Manual

DEVICE DESCRIPTION 2
7
GA24
www.krohne.com06/2013 - 4000836702 - MA G24-Ex-II2G-AD R03 en
2.4 Flammable products
Atmospheric conditions
Atmospheric conditionsAtmospheric conditions
Atmospheric conditions
An explosive atmosphere is a mixture of air and flammable gases, vapours, mists or dusts under
atmospheric conditions. The following values define it T
atm
= -20°C...+60°C /
-4°F...140°F and P
atm
= 0.8...1.1bar. Outside of this range, no key data are available as to ignition
behaviour for most mixtures.
Operating conditions
Operating conditionsOperating conditions
Operating conditions
Variable area flowmeters operate outside of atmospheric conditions, which means that
explosion protection according to Directive 94/9/EC (ATEX) – regardless of the zone assignment
– is fundamentally not applicable due to the lack of key safety data for the interior of the
measuring section.
2.5 Equipment category
Variable area flowmeters are designed in accordance with EN 60079-0 and EN 60079-11 in
category II 2 G for use in zone 1. The inside of the measuring unit is also approved for zone 1.
2.6 Types of protection
The variable area flowmeter is designed with protection type intrinsic safety, protection level "ia"
as per EN 60079-11.
The marking is: II 2G Ex ia IIC T6 Gb
II 2G Ex ia IIC T6 GbII 2G Ex ia IIC T6 Gb
II 2G Ex ia IIC T6 Gb
CAUTION!
Operation with flammable products is only permissible if no explosive fuel/air mixture is formed
on the interior of the flowmeter under operating conditions. The user is responsible for the safe
operation of the flowmeter with regard to the temperatures and pressures of the products used.
In case of operation with flammable products the measuring units must be included in the
periodic pressure tests of the system.
INFORMATION!
Definition of zone 1 according to EN 1127-1, Appendix B:
An area in which an explosive atmosphere may occasionally occur as a result of the mixture of
flammable substances in the form of gas, steam or mist with air under normal operation.
The marking contains the following information:
The marking contains the following information:The marking contains the following information:
The marking contains the following information:
II
IIII
II Explosion protection Group II
2
22
2 Device category 2
G
GG
G Gas explosion protection
ia
iaia
ia Intrinsically safe, protection level "ia"
IIC
IICIIC
IIC Suitable for gas groups IIC, IIB and IIA
T6
T6T6
T6 Suitable for temperature classes T6 ... T1
Gb
GbGb
Gb EPL, suitable for zone 1 or zone 2
AD_GA24_II2G_R03_en_4000836702_PRT.book Page 7 Wednesday, June 26, 2013 2:30 PM