The Merchant Shipping (Cargo Ship Construction) Regulations 1997

Inerting, ventilation and gas measurement Requirements for tankers constructed on or after 1st October 1994

25.—(1) Double hull and double bottom spaces shall be fitted with suitable connections for the supply of air.

(2) On oil tankers required to be fitted with inert gas systems—

(a) double hull spaces shall be fitted with suitable connections for the supply of inert gas;

(b) where hull spaces are connected to a permanently fitted inert gas distribution system, means shall be provided to prevent hydrocarbon gases from the cargo tanks entering the double hull spaces through the system;

(c) where such spaces are not permanently connected to an inert gas distribution system, appropriate means shall be provided to allow connection to the inert gas main.

(3) Suitable portable instruments for measuring oxygen and flammable vapour concentrations shall be provided. In selecting these instruments, due attention shall be given to their use in combination with the fixed gas-sampling line system referred to in paragraph (4).

(4) Where the atmosphere in double hull spaces cannot be reliably measured using flexible gas-sampling hoses, such spaces shall be fitted with permanent gas sampling lines. The configuration of such line systems shall be adapted to the design of such spaces.

(5) The materials of construction and the dimensions of gas sampling lines shall be such as to prevent restriction. Where plastic materials are used, they shall be electrically conductive.