Tanker safety - preventing accidental pollution
IMO's major function is to make
shipping of all types safer, including tankers. The measures
incorporated in the numerous safety conventions and recommendations apply to
these as well as other ships - and the safer a ship is, the less likely it is
to be involved in an accident.
SOLAS
The International Convention for
the Safety of Life at Sea (SOLAS), 1974 includes special
requirements for tankers. Fire safety provisions, for example, are much
more stringent for tankers than ordinary dry cargo ships, since the danger of
fire on board ships carrying oil and refined products is much greater.
It is not just fire which is
dangerous - in certain circumstances a single spark can cause a disaster, for
even tanks which contain no oil are filled with flammable gas which can
explode unless proper procedures are followed.
The normal method is to fill these
tanks with inert (non-explosive) gas from the ship's boiler flue: it is
cleaned and then pumped into the empty tanks, or into the spaces left above
the oil in loaded tanks. An inert gas system is required on all new
tankers and most existing tankers of 20,000 dwt and above.
Equipment duplication
IMO has introduced several
measures over the years which are designed to ensure that, in the event of
mechanical failure, the ship can still be controlled. SOLAS makes it
necessary for essential parts of the steering gear of tankers to be
duplicated.
As with other ships, much of the
navigational equipment of tankers must also be duplicated.
Mandatory towing arrangements
Since 1 January 1996 all new
tankers of 20,000 dwt and above have had to be fitted with an emergency
towing arrangement fitted at either end of the ship. Existing ships had to be
fitted with such an arrangement not later than 1 January 1999.
MARPOL 73/78 - Reducing the
consequences of accidents
The International Convention for
the Prevention of Pollution by Ships (MARPOL 73/78) includes regulations
regarding subdivision and stability which are designed to ensure that, in any
loading conditions, the ship can survive after being involved in a collision
or stranding.
Protective location of segregated
ballast tanks
The 1978 MARPOL Protocol
introduced the concept known as protective location of segregated ballast
tanks. This means that the ballast tanks (which are empty on the
cargo-carrying leg of the voyage and only loaded with water ballast for the
return leg) are positioned where the impact of a collision or grounding is
likely to be greatest. In this way the amount of cargo spilled after
such an accident will be greatly reduced.
The 1983 MARPOL amendments ban the
carriage of oil in the forepeak tank - the ship's most vulnerable point in
the event of a collision.
Double hulls
In 1992 MARPOL was amended to make
it mandatory for tankers of 5,000 dwt and more ordered after 6 July 1993 to
be fitted with double hulls, or an alternative design approved by IMO
(Regulation 13F (regulation 19 in the revised Annex I which entered into
force on 1 January 2007) in Annex I of MARPOL 73/78).
The requirement for double hulls
that applies to new tankers has also been applied to existing ships
under a programme that began in 1995 (Regulation 13G (regulation 20 in the
revised Annex I which entered into force on 1 January 2007) in Annex I of
MARPOL 73/78). All tankers would have to be converted (or taken out of
service) when they reached a certain age (up to 30 years old). This measure
was adopted to be phased in over a number of years because shipyard capacity
is limited and it would not be possible to convert all single hulled tankers
to double hulls without causing immense disruption to world trade and
industry.
Although the double hull
requirement was adopted in 1992, following the Erika incident off the
coast of France in December 1999, IMO Member States discussed proposals for
accelerating the phase-out of single hull tankers. As a result, in April
2001, IMO adopted a revised phase-out schedule for single hull tankers, which
entered into force on 1 September 2003 (the 2001 amendments to MARPOL 73/78).
The new revised MARPOL regulation 13G set out a stricter timetable for the
phasing-out of single-hull tankers.
In December 2003, further
revisions to 13G (regulation 20 in the revised Annex I which entered into
force on 1 January 2007) were made, accelerating further the phase-out
schedule. These amendments entered into force on 5 April 2005. A new
Regulation on the prevention of oil pollution from oil tankers when carrying
heavy grade oil (HGO) banned the carriage of HGO in single-hull tankers of
5,000 tons dwt and above after the date of entry into force of the regulation
(5 April 2005), and in single-hull oil tankers of 600 tons dwt and above but
less than 5,000 tons dwt, not later than the anniversary of their delivery
date in 2008.
