201946 Leaking fire main isolation valve

24 Jun 2019 MARS 2019

While in port the vessel was inspected by flag state authorities. They noted a deficiency related to the fire main isolation valve; the valve was leaking. A plan was made to open the valve to verify its condition and a risk assessment was conducted on that plan. The plan included blanking the line at the valve side and keeping the deck line available for firefighting while the maintenance work was underway.

Once opened, scale and dirt were found within the valve. The valve stem and the disc were re-buffed and cleaned and the valve refitted in position. The valve was then pressure tested and found to be holding well. Port state authorities boarded to confirm the valve was repaired and closed the deficiency.


The company investigation found, among other things:

  • The valve position is inverted at an angle for operation, which caused accumulation of scale and dirt in the bonnet of the valve.

Lessons learned

  • Check the functionality of the main fire isolation valve during every fire drill.
  • After considering the design and position of the valves the company decided to change the maintenance schedule for this equipment.
  • Opening, inspection and overhauling of all fire and foam isolation valves were revised.