Section 2 Classification

201. Classification

Structures built and surveyed

for the classification in accordance with this Rules or in accordance

with requirements deemed to be equivalent to this Rules by the Society will be assigned a class

and registered in the Register

of Ships.

202. Class notations

The class will be distinguished by the class notations and the class notations assigned to the struc- tures classed with the Society are to be in accordance with the requirements specified in Pt 1, Ch 1, 201. of Rules for the Classification of Steel Ships. However, "Fixed Offshore Structure" shall be assigned as a ship type notation and the following notations shall be assigned as special feature notations.

(1) The following special feature notations shall be assigned according to a type of the structure.

(A) Jacket

(B) GBS

(C) Compliant Tower

(D) Articulated Tower

(E) Special feature notations according to other types of the structure

(2) The following special feature notations shall be assigned according to a structure.

(A) Drilling

(B) Production

(C) Special feature notations according to other purposes of the structure

purpose of the

203. Maintenance of classification

1. Structures classed with the Society are to be subjected to the surveys to maintain and are to be maintained in good condition in accordance with the requirements Chapter.

the classification specified in this

2. Plans and particulars of any proposed alterations to the approved scantlings or arrangements of hull, machinery or equipment are to be submitted for approval by the Society before the work is com- menced and such alterations are to be surveyed by the Surveyor of the Society.

204. Classification Survey during Construction

1. General

At the Classification Survey during Construction, the hull, machinery and equipment are to be ex- amined in detail in order to ascertain that they meet the relevant requirements of this Rules.

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2. Submission of plans and documents

For a structure requiring Classification Survey during Construction, the plans and documents show- ing the details of the construction, scantlings, materials and particulars of the structure are to be submitted in triplicate and approved before the work is commenced. The same applies also to the cases of any subsequent modifications to the approved drawings or documents.

3. Presence of Surveyors

(1) At the Classification Survey during Construction, the presence of the Surveyor is required at the following stages of the work in relation to hull and equipment.

(A) When the tests of the materials specified in Pt 2, Ch 1 of Rules for the Classification

of Steel Ships and the equipment specified in Pt 4 of Rules for the Classification of Steel Ships are carried out.

(B) When the tests of welding specified in Pt 2, Ch 2 of Rules for the Classification of Steel Ships are carried out.

(C) When designated by the Society during shop work or sub-assembly.

(D) When each block is assembled and erected.

(E) When each part of the hull is completed.

(F) When structural tests, leak test, hose tests and non-destructive tests are carried out.

(G) When performance tests are carried out on closing appliances of openings, mooring equip- ment, cargo handling appliances, fire detection systems, etc.

(H) When each part of the fire protection construction is completed.

(I) When measurement of principal dimensions, hull deflection, etc. are carried out.

(J) When the onboard tests are carried out.

(K) When deemed necessary by the Society.

(2) At the Classification Survey during Construction, the presence of the Surveyor is required at the following stages of the work in relation to machinery.

(A) When the tests of materials of main parts of machinery specified in Pt 2 of Rules for the

Classification of Steel Ships are carried

(B) Main parts of machinery

(a) When the tests specified in either Pt

out.

5 or Pt 6 of Rules for the Classification of

Steel Ships according to the kind of machinery are carried out.

(b) When the materials are assembled sembled for installation on board.

for construction of the parts and the parts are as-

(c) When machining of the main parts is finished and, if necessary, at appropriate stages during machining.

(d) In case of welded construction, before welding is commenced and when it is completed.

(e) When the shop trials are carried out.

(C) When main parts of machinery are installed on board.

(D) When performance tests/onboard tests are carried out on measurement instruments, remote control devices of closing appliances, remote control devices for machinery and gears, auto- matic control devices, fire extinguishing equipments, piping, etc.

(E) When the sea trials are carried out.

(F) When deemed necessary by the Society.

(3) For structures requiring the mooring system when that system is installed on the structure.

4. Tests

At the Classification Survey during Construction, hydrostatic tests, leak tests, hose tests and per- formance tests, etc are to be carried out in accordance with the relevant requirements of this Rules.

5. Steel structures

(1) Application

The requirements of this paragraph are to apply to steel structures.

(2) Materials

The materials are to be in accordance with Ch 3, Sec 1.

