Section 3 Surveys

301. General

1. Structures classed with the Society are to be subjected to the following surveys to maintain the classification.

(1) Special Surveys

(2) Annual Surveys

(3) Continuous Surveys

(4) Alteration Surveys

(5) Occasional Surveys

2. Damage, failure and repair

(1) Damage, failure, deterioration or repair to the classed structure is to be submitted by the Owner for examination by the Surveyor at first opportunity. All repairs found necessary by the Surveyor are to be carried out to Surveyor's satisfaction.

(2) Where repairs to the structure are intended to be carried out at site, complete repair procedure

including the extent of proposed repair and the need for Surveyor's attendance on site is to be submitted to and agreed upon by the Surveyor reasonably in advance.

302. Annual Surveys

1. Due range

(1) Annual Surveys are to be carried out within three months before or after each anniversary date.

(2) Where Surveyors are engaged in the survey of a grouping of structures of similar design and location, and where requested by the operator, special consideration will be given to the timing of Annual Surveys such that all Periodical Survey due dates can be harmonized.

2. Survey items

(1) Each Annual Survey is to include a thorough Special attention will be given to the splash corrosion.

(2) Additionally, where it appears that significant

visual examination of all above water structures. zone for possible damage or deterioration from

deterioration or damage has occurred to an in-

(3)

(4)

(5)

stallation since the last survey, a general examination, by the diver, underwater camera, sub- mersible, or other suitable means, of the underwater structure, the sea floor, and the corrosion control system shall be carried out. Underwater examinations are to be contracted by the Operator and monitored by a Surveyor.

Any novel features incorporated in the design are to be given special attention according to

procedures agreed to during review of the design. Particular attention is to be given to sig- nificant modifications or repairs made as a result of findings at the previous survey.

The Annual Survey is also to include verification that the approved design life has not been exceeded. If the end of the design life has been reached then the provisions of Ch 4, Sec 3 of the Rules are to be applied and specific requirements for maintaining the class of the struc-

ture are to be obtained from the technical office.

Assessment of the degree of marine growth shall be carried out. Should marine growth be found to be thicker than the original approved design, it is to be removed. If the Operator de- cides to leave the marine growth greater than what is allowed in the approved design, the Operator is to show justification that the higher hydrodynamic loading due to the additional ma- rine growth will not affect the structural integrity of the structure.

Ch2 Classification and Surveys Ch 2

303. Special Surveys

1. Due range

(1) Special Surveys are to be carried out at least once every five years.

(2) If a Special Survey is not completed at one time, it will be credited as of the completion date of the survey provided the due date of the Special Survey is not overdue by more than six months.

(3) Where Surveyors are engaged in the survey of a grouping of structures of similar design and location, and where requested by the operator, special consideration will be given to the timing of

Special Surveys such that all Periodical Survey due dates can be harmonized.

(4) Continuous Survey

At the

system carried

request of the Owner and upon the Society's approval of the proposed arrangements, a

of Continuous Surveys may be undertaken whereby the Special Survey requirements are out in regular rotation to complete all of the requirements of the particular Special

Survey within a 5-year period. Each part(item) surveyed becomes due again for survey approx- imately five(5) years from the date of survey. The due parts(items) are generally to be com- pleted each year. Continuous items that are three(3) months or more overdue at the time of Annual Survey attendance will be basis for the Annual Survey not to be credited and for non- endorsement of the Certificate of Classification. Consideration may be given by the Society to an extension to complete survey items. If any defects are found during the survey, they are to be dealt with to the satisfaction of the Surveyor.

2. Survey items

(1) The requirements of the Annual Survey are to be met during the Special Survey. Additionally, underwater inspection of selected areas of the installation is to be carried out. Also, non-

destructive testing is to be carried out on representative joints of

necessary, structural supports of conductors and risers.

(2) The extent and methods to be employed in such testing, cleaning, ture are to be in accordance with an approved inspection plan.

the structures and if found

and inspection of the struc-

(3) The inspection plan, which is to be submitted for approval, is to cover all Special Surveys for

the design life of the structure. It is to enumerate in detail the items to be surveyed, the testing and inspection procedures to be employed, and where necessary, cleaning and nondestructive testing procedures.

