. The extinguishing efforts undertaken based on the precautionary principle, and in line with the applicable emergency preparedness principles, entailed extensive damage to parts of the facility.
In April, Equinor reported that the facility would remain closed until March 2022 due to the scope of the repairs needed to restore the facility to safe production.
Equinor has initiated modifications to the air intakes in the turbines to prevent similar incidents from occurring.
The incident was not caused by a single technical or human error, but was the result of several direct and underlying factors.
The investigation has considered underlying causes related to organisation, capacity, competence, and management. The findings will be followed up in a dedicated improvement initiative in Equinor.
Equinor is following up the findings in the internal investigation report within:
- Use of the anti-icing system, alarm and shutdown functions, as well as valves in hot oil return.
- Emergency preparedness management and training.
- Organisation, management ,and control.
Equinor is also following up all the orders and nonconformities in the Petroleum Safety Authority’s investigation of the fire, and will present a plan to the PSA for complying with the orders by 1 June 2021.
Read the article online at: https://www.lngindustry.com/liquid-natural-gas/12052021/equinor-concludes-investigation-into-fires-hammerfest-lng-and-tjeldbergodden-facilities/