When the heat is on
Coal has been a key feature of the shipping industry for hundreds of years, both as fuel in the steamship age and as a strategic cargo for all industrial and developing nations.
Yet the carriage of coal presents a series of challenges to the bulk sector, made more complicated by the rapid development of shipments from developing nations, where not only conditions of shipment are challenging, but where the very coal itself presents potential danger.
Although loads from Indonesia have been problematic, the issues and safety advice discussed below apply to the carriage of coal globally.
Practical and technical information
1. Why does coal self-heat?
Some types of coal undergo exothermic (heat producing) oxidation which under certain conditions, continues until the coal ignites. Conditions conducive to self-heating include:
- A ready supply of oxygen from the air
- A large surface area for oxidation
- Presence of moisture
- Insulation against heat loss
A mixed cargo of lump coal and fines can lead to highly conducive conditions for self-heating. The larger lumps allow freer airflow and insulate well, while fines provide a large surface area for oxidation. This is even worse when cargo is not trimmed flat.
2. Particular issues with loading coal in Indonesia
The self-heating problems with Indonesian coals relate to their nature and the way they are handled prior to and during loading. The majority of coal loaded off Kalimantan, Indonesia is prone to self-heating, which does not mean that it is unsafe to carry, only that precautions need to be taken.
Coal is often transported in barges for loading at anchor and can remain in these barges for days, if not weeks, before delivery to the ship. As barges are usually uncovered, coal is exposed to the elements, most notably, wind. Furthermore, if there are significant delays in providing cargo during loading, this may result in some holds being partially filled, while awaiting delivery of more cargo.
Any coal loaded in partially filled holds is unlikely to be trimmed, and is therefore exposed to air ingress (even with hatches closed). Thus, coals already susceptible to self-heating may well have been exposed for a protracted period, before or during loading, to the very conditions that promote self-heating.
3. Precautions to take
Coal is covered under the International Maritime Solid Bulk Cargo (IMSBC) Code. The master should follow requirements and advice given here. In particular, the cargo should not be loaded without a cargo declaration from the shipper consistent with the requirements of the Code. The cargo declaration should say whether the coal has a history of self-heating and a tendency to emit methane, a flammable gas. Experience shows that even when declarations are provided in Kalimantan, they may be inaccurate. Therefore, it is best to assume that the cargo has a propensity to self-heat and treat it accordingly.
In order to avoid problems of self-heating during the voyage (and possibly whilst loading), care should be taken to measure the temperature of the cargo prior to and during loading. Although not required by the IMSBC Code, a relatively inexpensive infrared thermometer can greatly assist the crew. This allows them to ‘scan’ the surface of the cargo prior to and during loading and quickly inform the master if temperatures are of concern. The IMSBC Code indicates that coal should not be loaded if it has a temperature in excess of 55ºC. It also states that holds should be closed after loading is completed and, if there is a delay of over one hour, during the work itself.
After loading, and unless advised otherwise, the IMSBC Code requires that holds should be surface-ventilated for the first 24 hours or until the methane concentration is acceptably low. Coals loaded off Kalimantan tend not to emit methane, so it may not be advisable to surface ventilate after loading unless high methane readings are recorded. According to the IMSBC Code, high methane readings are in excess of 20% of the lower explosion limit.
If a cargo of coal self-heats, the process will start as hot spots in the bulk cargo. Due to the insulating nature of coal, these hot spots may be at a much higher temperature than other coal in the proximity. Therefore, temperature measurements at isolated points in the closed hold may not indicate self-heating. Since carbon monoxide is produced when coal self-heats, the most effective early-warning system is carbon monoxide monitoring.
The atmosphere in each cargo hold should be monitored daily. If cargo is being surface ventilated, then this should stop for at least four hours before sampling.
Prior to and following departure the master should ensure that:
- Cargo is properly trimmed
- Once closed, holds are surface-ventilated for the first 24 hours or until the methane concentration is acceptably low, as required by the IMSBC Code
- Once ventilation is stopped, holds are sealed and gas monitored as required by the IMSBC Code
- Gas monitoring equipment on board is well maintained and regularly calibrated in accordance with the manufacturer’s instructions
- All enclosed spaces adjacent to the holds are regularly monitored and adequately ventilated
- On no account should anyone enter confined spaces without first
confirming that it is safe - there have been numerous deaths over the years from asphyxiation in enclosed spaces on board ships, such as cargo holds |
- If the cargo’s behaviour differs on the voyage from that specified in the cargo declaration, the master should report these differences to the owners and club
4. Steps to take if self-heating starts
The master should contact owners and the club if it appears that the cargo has started to self-heat. According to the IMSBC Code, this is “when carbon monoxide level in any cargo space reaches 50 ppm [parts per million] or exhibits a steady rise over three consecutive days”. Owners should urgently inform the club as it may be necessary to appoint an expert to assess the situation and provide additional advice.
If an expert is appointed, he is likely to require at least the following information:
- Hatch types and their condition and how the holds were closed and sealed after loading
- Type of temperature and gas monitoring instrumentation on board and whether crew has taken daily temperature and gas measurements. If they have been taking readings, a copy is required
- Calibration date of gas monitoring equipment
- Amount of coal loaded into each hold expressed as weight and percentage by volume
- Whether there is any marine bitumastic tape on board that can be used to seal the holds or, if not, whether it can be obtained. Alternatively, confirm whether there is polyurethane foam sealant
- Temperature of coal at loading
- Copy of the cargo declaration provided by the shippers and any special precautions required, as well as the intended use of the cargo (if known)
- Date(s) that the coal was loaded and the estimated time of arrival at the intended discharge port, which should be specified
- Comments or observations from the ship’s master, including the weather experienced on the voyage and any adverse weather conditions expected
5. Steps to take if there is a fire or advanced self-heating
If there is a fire or advanced self-heating the master should:
- Commence boundary cooling of the affected holds and consider heading towards the nearest port. Again, the club should be notified without delay as an expert’s attendance may be necessary
- Close all ventilation - this includes sealing ventilators, manways and all gaps. If there is no marine bitumastic tape or an acceptable alternative, such as foam, on board then an order should be placed as soon as possible. In the short term, wet rags can seal gaps and canvas sheets tied over ventilators to reduce air ingress to the cargo. Seek advice about cleating of the holds
- Check all spaces adjacent to the holds before entry.
