Section 12(2) in The Merchant Shipping (Cargo Ship Construction And Survey) Rules, 1974
(2)In a ship in which a bulkhead is required to be constructed of 'B' class panels, such panels shall be capable of preventing the passage of flame throughout a standard fire test of 30 minutes duration. Every incombustible 'B' class panel used for this purpose shall be such that if either face thereof is exposed to a standard fire test of 30 minutes duration, the average temperature on the unexposed face of the panel shall not increase at any time during the first 15 minutes of the test and during the entire period of the test it shall not exceed by more than 139°C above the initial temperature on that face nor shall the temperature at any one point thereon increase by more than 225°C above the initial temperature. Every combustible 'B' class panel used for this purpose shall be such that if either face thereof is exposed to a fire test of 30 minutes duration the average temperature on the unexposed face of the panel shall not increase by more than 139°C above the initial temperature on that face nor shall the temperature at any one point thereon increase by more than 225°C above the initial temperature.
