- Handling dangerous liquid chemicals in bulk involved numerous hazards.
- Information on the product to be handled should be available on board the ship and ashore before and during the operation.
- Ship and shore should agree in writing on the inert gas supply, specifying the volume required and the flow rate in cubic metres per minute.
Handling dangerous liquid chemicals in bulk involved numerous hazards. Careful considerations are essential during various stages of shipboard operations, says an article published on chemical tanker guide website.
Is information available giving the necessary data for the safe handling of the cargo and, where applicable, is a manufacturer’s inhibition certificate available?
Information on the product to be handled should be available on board the ship and ashore before and during the operation. This information should include:
i) a cargo stowage plan;
ii) a full description of the physical and chemical properties, including reactivity, necessary for the safe containment of the cargo;
iii) action to be taken in the event of spills or leaks;
iv) counter measures in the event of accidental personal contact;
v) fire fighting procedures and fire fighting media;
vi) procedures for cargo transfer, tank cleaning and gas freeing.
When cargoes required to be stabilised or inhibited are to be handled, information about them should be exchanged between ship and terminal.
Is sufficient and suitable protective equipment (including self-contained breathing apparatus) and protective clothing ready for immediate use?
Suitable protective equipment (including self-contained breathing apparatus and protective clothing), appropriate to the specific dangers of the product handled, should be readily available both on board and ashore in sufficient quantity for operational personnel.
Have counter measures in the event of accidental personal contact with the cargo been agreed ?
Sufficient and suitable means should be available to neutralise the effects and remove small quantities of spilled products. However, it is possible that unforeseen personal contact may occur.
To limit the consequences, sufficient and suitable countermeasures should be taken. Information on how to handle such contact with regard to the special properties of the products should be studied and available for immediate use.
A suitable safety shower and eye rinsing equipment should be fitted and ready for instant use in the immediate vicinity of places on board and ashore where operations regularly take place. Measures should be taken to ensure that the equipment is operable in all ambient conditions.
Is the cargo handling rate compatible with the automatic shutdown system, if in use?
Automatic shutdown valves may be fitted on the ship and shore. The action of such valves is automatically initiated when a certain level is reached in the tank being loaded either on board or ashore.
In cases where such systems are used, the cargo handling rate should be so adjusted that a pressure surge evolving from the automatic closure of any such valve does not exceed the safe working pressure of either the ship or shore pipeline system.
Alternative means, such as a recirculation system and buffer tanks, may be fitted to relieve the pressure surge created.
A written agreement should be made between the ship and shore supervisors indicating whether the cargo handling rate will be adjusted or alternative systems will be used.
Are cargo system gauges and alarms correctly set and in good order?
Ship and shore cargo system gauges and alarms should be checked regularly to ensure they are in good working order. In cases where it is possible to set alarms to different levels, the alarm should be set to the required level.
Are portable vapour detection instruments readily available for the products to be handled?
Equipment provided should be capable of measuring, as appropriate, flammable and/or toxic levels. Suitable equipment should be available to calibrate those instruments capable of measuring flammability, and any necessary calibration should be carried out before the cargo handling operation commences.
Has information on firefighting media and procedures been exchanged?
Information should be exchanged on the availability of fire fighting equipment and the procedures to be followed in the event of a fire on board or ashore.
Special attention should be given to any products being handled which may be water-reactive or require specialised fire fighting procedures.
Are transfer hoses of a suitable material, resistant to the chemical action of the cargoes?
Each transfer hose should be indelibly marked to show the products for which it is suitable, its specified maximum working pressure, the test pressure and the most recent date of testing at this pressure and, if used at temperatures other than ambient, its maximum and minimum service temperatures.
Is cargo handling being performed with permanent installed pipelines?
During cargo operations where the use of portable cargo lines on board or ashore is unavoidable, care should be taken to ensure that these lines are correctly positioned and assembled so that no additional danger exists from their use.
Where necessary, the electrical continuity of these lines should be checked. Non-permanent cargo lines should be kept as short as possible.
The use of non-permanent equipment inside tanks is not generally permitted unless the approval of the port authority has been obtained.
Where appropriate, have procedures been agreed for receiving nitrogen supplied from shore, either for inerting or purging ship’s tanks, or for line clearing into the ship?
Ship and shore should agree in writing on the inert gas supply, specifying the volume required and the flow rate in cubic metres per minute. The sequence of operating valves before beginning the operation and after completion should be agreed, so that the ship remains in control of the flow.
Attention should be given to the adequacy of open vents on a tank in order to avoid the possibility of over-pressurisation. The tank pressure should be closely monitored throughout the operation.
The ship’s agreement should be sought when the terminal wishes to use compressed nitrogen or air as a propellant, either for a line scraper to clear shore lines into the ship or to press cargo out of shore containment.
The ship should be informed of the pressure to be used and the possibility of receiving gas into the cargo tank.
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Source: chemical tanker guide
