7 Procedures for thickness measurements
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - International Codes - 2011 ESP Code – International Code on the Enhanced Programme of Inspections During Surveys of Bulk Carriers and Oil Tankers, 2011 – Resolution A.1049(27) - Annex A – Code on the Enhanced Programme of Inspections During the Surveys of Bulk Carriers - Part B – Code on the Enhanced Programme of Inspections During Surveys of Bulk Carriers Having Double-Side Skin Construction - 7 Procedures for thickness measurements

7 Procedures for thickness measurements

Parent topic: Part B – Code on the Enhanced Programme of Inspections During Surveys of Bulk Carriers Having Double-Side Skin Construction

7.1 General

  7.1.1 The required thickness measurements, if not carried out by the Administration, shall be witnessed by a surveyor of the Administration. The surveyor shall be on board to the extent necessary to control the process.

  7.1.2 The thickness measurement firm shall be part of the survey planning meeting to be held prior to commencing the survey.

  7.1.3 Thickness measurements of structures in areas where close-up surveys are required shall be carried out simultaneously with close-up surveys.

  7.1.4 In all cases the extent of the thickness measurements shall be sufficient as to represent the actual average condition.

  7.1.5 Procedural requirements for thickness measurements are set out in annex 12.

7.2 Certification of thickness measurement company

 The thickness measurements shall be carried out by a qualified firm certified by the Administration according to the principles stated in annex annex 5.

7.3 Number and locations of measurements

  7.3.1 Application

This section only applies to ships built under the IACS Common Structural Rulesfootnote (CSR). For ships not built under IACS CSR, the requirements for the number and locations of measurements shall be according to the requirements of the classification society recognized by the Administration depending on the ship's age and structural elements concerned.

  7.3.2 Number of measurements

Considering the extent of thickness measurements according to the different structural elements of the ship and surveys (renewal, intermediate and annual), the locations of the points to be measured are given for the most important items of the structure.

  7.3.3 Locations of measurements

7.3.3.1 Table 1 provides explanations and/or interpretations for the application of those requirements indicated in IACS CSR, which refer to both systematic thickness measurements related to the calculation of global hull girder strength and specific measurements connected to close-up surveys.

7.3.3.2 Figures 4 to 9 are provided to facilitate the explanations and/or interpretations given in table 1, to show typical arrangements of single-side skin bulk carriers.

Table 1 – Interpretations of requirements for the locations and number of points to be measured for CSR bulk carriers (single-side skin)
Item Interpretation Figure reference
Selected plates on deck, tank top, bottom, double bottom and wind-and-water area "Selected" means at least a single point on one out of three plates, which shall be chosen on representative areas of average corrosion  
All deck, tank top and bottom plates and wind-and-water strakes At least two points on each plate which shall be taken either at each 1/4 extremity of plate or at representative areas of average corrosion  
Transverse section A transverse section includes all longitudinal members such as plating, longitudinals and girders at the deck, side, bottom, inner bottom and hopper side plating, longitudinal bulkhead and bottom plating in top wing tanks Figure 4
All cargo hold hatch covers and coamings Including plates and stiffeners Locations of points are given in figure 5
Transverse section of deck plating outside line of cargo hatch openings Two single points on each deck plate (which shall be taken either at each 1/4 extremity of plate or at representative areas of average corrosion) between the ship sides and hatch coamings in the transverse section concerned  
All deck plating and underdeck structure inside line of hatch openings between cargo hold hatches "All deck plating" means at least two points on each plate shall be taken either at each 1/4 extremity of plate or at representative areas of average corrosion

"Under deck structure": at each short longitudinal girder: three points for web plating (fwd/middle/aft), single point for face plate, one point for web plating and one point for face plating of transverse beam in way. At each end of transverse beams, one point for web plating and one point for face plating

Extent of areas is shown in appendix 3 to annex 8B

Locations of points are given in figure 9
Transverse frame in double-side tank   Figure 4
Transverse bulkheads in cargo holds Includes bulkhead plating, stiffeners and girders, including internal structure of upper and lower stools, where fitted. Two selected bulkheads: one shall be the bulkhead between the two foremost cargo holds and the second may be chosen in other positions Areas of measurements are shown in appendix 3 to annex 8B

Locations of points are given in figure 7
One transverse bulkhead in each cargo hold This means that the close-up survey and related thickness measurements shall be performed on one side of the bulkhead; the side shall be chosen based on the outcome of the overall survey of both sides. In the event of doubt, the surveyor may also require (possibly partial) close-up survey on the other side Areas of measurements are shown in appendix 3 to annex 8B

Locations of points are given in figure 7
Transverse bulkheads in one topside, hopper and double bottom ballast tank Includes bulkhead and stiffening systems

The ballast tank shall be chosen based on the history of ballasting among those prone to have the most severe conditions

Locations of points are given in figure 8
Transverse webs in ballast tanks Includes web plating, face plates, stiffeners and associated plating and longitudinals

One of the representative tanks of each type (i.e. topside or hopper or side tank) shall be chosen in the forward part

Areas of measurements are shown in appendix 3 to annex 8B

Locations of points are given in figure 6

Figure 4: Transverse section of a double-side skin bulk carrier

Figure 5: Locations of measurements on hatch covers and coamings

Figure 6: Locations of measurements on structural members in ballast tanks of double-side skin bulk carriers (topside or hopper or side tank)

Figure 7: Locations of measurements on cargo hold transverse bulkheads

Figure 8: Locations of measurements on transverse bulkheads of topside, hopper and double bottom tanks

Figure 9: Locations of measurements on underdeck structure

7.4 Reporting

  7.4.1 A thickness measurement report shall be prepared and submitted to the Administration. The report shall give the location of measurements, the thickness measured as well as the corresponding original thickness. Furthermore, the report shall give the date when the measurements were carried out, type of measuring equipment, names of personnel and their qualifications and be signed by the operator. The thickness measurement report should follow the principles as specified in the recommended procedures for thickness measurements set out in annex 8A/annex 8B.

  7.4.2 The surveyor shall review the final thickness measurement reports and countersign the cover page.

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