Page 365 - Ship Construction.DJ Eyres 6Ed

Ch32-H8070.fm Page 354 Wednesday, October 18, 2006 7:06 AM
354 Ship Construction
the average temperature of the unexposed side to rise to 139°C above the
original temperature or not more than 180°C at any one point above the
original temperature during the standard fire test. The ‘A’ class division
rating is related to this time as follows.

Class Time
(min)
--- ใช้เพื่อการศึกษาเท่านั้น---
A–60 60
A–30 30
งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
A–15 15
A–0 0

Figure 32.1 shows typical steel divisions with typical proprietary non-asbestos
fibre reinforced silicate board insulation. ‘B’ class divisions are those which
are constructed as to be capable of preventing the passage of flame to the
end of half an hour of the standard fire test. Various patent board materials
are commonly used where ‘B’ class divisions are required and there are two
ratings B–0 and B–15. These relate to the insulation value such that the
average temperature of the unexposed side does not rise more than 139°C
above the original temperature and at any one point more than 225°C
ึ

Fire bulkhead

Open
Trunk to
25 mm ‘rockwool’ Fusible
batts pinned to damper Shut link
bulkhead insulated to melting
same standard point
19 mm Board A60 as bulkhead 70°C
(calcium silicate
matrix with non- ELEVATION Access cover for
asbestos fibres) manual operation
85 mm
t
A30 = 19 mm
t
t
A15 = 12 mm
Steel
damper

(a) USE OF PROPRIETARY PLAN
INSULATION BOARD
(b) VENT FIRE DAMPER
(GRAVITY RETURN TYPE)

FIGURE 32.1