Operating and Maintenance Manual - Air Conditioning Division Make sure that the fan is always
accompanied by this manual.
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Pay attention that the presence of dust increases ignition risks and needs further means of
protection (see the following). Please note that Comefri fans TZAF FF Atex, VTZ Atex, NTHZ
Atex, THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex, TLI Atex, TZAF Atex, THLZ Atex, HLZ
Atex, TLE Atex, THLE Atex are intended to move dust-free air or slightly dusty air.
Zone Explosive Atmosphere Dangerous concentration Potential spark source must
be avoided
0** Gas, vapour, mist (G) Constant or for a long time Even where few shutdowns
are expected
20 ** Dust (D) Constant or for a long time Even where few shutdowns
are expected
1 Gas, vapour, mist (G) Likely to occur More frequent shutdowns are
expected
21 ** Dust (D) Likely to occur More frequent shutdowns are
expected
2 Gas, vapour, mist (G) Rarely or for short time In normal operation
22 ** Dust (D) Rarely or for short time In normal operation
** Out of TZAF FF Atex, VTZ Atex, NTHZ Atex, THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex,
TLI Atex, TZAF Atex, THLZ Atex, HLZ Atex, TLE Atex, THLE Atex range of application.
As a consequence, the allowed use of the different category fans depending on the different
zones is:
Fan category Designed for zone Also applicable in zones
1 G *** 0 1, 2
1 D *** 20 21 , 22
2 G **** 1 2
2 D ***** 21 22
3 G 2 -
3 D ***** 22 -
*** Group II, category 1 fans are out of Comefri production.
**** Only for TZAF Atex and NTHZ Atex fan series
***** The use of the fan in dusty environments is out of the range of application of TZAF FF
Atex, VTZ Atex, NTHZ Atex, THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex, TLI Atex, TZAF
Atex, THLZ Atex, HLZ Atex, TLE Atex, THLE Atex.
Comefri TZAF FF Atex, VTZ Atex, NTHZ Atex, THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex,
TLI Atex, TZAF Atex, THLZ Atex, HLZ Atex, TLE Atex, THLE Atex fans in no-sparking execution
are suitable for atmospheres with a maximum 21 vol% oxygen content, absolute pressure from
0.8 bar to 1.1 bar and gas explosion Groups IIA and IIB.
Correspondence of the fan category to the inside/outside hazardous zone.
The explosion risk occurs either due to the explosive gas moved by the fan or due to the
presence of explosive gas in the areas where the fan is placed. The risk analysis must therefore
consider both outside and inside the fan.
TZAF FF Atex, VTZ Atex, NTHZ Atex, THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex, TLI Atex,
TZAF Atex, THLZ Atex, HLZ Atex, TLE Atex, THLE Atex fans can be installed (according to DIN
EN ISO 5801) in mode A (without inlet and outlet duct) or mode B (without inlet duct and with
outlet duct). Therefore they have the same explosive atmosphere and require the same
equipment category inside and outside.
TLE Atex, THLE Atex fans must have the same requirements as above when installed in mode
A and B. Installation in mode C (with inlet duct and without outlet duct) has the same
requirements as needed for modes A and B. TLE Atex and THLE Atex fans can also be
installed in mode D (with inlet and outlet ducts). In this case, provided the fan has been
requested in leak proof execution, the fan has to be designed for different category inside and
outside as indicated in the table below and according to the following: if the fan is placed in
open field or in a well ventilated room and considering that the leak proof execution is not
absolutely gas tight, then there is never more than one category of difference between the
highest category and the lowest category inside and outside.
This means for instance that an internal hazard 2 G automatically requires that the outside of
the fan is considered hazard category 3 G.
Category inside the fan enclosure
Non-explosive
atmosphere Category 3 gas Category 2 gas
Category outside the
fan enclosure
Non-
explosive
atmosphere No requirements inside: cat. 3
outside: no
requirements
inside: cat. 2
outside: cat. 3
Category 3
gas
inside: no
requirements
outside: cat. 3
inside: cat. 3
outside: cat. 3 Inside: cat. 2
outside: cat. 3
Category 2
gas inside: cat. 3
outside: cat. 2 inside: cat. 3
outside: cat. 2 inside: cat. 2
outside: cat. 2
If the fan is placed in a closed unventilated room, the category selected for the more restrictive
hazardous zone must be applied for both the outside and inside of the fan casing. This means
for instance that an internal hazard 2 G will require that the outside of the fan is considered 2 G
hazard category.
2.5.2 Temperature
The user must choose the appropriate temperature class than according to the minimum
ignition temperature of the gas, mist or dust (see table below). The temperature class indicates
the maximum surface temperature reached by the fan during operation in which the
temperature of the inlet fluid reaches 60°C (as indicated in 2.3).
Generally the maximum temperature rise will occur at minimum flow and maximum density. If
the system designer is unable to guarantee the safe minimum or maximum air flow, for category
2 fans, temperature monitoring devices have to be installed, which in case of a dangerous
temperature rise will automatically activate emergency functions, e.g. fan shut down or
bypassing, e.g. with dampers.
In case of presence of lightly dusty air, the ignition risk assessment shall consider the
temperature raising of dust or other material trapped between two moving parts or a moving
part and a fixed part, especially if material remains in contact with the same moving part for a
long period.
Cooke
Industries
-
Phone:
+64-9-579
2185
Fax:
+64-9-579
2181
Email:
[email protected] Web:
www.cookeindustries.co.nz
