Fixed hydrocarbon gas detection systems
System consists of a central unit for gas measurement and analysis. It has gas sampling pipeline connected to all ballast tanks, void spaces of double hull, double-bottom spaces adjacent to the cargo tanks including fore peak tank and any other tanks and spaces under bulkhead deck adjacent to cargo tanks.
System may be integrated with cargo pump-room gas detection system.
Each sampling line is independent. If non-metallic material is used then it is made electrically conductive. Never made up of Aluminium.
System has minimum 2 sampling points in each space.
In ballast tanks and void spaces, upper sampling point is not required.
Sampling lines to ballast tanks are cleaned by compressed air. There is alarm to indicate clogged sampling line.
Gas analysis unit
It is located in a safe space.
Gas detection unit
Shall sample at intervals of less than 30 min. Portable unit is provided (In case of failure of fixed unit)
Audible and visible alarms are provided at Cargo control room, Navigation Bridge and at the analysing unit when vapour concentration reached pre-determined value. This is not higher than 30% of the lower flammable limit (LFL). It is designed for readily testing and calibration.