The Condition Assessment Scheme (CAS) is intended to complement the requirements of Annex B of the Guidelines on the enhanced programme of inspections during surveys of bulk carriers and oil tankers (hereinafter called Enhanced Survey Programme). The CAS is to verify that the structural condition of single hull oil tankers at the time of survey is acceptable and, provided subsequent periodical surveys are satisfactorily completed and effective maintenance is carried out by the ship’s operator, will continue to be acceptable for a continued period of operation, as indicated in the Statement of Compliance.
The requirements of the CAS include enhanced and transparent verification of the reported structural condition and of the ship and verification that the documentary and survey procedures have been properly carried out and completed. The Scheme requires that compliance with the CAS is assessed during the Enhanced Survey Programme of Inspections concurrent with intermediate or renewal surveys.
The requirements of the CAS apply to:
- oil tankers of 5,000 tons deadweight and above and of 15 years and over after date of delivery of the ship, in accordance with regulation 13G(6);
- oil tankers subject to the provisions of regulation 13G(7), where authorization is requested for continued service beyond the anniversary of the date of delivery of the ship in 2010; and
- oil tankers of 5,000 tons deadweight and above and of 15 years and over after date of delivery of the ship, carrying crude oil as cargo having a density at 15oC higher than 900 kg/m3 but lower than 945 kg/m3 , in accordance with regulation 13H(6)(a).”
Contents of the revised MARPOL Annex I
A Category 2 or 3 oil tanker of 15 years and over after the date of its delivery shall comply with the Condition Assessment Scheme adopted by the Marine Environment Protection Committee by resolution MEPC.94(46), as may be amended, provided that such amendments shall be adopted, brought into force and take effect in accordance with the provisions of article 16 of the present Convention relating to amendment procedures applicable to an appendix to an Annex.
The Administration may allow continued operation of a Category 2 or 3 oil tanker beyond the date specified in paragraph (4) of this regulation, if satisfactory results of the Condition Assessment Scheme warrant that, in the opinion of the Administration, the ship is fit to continue such
operation, provided that the operation shall 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 after the date of its delivery, whichever is the earlier date.
Reg. 13H (6)(a)
The Administration may allow continued operation of an oil tanker of 5,000 tons deadweight and above, carrying crude oil having a density at 15ºC higher than 900 kg/m3 but lower than 945 kg/m3 , beyond the date specified in paragraph (4)(a) of this regulation, if satisfactory results
of the Condition Assessment Scheme referred to in regulation 13G(6) 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
operation shall not go beyond the date on which the ship reaches 25 years after the date of its delivery
- “Category 1 oil tanker” means oil tankers of 20,000 tons deadweight and above carrying crude oil, fuel oil, heavy diesel oil or lubricating oil as cargo, and of 30,000 tons deadweight and above carrying other oils, which do not comply with the requirements for protectively located segregated ballast tanks (commonly known as Pre-MARPOL tankers).
- “Category 2 oil tanker” means oil tankers of 20,000 tons deadweight and above carrying crude oil, fuel oil, heavy diesel oil or lubricating oil as cargo, and of 30,000 tons deadweight and above carrying other oils, which do comply with the protectively located segregated ballast tank requirements (MARPOL tankers), while
- “Category 3 oil tanker” means an oil tanker of 5,000 tons deadweight and above but less than the tonnage specified for Category 1 and 2 tankers.
Scope of the CAS
The CAS shall apply to surveys of the hull structure in way of cargo tanks, pump rooms, cofferdams, pipe tunnels, void spaces within the cargo area and all ballast tanks.
Relative to ESP, CAS is unique in two respects:
- CAS contains very specific responsibilities and deadlines for planning the survey, which must begin 8 months in advance of the survey’s commencement; and
- The flag Administration must review/monitor the survey and reporting process and issue the five-year full term CAS Statement of Compliance).
- The CAS survey shall be aligned to the Enhanced Programme of Inspection.