(3) Welder Qualification, Welding Procedure Specification and Weld Inspection

Welder Qualification, Welding Procedure Specification and Weld Inspection are to be in accord- ance with Ch 3, Sec 2.

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(4) Tolerances and Alignments

The overall structural tolerances, forming tolerances, and local alignment tolerances are to be commensurate with those considered in developing the structural design. Inspections are to be carried out to ensure that the dimensional tolerance criteria are being met. Particular attention is to be paid to the out-of-roundness of members for which buckling is an anticipated mode of failure.

(5) Corrosion Control System

The details of any corrosion control system employed for the structure are to be submitted for review. Installation and testing of the corrosion control system are to be carried out to the sat- isfaction of the attending Surveyor in accordance with the approved plans.

(6) Tightness and Hydrostatic Testing Procedures

Compartments which are designed to be permanently watertight or to be maintained watertight during installation are to be tested by a procedure approved by the attending Surveyor.

(7) Nondestructive Testing

(A) Nondestructive Testing is to be in accordance with Ch 3, Sec 2.

(B) All nondestructive testing records are to be reviewed and approved by the attending Surveyor.

(C) Additional nondestructive testing may be requested if deemed necessary by the attending

Surveyor.

(8) Installation of Structure

(A) Upon completion of fabrication and when the structure is to be loaded and transported to

site for installation, the load-out, tie-down and installation are to be surveyed by the attend- ing Surveyor.

Where the structure is fabricated inland, the supporting method the structure while fabricated

and storaging method of the welding consumables are to be satisfied by attending Surveyor. The Surveyor is to verify the following activities, as applicable to the planned structure, to ascertain whether they have been accomplished in a manner conforming to the approved procedures.

(a)

Load-out

(b) Tie-down

(c)

Positioning

(d) Installation

(e)

Final field erection and leveling

(B) Significant deviations from approved plans and procedures or any incidents may require re- submittal of supporting documentation to provide an assessment of the significance of devia- tion and any necessary remedial actions to be taken.

(C)

To ensure that over stressing of the structure during transportation has not occurred, the Society is to have access to towing records to ascertain if conditions during the towing op-

erations exceeded those employed in the analyses required in Ch 4, Sec 9.

6. Concrete structures

(1) Application

The requirements of this paragraph are to apply to concrete structures.

(2) Inspections Prior to Concreting

(A) Prior to their use in construction, the manufacture's of cement, reinforcing rods, prestressing tendons and appliances are to provide documentation of the pertinent physical properties. These data are to be made available to the attending Surveyor who will check conformity with the properties specified in the approved design.

(B) Forms and shores supporting the forms are to be inspected to insure that they are adequate in number and type, and that they are located in accordance with the approved plans.

(C) Reinforcing steel, prestressing tendons, post-tensioning ducts, anchorages and any included

steel are to be checked, as appropriate to the planned structure, for size, bending, spacing, location, firmness of installation, surface condition, vent locations, proper duct coupling, and

duct capping.

(3) Inspection of Batching, Mixing and Placing Concrete

(A) The production and placing of the concrete are to employ procedures which will provide a well mixed and well compacted concrete. Such procedures are also to limit segregation, loss

of material, contamination, and premature initial set during all operations.

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(B) Mix components of each batch of concrete are to be measured by a method specified in the quality control program. The designer is to specify the allowable variation of mix compo- nent proportions, and the constructor is to record the actual proportions of each batch.

(C) Testing during the production of concrete is to be carried out following the procedures specified in the quality control program. As a minimum, the following concrete qualities are

to be measured by the Constructor.

(a)

Consistency

(b) Air content

(c)

Strength

(D) Field testing of aggregate gradation, cleanliness, moisture content, and unit weight is to be

performed by the constructor following standards and schedules specified in the quality con- trol program. The frequency of testing is to be determined taking into account the uni- formity of the supply source, volume of concreting, and variations of atmospheric conditions. Mix water is to be tested for purity following methods and schedules specified in the qual- ity control program.

(4) Inspection of Form Removal and Concrete Curing

(A) The structure is to have sufficient strength to bear its own weight, construction loads and the anticipated environmental loads without undue deformations before forms and form sup- ports are removed. The schedule of form removal is to be specified in the quality control program, giving due account to the loads and the anticipated strength.

