Investigations into an explosion and fire on board a tanker revealed tht the cause of the casualty was probably due to static electricity. All personnel who were on the deck at the time of incident lost their lives. The badly damaged tanker eventually capsized and sank.
2. The explosion occurred when the tanker was transferring chemical from one tank to another tank. A flexible hose was used in the operations. One end of the 10 cm hose was attached to the 20 cm manifold through a reducer while the other end, with a metal flange, was placed in the receiving tank through a manhole. The flexible hose was held in position by the manhole cover and hung a few metres above the tank top. This arrangement resulted in an increase in pressure and velocity of the cargo at the discharge end of the flexible hose. The rate of flow in the hose was such that large charges of static electricity could have been built up in the tank. During the pumping operation, the metal flange at the free end of the suspended flexible hose had swung violently due to the high pressure. It is likely that, due to the static electricity produced, a spark was produced between the hose and the tank structure which ignited the explosive atmosphere in the tank. The massive explosion and fire sparked of further explosiions in the surrounding tanks on board the tanker.
3. The practice of allowing liquid to enter a cargo tank by any other means (eg. flexible hose)is fraught with danger and should not be adopted. It is essential to avoid free fall of liquid in the receiving tank as this may cause a build up of an electrostatic charge. Therefore, to safeguard against accidents during cargo operations, the proper pipeline system should be used.
4. Shipowners are urged to take note of this circular and bring it to the attention of masters, officer and all those responsible for cargo operations on board.
No comments:
Post a Comment