- The first CAS survey in accordance with regulation 13G(6) shall be carried out concurrent with the first scheduled intermediate or renewal survey after 5 April 2005, or when the ship reaches the 15 years of age, whichever occurs later.
- The first CAS survey in accordance with regulation 13G(7) shall be carried out concurrent with the scheduled intermediate or renewal survey due prior to the anniversary of the date of delivery of the ship in 2010.
- The first CAS survey in accordance with regulation 13H(6)(a) shall be carried out concurrent with the first scheduled intermediate or renewal survey after 5 April 2005.
- In the case where the Statement of Compliance issued following the first CAS survey under 5.3.2 is valid beyond the anniversary of the date of delivery of the ship in 2010, that CAS may be treated as the first CAS carried out in compliance with regulation 13G(7).
- Any subsequent CAS survey, required for the renewal of the Statement of Compliance, shall be carried out at intervals not exceeding 5 years and 6 months.
- Not withstanding the above, the Company may, with the agreement of the Administration, opt to carry out the CAS survey at a date earlier than the due date of the survey referred to above, provided that all the requirements of the CAS are complied with.
Preparations for the CAS survey
Early and detailed planning to identify areas of potential risk is a prerequisite for the successful and timely completion of the CAS. The following sequence of events shall be observed:
- Notification from the Company to the Administration and to the RO of its intention to proceed with the CAS shall be submitted not less than 8 months prior to the planned commencement of the CAS survey.
- Upon receipt of such notification the RO shall:
- issue to the Company the Survey Planning Questionnaire not later than 7 months prior to the planned commencement of the CAS survey; and
- advise the Company whether there have been any changes to the maximum acceptable structural corrosion diminution levels applicable to the ship.
- The Company shall complete and return the Survey Planning Questionnaire to the RO not less than 5 months prior to the planned commencement of the CAS survey. A copy of the completed questionnaire shall be forwarded by the Company to the Administration.
- The Survey Plan for the CAS shall be completed and submitted in signed order by the Company to the RO not less than 2 months prior to the planned commencement of the CAS survey. A copy of the Survey Plan for the CAS shall be forwarded by the Company to the
- In special circumstances, such as re-activation from lay-up or unexpected events such as an extended stoppage period for hull or machinery damage, the Administration may, on a case by case basis, relax the time frame,for commencement of CAS procedures. Such relaxation shall, at all times, be subject to the RO having sufficient time to complete the CAS survey and issue the Interim Statement of Compliance under regulation 13G(6) or 13H(6)(a), or the Administration to review the CAS Final Report and issue the Statement of Compliance under regulation 13G(7), as applicable, prior to re-entry of the ship to service.”
Survey Plan for the CAS
The Survey Plan for the CAS shall be developed by the Company in cooperation with the RO. The Administration may participate in the development of the Survey Plan, if it deems necessary. The RO shall be fully satisfied prior to the CAS survey being commenced. The CAS survey shall not commence unless and until the Survey Plan has been agreed.
In developing the Survey Plan, the following documentation shall be collected and reviewed with a view to identifying tanks, areas and structural elements to be examined:
- Basic ship information and survey status;
- Main structural plans of cargo and ballast tanks (scantling drawings), including information regarding use of high tensile steels (HTS);
- Condition Evaluation Report and, where relevant, any previous CAS Final Reports;
- Thickness measurement reports;
- Relevant previous damage and repair history;
- Relevant previous survey and inspection reports from both the RO and the Company;
- Cargo and ballast history for the last 3 years, including carriage of cargo under heated conditions;
- Details of the inert gas plant and tank cleaning procedures as indicated in the Survey Planning Questionnaire;
- Information and other relevant data regarding conversion or modification of the ship’s cargo and ballast tanks since the time of construction;
- Description and history of the coating and corrosion protection system (including anodes and previous class notations), if any;
- Inspections by the Company’s personnel during the last 3 years with reference to:
.1 structural deterioration in general;
.2 leakages in tank boundaries and piping;
.3 condition of the coating and corrosion protection system (including anodes), if any;
- Information regarding the relevant maintenance level during operation including:
.1 port State control reports of inspection containing hull related deficiencies;
.2 Safety Management System non-conformities relating to hull maintenance, including the associated corrective action(s); and
- Any other information that will help identify Suspect Areas and Critical Structural Areas.
