CB/T 257-2001 Test method for tightness of hull of steel seagoing vessels
Some standard content:
National Technical Committee for Ship Standardization Professional Standard CB*257-88
Test Method for Hull Tightness of Steel Seagoing Vessels
Published on May 25, 1988
National Technical Committee for Ship Standardization
Implemented on December 1, 1988
National Technical Committee for Ship Standardization Professional Standard Test Method for Hull Tightness of Steel Seagoing Vessels
Subject Content and Scope of Application
This standard specifies the test method for hull tightness of steel seagoing vessels during manufacture, repair or regular inspection. This standard does not apply to semi-submersible, deep-submersible work vessels and liquefied gas carriers. 2 General requirements
CB*257—88
Classification number: U13
Replaces CB257-79
2.1 The underwater part of the hull and the part that cannot be inspected after launching, or the part of the hull after the defect is repaired, shall be subjected to a tightness test before the ship is launched; the tightness test of other parts shall also be carried out after the hull is built. Exceptions are allowed for individual special parts after obtaining the consent of the ship surveyor. 2.2 Before the tightness test, all parts of the ship and the welds that have passed the inspection shall be cleaned of oxide chips and welding slag, and cleaned; paint, insulation materials or cement and other coatings shall not be applied to the watertight welds. 2.3 All structures connected to the watertight part of the hull by rivets, bolts or electric welding methods, deck fittings, equipment and all piping systems shall be installed before the test. If the installation work is to be carried out after the test, additional tests shall be carried out in accordance with the provisions of this standard within the scope agreed by the ship surveyor.
If the tested part needs to be laid with wooden planks or other forms of coverings, it should be carried out after the tightness test is passed. 2.4
2.5 During the test, if the outside temperature is below 0C, appropriate anti-freezing measures should be taken. 3 Test methods
The test can be carried out by flooding, flushing, spraying, applying kerosene, inflating or a combination of water and air and other equivalent test methods according to the different requirements of the hull structure strength and watertightness and oiltightness. 3.1 Water filling test
3.1.1 Fill the water to the specified height. After 15 minutes, check the welds under the condition of maintaining the water pressure height. There should be no leakage. 3.1.2 The water filling test should be carried out in intervals or cross orders. Adjacent cabins should not be tested at the same time for inspection. 3.1.3 During the test, the bottom keel piers and supports should be appropriately placed at the compartments of the flooded cabins to prevent hull deformation. 3.1.4 During the water filling test, if the ambient temperature is below 0°C, the water should be preheated. The preheating degree should be such that the outer surface of the cabin is not covered with water droplets during the test. The water leaking from the loose joints does not freeze. Generally, the water temperature is not lower than 5°C during the test. 3.1.5 During the water filling test, if it is required to increase the water pressure, a pressure pipe with a diameter of not less than 50mm can be installed on the top of the test cabin. 3.1.6 There should be an air pipe on the upper part of the cabin for the pressurized water filling test. There should be no air layer on the upper part of the cabin after water filling. 3.2 Water flushing test
3.2.1 Use a fire hose to spray water vertically to the joint to check whether the joint has leakage. 3.2.2 The diameter of the nozzle used for the test is not less than 16mm. 3.2.3 During the test, the water pressure in the hose should ensure that the height of the water spray upward from the test site is not less than 10m, and the nozzle is not more than 3m away from the tested joint.
3.2.4 During the test, the riveted structure should be flushed from the untwisted seam surface, the welded structure can be flushed from any side, and the vertical seam should be flushed from bottom to top. 3.3 Water spray test
Approved by the National Technical Committee for Ship Standardization on May 25, 1988, and implemented on December 1, 1988
CB*257-88
Water is sprayed on the tested seam to check the leakage of the seam. 3.4 Kerosene coating test
3.4.1 Apply chalk powder aqueous solution on one side of the weld first, with a total width of not less than 0mm, and test after drying. When the ambient temperature is below 0C during the test, a solvent (such as salt solution, alcohol, etc.) that does not freeze and does not affect the whiteness of the chalk powder can be used to prepare the solution. 3.4.2 Apply sufficient kerosene on the other side of the weld. A thin layer of kerosene should be maintained on the weld surface during the test. 3.4.3 When the ambient temperature is above 0°C, the test duration shall be as specified in Table 1. When the temperature is below 0°C, the test time shall be appropriately extended. Table
Test time
Weld thickness
3.5 Inflatable test
Horizontal weld
Vertical weld
3.5.1 Apply soap solution or other effective reagents on the inspection surface of the tested joint. During the test, if the ambient temperature is below 0°C, heating measures should be taken or non-condensing soap solution should be used. 3.5.2 During the inflation test, the test pressure is generally 3×10°～5×10'Pa (0.3～0.5kgf/cm). 3.5.3 Leakage inspection should be carried out after the test pressure is maintained for 15 minutes. The test duration is determined according to the time required for the appearance inspection. 3.5.4 Each tested cabin should be equipped with two pressure gauges and one safety valve that have passed the inspection. The gas should be introduced through a pressure regulator or a pressure reducing valve.
