TO ALL MEMBERS
FOR INSURANCE, OPERATIONS AND TECHNICAL DEPARTMENTS
Dear Sirs,
Loss Prevention Advice on Carriage of Direct Reduced Iron (DRI)
We refer to our circulars of September 1980, August 1981, and July 1982. Following the 23rd session of the IMCO (now International Maritime Organisation) Sub-Committee on Containers and Cargoes in January 1982, a working group set up at that session recommended certain amendments to the entry for Direct Reduced Iron in the IMO Bulk Cargo Code and its recommendations were subsequently ratified by the IMO Maritime Safety Committee.
Since 1982 two types of Direct Reduced Iron have been recognised in the IMO Code of Safe Practice for Solid bulk cargoes (BC Code). The first type is the highly reactive low density DRI in the form of pellets, lumps and cold moulded briquettes and is entered in the Bulk Cargo Code under reference BC 015. The second, less reactive, type is the high density variety of DRI, and is known as Hot Briquetted Iron HBI, or Hot Moulded Briquettes HMB. It is entered under reference BC 016.
The IMO Bulk Cargo Code reference BC 015 for direct reduced iron pellets, lumps and cold moulded briquettes contains "Shippers' Requirements" which read as follows:
Quote:
Prior to shipment, DRI should be aged for at least 72 hours, or treated with an air passivation technique, or some other equivalent method that reduces the reactivity of the material to at least the same level as the aged product.
1. Shipper should provide necessary specific instructions for carriage, either:
- Maintenance throughout the voyage of cargo spaces under an inert atmosphere containing less than 5% oxygen. The hydrogen content of the atmosphere should be maintained at less than 1% by volume; or
- That the DRI has been manufactured or treated with an oxidation and corrosion inhibiting process which has been proved, to the satisfaction of the competent authority, to provide effective protection against dangerous reaction with sea water or air under shipping conditions.
2. The provision of paragraph A may be waived or varied if agreed by the competent authorities of the countries concerned, taking into account the sheltered nature, length, duration, or any other applicable conditions of any specific voyage.
Unquote
In relation to paragraph A (2), in the early 1980's major manufacturers in Germany used a chemical "passivation". process to inhibit oxidation/corrosion. However, there was a serious fire on board a ship carrying this product. More recently in the early 1990's, a Russian manufacturer of low density DRI pellets claimed its product was passivated , but several DRI fires occurred in the Russian material shipped from Black Sea Russian and Ukrainian ports when it became wetted with sea water. To date no Passivation Process has been proven to be effective when the material is wetted with sea water, and therefore DRI pellets, lumps or cold moulded briquettes cannot be shipped under the dispensation given in paragraph A (2).
The Association therefore continues to believe that the only proven method of carrying the low density DRI product (BC 015) safely is by maintaining the cargo holds in an inert atmosphere throughout the voyage. The most effective method of providing an inert atmosphere is by injecting the inert gas at the bottom of the stow in order to force out the air within the stow, but inerting the atmosphere above the stow should be acceptable if the oxygen level is regularly monitored and maintained below 5% Oxygen.
On present information, it is not thought that the length or nature of the voyage contemplated in IMO Bulk Cargo Code BC 015, paragraph B (see above), can ever justify the waiver of the requirement of maintaining the cargo in an inert atmosphere.
Members are advised to ensure that the terms of their charterparties permit the carriage of direct reduced iron pellets, lumps and cold moulded briquettes in accordance with the recommendation that the cargo should always be carried in an inert atmosphere whatever the nature or length of the voyage contemplated.
It should be noted that the charterparties offered for the carriage of the Russian DRI pellets contain a clause requiring, not only that the vessel be seaworthy at the commencement, but also throughout the voyage. Thus the vessel would be at fault if sea water entered a hold and started a fire even if caused by heavy weather damage.
For the guidance of Members, we set out below a list of those countries known to have exported DRI, and whether known to be currently shipping: -
Country Product Current Comments
BC 015 Low Density Type
Canada Pellets Not known
Indonesia Pellets Yes Possibly also Briquettes
Mexico Pellets Not known
Germany Pellets Not known Passivated but serious fire broke out in a cargo of the passivated product in 1981.
Trinidad Pellets Not known
Nigeria Pellets Not known
Russia Pellets Yes Of great concern because there have been 8-10 fires between 1990 and 1996 in this product, despite claimed passivation.
South Africa Lumps Yes
BC 016 High Density Type
Venezuela Briquettes Yes Fire in about 1990, possibly due to excess of "fines".
India Briquettes Yes Fire in 1994 due to excess "fines".
The following recommendations to Masters and Owners should be acted on before loading DRI and during its carriage:-
(A) Low Density DRI Pellets, Lumps, and Cold Moulded Briquettes
(a) It should be noted that, under the requirements of the Bulk Cargo Code, certificates are required at the time of shipment from both the shipper and a "competent person". The Master should be assured by the "competent person" that, in certifying the stability and suitability of the cargo for shipment, he has considered the period and conditions of storage of the cargo before loading and its temperature
(b) The ship should inspect and hose test its hatches before loading to ensure they are watertight. In addition the ship should be equipped with systems for continuous monitoring of the temperature, and of oxygen and hydrogen concentrations of the holds during the voyage.
(c) Only certified safe electrical equipment and associated wiring should be installed in any cargo space or adjacent closed spaces or deck-houses where flammable gases may accumulate. In such spaces through runs of cable should be suitably mechanically protected, should have no joints and be of a type approved for oil tankers or be enclosed in heavy gauge screen steel conduits.
