Engineering tool
Weld NDT scope planner
Enter the weld lengths and joint counts of your hull. The tool gives the number of test points from the midship formula and the minimum amount of testing the CCS Rules write down for critical joints.
Test points inside 0.6L amidships
Clause 5.3.2.4 gives the number of test points for the strength deck and the shell inside 0.6L amidships as n = 0.16k(i + 0.1W_T) + 0.04W_L, where k is the midship section girth, openings excluded, divided by the number of strakes seen in the section.
Butt joints (5.3.2.6 items 1 to 4)
Butt weld crossings on watertight and tank bulkheads, the inner bottom and the hopper sloping plates (5.3.2.6 (1))
One in every 4. Radiography or ultrasonic.
Butt joints of longitudinal stiffeners and girders on the bottom, side and deck, inside 0.4L amidships (5.3.2.6 (2))
One in every 10. Radiography or ultrasonic.
Butt joints of longitudinal stiffeners and girders on the bottom, side and deck, outside 0.4L amidships (5.3.2.6 (2))
One in every 20. Radiography or ultrasonic.
Corners of the strength deck hatch corner insert plates, each corner at least 2 places (5.3.2.6 (3))
At least 2 at each. Radiography or ultrasonic.
Butt joints 50 mm thick and over, for example sternpost, shaft bracket, stabiliser fin recess, mast post (5.3.2.6 (4))
At least 100% of the weld length. Radiography or ultrasonic.
Full penetration fillet welds (5.3.2.6 item 5)
Main engine seat face plate to web (5.3.2.6 (5) a)
At least 100% of the weld length.
Rudder horn and shaft bracket to the shell plating (5.3.2.6 (5) b)
At least 100% of the weld length.
Rudder seal plate to the rudder casting (5.3.2.6 (5) c)
At least 100% of the weld length.
Edge reinforcement of openings over 300 mm in the strength deck, sheer strake and bottom plating inside 0.6L, and pipe penetrations (5.3.2.6 (5) d)
At least 100% of the weld length.
Toe connections of longitudinal hatch coaming end brackets to the deck plating, inside 0.6L amidships (5.3.2.6 (5) e)
At least 100% of the number.
Toe connections of longitudinal hatch coaming end brackets to the deck plating, outside 0.6L amidships (5.3.2.6 (5) e)
One in every 2.
Inner bottom to transverse bulkhead, bottom stool or transverse floor, and bottom stool to transverse bulkhead (5.3.2.6 (5) f)
At least 35% of the weld length.
Hopper sloping plate to the inner bottom or the inner shell (5.3.2.6 (5) g)
At least 25% of the weld length.
Transverse corrugated bulkhead to the topside tank (5.3.2.6 (5) h)
At least 35% of the weld length.
Deck stringer to the sheer strake (5.3.2.6 (5) i)
10% of the weld length, and 1 m more at every closure joint inside 0.6L amidships.
Surface crack testing (5.3.2.6 item 6)
Welds of steel castings and forgings, and welds made under stress or at low temperature (5.3.2.6 (6) a)
At least 100% of the weld length. Surface crack testing.
Important welds in plate 30 mm thick and over, for example the sternpost, welded masts and bulkhead pedestals (5.3.2.6 (6) b)
At least 100% of the weld length. Surface crack testing.
Welds in areas of high stress (5.3.2.6 (6) c)
At least 100% of the weld length. Surface crack testing.
Other welds with a groove depth of 30 mm and over (5.3.2.6 (6) d)
At least 20% of the weld length. Surface crack testing.
Crane base joints (5.3.2.9)
Full penetration fillet welds, ultrasonic testing (5.3.2.9 (1))
At least 100% of the weld length. Ultrasonic, and magnetic particle or penetrant.
Partial penetration or ordinary fillet welds (5.3.2.9 (2))
At least 100% of the weld length. Magnetic particle or penetrant.
Cargo tanks of chemical tankers (5.3.2.8)
Tank perimeter welds, minimum length tested for surface cracks (5.3.2.8 (2))
At least 10% of the weld length. Surface crack testing.