The Survey Plan shall include relevant information so as to enable the successful and efficient execution of the CAS survey and shall set out the requirements with respect to close-up surveys and thickness measurements.
The Survey Plan shall include:
- Basic ship information and particulars;
- Main structural plans of cargo and ballast tanks (scantling drawings), including information regarding use of high tensile steels (HTS);
- Arrangement of tanks;
- List of tanks with information on their use, extent of coatings and corrosion protection systems;
- Conditions for survey (e.g. information regarding tank cleaning, gas freeing, ventilation, lighting, etc.);
- Provisions and methods for access to structures;
- Equipment for surveys;
- Identification of tanks and areas for the close-up survey;
- Identification of tanks for tank testing
- Identification of areas and sections for thickness measurement;
- Identification of the Thickness Measurement (TM) firm;
- Damage experience related to the ship in question; and
- Critical Structural Areas and Suspect Areas, where relevant.
Documentation on board
The Company shall ensure that, in addition to the agreed Survey Plan, all other documents used in the development of the Survey Plan are available on board at the time of the CAS survey. Prior to the commencement of any part of the CAS survey, the attending surveyor(s) shall examine and ascertain the completeness of the on board documentation and shall review its contents with a view to ensuring that the Survey Plan remains relevant.
CAS Survey Requirements
- Prior to the commencement of any part of the CAS survey a meeting shall be held between the attending surveyor(s), the Company’s representative(s) in attendance, the TM Firm Operator (as applicable) and the master of the ship for the purpose of ascertaining that all the arrangements envisaged in the Survey Plan are in place, so as to ensure the safe and efficient execution of the survey work to be carried out.
- The CAS survey shall be carried out by not less than two qualified exclusive surveyors of the RO. A qualified surveyor of the RO shall attend on board during the taking of the thickness measurements for the purpose of controlling the process.
- The RO shall designate the surveyor(s) and any other personnel who will be engaged in the CAS of each vessel and shall keep records to this end. A qualified surveyor(s) shall have documented experience in carrying out intermediate or renewal surveys in accordance with the Enhanced Survey Programme of Inspection for tankers. In addition, all RO personnel to be assigned duties in connection with the CAS shall complete, prior to the assignment of such duties, an appropriate training and familiarization programme to enable the RO to ensure the consistent and uniform application of the CAS. The Administration shall require the RO to keep records of the qualifications and experience of the surveyors and of other personnel assigned to carry out work for the CAS. The Administration shall require the RO to monitor the performance of the personnel who have carried out or have been engaged in any CAS work and to keep records to this end.
- When the CAS survey is split between survey stations, a list of the items examined and an indication of whether the CAS survey has been completed shall be made available to the attending surveyors at the next survey station prior to continuing the CAS survey.
- Whenever the attending surveyors are of the opinion that repairs are required, each item to be repaired shall be identified in a numbered list. Whenever repairs are carried out, details of the repairs effected shall be reported by making specific reference to relevant items in the numbered list.
- Whenever the attending surveyors are of the opinion that it is acceptable to defer hull repairs beyond the due date previously assigned, such a decision shall not be left to the sole discretion of the attending surveyors. The RO Headquarters shall be consulted in such circumstances and shall give specific approval to the recommended action.
- The CAS survey is not complete unless all recommendations/conditions of class which relate to hull structures under review by the CAS survey have been rectified to the satisfaction of the RO.
Conditions for survey
- The Company shall provide the necessary facilities for a safe conduct of the CAS survey.
