Seacocks - are they safe?

Fittings used are often made from forged brass. Whilst these valves are in common use, ordinary brass such as this is subject to de-zincification in sea water. The ISO standard relating to metallic valves and skin fittings below the waterline, ISO 9093-1, only requires the valves and associated fittings to have a service life of 5 years in terms of corrosion resistance. The valves and fittings can often pass all the tests described above but consideration should nevertheless be given to replacing them with DZR (de-zincification resistant brass) or bronze, both of which have a much longer potential life.