On no account must anyone enter confined spaces without first confirming that it is safe - Provide owners and the P&I club with all temperature and gas monitoring records for the voyage. If the ship does not have any reliable gas monitoring equipment, then it is operating in contravention of the requirements of the IMSBC Code for the carriage of coal. Owners urgently need to equip the ship so that cargo monitoring can commence and the situation properly managed
Legal considerations
Basic position at common law:
Express contractual provisions
Where the charter expressly forbids the carriage of certain specified cargo (regardless of its nature) owners can refuse to load it. Charterers will breach the charterparty if they insist on loading.
Implied obligations
Law requires that the charterer/shipper give advance warning to the owner so that they can refuse to load in case the cargo is non-contractual, or take the right precautions.
Brass vs. Maitland (1856) 6 E. & B. 470.
Hague-Visby Rules
There is a clear-cut provision under Article IV, Rule 6:
“Goods of an inflammable, explosive or dangerous nature to the shipment whereof the carrier, master or agent of the carrier has not consented with knowledge of their nature and character, may at any time before discharge be landed at any place, or destroyed or rendered innocuous by the carrier without compensation and the shipper of such goods shall be liable for all damages and expenses directly or indirectly arising out of or resulting from such shipment. If any such goods shipped with such knowledge and consent shall become a danger to the ship or cargo, they may in like manner be landed at any place, or destroyed or rendered innocuous by the carrier without liability on the part of the carrier except to general average, if any.”
The above liabilities and obligations can be considered strict.
Charterparty terms
Most charterparties have detailed clauses that permit or prohibit cargoes and, in the case of special cargoes, provide specific terms under which carriage is allowed.
The key, from an owner’s perspective, is to ensure that the terms are expansive and detailed to remove room for doubt - and expensive disputes - later on.
The position of the time charterer must also be carefully considered, especially if the next charter is a voyage charter. The time charter operator needs to ensure that obligations to one party that cannot be demanded of the other are rejected. Put simply - if you are not Back to Back (BTB) then the risk is on you and you alone.
Advice to owners
Beyond ensuring the charterparty terms are sufficiently clear, it is essential to instruct masters and crew that:
- Only safe cargoes may be loaded. If in doubt stop loading
- Cargoes must always be loaded in strict conformity with the BC Code (and soon the IMSBC)
- All necessary documentation must be provided prior to commencement of loading. Failure to do so should allow the master to refuse loading, but with hire/laytime/demurrage continuing
- Certificates must be produced by recognised and reputable testing facilities
- A pre-loading survey is carried out at charterers’ time, risk and cost.
NB! Such matters, as others, must be expressed in the charterparty terms
If in doubt, the master and officers should not be afraid to stop operations and insist that their legitimate demands be met. It is usually a good idea for the local correspondent to assist the master at this point, as disputes over time will no doubt follow - even if the load is ultimately found to be safe. The master should be confident that he has the right to reasonably satisfy himself about the cargo and to investigate any necessary issues.
Should a problem occur while the vessel is at sea then immediate contact and help should be sought from the club. A fire on board is one of the most risky situations a vessel can face. Quick investigation and advice can help bring a potentially serious situation back under control.
Advice to charterers
As charterers, the key is to ensure that obligations owed to owners in relation to the cargo are fully Back to Back (BTB) down the charter chain and also apply in respect of any COA, fixture note, other shipment contract or direct sales/purchase arrangement with the shipper. If you are not BTB you can suffer a big loss and recover it from no one. Being caught in the middle and squeezed from both sides is the worst position to be in.
Another key issue is to check who you are contracting with. A ‘good’ legal claim is still worthless if the counterparty is a paper entity with a corporate set-up designed to make enforcement of claims difficult, if not impossible. This is especially true when dealing with small trading companies acting as voyage charterers, where there may be little or no track record in the market. Another issue is that shippers sometimes operate non-licensed mining and cargo facilities, which introduce a whole new set of complications.
The charterer needs to know that under the law they have a clear duty to only load safe cargo. Indeed, under normal NYPE 1946 provisions, charterers bear all the risk for cargo safety, loading and stowage. Case law has shown that the master has little or no responsibility to intervene and consequences may land fully with the charterer, even if the master could have prevented the problem.
As the primary onus is on the charterer, loss prevention is worth its weight in gold. The extra time and expense to do this right, prevents the charterer from suffering the costs of serious delay (in one case the vessel was stuck for three months with a partially loaded, liquefying cargo), extra cargo-handling charges (for discharge of the unsafe cargo) and the liability for the full value of the vessel, the cargo and loss of life should a tragedy occur.
How can Skuld help?
As always, members should consider Skuld a ‘first port of call’ if they have a problem or just a query. Skuld’s claims handlers and technical services have a wealth of experience dealing with this type of problem. Our local correspondents, surveyors and experts are equally experienced and can give pro-active help very quickly to solve even the trickiest issue.
If in doubt : call us.
Prepared with the technical input and practical advice of Dr. John Allum, Resident Director, Burgoynes Hong Kong office.