- In cases where the provisions of safety and required access are judged by the attending surveyors not to be adequate, the CAS survey of the spaces involved shall not proceed. In order to enable the attending surveyors to carry out the CAS survey, provisions for proper and safe access, shall be agreed between Company and Recognised Organisation.
- Details of the means of access are provided in the Survey Planning Questionnaire.
- Tanks and spaces shall be safe for access. Tanks and spaces shall be gas free and shall be ventilated. Prior to entering a tank, void or enclosed space, it shall be verified that the atmosphere in the tank is free from hazardous gas and contains sufficient oxygen.
- Tanks and spaces shall be sufficiently clean and free from water, scale, dirt, oil residues, corrosion scale, sediments etc., to reveal significant corrosion, deformation, fractures, damages or other structural deterioration as well as the condition of the coating.
- Sufficient illumination shall be provided to reveal significant corrosion, deformation, fractures, damages or other structural deterioration as well as the condition of the coating.
- Where soft coatings have been applied, safe access shall be provided for the attending surveyor(s) to verify the effectiveness of the coating and to carry out an assessment of the conditions of internal structures, which may include spot removal of the coating. Where the presence of soft coating inhibits safe access, the soft coating shall be removed.
- The attending surveyor(s) shall always be accompanied by at least one responsible person assigned by the Company experienced in tank and enclosed spaces inspection. In addition a backup team of at least two experienced persons shall be stationed at the hatch opening of the tank or space that is being surveyed. The back-up team shall continuously observe the work in the tank or space and shall keep lifesaving and evacuation equipment ready for use.
Access to structures
For overall survey, means shall be provided to enable the attending surveyors to examine the structure in a safe and practical way.
- For close-up survey, one or more of the following means for access, acceptable to the attending surveyors, shall be provided:
- permanent staging and passages through structures
- temporary staging and passages through structures
- lifts and moveable platforms
- rafts or boats
- other equivalent means.
- Surveys of tanks or spaces by means of rafts or boats may only be undertaken with the agreement of the attending surveyors, who shall take into account the safety arrangements provided, including weather forecasting and ship response in reasonable sea conditions.
- When rafts or boats will be used for close up survey the following conditions shall be observed:
- only rough duty, inflatable rafts or boats, having satisfactory residual buoyancy and stability even if one chamber is ruptured, shall be used;
- the boat or raft shall be tethered to the access ladder and an additional person shall be stationed down the access ladder with a clear view of the boat or raft;
- appropriate lifejackets shall be available for all participants;
- the surface of water in the tank shall be calm (under all foreseeable conditions the expected rise of water within the tank shall not exceed 0.25 m) and the water level
either stationary or falling. On no account shall the level of the water be rising while the boat or raft is in use;
- the tank or space must contain clean ballast water only. Even a thin sheen of oil on the water is not acceptable;
- at no time shall the water level be allowed to be within 1 m of the deepest under deck web face flat so that the survey team is not isolated from a direct escape route to the tank hatch. Filling to levels above the deck transverses shall only be contemplated if a deck access manhole is fitted and open in the bay being examined, so that an escape route for the survey party is available at all times;
- if the tanks (or spaces) are connected by a common venting system, or Inert Gas system, the tank in which the boat or raft is to be used shall be isolated to prevent a transfer of gas from other tanks (or spaces).
- In addition to the above rafts or boats alone may be allowed for inspection of the under deck areas for tanks or spaces, if the depth of the webs are 1.5 m or less.
- If the depth of the webs is more than 1.5 m, rafts or boats alone may be allowed only:
- when the coating of the under deck structure is in GOOD condition and there no evidence of wastage; or
- if a permanent means of access is provided in each bay to allow safe entry and exit. This means of access is to be direct from the deck via a vertical ladder and a small platform shall be fitted approximately 2 m below the deck.
- If neither of the above conditions are met then staging shall be provided for the survey of the under deck area.
Equipment for survey
Thickness measurement shall normally be carried out by means of ultrasonic test equipment. The accuracy of the equipment shall be proven to the attending surveyor(s) as required.
