Handling dangerous liquid chemicals in bulk involved numerous hazards. Careful considerations are essential during various stages of shipboard operations. Below check items are described as guidance only.
1. 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.
2. 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.
3. 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.
4. 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.
5. 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.
6. 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.
7. 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.
8. 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.
9. 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.
10. 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.
Related Info:
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Edible oils Heating Instructions
Heating instructions should also be detailed, and these should state the in-transit temperature, loading/ discharging temperature and the allowed daily rate of increase of temperature. Rapid heating of certain grades can cause scorching of the cargo, and overheating the cargo can promote oxidation, hydrolysis, scorching and discoloration of the cargo. Rapid heating can also cause an increase in FFA content, which causes the load to turn sour, and is used as a measure of cargo quality, especially for palm oil.
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What is putrefaction process of liquid chemicals ?
Most animal and vegetable oils undergo decomposition over time, a natural process known as putrefaction (going off), that generates obnoxious and toxic vapours and depletes the oxygen in the tank. Tanks that have contained such products must be carefully ventilated and the atmosphere tested prior to tank entry .
.....
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Carriage of inhibited flammable chemical products in cargo tanks
In certain conditions of heat, pressure and in the presence of Oxygen, some chemical cargo types can become viscous and possibly solid and dense in nature. This self reaction can cause some cargoes , especially in the presence of high temperatures and Oxygen, to begin an exothermic reaction, becoming self heating and rapidly expanding which may result in possibly disastrous consequences for the vessel.
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Cargo sampling safety precautions
Cargo samples are evidence of the condition of the product during the various phases of transport (storage at terminal, arriving on board, loading, passage, discharging). This procedure describes sample-taking procedures and the legal background. Suitable PPE is to be worn when taking samples. Sample bottle to be flushed prior collecting sample.
.....
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Cargo segregation requirement for chemical tankers
In the case of two or more liquid chemical cargoes which react with one another in a hazardous manner, segregation must be done The product data sheets, together with the BCH/IBC Codes are to be studies carefully to determine the compatibility restrictions when carrying different groups of cargoes.
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How to avoid solidification in cargo tanks ?
Solidification in the cargo tanks can occur when solidifying cargoes are stowed adjacent to “cold
cargoes” or cold ballast water in adjacent spaces.
Tank bottoms must therefore always be checked for hard factions especially when carrying vegetable
and animal oils, at regular intervals throughout the voyage and always prior to arrival in the
discharge port.
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Cargo compatibility and reactivity of various chemical cargo
Transporting of dangerous and noxious liquid chemicals in bulk involved various risk factors.
Between some chemicals violent reactions may occur if the chemicals are mixed in certain proportions. The result may possibly be an eruption and
tank rupture. Such an occurrance must be prevented. Water may also have to be considered in this respect.
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Determining presence of contaminants
in chemical cargo
To maintain product quality onboard modern chemical tankers any contaminants in the cargo need to be observed. Following guideline may be useful determining various product contaminants in noxious liquid chemicals.
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Ship shore cargo connection safe method
The connection at the manifold of hoses or metal cargo arms for cargo handling is the primary cargo connection between ship
and shore, and it is essential that both parties take proper care preparing for the connection. Flange faces, gaskets and seals
used at this point should be clean and in good condition. Minimum standards for hoses are laid down in the IBC Code. The
hoses should be in good condition and installed with gaskets which are suitable for the chemical product to be handled.
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Venting of cargo tanks safety procedure
Cargo tanks of a chemical tanker are required to be provided with
venting systems to prevent both over and under pressurisation of the tank. Two types of
venting system are specified by the Code, namely “open” and “controlled”.
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Ship to ship transfer operation
The ship to ship (STS) transfer of cargoes carried on chemical tankers is a frequent operation, and the following article addresses some special safety aspects of the preparations and procedures that may be found necessary for STS operations.
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Ship shore safety checklist while alongside a terminal
Due regard should be given to the need for adequate fendering arrangements.
Ships should remain adequately secured in their moorings. Alongside piers or quays, ranging of the ship should be
prevented by keeping all mooring lines taut: attention should be given to the movement of the ship caused by wind,
currents, tides or passing ships and the operation in progress. Wire ropes and fibre ropes should not be used together in
the same direction (i.e. breasts, springs, head or stern) because of the difference in their elastic properties.
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Cargo compatibility chart for handling dangerous liquid chemicals in bulk
Determine the group numbers of the two cargoes by referring to the alphabetical
listing of cargoes and the corresponding groups. Many cargoes are listed under their
parent names: unless otherwise indicated, isomers or mixtures of isomers of a
particular cargo are assigned
to the same group.
- Cargo handling safe practice for chemical products
Check cargo hoses to see that they have not deteriorated, that flange connections are intact, that there is an
electrical bond between hose flanges and that the working pressure for the hose is marked on it. If there is any
doubt about the hose's condition, find out when the hose was last pressure tested .
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Risk with noxious liquid cargo contact
Different chemicals affect the human body in many different ways. A general information and some practical advice are available in Appendix,7, of "Medical first aid guide for use in
accidents involving dangerous goods" published by IMO, WHO and ILO ref (36).
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How take a sample of noxious liquid cargo ?
Cargo samples are evidence of the condition of the product during the various phases of transport
(storage at terminal, arriving on board, loading, passage, discharging).For protection against possible cargo claims it is very important that cargo sampling is
correctly carried out.
Related info:
Reference publications
- Equipment Manufacturers Instruction Manuals
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MARPOL – 73/78 (latest consolidated edition)
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International Safety Guide for Oil Tankers and Terminals (ISGOTT)
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CFR 33 parts 125 to 199
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Ship to Ship Transfer Guide (Petroleum)
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MSDS for particular cargo carried
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Chemical Tank Cleaning Guide
Main Info pages!
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Preparation for unloading
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Inert gas systems
|||Gas freeing
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Nitrogen handling
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Chemical handling Safe practice
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Cargo & Ballast pumps
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Cargo tanks
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|||Special cargoes
|||Spills emergencies
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