Demolition Procedures of Vessel from 
Chang Jiang Ship-Breaking Yard


1.0 Preparation

1.1 Vessel condition
v Collect and review all the information and drawing of the vessel and the distribution of hazardous materials by the Toxic list inventory provided by the ship owner. The drawing include General Arrangement Plan, Basic Construction Plan, Shell Expansion Plan, Tank Capacity Plan, Engine Room Plan, Bridge Equipment Plan and the information of ship- reformation. According to the list and distribute plan of hazardous material on board from ship owner, demolition procedures are discussed.Underand the whole vessels structure;examine the thickness of the shell plate and the condition of the corrosion.
All asbestos on board should be marked position and confirm the quantity of those hazardous materials e.g.asbestos etc.
Distribute of liquid (e.g. oil, water) on board should be surveyed, especially oil hold and oil tank. The liquid of brand name, location and quantity should be listed.
According to the list and distribution plan of poisoned material on board from ship owner, the poison, inflammable material, the explosive and other dangerous goods should be located and marked.

1.2 Development of procedures
v In order to minimize the accident, safety measures are taken as follows:
- To prevent fire, explosion and pollution to environment
- To protect the vessel from damage of typhoon and flood, collapse and sinking.
- To protect the working people from poisoning, suffocation and injury
Base on vessel 's information, the demolition procedures are developed with concerning real situation as follows:
- Arrange demolition place, power supply, crane's installation and the procedures of different phases to meet the required quality, safety and demolition time.
- State the criteria and main points on different phases
- Draft drawings of demolition sequences
- State the demolition procedures of main parts (e.g. maim engine, boiler) in detail and its requirement
- Make use of the steps and requirements of protective equipment of demolition
-Adopt the safety and environmental measures

1.3 Mooring
v The facilities of wharf are frequently examined including bollards, wires, anchors, anchor 's cables and winches.
v Oil barriers should be used to protect the environment from oil leakage.
v All water-tightness facilities on board should be examined, especially at the bottom and the stern of vessel. Valves at the bottom should also be closed and checked.
v Access should be provided on board and boarding or leaving the vessel.
vFire preventive measures should be provided for fire fighting under hotwork.
v Power supply on shore should not be connected to the electrical circuits on board directly. The separate circuit should be observed easily to prevent electrical stock.

2.0 Facilities and Equipment

2.1 Hold Clearing
v All oil in holds, tanks and hydraulic service tanks on board should be collected and passed to the related people of harbor Supervision Authority of Jiang Yin to handle with.
v Barrels of paint, containers, high-pressure container, pyrotechnics and other inflammable or explosive material should be removed from vessel.
v Closed area such as oil holds, machine room and other areas that are suspected to contain inflammable gas should be well-ventilated, free of gas and oil sludge. It should be ensured that the oil mist 's density should be below the explosion lower limit by 1%.
v Treatment of oily water should be done with Harbor Supervision Authority of Jiang Yin, including the ballast water which doses not comply with discharging standards.
v The amount of oxygen in oil holds should be higher than 18%
v All free fighting systems including CO2, insert gas etc. should be removed.
v All woodworks, equipment fittings and tools etc. should be removed.
v All asbestos and fiberglass materials should be removed.

2.2 Superstructure and Deck Demolition
v Demolition sequences on superstructure are from the top to the bottom and from the inside to the outside. Care should be taken to avoid sparking in oil holds.
v Facilities on deck may be demolished first except the essential facilities.
v Oil pipes and electrical cables should be demolished without beating. Pipes, which are located vertically to deck, should be cut without naked flame.

2.3 Engine Room Demolition
v Holds clearing should be checked again to ensure that the inflammable material and the explosive are totally removed. Pressurized containers should be depressurized.
v Demolition works should not be carried out on the same vertical plane.
v After demolition of superstructure, facilities in engine room are given priority to be demolished. For example, steering gear system should be demolished as soon as possible to minimize local stress, which will contribute bending moment to the vessel in longitudinal direction and result in collapse and sinking of the vessel.
v Aft pump room should be demolished as soon as possible without naked flame after carrying out gas-free test and removing oil sludge. That will ensure demolition of engine room facilities be in safe and also facilitate the accessibility to forward holds.
v Demolition of engine room should not be in open area.
v Demolition principles are as follows:
- Starting with easier parts
- From small to dig
- From top to bottom
- Port and starboard balancing
- Transferring the demolished components immediately
- Keeping accesses in clear
v Oil pipes, which contain oil, should be handled first. Oil sludge should be removed before naked-flame demolition. The action can prevent oil pollution, fire and explosion.
v To open the cover of engine room, manholes of oil tanks should be closed to avoid catching fire. If it is necessary to open, all tanks should be gas-free, well-ventilated etc.
v Oily-water mixture leaked from stern tubes, water tanks and pipe should be handled instantly.

2.4 Hull Body Demolition
v It is very important to balance the vessel during demolition.
v Demolition of hull should follow the predetermined sequences and bases on the drawings of demolition sequences.
v There are some limitations on demolition sequences:
- To demolish forward and aft first and followed by amidships
- To demolish components in transverse direction, then in longitudinal direction later
- Not allowed to demolish longitudinal components in same transverse plane
- To avoid a vertical cut though the joint of horizontal cut directly that spreads the stress on the joint
v If the engines  are situated on the aft. First, demolition of forward peak hold can be carried out while demolition works on engine room 's facilities completed, demolition of Hold No.1 can be started. Furthermore, demolishing from the forward and the aft to the amidships can be started after the completion of demolition on engine room 's facilities.
v Shell plating should be always examined. If cracks are observed, the support of vessel should be strengthened.
v To preserve sufficient freeboard, ship strength can be maintained and seawater is prevented to flood into the holds.
v Watertightness of bulkheads should be maintained to ensure that the vessel is afloat. Demolition of the double bottom should be carried out in dry dock after gas-free test as it contains oil sludge and pollutants.

2.5 Minor Strucyures
v Demolished components should be clear of rust and dirt, which should be handled properly.
v Components should be demolished in accordance with their profiles and collected separately. When using gas out, workers should stay at position that wind will not blow the fire to the human body. Measures should be taken to avoid breathing in heavy metal's particles including zinc, cadmium, beryllium, iron oxides, mercury and lead etc.