Lloyds' Alert: Secondary Means of Venting on Tankers
Changes to SOLAS Regulations II-2/4.5.3 (Cargo Tank Venting) and II-2/11.6 (Protection of Cargo Tank Structure against Pressure or Vacuum in Tankers) adopted through Resolution MSC.392(95) will apply to tankers constructed on or after January 1, 2017.
The changes mean that these ships must have an independent, secondary means of venting for each tank: that is, a full flow pressure/vacuum (P/V) valve or a pressure sensor that provides an alarm on detecting over-pressure or under-pressure.
Note: a pressure sensor is only acceptable as a secondary means if a full flow P/V valve is fitted as the primary means of venting for each cargo tank, as per the arrangement in SOLAS Regulation II-2/11.6.1.2.
These changes have been made to protect tanks in the event of a mechanical failure or inadvertent closure of the isolating valves or devices on the inert gas main/vent branch pipework.
