Statens vegvesen (The Norwegian Public Roads Administration) conducts extra inspections of fans in several tunnels after discovering nonconformities.

The deviations were first uncovered through routine inspections, and Statens vegvesen has also recorded incidents where parts from impellers (the part that rotates in the fan) have fallen down while in operation.

The deviations that are registered are, among other things, related to cracking and corrosion.

- Since inspection findings and the specific events have in common that these are fans from the same supplier, we have initially chosen to carry out extra inspections in the 77 tunnels where we have such fans. We have a dialogue with the supplier, and they are familiar with our findings and measures, says department director Tore Lysberg in Statens vegvesen.

Eventually, several of the 239 national highway tunnels with fans will be investigated.
Adjusts the Vifts

Until results from the inspections are available, assessments are made of the need for mitigating measures in the relevant tunnels. Such measures are, for example, adjusting the insert point for automatic start -up of ventilation or manual control of the fans.

In cases where the inspections detect errors, the relevant fans are taken out of operation or the mitigation measures are implemented, based on risk assessment for the individual tunnel.
Supplementary analyzes

In addition to the ongoing extra inspections, Statens vegvesen has engaged SINTEF Manufacturing AS to perform material analyzes on impellers from different suppliers. The Norwegian Public Roads Administration also goes through its own maintenance routines for tunnel change.

- It is too early to draw conclusions about how extensive the deviations are and what is the cause. When we discover non-conformities, we will always investigate these more closely. It should be safe to drive in the tunnel, so until we have received the answers, we take measures so that the safety of road users is taken care of, says Tore Lysberg.

SINTEF is scheduled to submit the first part of its report in the spring of 2025.

Statens vegvesen has informed the county municipalities, Nye Veier, Bane NOR and the municipality of Oslo about their findings and measures.

Facts:

• 592 is the number of tunnels for which Statens vegvesen is responsible for.
• 239 is the number of tunnels with fans
• 77  is the number of tunnels where additional inspections are now being carried out
• 4900 (approx.) is the number of fans in the tunnels for which Statens vegvesen is responsible for
• 1500 (approx) is the number of fans in the 77 tunnels where additional inspections are carried out

Translated from Statens vegvesen press release (original in Norwegian).

Statens vegvesen gjør ekstra undersøkelser av tunnelvifter i 77 tunneler. Bård Asle Nordbø Statens vegvesen