Accelerated phase-out for single-hull tankers
Under the revised regulation 13G
(regulation 20 in the revised Annex I which entered into force on 1 January
2007) of Annex I of MARPOL, the final phasing-out date for Category 1 tankers
(pre-MARPOL tankers) was 2005. The final phasing-out date for category 2 and
3 tankers (MARPOL tankers and smaller tankers) was brought forward to 2010,
from 2015.
The full timetable for the phasing out of single-hull tankers is as follows:
Condition Assessment Scheme (CAS)
Under the revised regulation, the
Condition Assessment Scheme (CAS) is applicable to all single-hull tankers
of 15 years, or older.
The revised regulation allows the
Administration (flag State) to permit continued operation of category 2 or 3
tankers beyond 2010 subject to satisfactory results from the CAS, but the
continued operation must not go beyond the anniversary of the date of
delivery of the ship in 2015 or the date on which the ship reaches 25 years
of age after the date of its delivery, whichever is earlier.
In the case of certain Category 2
or 3 oil tankers fitted with only double bottoms or double sides not used for
the carriage of oil and extending to the entire cargo tank length or double
hull spaces, not meeting the minimum distance protection requirements, which
are not used for the carriage of oil and extend to the entire cargo tank
length, the Administration may allow continued operation beyond 2010,
provided that the ship was in service on 1 July 2001, the Administration is
satisfied by verification of the official records that the ship complied with
the conditions specified and that those conditions remain unchanged. Again,
such continued operation must not go beyond the date on which the ship
reaches 25 years of age after the date of its delivery.
A new MARPOL regulation 13G
(regulation 21 in the revised Annex I which entered into force on 1 January
2007) on the prevention of oil pollution from oil tankers when carrying heavy
grade oil (HGO) bans the carriage of HGO in single-hull tankers of 5,000 tons
dwt and above after the date of entry into force of the regulation (5 April
2005), and in single-hull oil tankers of 600 tons dwt and above but less than
5,000 tons dwt, not later than the anniversary of their delivery date in
2008.
Under the new regulation, HGO
means any of the following:
In the case of certain Category 2
or 3 tankers carrying heavy grade oil as cargo, fitted only with double
bottoms or double sides, not used for the carriage of oil and extending to
the entire cargo tank length, or double hull spaces not meeting the minimum
distance protection requirements which are not used for the carriage of oil
and extend to the entire cargo tank length, the Administration may allow
continued operation of such ships beyond 5 April 2005 until the date on which
the ship reaches 25 years of age after the date of its delivery.
Regulation 13G (regulation 21 in
the revised Annex I which entered into force on 1 January 2007) also allows
for continued operation of oil tankers of 5,000 tons dwt and above, carrying
crude oil with a density at 15ºC higher than 900 kg/ m3 but lower than 945
kg/ m3, if satisfactory results of the Condition Assessment Scheme warrant
that, in the opinion of the Administration, the ship is fit to continue such
operation, having regard to the size, age, operational area and structural
conditions of the ship and provided that the continued operation shall not go
beyond the date on which the ship reaches 25 years after the date of its
delivery.
The Administration may allow
continued operation of a single hull oil tanker of 600 tons deadweight and
above but less than 5,000 tons deadweight, carrying heavy grade oil as cargo,
if, in the opinion of the Administration, the ship is fit to continue such
operation, having regard to the size, age, operational area and structural
conditions of the ship, provided that the operation shall not go beyond the
date on which the ship reaches 25 years after the date of its delivery.
The Administration of a Party to
the present Convention may exempt an oil tanker of 600 tons deadweight and
above carrying heavy grade oil as cargo if the ship is either engaged in
voyages exclusively within an area under the Party's jurisdiction, or is engaged
in voyages exclusively within an area under the jurisdiction of another
Party, provided the Party within whose jurisdiction the ship will be
operating agrees. The same applies to vessels operating as floating storage
units of heavy grade oil.
A Party to MARPOL 73/78 shall be
entitled to deny entry of single hull tankers carrying heavy grade oil which
have been allowed to continue operation under the exemptions mentioned above,
into the ports or offshore terminals under its jurisdiction, or deny ship-to-ship
transfer of heavy grade oil in areas under its jurisdiction except when this
is necessary for the purpose of securing the safety of a ship or saving life
at sea.
