On 22 October 2024, fire broke out in the high-voltage room in the M40 module on Equinor’s Sleipner B facility. On the same day, Havtil decided to investigate the incident and asked the police to assist in its investigation.
Sleipner B is a production platform on the Sleipner field. The facility is controlled remotely from Sleipner A, with personnel from operations and maintenance periodically on board. When the fire occurred, there was no-one on board Sleipner B, and the incident was handled by the emergency response management on Sleipner A.
After the first of several smoke alarms in the high voltage room of the M40 module went off at 04:35, emergency response management was mobilised, notification was made in accordance with the emergency response plan and an emergency response vessel was summoned.
Sleipner B was shut down and depressurised, the platform was de-energised and was then on an uninterruptible power supply (UPS).
A team of seven people was mobilised on Sleipner A to travel over to Sleipner B to obtain an overview of what had happened. They were to check the switchboard room and vent smoke observed on camera, as well as restore UPS charging.
Based on what has emerged during the investigation, it appears that a lot of attention was paid to Sleipner B’s imminent loss of power (UPS), and that this affected the actions taken and decisions made.
The team on Sleipner B reported to Sleipner A that they could not find any obvious cause of smoke, leading the emergency response management to consider that the situation was under control.
On Sleipner B, they attempted to restore the power supply, when a new smoke development occurred. The power supply was again shut off and the team on board withdrew and returned to Sleipner A. The last smoke observation was approximately 13 hours after the first smoke detection and preventative cooling was terminated after approximately 17 hours.
The equipment that burned in the high-voltage room was a Variable Speed Drive (VSD), a device that regulates the speed of the electric motor that powers the export gas compressor.
Actual and potential consequences
The actual consequence of the incident was material damage and a long production shutdown.
The material damage resulting from the fire was a destroyed VSD, smoke and soot damage in the rest of the high-voltage room, as well as some smoke and soot damage in nearby rooms. In addition, thermal insulation in a ceiling above the VSD was destroyed.
In addition to the damage from the fire, there were also substantial material damage to the facility from firefighting (FIFI) systems for cooling the area.
In the investigation, we assessed that there was little risk of the fire spreading beyond the module it was in.
As there were no personnel on board, we have assessed that there was no danger to the life and health of personnel.
Direct and underlying causes
The direct cause of the fire is uncertain. We know that there was a cooling water leak, but we are uncertain as to whether this was before the fire, or a consequence of it. Our assessment is that the most likely cause of the fire was an electrical fault in the VSD, but based on investigations in the room and various logs, we cannot say with certainty what the direct cause of the fire was.
We assume that the fire developed because two fire doors into the high voltage room were opened for ventilation and/or because the voltage from the Sleipner A was reapplied.
Given that there is uncertainty as to the direct cause of the fire, there is also uncertainty concerning any underlying causes. Heat production and cooling water leakage were observed internally in the VSD, but it is uncertain whether the heat production caused the cooling water leakage or was the result of it.
Non-conformities
In the investigation, we identified seven non-conformities. These were:
- Deficient management of risk and technical solutions
- Deficiencies in handling of hazard and accident situations
- Deficiencies in firewall
- Missing navigation light
- Documentation not updated
- Deficiencies in ventilation
- Inadequate facility-specific training and drills
Suggestion for amended guideline text
The incident at Sleipner B has led the investigation group to produce a proposal to change the guideline text to section 37 of the Facilities Regulations on fixed fire-fighting systems on facilities that are not permanently manned.
Order
The investigation identified serious breaches of the regulations; see, in the report, non-conformity 12.1.1 (deficient management of risk and technical solution), non-conformity 12.1.2 (deficiencies in handling of hazard and accident situations) and non-conformity 12.1.7 (inadequate facility-specific training and drills).
On this basis, we have issued Equinor with the following order:
Pursuant to the Framework Regulations, section 69 concerning administrative decisions, Equinor Energy AS is ordered to:
- Review the company’s decision-making routines and practices
a. concerning identified weaknesses that may lead to incidents with serious consequences but of low probability
b. where technical solutions are identified and implemented that deviate from established practices,
with reference to the Management Regulations, section 4 concerning risk reduction, first paragraph; the Facilities Regulations, section 5 concerning the design of facilities; the Management Regulations, section 6 concerning the management of health, safety and the environment, first paragraph, and section 11 concerning the basis for making decisions and decision criteria, first paragraph. - Identify measures and establish a plan to provide the necessary facility-specific training and drills on, or associated with, Sleipner B so that personnel are at all times able to handle operational disturbances and hazard and accident situations in an effective manner, with reference to the Activities Regulations, section 23 concerning training and drills, first paragraph, and section 77 concerning the handling of hazard and accident situations.
The deadline for complying with part 1 of the order is 31 March 2026.
The deadline for complying with part 2 of the order is 31 December 2025.