Properties and characteristics
1. Coals may emit methane, a flammable gas. A methane/air mixture containing between
5% and 16% methane constitutes an explosive atmosphere which can be ignited by sparks
or naked flame, e.g. electrical or frictional sparks, a match or lighted cigarette. Methane
is lighter than air and may, therefore, accumulate in the upper region of the cargo space or
other enclosed spaces. If the cargo space boundaries are not tight, methane can seep
through into spaces adjacent to the cargo space.
2. Coals may be subject to oxidation, leading to depletion of oxygen and an increase in
carbon dioxide concentrations in the cargo space (see Appendix 7 of this Code.)
3. Some coals may be liable to self-heating that could lead to spontaneous combustion in the
cargo space. Flammable and toxic gases, including carbon monoxide, may be produced.
Carbon monoxide is an odourless gas, slightly lighter than air, and has flammable limits
in air of 12% to 75% by volume. It is toxic by inhalation with an affinity for blood
haemoglobin over 200 times that of oxygen.
4. Some coals may be liable to react with water and produce acids which may cause
corrosion. Flammable and toxic gases, including hydrogen, may be produced. Hydrogen
is an odourless gas, much lighter than air, and has flammable limits in air of 4% to 75%
Segregation and stowage requirements
1. Boundaries of cargo spaces where materials are carried should be resistant to fire and
2. Coals should be "separated from" goods of classes 1 (Division 1.4), 2, 3, 4 and 5 in
packaged form (see IMDG Code) and .separated from. solid bulk materials of classes 4
3. Stowage of goods of class 5.1 in packaged form or solid bulk materials of class 5.1 above
or below a cargo should be prohibited.
4. The master should ensure that the coal cargo is not stowed adjacent to hot areas.
5. Coals should be "separated longitudinally by an intervening complete compartment or
hold from "goods of class 1 other than Division 1.4.
General requirements for all coals
1. Prior to loading, the shipper or his appointed agent should provide in writing to the master the characteristics of the cargo and the recommended safe handling procedures for loading and transport of the cargo. As a minimum, the cargo.s contract specifications for moisture content, sulphur content and size should be stated, and especially whether the cargo may be liable to emit methane or self-heat.
2. The master should be satisfied that he has received such information prior to accepting
the cargo. If the shipper has advised that the cargo is liable to emit methane or self-heat,
the master should additionally refer to the "Special precautions."
3. Before and during loading, and while the material remains on board, the master should
observe the following:
3.1 All cargo spaces and bilge wells should be clean and dry. Any residue of waste material
or previous cargo should be removed, including removable cargo battens, before loading.
3.2 All electrical cables and components situated in cargo spaces and adjacent spaces should
be free from defects. Such cables and electrical components should be safe for use in an
explosive atmosphere or positively isolated.
3.3 The ship should be suitably fitted and carry on board appropriate instruments for
measuring the following without requiring entry in the cargo space:
3.3.1 concentration of methane in the atmosphere;
3.3.2 concentration of oxygen in the atmosphere;
3.3.3 concentration of carbon monoxide in the atmosphere; and
3.3.4 pH value of cargo hold bilge samples.
4. These instruments should be regularly serviced and calibrated. Ship personnel should be
trained in the use of such instruments. Details of gas measurement procedures are given
at the end of this appendix.
5. It is recommended that means be provided for measuring the temperature of the cargo in
the range 0oC to 100oC. Such arrangements should enable the temperature of the coal to
be measured while being loaded and during voyage without requiring entry into the cargo
6. The ship should carry on board the self-contained breathing apparatus required by
SOLAS regulation II-2/10.10. The self-contained breathing apparatus should be worn
only by personnel trained in its use (see also Appendix 7 of this Code).
7. Smoking and the use of naked flames should not be permitted in the cargo areas and
adjacent spaces and appropriate warning notices should be posted in conspicuous places.
Burning, cutting, chipping, welding or other sources of ignition should not be permitted in
the vicinity of cargo spaces or in other adjacent spaces, unless the space has been properly
ventilated and the methane gas measurements indicate it is safe to do so.
8. Prior to departure, the master should be satisfied that the surface of the material has been
trimmed reasonably level to the boundaries of the cargo space to avoid the formation of
gas pockets and to prevent air from permeating the body of the coal. Casings leading into
the cargo space should be adequately sealed. The shipper should ensure that the master
receives the necessary co-operation from the loading terminal.
9. The atmosphere in the space above the cargo in each space should be regularly monitored
for the presence of methane, oxygen and carbon monoxide. Details of gas monitoring
procedures are given at the end of this appendix. Records of these readings should be
maintained. The frequency of the testing should depend upon the information provided
by the shipper and the information obtained through the analysis of the atmosphere in the
10. Unless expressly directed otherwise, all holds should be surface ventilated for the first
24 hours after departure from the loading port. During this period, one measurement
should be taken from one sample point per hold.