- One or more of the following fracture detection procedures may be required if deemed necessary by the attending surveyor(s):
- radiographic equipment
- ultrasonic equipment
- magnetic particle equipment
- dye penetrant
- other equivalent means.
- Explosimeter, oxygen-meter, breathing apparatus, lifelines, riding belts with rope and hook and whistles together with instructions and guidance on their use shall be made available during the CAS survey. A safety check-list shall be provided.
- Adequate and safe lighting shall be provided for the safe and efficient conduct of the CAS survey.
- Adequate protective clothing shall be made available and used (e.g. safety helmet, gloves, safety shoes, etc) during the CAS survey.
Surveys under CAS
An overall survey of all spaces set out in Scope of CAS shall be carried out which includes surveys of the hull structure in way of cargo tanks, pump rooms, cofferdams, pipe tunnels, void spaces within the cargo area and all ballast tanks.
- All web frame rings, in all ballast tanks (Complete transverse web frame ring including adjacent structural members.)
- All web frame rings, in a cargo wing tank (Complete transverse bulkhead, including girder and stiffener systems and adjacent members.)
- A minimum of 30% of all web frame rings, in each remaining cargo wing tank (Complete transverse web frame ring including adjacent structural members.)
- All transverse bulkheads, in all cargo and ballast tanks (Complete transverse bulkhead, including girder and stiffener systems and adjacent members.)
- A minimum of 30% of deck and bottom transverses including adjacent structural members, in each cargo centre tank.
- Additional complete transverse web frame rings or deck and bottom transverse including adjacent structural members as considered necessary by the attending surveyor.
- Within the cargo area:
- Each deck plate
- Three transverse sections
- Each bottom plate
- Measurements of structural members subject to close-up survey according for general assessment and recording of corrosion pattern.
- Suspect areas
- Selected wind and water strakes outside the cargo area.
- All wind and water strakes within the cargo area.
- Internalstructure in the fore and aft peak tanks
- All exposed main deck plates outside the cargo area and all exposed first tier superstructure deck plates
A survey report shall be completed for the CAS survey. The report shall indicate the date, location (place), and where relevant, whether or not the CAS survey was carried out in drydock afloat or at sea. When the CAS survey is split between different survey stations, a report shall be made for each portion of the CAS survey.
Survey records relating to the CAS survey, including actions taken, shall form an auditable documentary trail.
Extent of the Survey:
- identification of the spaces where an overall survey has been carried out;
- identification of location, in each space, where a close-up survey has been carried out, together with the means of access used; and
- identification of the spaces, and locations in each space, where thickness measurements have been carried out; and
Results of the Survey:
- extent and condition of coating in each space. Identification of spaces fitted with anodes and the overall condition of the anodes;
- structural condition reporting for each space, which shall include information on the following, as applicable:
- corrosion (location and type of corrosion such as grooving, pitting, etc.);
- cracks (location, description and extent);
- buckling (location, description and extent);
- indents (location, description and extent); and
- areas of substantial corrosion; and
Actions taken with respect to findings:
- details of repairs completed on structural members in identified spaces, including the repair method and extent; and
- list of items to be kept under observation for planning future inspections and surveys including any thickness measurements.
Where no defects are found, this shall be stated in the report for each space. The narrative report shall be supplemented by photographs showing the general condition of each space, including representative photographs or sketches of any of the above reported items. The thickness measurement report shall be verified and endorsed by the attending. The attending surveyors shall sign the CAS survey report.
Review of the CAS by the RO
The RO Headquarters shall carry out a verification review of the CAS survey reports, the documents, photographs and other records relating to the CAS for the purpose of ascertaining and confirming that the requirements of the CAS have been met. The RO reviewing personnel shall not be engaged in any way whatsoever with the CAS survey under review.
CAS Final Report to the Administration
The RO shall prepare a CAS Final Report to the Administration upon completion of the CAS survey and following the review of the CAS survey reports by the RO’s Headquarters. The CAS Final Report shall be submitted by the RO to the Administration without delay and in any case not later than 2 months prior to the date the ship is required to be issued with a Statement of Compliance.
