Q50 SAFETY OF LIFE AT SEA 



I 



meets the above requirements for integrity and temperature 

 rise. 



(d) " B " Class or Fire-retarding Divisions are those divisions formed by 

 bulkheads which are so constructed that they will be capable of 

 preventing the passage of flame up to the end of the first one-half 

 hour of the standard fire test. In addition they shall have an 

 insulating value to the satisfaction of the Administration, having 

 regard to the nature of the adjacent spaces. In general, where 

 such bulkheads are required to form fire-retarding divisions between 

 spaces, they shall be of such material that, if either face is exposed 

 for the first one-half hour period of the standard fire test, the 

 average temperature on the unexposed face will not increase at any 

 time during the test by more than 250°F. (or 139°C.) above the 

 initial temperature, nor shall the temperature at any point on the 

 face including any joint rise more than 405 °F. (or 225 °C.) above 

 the initial temperature. For panels which are of incombustible 

 materials it will only be necessary to comply with the above 

 temperature rise limitation during the first 15-minute period of 

 the standard fire test, but the test shall be continued to the end 

 of the one-half hour to test the panel's integrity in the usual 

 manner. All materials entering into the construction and erection 

 of incombustible " B " Class divisions shall themselves be of 

 incombustible material. Reduced amounts of insulation or none 

 at all may be provided where in the opinion of the Administra- 

 tion a reduced fire hazard is present. The Administration may 

 require a test of an assembled prototype bulkhead to ensure that 

 it meets the above requirements for integrity and temperature rise. 



(e) Main Vertical Zones are those sections into which the hull, super- 

 structure, and deck houses are divided by " A " Class divisions, 

 the mean length of which on any one deck does not, in general, 

 exceed 131 feet (or 40 metres). 



(/) Control Stations are those spaces in which radio, main navigating or 

 central fire-recording equipment or the emergency generator is 

 located. 



ig) Accommodation Spaces are those used for public spaces, corridors, 

 lavatories, cabins, offices, crew quarters, barber shops, isolated 

 pantries and lockers and similar spaces. 



Ch. 2 



