Definition(s)
“B” class divisions
“B” class divisions are as defined in SOLAS regulation II-2/3.
Source: IMO Resolution A.1023(26), Code for the Construction and Equipment of Mobile Offshore Drilling Units (2009 MODU Code), 2009. Global Standards
"B" Class Divisions
"B" class divisions are those divisions formed by bulkheads, decks, ceilings or linings which comply with the following criteria:
.1 they are constructed of approved non-combustible materials and all materials used in the construction and erection of "B" class divisions are non-combustible, with the exception that combustible veneers may be permitted provided they meet other appropriate requirements of this chapter;
.2 they have an insulation value such that the average temperature of the unexposed side will not rise more than 140ºC above the original temperature, nor will the temperature at any one point, including any joint, rise more than 225ºC above the original temperature, within the time listed below:
class "B-15" 15 min
class "B-0" 0 min
.3 they are constructed as to be capable of preventing the passage of flame to the end of the first half hour of the standard fire test; and
.4 the Administration has required a test of a prototype division in accordance with the Fire Test Procedures Code to ensure that it meets the above requirements for integrity and temperature rise. <Chapter II-2, part A, regulation 3>.
Source: IMO Resolution MSC.99(73), amendments to the International Convention for the Safety of Life at Sea, 1974, as amended, 5 December 2000, International Maritime Organization. Legislation
"B" Class Divisions (fire divisions)
‘B’ Class divisions are those divisions formed by bulkheads, decks, ceilings or linings which comply with the following criteria:
(a) They are to be so constructed as to be capable of preventing the passage of flame to the end of the first half hour of the standard fire test.
(b) They are to have an insulation value such that the average temperature of the unexposed side will not rise more than 140°C above the original temperature, nor will the temperature at any one point, including any joint, rise more than 225°C above the original temperature, within the time listed below:
Class ‘B-15’- 15 minutes
Class ‘B-0’ - 0 minutes
(c) They are to be constructed of approved noncombustible materials and all materials used in the construction and erection of ‘B’ Class divisions are to be non-combustible, with the exception that combustible veneers may be permitted, provided they meet other appropriate requirements of this Chapter.
(d) In accordance with the Fire Test Procedures Code, a test of a prototype division may be required to ensure that it meets the above requirements for integrity and temperature rise.
Source: Rules and Regulations for the Classification of Mobile Offshore Units, Part 7, Safety Systems, Hazardous Areas and Fire, June 2013, Lloyd’s Register, Global Standards