The CAS Final Report shall, at least, include:
- General particulars:
- Ship’s name
- IMO number
- Flag State
- Port of registry
- Gross tonnage
- Deadweight (metric tonnes)
- Summer load line draught
- Date of delivery
- Category of ship
- Date for compliance with regulation 13F
- Report identification reference
- A summary as to where, when, by whom and how the CAS survey was carried out;
- A statement identifying all survey documentation, including the Survey Plan;
- A statement as to the condition of the corrosion prevention system(s) applied to the spaces;
- A statement identifying all thickness measurement reports;
- A summary of the findings of the overall surveys;
- A summary of the findings of the close-up surveys;
- A summary of the hull repairs carried out;
- An identification, together with the location, the extent and the condition, of all areas with substantial corrosion;
- A summary of the results of the evaluation of the thickness measurements,
- Including identification of the areas and sections where thickness measurements were carried out;
- An evaluation of the structural strength of the vessel and an assessment of compliance with the acceptance criteria;
- A statement as to whether all the applicable requirements of the CAS have been met;
- A recommendation to the Administration as to whether the ship should be allowed to continue operating until the date envisaged in regulation 13G for compliance with the requirements of regulation 13F or for the period of validity of the CAS, if earlier; [New-build tankers are covered by Regulation 13F, while regulation 13G applies to existing crude oil tankers of 20,000 dwt and product carriers of 30,000 dwt and above. Regulation 13G came into effect on 6 July 1995. Regulation 13F requires all new tankers of 5,000 dwt and above to be fitted with double hulls separated by a space of up to 2 metres (on tankers below 5,000 dwt the space must be at least 0.76m)]
The Administration shall review the CAS Final Report prior to the issue of the Statement of Compliance, shall record and document the findings and conclusions of the review and its decision as to the acceptance or rejection of the CAS Final Report and shall produce a Review Record. The Administration shall ensure that any persons assigned to monitor the execution of the CAS or to review a CAS Final Report:
- are adequately qualified and experienced to the satisfaction of the Administration;
- are under the direct control of the Administration; and
- have no connection whatsoever with the RO which carried out the CAS survey under review
For the purpose of the CAS:
- “MARPOL 73/78” means the Protocol of 1978 relating to the International Convention for the Prevention of Pollution from Ships, 1973, as amended.
- “Regulation” means the regulations contained in Annex I of MARPOL 73/78.
- “Recognized Organization (RO)” means an organization recognized by the Administration to perform the surveys in accordance with the provisions of regulation 4(3) of Annex I of MARPOL 73/78.*
- “Administration” means the Government of the State as defined in Article 2(5) of MARPOL 73/78.
- “Company” means the owner of the ship or any other organization or person such as the manager or the bareboat charterer, who has assumed the responsibility for the operation of the ship from the owner of the ship and who, on assuming such responsibility, has agreed to take over all duties and responsibilities
imposed by the International Safety Management (ISM) Code.
- “Substantial corrosion” means an extent of corrosion such that the assessment of the corrosion pattern indicates wastage in excess of 75% of the allowable margins, but within acceptable limits.
- “GOOD condition” means a coating condition with only minor spot rusting.
- “Thickness Measurement (TM) Firm” means a qualified company certified by a RO in accordance with the principles stipulated in annex 7 to Annex B to resolution A.744(18), as amended.
- “Critical Structural Areas” are locations which have been identified from calculations to require monitoring or from the service history of the subject ship or from similar or sister ships to be sensitive to cracking, buckling or corrosion which would impair the structural integrity of the ship.
- “Suspect Areas” are locations showing substantial corrosion and/or are considered by the attending surveyor to be prone to rapid wastage.
- “Organization” means the International Maritime Organization.
In order to assist further, the text of Resolutions 94(46), 99(48), 111(50) and 112(50) have been provided below in download section.