11. If after 24 hours the methane concentrations are at an acceptably low level, the ventilators
should be closed. If not, they should remain open until acceptably low levels are
obtained. In either event, measurements should be continued on a daily basis.
12. If significant concentrations of methane subsequently occur in unventilated holds, the
appropriate special precautions as described in section 2.2.1 should apply.
13. The master should ensure, as far as possible, that any gases which may be emitted from
the materials do not accumulate in adjacent enclosed spaces.
14. The master should ensure that enclosed working spaces, e.g. storerooms, carpenter.s
shop, passageways, tunnels, etc. are regularly monitored for the presence of methane,
oxygen and carbon monoxide. Such spaces should be adequately ventilated.
15. Regular hold bilge testing should be systematically carried out. If the pH monitoring
indicates that a corrosion risk exists, the master should ensure that all bilges are kept dry
during the voyage in order to avoid possible accumulation of acids on tank tops and in the
16. If the behaviour of the cargo during the voyage differs from that specified in the cargo
declaration, the master should report such differences to the shipper. Such reports will
enable the shipper to maintain records on the behaviour of the coal cargoes, so that the
information provided to the master can be reviewed in the light of transport experience.
17. The Administration may approve alternative requirements to those recommended in this
1 Coals emitting methane
If the shipper has advised that the cargo is liable to emit methane or analysis of the atmosphere in
the cargo space indicates the presence of methane in excess of 20% of the Lower Explosion
Limit (LEL), the following additional precautions should be taken:
.1 Adequate surface ventilation should be maintained. On no account should air be
directed into the body of the coal as air could promote self-heating.
.2 Care should be taken to vent any accumulated gases prior to removal of the hatch
covers or other openings for any reason, including unloading. Cargo hatches and
other openings should be opened carefully to avoid creating sparks. Smoking and
the use of naked flame should be prohibited.
.3 Personnel should not be permitted to enter the cargo space or enclosed adjacent
spaces unless the space has been ventilated and the atmosphere tested and found
to be gas-free and to have sufficient oxygen to support life. If this is not possible,
emergency entry into the space should be undertaken only by trained personnel
wearing self-contained breathing apparatus under the supervision of a responsible
officer. In addition, special precautions to ensure that no source of ignition is
carried into the space should be observed (see also Appendix 7 of the Code).
.4 The master should ensure that enclosed working spaces, e.g. storerooms,
carpenter.s shops, passageways, tunnels, etc. are regularly monitored for the
presence of methane. Such spaces should be adequately ventilated and, in the
case of mechanical ventilation, only equipment safe for use in an explosive
atmosphere should be used. Testing is especially important prior to permitting
personnel to enter such spaces or energizing equipment within those spaces.
2 Self-heating coals
.1 If the shipper has advised that the cargo is liable to self-heat, the master should
seek confirmation that the precautions intended to be taken and the procedures
intended for monitoring the cargo during the voyage are adequate.
.2 If the cargo is likely to self-heat or analysis of the atmosphere in the cargo space
indicates an increasing concentration of carbon monoxide, then the following
additional precautions should be taken:
.2.1 The hatches should be closed immediately after completion of loading in
each cargo space. The hatch covers can also be additionally sealed with a
suitable sealing tape. Surface ventilation should be limited to the absolute
minimum time necessary to remove methane which may have
accumulated. Forced ventilation should not be used. On no account
should air be directed into the body of the coal as air could promote
.2.2 Personnel should not be allowed to enter the cargo space, unless they are
wearing self-contained breathing apparatus and access is critical to
safety of life and the safety of the ship (see also Appendix 7 of this Code.)
.2.3 When required by the competent authority, the carbon monoxide
concentration in each cargo space should be measured at regular intervals
to detect self-heating.
.2.4 If at the time of loading, when the hatches are open, the temperature of the
coal exceeds 55°C, expert advice should be obtained.
.2.5 If the carbon monoxide level is increasing steadily, a potential self-heating
may be developing. The cargo space should be completely closed down
and all ventilation ceased. The master should seek expert advice
immediately. Water should not be used for cooling material or fighting
coal cargo fires at sea, but may be used for cooling the boundaries of the
.2.6 Information to be passed to owners. The most comprehensive record of
measurements will always be the log used to record daily results. The coal
cargo monitoring log for the voyage should be faxed, or the appropriate
content should be telexed to the vessel's owners.
