Hochiki IFD-E(IS) - Manual (Page 3)

Hochiki Europe (UK) Ltd 3
2-3-0-809/ISS2/JUL07
These flame detectors are designed to meet the requirements of Group II apparatus. For the type of
protection “
i” intrinsically safe, Group II is subdivided into Equipment Categories, Type of Explosive
Atmosphere (Table 1), Type of Protection Code (Table 2), Temperature Class (Table 3) and Gas Group
(Table 4).
Equipment Markings
Type of Explosive
Atmosphere
Group II
G - gas vapour mist
Equipment
Category
Definition
Zone
1 - very high level of protection
in which explosive atmosphere mixtures of
air gases, vapours or mist are present
continuously, for long periods
0
2 - high level of protection
in which explosive atmosphere mixture of
air and gases, vapours or mist are likely to
occur
1
3 - normal level of protection
in which explosive atmosphere mixtures of
air and gases, vapours or mist are unlikely
to occur and if it occurs it will exist only for a
short period
2
These Flame Detectors are suitable for all the above equipment categories.
Note: The detectors are not certified for explosive dust atmospheres.
Table 1Equipment Categories and Type of Explosive Atmosphere (Group II)