Further to information provided in information note Firefighting foam on helidecks, we have been provided with the following information arising from a foam sample test onboard a vessel with a helideck.
The company reports that the results from a sample from the helideck foam monitor tank submitted for testing were perplexing. They stated that the foam had a very high concentration of water, as opposed to 0%.
Investigations were carried out onboard to comprehend this high concentration of water in the foam sample. After various tests it was concluded that the non-return valve located between the foam tank and pipework from the pump to the helideck foam monitor had been leaking.
This was not immediately noticed. However, the consequences of this could have been devastating – should a helicopter fire on the helideck have occurred, the vessel would have been using a mixture of foam concentrate and water which was incapable of producing the required blanket of foam.
The company concerned has instructed its helideck-equipped vessels to take the following measures to prevent recurrence of this:
- Where possible, test non-return valves for leakage;
- Enter the non-return valve item into the vessel’s planned maintenance system for inspection and testing on a frequent basis when convenient;
- Schedule to fit an isolation valve between the foam tank and non-return valve.