(d) The temperature of the cargo should be monitored during loading and, if more than 65oC and increasing, the Master should call for the assistance of the local P & I correspondent and the "competent person" providing the certificate of suitability for shipment. During loading or discharging no smoking, burning, cutting, chipping or other source of ignition should be allowed in the vicinity of the holds.
Movable cargo lights, if used, must be not less than 10ft (3 m) from the coaming in a position where they are not likely to be broken during operations, and not over the square of the hatch. As far as is reasonably practical the DRI should not be dropped from a height into the hold.
(e) During loading the direct reduced iron must either be protected from exposure to rain or snow or else loading should be stopped and hatches covered.
DRI, which has been exposed to wetting on an open-conveyor or elsewhere, should be rejected.
(f) The ship should be fitted with means of introducing inert gas immediately after completion of loading and be capable of maintaining an inert atmosphere during the voyage. The preferred inert gas is nitrogen, but if this is not obtainable carbon dioxide may be used.
(g) If possible, piping should be arranged so that the inert gas may be put in at the bottom of the stow at several points in the hold so as to force out effectively the air within the stow.
(h) The amount of inert gas put in should be such as to keep the oxygen concentration below 5% by volume.
(i) If water enters a hold containing air, hydrogen is likely to be evolved with the development of heat. The heat may be sufficient to cause ignition. For this reason every precaution should be taken to exclude water. Particular attention should be paid to bilges, adjacent ballast tanks and the watertightness of the hatches and other openings on the weather deck. inspection of these openings should be made regularly throughout the voyage, particularly after heavy weather, and any defects should be remedied.
(j) On completion of loading and closing of hatches, they should be sealed by tape, but care must be taken not to use a flame to soften the bitumen tape, because hydrogen accumulated in the hold could be ignited and cause an explosion. After the hatches are sealed inert gas should be introduced in accordance with (f) to (h) above. This may conveniently be done from a shore based supply thereby reducing the on-board capacity required. It should be noted that the on-board supply required for topping up must be additional to the ship's carbon dioxide system, if fitted.
(k) Hydrogen gas is liable to escape even through small openings. Care should be taken to guard against its possible accumulation in adjacent enclosed spaces. The ship should carry a suitable portable meter for measuring hydrogen concentrations as indicated in (b) above.
(l) During the voyage monitoring of the oxygen concentration will indicate whether air has entered the hold and whether more inert gas is required to maintain the oxygen concentration below 5% by volume. If monitoring shows a continuing increase in hydrogen, and/or rise in temperature, a fire situation may be developing, and advice should be sought.
(m) If a fire situation develops the ship should make for the nearest suitable port. Water, steam or additional carbon dioxide should not be used at this stage to counteract the fire as a reaction with the cargo may result. If, however, nitrogen gas is available then use of this gas to keep the oxygen concentration down will contain the fire.
(n) Should heavy weather severely damage the hatches so that they cannot be repaired and water enters the hold a fire situation is likely to develop. The ship should make for the nearest suitable port and seek assistance.
(o) DRI reacts with oxygen reducing its level in the atmosphere in a hold and therefore entering a hold without breathing apparatus must be prohibited at any time unless the hatch covers are completely open and the holds effectively ventilated. If entry of the hold with breathing apparatus is required, this should only be done with full back-up assistance.
(p) If a DRI fire is developing, and hydrogen is being produced, opening of hatches may result in a spark induced fire or explosion. In such circumstances hatches should not be opened without expert advice which may be obtained through the local P&I correspondents.
(q) During discharge the direct reduced iron should be kept dry. Any dust accumulated on decks or elsewhere during loading or discharge should be washed off as soon as possible to prevent adhesion.
(B) High Density Hot Briquetted Iron (HBI) or Hot Moulded Briquettes (HMB)
(a) The Master should adopt the same procedures as for Low Density DRI in relation to:
(i) certification by a "competent person"
(ii) the condition of electrical wiring and equipment in the hold
(iii) the exclusion of water from the hold
(iv) the exclusion of sources of ignition during loading and discharge
(v) the possible accumulation of hydrogen in adjacent spaces.
(b) The main hazard arises from the evolution of hydrogen if water enters the stow. For this reason, effective ventilation should be carried out whenever possible. The equipment used for forced ventilation should be such as to avoid the possibility of ignition of gas/air mixtures.
(c) Prior to loading the briquettes may have been stored uncovered, exposed to rain. This is not necessarily objectionable provided that the cargo is not obviously wet at the time of loading, However, loading should cease during periods of rain and the holds should be closed. The bottom layer of piles on the quay prior to loading may be excessively wet and should be rejected if obviously wet.
(d) The Master should be assured by the "competent person" that all practical steps have been taken to ensure that the cargo delivered to the ship does not contain more than 5% fines. The bottom layer of piles may contain excessive 'fines' and again should be rejected if the material is obviously different to the rest of the cargo. As far as is practical, dropping the DRI from a height into the hold should be avoided to prevent disintegration of the briquettes.
(e) On completion of loading and prior to sailing if weather and circumstances permit, the hold should be left open. as long as possible to allow the cargo to cool (it is likely to heat up a little after loading) and to allow the dissipation of any hydrogen evolved.
(f) The temperature of the stow should be taken. If it is in excess of 65oC sailing should be postponed until it is clear that it is falling. If it continues to rise the master should call for the assistance of the local P & I correspondent.
(g) Should the master suspect a serious abnormality in the temperature of the cargo during the voyage he should make for a port of refuge and seek assistance. Ventilation should continue in the meantime.
(h) Any dust accumulated on decks or elsewhere during loading or discharge should be washed off as soon as possible to prevent adhesion.
Any decision to carry DRI in contravention of this advice should be discussed with the Association before loading commences.
This Circular supersedes all previous circulars on this subject.