Step 1 of 4•3 minutes read
Whenever a flammable atmosphere could potentially be present, the following measures must be taken to prevent electrostatic hazards:
The following additional precautions should be taken against static electricity during ullaging, dipping, gauging or sampling of static accumulator oils:
Banning the use of all metallic equipment for dipping, ullaging and sampling during loading and for 30 minutes after completion of loading. After the 30 minute waiting period, metallic equipment may be used for dipping, ullaging and sampling, but it must be effectively bonded and securely earthed to the structure of the ship before it is introduced into the tank, and must remain earthed until after removal.
Banning the use of all non-metallic containers of more than 1 litre capacity for dipping, ullaging and sampling during loading and for 30 minutes after completion of loading. Non-metallic containers of less than 1 litre capacity may be used for sampling in tanks at any time, provided that they have no conducting components and that they are not rubbed prior to sampling. Cleaning with a high conductivity proprietary cleaner, a solvent such as 70:30% IPA:toluene mix, or soapy water, is recommended to reduce charge generation. To prevent charging, the container should not be rubbed dry after washing.
Operations carried out through a correctly designed and installed sounding pipe are permissible at any time. It is not possible for any significant charge to accumulate on the surface of the liquid within the sounding pipe and therefore no waiting time is required. However, the precautions to be observed against introducing charged objects into a tank still apply and if metallic equipment is used it should be bonded before being inserted into the sounding pipe. Detailed guidance on precautions to be taken during ullaging, dipping and sampling of static accumulator oils is given in Section 18.104.22.168 of ISGOTT 6th edition published by the ICS and OCIMF . These precautions should be rigidly adhered to in order to avoid hazards associated with the accumulation of an electrical charge on the cargo which could form part of the links of the chain of events leading to a fire or explosion.