Emerson Process Management GmbH & Co. OHGS-2
X-STREAM XEFD
Instruction Manual
HASXEDE-IM-EX
03/2012
Terms Used In This Instruction Manual
ATEX
Directive 94/9/EC, commonly called the
ATEX („Atmosphères Explosibles“) directive,
dealing with equipment intended to be used
in potentially explosive atmospheres.
This directive is valid for equipment to be
sold into and/or installed and operated in the
European Union (EU).
Zone 1
Where ignitable concentrations of ammable
gases can exist some of the time under nor-
mal operating conditions.
(A guideline value [not part of a standard ] is
10 to 1.000 hours per year.)
Zone 2
Where ignitable concentrations of ammable
gases are not likely to exist under normal
operating conditions.
(A guideline value [not part of a standard ] is
less than 10 hours per year.)
Division 2
Where ignitable concentrations of ammable
gases are not likely to exist under normal
operating conditions (similiar to Zone 2).
Lower Explosion Limit (LEL)
Volume ratio of ammable gas in air below
which an explosive gas atmosphere will not
be formed: the mixture of gas and air lacks
sufî‚¿cient fuel (gas) to burn.
Upper Explosion Limit (UEL)
Volume ratio of ammable gas in air above
which an explosive gas atmosphere will not
be formed: the mixture of gas and air is too
rich in fuel (deî‚¿cient in oxygen) to burn.
Flammable Gas(es)
Gases and gas mixtures are assigned to be
ammable if they might become ignitable
when in a mixture with air.
Explosive Gas(es)
Flammable Gases and gas mixtures in a mix-
ture with air within the explosive limits.
Intrinsically Safe Cell (IS Cell)
Cells supplied with an intrinsically safe power
signal, approved by a Test Institute, to operate
with explosive gases.
The design ensures the IS cells remains safe
even in case of failure and explosive gases
are not ignited.
Infallible Containment
This term is derived from the standards of
explosion protection especially from the re-
quirements for pressurized housings: thus an
infallible containment can be characterized
by no intended leakage into the gas paths
enabling gas to enter the inner compartment
of the analyzer housing.
Protection Class IP66 / NEMA 4X
Both terms are used to specify conditions for
equipment to be installed outdoor.
IP stands for Ingress Protection, the î‚¿rst num-
ber speciî‚¿es protection against solid objects
(6. = dust tight) while the second number
speciî‚¿es the degree of protection against
liquids (.6 = heavy seas).
NEMA stands for National Electrical Manuf-
acturers Association. 4X speciî‚¿es a degree
of protection to personnel against incidental
contact with the enclosed equipment; to pro-
vide a degree of protection against falling dirt,
rain, sleet, snow, windblown dust, splashing
water, and hose-directed water; and that will
be undamaged by the external formation of
ice on the enclosure