CEA 4001 - Page 34

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5.2.1 Light Hazard - LH
Covers non-industrial occupancies with low fire loads and combustibility and with no single area greater
than
126m² with a fire resistance of at least 30 minutes.
5.2.2 Ordinary Hazard - OH
Covers trading and industrial occupancies where combustible materials with a medium fire load and medium
combustibility
are processed or manufactured.
Ordinary Hazard - OH, is sub-divided into 4 groups:
- OH1, Ordinary Hazard Group 1;
- OH2, Ordinary Hazard Group 2;
- OH3, Ordinary Hazard Group 3;
- OH4, Ordinary Hazard Group 4.
Materials may be stored in occupancies classified as OH1, 2 and 3 provided the following conditions are met:
a) The protection throughout the room shall be designed to at least OH3 ;
b) The maximum storage heights shown in Table 2 shall not be exceeded.
When the process area is classified as OH4, storage areas shall be treated as HHS.
c) Blocks of storage including surrounding aisles shall not exceed 216m2 or an area specified by the
authorities.
Blocks of storage shall be separated by aisles all around (see table 2). The aisle shall be
kept free of storage.
T
Table 2: Maximum storage heights for OH occupancies
Storage category
Maximum storage height h
(m)
Width of aisles
surrounding blocks
of
storage
(m)
Free standing or
block storage
(ST1)
All other cases
I
II
III
IV
4,0
3,0
2,1
1,2
3,5
2,6
1,7
1,2
2,0
2,0
2,0
2,0
NOTE: for storage heights exceeding these values, see 5.2.4.
5.2.3 High Hazard, Process - HHP
Covers trading and industrial occupancies where the materials concerned have a high fire load and high
combustibility
and are capable of developing a quickly spreading or intense fire.
High Hazard, Process risks - HHP, is sub-divided into 4 groups:
- HHP1, High Hazard Process Group 1;