Environmental Control
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Construction and Classification of Ships for the Carriage of Liquid Chemicals in Bulk, July 2022 - The Rules and Regulations for the Construction and Classification of Liquid Chemicals in Bulk - Environmental Control

Environmental Control

Parent topic: The Rules and Regulations for the Construction and Classification of Liquid Chemicals in Bulk

9.1 General

9.1.1 Vapour spaces within cargo tanks and, in some cases, spaces surrounding cargo tanks may require to have specially controlled atmospheres.

LR 9.1(a) For the purposes of inerting, Resolutions A.566(14) and IMO Resolution A.567(14) – Regulation for Inert Gas Systems on Chemical Tankers – (Adopted on 20 November 1985), as may be amended, in the IMO publication of 14th Assembly Resolutions, are to be complied with as applicable.

9.1.2 There are four different types of control for cargo tanks, as follows:

  1. Inerting: by filling the cargo tank and associated piping systems and, where specified in chapter 15, the spaces surrounding the cargo tanks, with a gas or vapour which will not support combustion and which will not react with the cargo, and maintaining that condition.

  2. Padding: by filling the cargo tank and associated piping systems with a liquid, gas or vapour which separates the cargo from the air, and maintaining that condition.

  3. Drying: by filling the cargo tank and associated piping systems with moisturefree gas or vapour with a dewpoint of -40°C or below at atmospheric pressure, and maintaining that condition.

  4. Ventilation: forced or natural.

9.1.3 Where inerting or padding of cargo tanks is required by the Code in column "h" of Chapter 17 of the IBC Code:

  1. An adequate supply of inert gas for use in filling and discharging the cargo tanks shall be carried or shall be manufactured on board unless a shore supply is available. In addition, sufficient inert gas shall be available on the ship to compensate for normal losses during transportation.

  2. The inert gas system on board the ship shall be able to maintain a pressure of at least 0.007 MPa gauge within the containment system at all times. In addition, the inert gas system shall not raise the cargo tank pressure to more than the tank's relief-valve setting.

  3. Where padding is used, similar arrangements for supply of the padding medium shall be made as required for inert gas in Ch 1, 9.1 General 9.1.3 and Ch 1, 9.1 General 9.1.3.(b).

  4. Means shall be provided for monitoring ullage spaces containing a gas blanket to ensure that the correct atmosphere is being maintained.

  5. Inerting or padding arrangements or both, where used with flammable cargoes, shall be such as to minimize the creation of static electricity during the admission of the inerting medium.

9.1.4 Where drying is used and dry nitrogen is used as the medium, similar arrangements for supply of the drying agent shall be made to those required in Ch 1, 9.1 General 9.1.3. Where drying agents are used as the drying medium on all air inlets to the tank, sufficient medium shall be carried for the duration of the voyage, taking into consideration the diurnal temperature range and the expected humidity.

9.2 Environmental control requirements for individual products

9.2.1 The required types of environmental control for certain products are shown in column h in the table of LR 17.1 General.

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