The following minimum information is essential if an accurate assessment of the situation is to
(a) identity of the holds involved; monitoring results covering carbon monoxide,
methane and oxygen concentrations;
(b) if available, temperature of coal, location and method used to obtain results;
(c) time gas sample taken (monitoring routine);
(d) time ventilators opened/closed;
(e) quantity of coal in hold(s) involved;
(f) type of coal as per shipper.s declaration, and any special precautions indicated on
(g) date loaded, and ETA at intended discharge port (which should be specified); and
(h) comments or observations from the ship.s master.
Procedures for gas monitoring of coal cargoes
1.1 Carbon monoxide monitoring, when conducted in accordance with the following
recommendations, will provide a reliable early indication of self-heating within a coal cargo.
This allows preventive action to be considered without delay. A steady rise in the level of
carbon monoxide detected within a hold is a conclusive indication that self-heating is taking
1.2 All vessels engaged in the carriage of coal should carry on board an instrument for
measuring methane, oxygen and carbon monoxide gas concentrations, so that the atmosphere
within the cargo space may be monitored. This instrument should be regularly serviced and
calibrated in accordance with the manufacturer.s instructions. When properly maintained and
operated, this instrument will provide reliable data about the atmosphere within the cargo space.
Care needs to be exercised in interpreting methane measurements carried out in the low oxygen
concentrations often found in unventilated cargo holds. The catalytic sensors normally used for
the detection of methane rely on the presence of sufficient oxygen for accurate measurement.
This phenomenon does not affect the measurement of carbon monoxide, or measurement of
methane by infrared sensor. Further guidance may be obtained from the instrument
2 Sampling and measurement procedure
2.1.1 An instrument is required which is capable of measuring methane, oxygen and carbon
monoxide concentrations. The instrument should be fitted with an aspirator, flexible connection
and a length of tubing to enable a representative sample to be obtained from within the square of
the hatch. Stainless steel tubing approximately 0.5 m in length and 6 mm nominal internal
diameter with an integral stainless steel threaded collar is preferred. The collar is necessary to
provide an adequate seal at the sampling point.
2.1.2 A suitable filter should be used to protect the instrument against the ingress of moisture as
recommended by the manufacturer. The presence of even a small amount of moisture will
compromise the accuracy of the measurement.
2.2 Siting of sampling points
2.2.1 In order to obtain meaningful information about the behaviour of coal in a hold, gas
measurements should be made via one sample point per hold. To ensure flexibility of
measurement in adverse weather, however, two sample points should be provided per hold, one
on the port side and one on the starboard side of the hatch cover. (Refer to the diagram below.)
Measurement from either of these locations is satisfactory.
2.2.2 Each sample point should comprise a hole of diameter approximately 12 mm positioned
as near to the top of the hatch coaming as possible. It should be sealed with a screw cap to
prevent ingress of water and air. It is essential that this cap is securely replaced after each
measurement to maintain a tight seal.
2.2.3 The provisions of any sample point should not compromise the seaworthiness of the
2.3.1 Ensure that the instrument is calibrated and working properly in accordance with the
manufacturer.s instructions. Remove the sealing cap, insert the stainless steel tube into the
sampling point and tighten the integral cap to ensure an adequate seal. Connect the instrument to
the sampling tube. Draw a sample of the hold atmosphere through the tube, using the aspirator,
until steady readings are obtained. Log the results on a form which records cargo hold, date and
time for each measurement.
2.4 Measurement strategy
2.4.1 The identification of incipient self-heating from measurement of gas concentrations is
more readily achieved under unventilated conditions. This is not always desirable because of the
possibility of the accumulation of methane to dangerous concentrations. This is primarily, but
not exclusively, a problem in the early stages of a voyage. Therefore it is recommended that
holds are initially ventilated until measured methane concentrations are at an acceptably
2.5 Measurement in unventilated holds
2.5.1 Under normal conditions one measurement per day is sufficient as a precautionary
measure. However, if carbon monoxide levels are higher than 30ppm then the frequency should
be increased to at least twice a day at suitably spaced intervals. Any additional results should be
2.5.2 If the carbon monoxide level in any hold reaches 50 ppm a self-heating condition may be
developing and the owners of the vessel should be notified.
2.6 Measurement in ventilated holds
2.6.1 If the presence of methane is such that the ventilators are required to remain open, then a
different procedure should be applied to enable the onset of any incipient self-heating to be
2.6.2 To obtain meaningful data the ventilators should be closed for a period before the
measurements are taken. This period may be chosen to suit the operational requirements of the
vessel, but it is recommended that it is not less than four hours. It is vital in the interests of data
interpretation that the shutdown time is constant whichever time period is selected. These
measurements should be taken on a daily basis. If the carbon monoxide results exhibit a steady
rise over three consecutive days, or exceed 50 ppm on any day, the owners of the vessel should