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RECOMMENCE PRACTICE IACS

http://www.iacs.org.uk/publications/publications.aspx?pageid=4&sectionid=5

2014/01 edition (entry into force 2014/01/01) Article 6 Inspections and checks 

6.1 General

6.1.1 

Materials, workmanship, structures and welded connections are to be subjected, at the beginning of the work, during construction and after completion, to inspections by the Shipbuilder suitable to check compliance with the applicable requirements, approved plans and standards.

6.1.2 

The Shipbuilder is to make available to the Surveyor a list of the manual welders and welding operators and their respective qualifications.

The Shipbuilder's internal organisation is responsible for ensuring that welders and operators are not employed under improper conditions or beyond the limits of their respective valid qualifications and that welding procedures are adopted within the approved limits and under the appropriate operating conditions.

6.1.3 

The Shipbuilder is responsible for ensuring that the operating conditions, welding procedures and work schedule are in accordance with the applicable requirements, approved plans and recognised good welding practice.

6.1.4 

The Shipbuilder is responsible for ensuring that non-destructive examination (NDE) procedures and plans are adhered to during the construction and that NDE reports are made available to the Society.

6.2 Non-destructive examination 

6.2.1 

Non-destructive examination techniques refer to the testing methods applicable to the detection of surface imperfections (Visual Testing, Magnetic particle Testing, Liquid penetrant Testing) or sub-surface imperfections (Ultrasonic Testing, Radiographic Testing).

6.2.2 

NDE of hull welds are to be performed in accordance with written procedures accepted by the Society. Such procedures are to contain appropriate details about the applied codes or standards, testing method, equipment, calibration, testing conditions and personnel qualification. For each

NDE technique, appropriate details means typically the details described in IACS Recommendation 20.

6.2.3 

The NDE acceptance criteria defined by the Shipbuilder are to be submitted to the Society and should comply with the IACS Recommendation 20 or with a recognized standard which has been accepted by the Society.

Where applicable, specific criteria defined in Ch 12, Sec 2, for special structural details are to be refered to.

6.2.4 

All finished welds are to be subjected to visual testing by the Shipbuilder's qualified personnel.

6.2.5 

After completion of the welding operation and workshop inspection, the structure is to be presented to the Surveyor for general visual examination at a suitable stage of fabrication.

As far as possible, the results on non-destructive examinations are to be submitted.

6.2.6 

Radiographic testing is to be carried out on the welded connections of the hull in accordance with [6.3]. The results are to be made available to the Society. The surveyor may require to witness some testing preparations.

6.2.7 

The Society may accept radiographic testing to be replaced by ultrasonic testing.

6.2.8 

The Shipbuilder's NDE plan describing the extent, type and location of NDE is to be submitted to the Society for acceptance.

6.2.9 

When the non-destructive examinations reveal the presence of unacceptable indications, the relevant connection is to be repaired to an extent and according to a procedure agreed with the Surveyor.

The repaired zone is then to be submitted to non-destructive examination, using a method deemed suitable by the Surveyor to verify that the repair is satisfactory.

Additional examinations may be required by the Surveyor on a case by case basis.

6.2.10 

Ultrasonic and magnetic particle testing may also be required by the Surveyor in specific cases to check the base material.

6.3 Radiographic testing 

6.3.1 

Radiographic testing is to be carried out on the welded butts of shell plating, strength deck plating as well as of members contributing to the longitudinal strength.

Radiographic Testing may also be required for the joints of members subject to heavy stresses.

The requirements [6.3.2] to [6.3.5] constitute general rules: the number of radiographs may be increased where requested by the Surveyor, mainly where visual inspection or radiographic soundings have revealed major defects, specially for butts of sheerstrake, stringer plate, bilge strake or keel plate.

Provisions alteration to these rules may be accepted by the Society when justified by the organisation of the Shipbuilder or of the inspection department; the inspection is then to be equivalent to that deduced from [6.3.2] to [6.3.5].

6.3.2 

As far as automatic welding of the panels butt welds during the premanufacturing stage is concerned, the Shipbuilder is to carry out random non-destructive testing of the welds (radiographic or ultrasonic testing) in order to ascertain the regularity and the constancy of the welding inspection.

6.3.3 

In the midship area, radiographies are to be taken at the joinings of panels.

Each radiography is situated in a butt joint at a cross-shaped welding.

In a given ship cross-section bounded by the panels, a radiography is to be made of each butt of sheerstrake, stringer, bilge and keel plate; in addition, the following radiographies are to be taken:

bottom plating: two deck plating: two side shell plating: two each side.

For ships where B + D ≤ 15 m, only one radiography for each of the above items is required.

This requirement remains applicable where panel butts are shifted or where some strakes are built independently from the panels. It is recommended to take most of these radiographies at the intersections of butt and panel seams.

Still in the midship area, radiographic testing is to be carried out, at random, of the following main members of the structure:

butts of continuous longitudinal bulkheads butts of longitudinal stiffeners, deck and bottom girders contributing to the overall

strength assembly joints of insert plates at the corners of the openings.

Moreover, radiographic testing is to be carried out, at random, of the weldings of the bilge keel and of intermediate flat.

6.3.4 

Outwards the midship area, a programme of radiographic testing at random is to be set up by the Shipbuilder in agreement with the Surveyor for the major points. It is further recommended:

to take a number of radiographies of the very thick parts and those comprising restrained joint, such as sternframes, shaft brackets, stabiliser recesses, masts

to take a complete set of radiographies or to increase the number of radiographies for the first joint of a series of identical joints. This recommendation is applicable not only to the assembly joints of prefabricated members completed on the slip, but also to joints completed in the workshop to prepare such prefabricated members.

6.3.5 

Where a radiography is rejected and where it is decided to carry out a repair, the Shipbuilder is to determine the length of the defective part, then a set of radiographies of the repaired joint and of adjacent parts is to be taken. Where the repair has been decided by the inspection office of the Shipbuilder, the film showing the initial defect is to be submitted to the Surveyor together with the film taken after repair of the joint.