Tankers: Update on new statutory requirements


tanker_deckOn 1 January 2016, we will see the entry into force of new requirements for inert gas, stability instruments and ODME, especially concerning tankers. The following is a recap of the new requirements and the implications they may have. In recent years, there have been several incidents involving intank explosions on small oil and chemical tankers, many of which occurred in connection with gas-freeing and tank cleaning. The main reason is believed to be the lack of an inert atmosphere in the cargo tank, as these tankers are currently exempted from using inert gas.

As a consequence, it has been decided to lower the SOLAS inert gas limit from 20,000dwt to 8,000dwt. In addition, chemical tankers’ current exemption from inerting tanks of less than 3,000m3 will be lifted for new ships. Since this is not a retroactive requirement, it will only apply to new tankers constructed on or after 1 January 2016. In-tank inspections, a practice quite common prior to loading many chemicals, might cause logistical challenges and port congestion as new chemical tankers above 8,000dwt – irrespective of their tank size – will now have to purge their tanks alongside after the tank inspection when taking on low-lash products.

As a means to avoid this, the revised SOLAS allows the application of inert gas to be postponed until after loading but before the commencement of unloading. It should be noted, however, that because of the risk of generating static electricity by using exhaust gas, only nitrogen is acceptable for this purpose. This further implies that, in order to utilize this option, an N2 inert-gas plant should be installed on board, and of course this is something to bear in mind in connection with newbuilding specifications.

Consequential amendments have also been made to the FSS and IBC Codes. In the FSS Code, it is basically the oxygen limit for inert gas supplied to the tanks which has been reduced from 8% to 5%. The amendments made to the IBC Code include operational changes in the gas freeing and handling of inhibited products where the inhibitor is oxygen dependent and the products must at the same time be carried in an inert atmosphere.

The revised gas-freeing requirements are now more aligned with what is required for oil tankers under SOLAS, ie, that the tanks requiring inert gas should, after tank cleaning, be purged down to a certain limit of flammable vapours before gas freeing with fresh air may take place. Products protected by an oxygen-dependent inhibitor are currently not to be carried in an inert atmosphere, in other words such products are today carried in tanks of less than 3,000m3 on ships above 20,000dwt when the flashpoint is less than 60°C, the only exemption being for Styrene Monomer, which may be carried under inert conditions subject to special provisions.

In order to still be able to ship these products on new ships above 8,000dwt in future, the use of inert gas has been allowed provided it is not applied until discharging commences and the O2 level is kept above that stated to be the minimum O2 level on the inhibitor certificate. And, for the reasons previously mentioned, the postponed application of inert gas requires the inert-gas medium to be N2 and an N2 inert-gas plant to be fitted.


New requirements for onboard stability instruments will be applicable to all tankers effective from 1 January 2016. MARPOL Annex I, the IBC/BCH Code and the IGC Code have all been amended, requiring tankers to be fitted with a stability instrument capable of handling both intact and damage stability. The new requirement is retroactive and applies to both new and existing ships as follows:

■ Ships constructed on or after 1 January 2016, at delivery.

■ Ships constructed before 1 January 2016, at the first renewal survey on or after 1 January 2016 but no later than 1 January 2021.

An instrument already installed, capable of verifying both intact and damage stability, may be accepted by the Flag Administration. There are some openings for waiving the requirement, for example for ships operating only in a limited number of loading conditions.

ODME type-approved for bio-fuel blends

Bio-fuel blends consist of a bio-fuel part, which is considered to be a chemical subject to MARPOL Annex II and the IBC Code, and a petroleum part, which is subject to MARPOL Annex I. One example is a mixture of ethanol and gasoline. For bio-fuel blends, a cut-off limit of 75% has been agreed on, determining the regime to which the blend is subject – MARPOL Annex I or Annex II, ie, if the petroleum part is 75% or more the blend is considered to be an oil governed by MARPOL Annex I. Up to now, bio-fuel blends have been allowed to be shipped under MARPOL Annex I without the ODME being type-approved for the specific blend. This has been considered all right as long as the resulting slop has beendelivered ashore to a reception facility. However, as of 1 January 2016 this is no longer an option. From this date, in order to still ship a bio-fuel blend under Annex I, a non-compliant ODME has to be upgraded or replaced and the blend in question should be included in the new type-approval certificate.

Source: DNV GL

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