Hach si792 T, User Manual, Page: 110 / 116

ATEX safety instructions
108
Instructions" and comprise information on the environmental
conditions, on installation/setting up and commissioning, on correct
operation (= usage), on assembly and de-installation, on
maintenance.
4. Attention is to be paid to the action of moisture, ambient
temperature and chemicals. The instruction manual contains an
overview, in tabular form, of the chemical resistance of the housing
materials PFA Teflon and PEEK. If it is not possible to derive a clear
assessment from this information, then more detailed tables are to
be used. If it is still not possible to perform a clear assessment on
safe usage, or applications areas other than those described are
intended, then the application must be clarified with Hach Company/
Hach Lange GmbH.
5. A condition for the safe usage of sensors is compliance with the
stated environmental conditions and temperature ranges.
6. Due to the mechanical dimensions and the materials used, in
certain process conditions such as dry environments or gas
streams, hazards may arise due to electrostatic charging that could
produce sparks capable of ignition when discharged. It is therefore
necessary to comply with the following (refer to
Figure 19 ):
• The sensors are only allowed to be used in media with a
conductivity > 1 nS/m.
• The sensors are only allowed to be used in media with a flow
velocity < 2 m/S.
• The
5
/
8
-11UNC metal fitting must be earthed.
7. ONLY the types 3708E2T, 3727E2T and 3728E2T sensors are
intended for operation in intrinsically safe "ia" circuits and for
mounting in the boundary wall between zone 0 and the less
endangered area. They are equipped with an industrial self-sealing
¾-inch NPT process connection or with an industrial plumbing
connection with 2-inch flange and EPDM seal (compliant with 3-A