(4) The plan is to include sufficiently detailed drawings which can be used by the Surveyor to ref- erence and locate the items to be surveyed.

(5) Divers carrying out structural inspections and nondestructive testing on the underwater structures are to be suitably qualified.

(6) The Special Survey is also to include monitoring of the effectiveness of the corrosion protection system. The effectiveness of the corrosion protection system is to be monitored by taking meas-

urements of the potential voltages generated by such systems.

(7) Scour in way of platform legs, tilt and subsidence are also to be checked and witnessed by the attending Surveyor.

(8) If the end of the design life has been reached then the provisions of Ch 4, Sec 3 are to be

applied and specific requirements for maintaining the class of the structure are to be obtained from the technical office.

(9) thickness measurements

(A) For the following areas, thickness measurement are required to be taken.

(a) Structures in way of the splash zone

(b) Suspect areas

(B) Fixed Offshore Structures consisting of converted self-elevating units will require thickness measurement where accessible in accordance with the applicable thickness measurement re- quirements contained in Guidance for Mobile Offshore Drilling Units.

Ch2 Classification and Surveys Ch 2

304. Occasional Surveys

1. Reactivation Surveys

In the case of structures which have been out of service for an extended period, the requirements for surveys on reactivation are to be specially considered in each case, due regard being given to the status of surveys at the time of the commencement of the deactivation period, the length of the period, and conditions under which the structure had been maintained during that period.

2. Incomplete Surveys

When a survey is not completed, the Surveyors are to report immediately upon the work done in order that the Operator and the Head Office may be advised of the parts still to be surveyed.

3. Self-elevating Units Deployed as Fixed Offshore Structure

(1) Self-elevating Mobile Offshore Units which have been converted to site dependent platform structures will be subjected to surveys as applicable in these sections in addition to the appli- cable structural examinations required by Guidance for Mobile Offshore Drilling Units.

(2) Surveys are to include Annual and Special Surveys with an underwater exam in lieu of dry- docking of the above mud line sections of the legs, mats, spud cans and platform twice in each five year Special Survey period in accordance with applicable sections of Guidance for Mobile

Offshore Drilling Units.

(3) Spud cans and mats which will be located below the mud line will be considered inaccessible and fatigue, structural and corrosion analyses shall be provided to justify the integrity of these

4. inaccessible areas for the design life of the structure.

Survey for extension of use

(1) Existing structures to be used at the same location for an extended period of time beyond their original design life are subject to additional surveys to determine the actual condition of the structure.

(2) The extent of the survey will depend on the completeness of the existing survey documents.

The Society will review and verify maintenance manual, logs and records. Any alterations, re-

pairs or installation of equipment since installation should be included in the records.

(3) Those survey requirements in 303. for the Special Survey have to be included in the survey for extension of use.

(A) Splash zone

(B) Inspection of above water and under water structural members and welds for damages and deteriorations

(C) Examination of corrosion protection systems

(D) Measurements of marine growth

(E) Sea floor condition survey

(F) Examination of secondary structural attachments, risers and riser clamps

(4) Special attention should be given to the following critical areas.

(A) Areas of high stress

(B) Areas of low fatigue

(C) Damage incurred during installation or while in service

(D) Repairs or modifications made while in service

(E) Abnormalities found during previous surveys

(5) An inspection report of the findings is to be submitted to the Society for review and evaluation of the condition of the structure.

(6) The need for more frequent future Periodical Surveys will be determined based on the calcu-

5. lated remaining fatigue life and past inspection results.

Relocation of existing structures

(1) Existing structures that are classed at a specified location require special consideration when re- location to a new site is proposed.

(2) The Owner is to advise the Society of the proposal to change locations addressing removal, transportation and re-installation aspects of the change.

(3) Survey requirements described in 4. and 204. wherever applicable, are to be complied with in

addition to an engineering analyses required to justify the integrity of the structure for the de-

Ch2 Classification and Surveys Ch 2