Class B Fire Division
A division manufactured in incombustible materials that satisfies the following criteria:
a) it prevents the spread of flames for at least half an hour of the standardised fire test,
b) it is designed so that the average temperature on the unexposed side does not rise more than 140°C above the original temperature. In addition, the temperature at any single point shall not rise more than 225°C above the original temperature within the following timeframes:
– class B-30: 30 minutes,
– class B-15: 15 minutes,
– class B- 0: 0 minutes.
Source: Regulations relating to design and outfitting of facilities, etc. in the petroleum activities (the Facilities Regulations), Norway, April 2010 (amended December 2012). Regulations