In May, the Norwegian authorities criticized COSL Drilling Europe of not living up to safety regulations following a fatal accident involving the COSL Innovator rig, which last year was hit by a massive wave, taking the life of an employee and crushing 17 of the rig's 20-25 meter-high windows.
Now the Petroleum Safety Authority Norway (Petroleumstilsynet) and the Norwegian maritime directorate have withdrawn their findings of safety violations.
This follows after doubts emerged as to how the regulations should be interpreted. According to the authority, there have been uncertainties "when it comes to calculation methods associated with horizontal waves on removable devices."
The accident report has now been adjusted so that it reflects that COSL Innovator did not breach regulations during the time of the accident, which occurred in December 2015.
The authority had initially concluded that the rig sat too low in the water. COSL Innovator did not have a 1.5 meter air gap between the underside of the lowest deck and the highest wave crest, read the report, nor was the structure sufficiently dimensioned to withstand horizontal wave loads. According to the revised report, the missing air gap does not represent a breach of regulations.
Additionally, the authority found deficiencies in the emergency response process on board the rig.
COSL Innovator was hit by a wave of up to 30 meters, which smashed 11 windows on the middle deck and six windows on the lowest deck. The Windows sat at approximately 20-25 meters over the ocean surface.
The Maritime Directorate, the Petroleum Safety Authority Norway and the classification bureau DNV GL will now ensure that the insights gleaned from the case will be incorporated into the regulation framework.
"This includes improved guidelines for the calculation of the air gap and horizontal waves on the half-sunken structures," write the authorities.