The revised MARPOL Annex I
Regulations for the prevention of pollution by oil was adopted in October
2004 and entered into force on 1 January 2007. It incorporates the various
amendments adopted since MARPOL entered into force in 1983, including the
amended regulation 13G (regulation 20 in the revised Annex) and regulation
13H (regulation 21 in the revised annex) on the phasing-in of double hull
requirements for oil tankers. It also separates, in different chapters, the
construction and equipment provisions from the operational requirements and
makes clear the distinctions between the requirements for new ships and those
for existing ships. The revision provides a more user-friendly, simplified
Annex I.
Following the entry into force, on
1 January 2007, of the Revised Annex I to MARPOL 73/78, references to regulations
regaarding double hulls must be updated taking into account the new numbering
system in the revised Annex I according to the following table:
For a comprehensive
cross-reference table between "old" and "new" regulation
numbers in MARPOL Annex I, please refer to MEPC/Circ.421 (also included in
the Additional Information section of the 2006 consolidated edition of MARPOL
(IMO sales No.IC520E))
Enhanced inspections
Since 1995 all tankers and bulk
carriers aged five years and over have been subject to a specially enhanced
inspection programme which is intended to ensure that any deficiencies - such
as corrosion or wear and tear resulting from age or neglect - are detected.
Guidelines on enhanced surveys on
tankers and bulk carriers are contained in Assembly resolution A. 744 (18),
adopted in November 1993, as amended.
Since 1 January 1996, Governments
have been able to propose to IMO the introduction of mandatory ship reporting
systems in areas where there are special environmental or navigational
concerns.
Mandatory reporting systems
require ships to report in to shore authorities when they reach a designated
routeing system and give the ship's name, cargo and other information. This
enables the ship to be identified on radar and its course plotted throughout
the system.
In December 2000, IMO adopted
mandatory requirements for the carriage of automatic identification
systems (AISs) capable of providing information about the ship to other ships
and to coastal authorities automatically. The regulation in SOLAS chapter V –
Safety of Navigation, requires AIS to be fitted aboard all ships of 300 gross
tonnage and upwards engaged on international voyages, cargo ships of 500
gross tonnage and upwards not engaged on international voyages and passenger
ships irrespective of size built on or after 1 July 2002.
Existing tankers (those
constructed before 1 July 2002), had to fit AIS not later than the first
survey for safety equipment on or after 1 July 2003.
The International Regulations for
the Prevention of Collisions at Sea, 1972 (COLREGS) contains special
provisions for ships such as tankers which, by virtue of their draught, have
a reduced ability to manoeuvre.
The International Convention on
Standards of Training, Certification and Watchkeeping for Seafarers, 1978, as
amended in 1995 (STCW) includes several requirements aimed specifically at
those working on tankers.
ISM Code
The International Safety
Management (ISM) Code was adopted in 1994 and became mandatory for tankers in
1998. The ISM Code imposes strict standards on shipping companies.
The sinking of the Erika
off the coast of France in December 1999 led to a new, accelerated phase-out
schedule for single-hull tankers - the revision of regulation 13G (regulation
20 in the revised Annex I which entered into force on 1 January 2007) of
MARPOL 73/78.
The investigations into the Erika incident carried out by the French government and the Maltese maritime authority concluded that age, corrosion, insufficient maintenance and inadequate surveys were all strong contributing factors to the structural failure of the ship. There was a wide consensus that the Erika and other the recent accidents involving oil tankers pointed to a need for additional international measures to eradicate substandard vessels, particularly substandard oil tankers given the catastrophic impact such ships may have on the marine environment in the case of an accident. Besides the revised phase-out scheme for single-hull tankers, IMO also adopted other measures in response to the incident:
The Prestige incident of
November 2002 led to further calls for amendments to the phase-out schedule
for single hull tankers.
The MEPC at its 49th session in July 2003 agreed to an extra session of the Committee, to be convened in December 2003, to consider the adoption of proposals for an accelerated phase-out scheme for single hull tankers, along with other measures including an extended application of the Condition Assessment Scheme (CAS) for tankers. |
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