Welds where longitudinal girders and horizontal stiffeners meet the transverse bulkhead, minimum length tested for surface cracks (5.3.2.8 (3))
At least 10% of the weld length. Surface crack testing.
Bottom and side longitudinal members, where they meet the transverse bulkhead (5.3.2.8 (4))
At least 30% of the weld length. Surface crack testing.
Horizontal stiffeners of the longitudinal bulkhead, where they meet the transverse bulkhead (5.3.2.8 (4))
At least 20% of the weld length. Surface crack testing.
Continuous transverse members passing through the longitudinal bulkhead (5.3.2.8 (5))
At least 10% of the weld length. Surface crack testing.
Locations to test by sampling (5.3.2.7), no quantity given
- The start and stop ends of automatic butt welds such as electroslag, electrogas and submerged arc welds.
- Butt joints of the keel.
- Butt welds on the inner shell and the watertight bulkheads of oil tankers.
- Butt welds on the longitudinal hatch coamings and top plates of container ships.
- Except for container ships, butt welds on longitudinal hatch coamings and top plates longer than 0.15L.
- Butt welds where the structure of the superstructure or the deck above changes abruptly.
- Critical locations found by direct strength calculation or fatigue assessment.
- Penetration welds that cannot be reached during in-service survey, for example the sharp corner welds in the bulbous bow.
- Other important, highly stressed welds that carry load and could affect the ship if they fail.
Clause 5.3.2.3 lets the yard and the surveyor agree the quantity and location. Clause 5.3.2.5 asks for a higher test density in critical areas such as the shaft bracket, the stem and sternpost areas, the bow slamming area and the ice-strengthened area. Clause 5.3.2.10 extends a test along the weld when a defect may run on, and 5.3.2.11 asks for more tests when the pass rate falls below 80%. Clause 5.3.2.12 requires the locations and results to be recorded in a report and submitted to the surveyor. For cargo tanks of chemical tankers, 5.3.2.8 item 1 also asks for a test at every weld crossing on the tank bulkhead plating.
What this tool covers
CCS Rules for Materials and Welding 2021, Part 3 Chapter 5, clause 5.3.2: the test point formula of 5.3.2.4, the 10% to 20% rule outside 0.6L of 5.3.2.5, the critical joints of 5.3.2.6, the cargo tanks of chemical tankers in 5.3.2.8, and crane base joints in 5.3.2.9. Percentages are applied to the weld length or to the number of joints, and counts are rounded up.
What it does not cover
The test method and acceptance standard, the choice of test positions, and the locations listed in 5.3.2.7, for which the rule says to test by sampling but gives no quantity. Clause 5.3.2.3 lets the yard and the surveyor agree the quantities and locations, so the plan you finally follow may differ from the minimum shown here.
Questions about the testing scope
- Is the number of test points fixed by the rule?
- No. Clause 5.3.2.3 says the quantity and location of the non-destructive tests may be agreed between the yard and the surveyor, taking account of the ship type, the welding method and past quality records. This tool shows the quantities the rule itself writes down.
- What happens when a test finds a defect?
- Clause 5.3.2.10 says that if a defect not allowed inside the weld may extend, the test must be extended along the weld, at one or both ends, until the defect ends. Clause 5.3.2.11 says the surveyor may increase the number of tests when the pass rate falls below 80% or the quality at a location is in doubt.
- How many of the 5.3.2.7 locations must be tested?
- The rule does not say. Clause 5.3.2.7 lists nine kinds of location that are to be tested by sampling, and it gives no quantity, so the tool lists them without a number.
Source
Every formula and percentage was read from the page images of the CCS Rules for Materials and Welding 2021, pages 3-57 to 3-59. This is the CCS rule, not an IACS unified requirement. Your society's own rules govern.
This is a planning aid, not an inspection plan. The plan approved by your surveyor governs. For plate ready to ship, contact us. Request a quote