INTERNATIONAL MARITIME ORGANIZATION E IMO SUB-COMMITTEE ON DANGEROUS GOODS, SOLID CARGOES AND CONTAINERS 9th session Agenda item 4 DSC 9/4/3 1 July 2004 Original: ENGLISH REVIEW OF THE BC CODE, INCLUDING EVALUATION OF PROPERTIES OF SOLID BULK CARGOES Transport of Wood Pellets Submitted by Canada and Sweden SUMMARY Executive summary: Wood pellets are currently transported under the entry of Wood Pulp pellets in the BC Code or under no code at all since there is no description under the BC Code applicable for Wood Pellets. Wood Pellets consist of clusters of fractionalized wood such as sawdust and planer shavings, which are densified under high pressure. Wood Pulp is produced by chemical or mechanical separation of individual fibres of wood, which are dried and normally transported in bales, not as pellets. It is proposed that the proper shipping name should be corrected by adding a new bulk shipping name and schedule for Wood Pellets. Whether to delete the current BC Code 080 since it does not appear to exist a corresponding product or simply to adjust the definition to conform to Wood Pellets may be a matter of consideration Action to be taken: Paragraph 8 Wood pellets should also have a proper consideration under MSC/Circ.671 now under review Related documents: DSC 9/4; MSC/Circ.671 Introduction 1 The BC Code provides regulations for the transport of Wood Pulp Pellets, BC No. 080. According to consigners, shippers and importers Wood Pulp Pellets do not exist. Wood Pulp is not normally formed into pellets but is rather dried and pressed into sheets, which are baled and shipped in packages as break bulk. However, a product called Wood Pellets is transported in ocean vessels to an increasing degree and can not properly be classified under BC No 080. The description for Wood Pellets is that they are light blond to dark brown in colour depending on For reasons of economy, this document is printed in a limited number. Delegates are kindly asked to bring their copies to meetings and not to request additional copies.
- 2 - raw material used or process used in the manufacturing, very hard and cannot be easily squashed. Pellets are made from compacted and fractionalized woodchips and/or sawdust. 2 Wood Pellets are sometimes transported under the entry Wood Pulp Pellets or no Code at all since there is no appropriate equivalent BC available. This may lead to serious consequences due to confusion and misrepresentation. 3 Wood Pellets are a combustible material, used as fuel, not only in stoves and fireplaces, but also in power stations for central heating and generation of electricity. Some qualities of Wood Pellets are used as animal bedding due to the absorbing qualities of the pellets. Wood Pellets are normally shipped at low moisture content of about 4-8% for commercial reasons. To minimize damage to Wood Pellets when extinguishing smouldering or fire, carbon dioxide is recommended although foam and water would also be effective. 4 The revised draft MSC/Circ.671, table 1, states that Wood pulp pellets with a moisture content of 15% or more are non-combustible or constitute a low fire risk and gives the Administration the possibility of granting an exemption from fixed fire-extinguishing systems in cargo spaces. The above statement and concept is essentially wrong and misleading since all biomass is combustible, even with moisture content of up to 60% which is the case with wood chips used for municipal district heating. In fact, the general rule is that a moisture content of 15% or more is cause for concern since it causes a gradual biological decomposition of the wood and in the process generates heat and asphyxiating and combustible gases which eventually may cause spontaneous smouldering or open fire. Wood Pellets with moisture content of 4-8% can not cause spontaneous combustion in normal ambient conditions. The concern would rather be for chips, pellets or any other woody material with a moisture content of 15% or more that there may be a risk of spontaneous combustion and this is indicated so in the proposed schedule. Proposal 5 Canada and Sweden propose that there is an entry for Wood Pellets in the BC Code or Wood Pulp Pellets corrected and revised to Wood Pellets. 6 Furthermore, proper consideration should be given in MSC/Circ.671 for Wood Pellets as defined herein. An alternative is to take the revised Wood Pellets away from the circular since it is a combustible material. Another alternative is to remove the revised Wood Pellets from table 1 to table 2 as battening down and limitation of access of air in such cases would be considered acceptable. 7 A new proposed schedule and entry in the BC Code is attached at annex for Wood Pellets. Action requested of the Sub-Committee 8 The Sub-Committee is invited to consider the above proposals and to take action as appropriate. ***
