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Operating Requirements for Ships carrying liquefied gas

Every LNG or LPG tanker should meet Operating Requirements like cargo info and transfer operations, system and controls, personal training and etc.

Cargo information

Information shall be on board and available to all concerned, giving the necessary data for the safe carriage of the cargo. Such information shall include but not limited for each product carried:

  • a full description of the physical and chemical properties necessary for the safe containment of the cargo;
  • action to be taken in the event of spills or leaks;
  • counter measures against accidental personal contact;
  • fire fighting procedures and fire fighting media;
  • procedures for cargo transfer, gas freeing, ballasting, tank cleaning and changing cargoes;
  • special equipment needed for the safe handling of the particular cargo;
  • minimum allowable inner hull steel temperatures;
  • and emergency procedures.

Products required to be inhibited should be refused if the certificate required by “Special Requirements for LNG and LPG gas carriers”Inhibition is not supplied.

A copy of the IGC-Code or national regulations incorporating the provisions of the IGC-Code should be on board every ship covered by the IGC-Code.

Compatibility

The Master should ascertain that the quantity and characteristics of each product to be loaded are within the limits indicated in the International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk provided for in Section 1, A.5 and the Loading and Stability booklet provided for in Section 2, 2.5 and that the products are listed in the International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk as required under Section 3 of the Certificate.

Care should be taken to avoid dangerous chemical reactions if cargoes are mixed. This is of particular significance in respect of:

  1. tank cleaning procedures required between successive cargoes in the same tank;
  2. and simultaneous carriage of cargoes which react when mixed. This should be permitted only if the complete cargo systems including, but not limited only if the complete cargo system including, but not limited to, cargo pipework, tanks, vent systems and refrigeration systems are separate as defined in Section 1,C.32.

Personnel training

Personnel Reference is made to the provisions of the International Convention on Standards of Training, Certification and Watchkeeping for seafarers, 1978 and in particular to the “Mandatory Minimum Requirements for the Training and Qualifications of Masters, Officers and Ratings of Chemical Tankers” – Regulation V/2, Chapter V of the Annex to that Convention and to Resolution 11 of the International Conference on Training and Certification of Seafarers, 1978.x involved in cargo operations should be adequately trained in handling procedures. All personnel should be adequately trained in the use of protective equipment provided on board and have basic training in the procedures, appropriate to their duties, necessary under emergency conditions.

Officers should be trained in emergency procedures to deal with conditions of leakage, spillage or fire involving the cargo Reference is made to the Medical First Aid Guide for use in Accidents Involving Dangerous Goods (MFAG), which provides advice on the treatment of casualties in accordance with the symptoms exhibited as well as equipment and antidotes that may be appropriate for treating the casualty, and to the relevant provisions of STCW Code, parts A and Bx. A sufficient number of them should be instructed and trained in essential first aid for the cargoes carried.

Entry into spaces

Personnel should not enter cargo tanks, hold spaces, void spaces, cargo handling spaces or other enclosed spaces where gas may accumulate unless:

  • the gas content of the atmosphere in that space is determined by means of fixed or portable equipment to ensure oxygen sufficiency and the absence of toxic atmosphere;
  • or personnel wear breathing apparatus and other necessary protective equipment and the entire operation is under the close supervision of a responsible officer.

Personnel entering any space designated as gas dangerous on a ship carrying flammable products should not introduce any potential source of ignition into the space unless it has been certified gas free and is maintained in that condition.

For internal insulation tanks, special fire precautions should be taken in the event of hot work carried out in the vicinity of the tanks. The gas absorbing and de-absorbing characteristics of the insulation material should thereby be taken into account.

For internal insulation tanks, repairs should be carried out in accordance with the procedures provided for in “Cargo containment system of gas vessel”Internal insulation tanks.

Carriage of cargo at low temperature

When carrying cargoes at low temperatures:

  1. if provided the heating arrangements associated with cargo containment systems should be operated in such a manner as to avoid the temperature falling below that for which the material of the hull structure is designed;
  2. loading should be carried out in such a manner as to ensure that unsatisfactory temperature gradients do not occur in any cargo tank, piping, or other ancillary equipment;
  3. and when cooling down tanks from temperatures at or near ambient the cool down procedure laid down for that particular tank, piping and ancillary equipment should be followed closely.

Protective equipment

Personnel should be made aware of the hazards associated with the cargo being handled and should be instructed to act with care and use the appropriate protective equipment as mentioned in “Personal protection of crew on Gas Carriers”Protective equipment during cargo handling.

Systems and controls

Cargo emergency shut-down and alarm systems involved in cargo transfer should be tested and/or checked before cargo handling operations begin. Essential cargo handling controls should also be tested and checked prior to transfer operations.

Cargo transfer operations

Transfer operations including emergency procedures should be discussed between ship personnel and the persons responsible at the shore facility prior to commencement and communications maintained throughout the transfer operations.

LNG tanker in port
LNG tanker Valletta
Source: foter.com

The closing time of the valve referred to in “Cargo Tank Instrumentation on Gas Tankers”Overflow control (i.e. time from shut-down signal initiation to complete valve closure) should not be greater than:

3600·ULR [s],

Where:

  • U – ullage volume at operating signal level [m3];
  • LR – maximum loading rate agreed between ship and shore facility [m3/h].

The loading rate should be adjusted to limit surge pressure on valve closure to an acceptable level taking into account the loading hose or arm, the ship and the shore piping systems where relevant.

Additional operating requirements

Additional operating requirements will be found in the following paragraphs of the Rules:

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