Emerson Process Management GmbH & Co. OHG
S-2
X-STREAM XEFD
Instruction Manual
HASXEDE-IM-EX
07/2017
Terms Used In This Instruction Manual
ATEX
Directive 2014/34/EU, 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).
Containment System
Part of the equipment containing the flamma
-
ble substance that may constitute an internal
source of release into the Ex d enclosure.
Division 2
Where ignitable concentrations of flammable
gases are not likely to exist under normal
operating conditions (similiar to Zone 2).
Explosive Gas Atmosphere
Mixture of flammable substances in the form
of gas or vapor with air under atmospher-
ic conditions, which after ignition permits
self-sustaining flame propagation.
Flammable Gas or Vapor
Gas or vapor which, when mixed with air in
certain proportions, will form an explosive gas
atmosphere. If the gas, which will be analyzed
in the X-STREAM gas analyzers inside the con-
tainment system has a concentration above LFL.
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.
Lower Explosion Limit (LEL)
Volume ratio of flammable gas in air below
which an explosive gas atmosphere will not
be formed: the mixture of gas and air lacks
sufficient fuel (gas) to burn.
Lower Flammable Limit (LFL)
The concentration of flammable gas, vapor
or mist below which an explosive gas atmo
-
sphere will not be formed when mixed with air.
Protection Class IP66 / NEMA 4X
Both terms are used to specify conditions for
equipment to be installed outdoor.
IP
stands for Ingress Protection, the first num
-
ber specifies protection against solid objects
(
6. = dust tight
) while the second number
specifies the degree of protection against
liquids (.
6 = heavy seas
).
NEMA
stands for National Electrical Manu-
facturers Association.
4X
specifies 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.
Upper Explosion Limit (UEL
)
Volume ratio of flammable gas in air above
which an explosive gas atmosphere will not
be formed: the mixture of gas and air is too
rich in fuel (deficient in oxygen) to burn.
Zone 1
Where ignitable concentrations of flammable
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 flammable
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.)