PROPOSED NEW BC CODES SCHEDULE FOR WOOD PELLETS WOOD PELLETS BC No 08X DESCRIPTION The Wood Pellets are light blond to chocolate brown in colour; very hard and cannot be easily squashed. Wood Pellets have a typical specific density between 1,100 to 1,700 kg/m 3 and a bulk density of 600 to 750 kg/m 3. Wood Pellets are made of sawdust, planer shavings and other wood waste such as bark coming out of the lumber manufacturing processes. Normally there are no additives or binders blended into the pellet, unless specified. The raw material is fragmented, dried and extruded into pellet form. The raw material is compressed approximately 3.5 times and the finished Wood Pellets typically have a moisture content of 4-8 %. Wood Pellets is used as a fuel in district heating and electrical power generation as well as a fuel for small space heaters such as stoves and fireplaces. Wood Pellets are also used as animal bedding due to the absorption characteristics. Such Wood Pellets typically have a moisture content of 8-10 %. CHARACTERISTICS ANGLE OF REPOSE BULK DENSITY STOWAGE FACTOR Approximately 30 degrees 600 to 750 kg/m 3 1.4 to 1.6 m 3 /tonne 50 to 57 ft 3 /tonne SIZE CLASS GROUP Cylindrical with 3 to 12 mm diameter by 10 to 20 mm long MHB B HAZARD Shipments may be subject to oxidation leading to depletion of oxygen and increase of carbon monoxide and carbon dioxide in cargo and communicating spaces. Swelling if exposed to moisture. Wood Pellets, like any other wood material, may ferment over time if moisture content is over 15% leading to generation of asphyxiating and flammable gases which may cause spontaneous combustion. Handling of Wood Pellets may cause dust to develop. Risk of explosion at high dust concentration.
Page 2 STOWAGE AND SEGREGATION Segregate as for Class 4.1 materials. HOLD CLEANLINESS Clean and dry without any residue of previous cargoes. Avoid using fittings and other material such as lids for holding loops etc. in cargo holds, which may co-mingle with cargo during discharge causing damage during use of the Wood Pellets. WEATHER PRECAUTIONS Avoid exposure to water droplets and high moisture, keep dry at all times. LOADING Trim in accordance with the cargo information required by SOLAS VI/2. If doubt exists, trim reasonably level to the boundaries of the cargo space so as to minimize the risk of shifting and to ensure that adequate stability will be maintained during the voyage. PRECAUTIONS Entry of personnel into cargo spaces or commutating spaces should not be permitted until tests have been carried out and it has been established that the oxygen content has been restored to a normal level. Avoid close or direct contact of Wood Pellets and cargo hold lighting such as hot halogen lamps. Most wood material has an ignition temperature of approximately 270 C. Fuses to such lights should be removed or secured while cargo is present in the hold. VENTILATION See precautions. Remove any wet material, if unremovable secure ventilation of wet material. CARRIAGE Keep dry, avoid moisture ingress and condensation during voyage. No other special requirements. DISCHARGE See precautions. CLEAN UP Avoid generating high concentrations of dust during handling of material. No other special requirements.
Page 3 EMERGENCY PROCEDURES SPECIAL EMERGENCY EQUIPMENT TO BE CARRIED Oxygen or combined carbon monoxide/dioxide meter when entering confined spaces, which has not been properly ventilated. EMERGENCY PROCEDURES Nil EMERGENCY ACTION IN THE EVENT OF FIRE Batten down; use ship s fixed fire-fighting installation if fitted. Exclusion of air may be sufficient to control fire. Extinguish fire with carbon dioxide, foam or water MEDICAL FIRST AID Refer to the Medical First Aid Guide (MFAG) as amended.