(B) Curing procedures for use on the structure are to be specified in the quality control

program. When conditions at the construction site cause a deviation from these procedures, justification for these deviations is to be fully documented and included in the construction records.

(C) Where the construction procedures require the submergence of recently placed concrete, spe- cial methods for protecting the concrete from the effects of salt water are to be specified in the quality control program. Generally, concrete should not be submerged until 28 days after placing (See also Ch 4, Sec 6, 602. 2).

(5) Inspection of Prestressing and Grouting

(A) A schedule indicating the sequence and anticipated elongation and stress accompanying the tensioning of tendons are to be prepared. Any failures to achieve proper tensioning are to be immediately reported to the designer to obtain guidance as to needed remedial actions.

(B) Pre- or post-tensioning loads are to be determined by measuring both tendon elongation and tendon stress. These measurements are to be compared, and should the variation of measure-

ments exceed the specified amount, the cause of the variation is to be determined and any

necessary corrective actions are to be accomplished.

(C) The grout mix is to conform to that specified in the design. The constructor is to keep re- cords of the mix proportions and ambient conditions during grout mixing. Tests for grout viscosity, expansion and bleeding, compressive strength, and setting time are to be made by the constructor using methods and schedules specified in the quality control program. Employed procedures are to ensure that ducts are completely filed.

(D) Anchorages are to be inspected to ensure that they are located and sized as specified in the design. Anchorages are also to be inspected to assure that they will be provided with ad-

equate cover to mitigate the effects of corrosion.

(6) Inspection of Joints

Where required, leak testing of construction joints is to be carried out using procedures speci- fied in the quality control program. When deciding which joints are to be inspected, consid- eration is to be given to the hydrostatic head on the subject joint during normal operation, the

consequence of a leak at the subject joint, and service.

(7) Inspection of Finished Concrete

(A) The surface of the hardened concrete is to combing, pop-outs, spalling and other surface

the ease of repair once the platform is in

be completely inspected for cracks, honey- imperfections. When such defects are found,

their extent is to be reported to the Surveyor and to the designer for guidance on any nec-

essary repairs.

(B) The structure is to be examined using a calibrated rebound hammer or a similar non-

destructive testing device. Where the results of surface inspection, cylinder strength tests or nondestructive testing do not meet the design criteria, the designer is to be consulted regard- ing remedial actions which are to be taken.

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(C) The completed sections of the structure are to be checked for compliance to specified de- sign tolerances for thickness, alignment, etc., and to the extent practicable, the location of reinforcing and prestressing steel and post-tensioning ducts. Variations from the tolerance limits are to be reported to the designer for evaluation and guidance as to any necessary re- medial actions.

(8) Other Inspection

(A) Upon completion of fabrication and when the structure is to be loaded and transported to site for installation, the load-out, tie-down and installation are to be surveyed by the attend- ing Surveyor.

As applicable, at the construction site, the surveyor is to be satisfied that proper consid- eration is being given to the support of the structure during construction, the storage of ce-

ment and prestressing tendons in weathertight areas, the storage of admixtures and epoxies

to manufacturer's specifications, and the storage of aggregates to limit segreation, con- tamination by deleterious substances and moisture variations within the stock pile.

(B) The Surveyor is to witness the following operations as applicable to the planned structure,

to verify that they have been accomplished in a manner conforming to plans or drawings covering these operations.

(a)

load-out and tie-down

(b) Towing arrangements

(c)

Positioning at the site

(d) Installation

(e)

Final field erection

Significant deviations from approved plans and procedures may require re-submittal of sup-

porting documentation to provide an assessment of the significance of the deviation and the remedial action to be taken.

(C) To ensure that over-stressing of the structure during transportation has not occurred, the Society is to have access to towing records to ascertain if conditions during the towing op-

erations exceeded those employed in the analyses required in Ch 4, Sec 9 of the Rules.

205. Classification Survey after Construction

1. General

At the Classification Survey after Construction, the examination of the hull, machinery and equip- ment are carried out as required for the Special Survey corresponding to the age, kind and purpose of the structures and the actual scantlings, etc. of the main parts of structures are to be measured as necessary.

2. Submission of plans and documents

At the Classification Survey after Construction, plans and documents as may be required for the

Classification Survey during Construction are to be submitted. If plans and obtained, facilities are to be given for the Surveyor to take the necessary structure.

documents cannot be information from the

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