Where two or more cargoes that may react chemically in a
dangerous manner are carried simultaneously, separate systems as defined
in 1.2.47, each complying with availability criteria as specified
in 7.8, shall be provided for each cargo. For simultaneous carriage
of two or more cargoes that are not reactive to each other but where,
due to properties of their vapour, separate systems are necessary,
separation may be by means of isolation valves.