3.6 Water filling and air filling mixed test
Apply soap solution or other effective reagents on the inspection surface of the tested joint. 3.6.1
3.6.2 During the test, if the ambient temperature is below 0℃, the water should be preheated. The preheating degree should be such that the outer surface of the cabin is not covered with water drops during the test, and the water leaking from the loose joints does not freeze. Generally, the water temperature during the test is not lower than 5℃. 3.6.3 First fill water to the lower edge of the manhole of the cabin, and then inflate to 3×10°～5×10\Pa. The leakage inspection should be carried out after the test pressure is maintained for 15 minutes. The test duration is determined according to the time required for the appearance inspection. 3.6.4 The test should be carried out in intervals or cross orders. 3.6.5 Each tested compartment shall be equipped with two pressure gauges and one safety valve that have passed the inspection. The gas shall be introduced through a pressure regulator or a pressure reducing valve.
Test requirements
The hull tightness test shall be carried out in accordance with the test indicators in Table 2 and the following requirements. 4.1
Peak tank
Double bottom tank
Top side tank or side water tank
Bottom of single bottom tank
Deep water tank
Deep oil tank or cargo oil tank
Cofferdam
CB*257-88
When used as a water tank
When used as a fuel oil tank
Side shell, decks, bulkheads, and the top and first-floor deckhouses in the open air Outer walls, weathertight doors and windows, hatch coamings and hatch covers of deckhouses above the first deck
Submarine valve chest
Energy, draft tubewww.bzxz.net
Without flushing equipment
With flushing equipment
Outer walls and doors and windows of deckhouses above the first deck, such as kitchens, pantries, laundry rooms, bathrooms, toilets, battery rooms, etc. Test requirements
Height of water column to the top of air pipe
To above the top of the tank 2. 5m2 water column height
To air pipe top water column height
To air pipe top water column height
To center inner keel panel water column height
To air pipe top water column height
To 2.5m water column height above tank top
To tank top at 1:0.6m water column height
To full load waterline water column height
Hydrogen flushing test
To 1m water column above bulkhead deck Height
Can be determined by the pressure during flushing Test pressure Inflation test: air pressure = 5×10d+2.5×10*Pa(0.05d+0.25kgf/cm2)(d is full load draft, m) Kerosene coating test or water filling test is carried out on the lower edge of the wall, and the water pressure height reaches the door sill
Water spray test
Note: 1) For ships with a depth of less than 5m, the height of the water column above the deck can be 0.5 times the depth. 2) Except for weathertight doors and windows.
4.2 The peak tank, double bottom tank, top side tank, side water tank, cargo oil tank and oil storage deep tank of oil tanker, deep water tank, pump room, cofferdam, seabed valve box, energy and diversion pipe of the ship are subject to water filling test or inflation test. 4.3 Watertight components such as shaft tunnels, bulkheads, superstructure decks, exposed parts and outer walls of deckhouses, watertight doors and windows, hatch coamings and hatch covers, and other compartments not included in Article 3.2 shall be subjected to water flushing test or kerosene test. 4.4 For compartments that must be subjected to water filling test, if the test compartment has a large volume, after obtaining the consent of the ship surveyor, a mixed test of water filling and inflation may be used instead of water filling test.
4.5 When it is difficult to inspect from adjacent compartments due to dense, narrow, sharp corners, etc., it is not allowed to use the inflation test method for hull tightness test.
4.6 For hull structures with a plate thickness greater than 6.mm, if the strength permits, an inflation test may be used instead of a water filling test. 4.7 The water flushing test may be replaced by a kerosene test. 4.8 The watertight welds in the flat or three-dimensional sections during block construction may be tested for tightness by kerosene before being put on the slipway for closure.
4.9 Kerosene test is not allowed for structures that use rubber gaskets to ensure watertightness, riveted and bolted structures. cB* 25788
The test requirements for ship repairs shall comply with the provisions of Table 2, and the test scope shall be determined by the ship survey department according to the nature of the repair work. 4. 10
Additional remarks:
This standard was proposed by the Ocean Transport Ship Technical Committee and is under the jurisdiction of Shanghai Ship Design Institute. This standard was drafted by Jiangnan Shipyard.
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