Hochiki IFD-E-IS User Manual
IFD-E(IS)
Intrinsically Safe Flame Detector
User Manual
2 Hochiki Europe ( UK ) Ltd
General
Description
This Install ation Guide gives information on the intrinsically safe (I.S.) version of t he flame detectors that
have been approv ed by BASEEFA (British Approvals Service for Electrical Equipment in Flammable
Atmospheres). The requirements of the European Community Directive 94/ 9/EC, t he ATmosphere
EXplosives AT E X Directive have been met. The approval have been accessed to European Standards
EN 50014, EN 50020 and EN 50284.
The detector s are cer tif ied
The range comprises single infra-red (IR), dual infra-red (IR²) and tri ple infra-red (IR³ ) flam e detectors.
The detector housings are available in zi nc met al alloy or stainless steel and also stai nless steel
(antistati c ) glass fi lled polycarbonate.
The guide also provi des i nformation on intri nsi c safety, the applicati on, maintenance, installation and
adjustments of the detectors. Reference to ot her indiv i dual detector publi c ations can be made for more
information on none intrinsically safety issues. These public ations are available on request.
II 1 G EEx ia IIC T4 and can be used with all listed gase s.
Introduction to Intrinsic Safety
There are many places where an explosive mixture of air and gas or vapour is or may be pr esent
continuously , intermittentl y or as a result of an ac ci dent. These are defined as hazardous areas by BS
EN 50014:1998, El ect ri c al appar atus for potentially explosiv e atmospheres – General requirem ents.
Hazardous areas are common in petroleum and chemical engineering plants and in f act ori es proces si ng
and storing gases, solvents, paints and other v olatile substances.
Electri c al equipm ent 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 ar e a number of met hods
available to achieve this – oil immersion, pressuri se d appar atus and powder fill ing, for example, but the
two most common used are flam epr oof enclosures and intrinsic safety.
Flameproof equipment is contained i n a box so strong that an i nter nal explosion will neither damage the
box nor be transmitt ed outside the box. The surface must remain cool enough not to ignit e the explosive
mixture.
When flameproof equipment is interconnected, flameproof wiri ng must be used. This method is most
valuable when high power l evels are unavoidable but it is not acceptable for areas in which an ex plosive
gas/air mixt ur e m ay be conti nuousl y present or present for long per iods.
For this reason these flame detectors are made int rinsically safe rather than fl am epr oof. Intrinsic ally safe
equipment operates at such low power and with such small amounts of stored energy t hat it i s incapable
of causing ignition:
In normal conditions
With a single fault (for ib type of protection c ode)
With any combination of two faults (for ia type of protection code)
In any of these conditi ons every component must remain cool enough not to ignite gases for which it is
approved. See Table 2
Classification of Hazardous Areas
EN 50014 states that el ec trical apparatus for potentially explosive atm ospheres is divided into:
Group I: Electrical appar atus for mines susceptible to fire damp;
Group II: Electri c al appar atus for places with a pot entially explosive atm osphere, other than
mines susceptible to fire damp.
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Hochiki Europe ( UK ) Ltd 3
These flame det ector s are designed to meet the requirements of Group II apparat us. For the type of
protection “i” intrinsi c ally safe, Group II is subdivided into Equi pm ent Cat egories, Type of Expl osive
Atmosphere (Table 1), Type of Protection Code (Table 2), Temperature Class (Table 3) and Gas Group
(Table 4).
Equipment Markings
Type of Explosive
Equipment
Category
Definition
Atmosphere Group II
G - gas vapour mist
Zone
1 - very high level of pr otection
in which explosive atmosphere mixtures of
0
air gases, vapours or mist are present
continuously, for long periods
2 - high level of protec tion
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 Det ector s 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 )
2-3-0-809/ISS2/JUL07
4 Hochiki Europe ( UK ) Ltd
Temperature
Code
Type of
Protection
Code
Equipment
Category
Class
Referred to
ambient of
-20°C to +40°C
T6 85°C
T5 100°C
Maximum Surface
Temperature
ia Intrinsic safety 1
ib Intrinsic safety 2
d Flameproof 3
These Flame Detectors are approved ia.
Table 2 – Type of Protecti on Codes
Gas Group Representative Gas Other Gases, Liquids & Vapours
IIC
IIB
IIA
Hydrogen Acetylene, Car bon Disulphide
Ethylene Diethyl ether, Tetrafluroethylene
Methane Butane, Met hanol, Petroleum, Propane, Styrene
These Flame Detectors are approved IIC for listed gases in EN 50014.
T4 135°C
T3 200°C
T2 300°C
T1 450°C
Detectors approved to T4 at 40°C
Table 3 – Temperat ur e Classif ic ations
2-3-0-809/ISS2/JUL07
Table 4 – Subdivisions of Group II Gases
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