Hochiki IFD-E-EXD User Manual
IFD-E(Exd)
Explosion-Proof Flame Detector
User Manual
2 Hochiki Europe (UK) Ltd
General
Description
This Installation Guide gives information on the Flameproof (EExd) version of the flame detectors that
have been approved by ISSeP (Institut Scientifique de Service Public; notified body number:492). The
requirements of the European Community Directive 94/9/EC, the ATmosphere EXplosives ATEX
Directive have been met. The approval has been assessed by reference to the following standards,
EN50014:1997+A1 and A2:1999, EN 50018:2000 and pr AA EN 50018 plus a review again st EN60 0791:2004 which showed that there were no changes which materially affected the “state of technological
progress” with respect to the product. EN50281-1-1:1998.
The detector enclosure is certified
The detector is triple infra-red (IR³) and the housing is copper-free aluminium alloy (LM25).
The guide also provides information on Flameproof (type‘d’) enclosures, the application, maintenance,
installation and adjustments of the detectors. Reference to other individual detector publications can be
made available for more information on none Flameproof issues. These publications are available on
request.
NOTE: Information in this guide is given in good faith, but the manufacturer cannot be held responsible
for any omissions or errors. The company reserves the right to change the specifications of
products at any time and without prior notice.
II 1 G EEx ia IIC T4 and can be used with all listed gases.
Introduction to Flameproof Enclosures
There are many places where an explosive mixture of air and gas or vapour is or may be present,
intermittently or as a result of an accident. These are defined as hazardous areas by EN 60079-0
(formally EN 50014), Electrical apparatus for explosive gas atmospheres – General requirements.
Hazardous areas are common in petroleum and chemical engineering plants and in factories processing
and storing gases, solvents, paints and other volatile substances.
Electrical equipment for use in these areas needs to be designed so that it cannot ignite an explosive
mixture, not only in normal operation but also in fault conditions. There are a number of methods
available to achieve this – oil immersion, pressurised apparatus and powder filling, for example, but the
two most common used are intrinsic safety and flameproof enclosures.
Flameproof equipment is contained in a box so strong that an internal explosion will neither damage the
box nor be transmitted outside the box. The surface must remain cool enough not to ignite the explosive
mixture.
When flameproof equipment is interconnected, flameproof wiring must be used. This method is most
valuable when high power levels are unavoidable but it is not acceptable for areas in which an explosive
gas/air mixture may be continuously present or present for long periods.
For this reason these flame detectors are made intrinsically safe rather than flameproof. Intrinsically safe
equipment operates at such low power and with such small amounts of stored energy that it is incapable
of causing ignition:
In normal conditions
With a single fault (for ib type of protection code)
With any combination of two faults (for ia type of protection code)
In any of these conditions every component must remain cool enough not to ignite gases for which it is
approved. See Table 4
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Classification of Hazardous Areas
EN 60079-0 (formally EN50014) states that electrical apparatus for potentially explosive atmospheres is
divided into:
Group I: Electrical apparatus for mines susceptible to fire damp;
Group II: Electrical apparatus for places with a potentially explosive atmosphere, other than
mines susceptible to fire damp.
These flame detectors are designed to meet the requirements of Group II apparatus. For the type of
protection “d” Flameproof, 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).
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4 Hochiki Europe (UK) Ltd
Equipment Markings
Type of Explosive
Atmosphere Group II
Equipment
Category
Definition
G - gas vapour mist
D - dust
Zone
1 - very high level of protection
in which explosive atmosphere mixtures of
0
air gases, vapours or mist are present
continuously, for long periods
2 - high level of protection
in which explosive atmosphere mixture of
1
air and gases, vapours or mist are likely to
occur
3 - normal level of protection
in which explosive atmosphere mixtures of
air and gases, vapours or mist are unlikely
2
to occur and if it occurs it will exist only for a
short period
These Flame Detectors are suitable for equipment categories 2 and 3, G or D.
Note: The detectors are not certified for category 1 areas, see ‘IS’ products.
Table 1Equipment Categories and Type of Explosive Atmosphere (Group II)
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Temperature
Class
Referred to
ambient of
Maximum Surface
Temperature
-20°C to +40°C
T6 85°C
T5 100°C
Code
Type of
Protection
Code
Equipment
Category
ia Intrinsic safety 1
T4 135°C
ib Intrinsic safety 2
T3 200°C
d Flameproof 3
T2 300°C
These Flame Detectors are approved ia.
Table 2 – Type of Protection Codes
T1 450°C
Detectors approved to T4 at 40°C
Table 3 – Temperature Classifications
Gas Group Representative Gas Other Gases, Liquids & Vapours
IIC
IIB
IIA
Hydrogen Acetylene, Carbon Disulphide
Ethylene Diethyl ether, Tetrafluroethylene
Methane Butane, Methanol, Petroleum, Propane, Styrene
These Flame Detectors are approved IIC for listed gases in EN 50014.
Table 4 – Subdivisions of Group II Gases
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