
Emerson Process Management GmbH & Co. OHGS-2
X-STREAM XE Instruction Manual
HASXEE-IM-HS
10/2012
TERMS USED IN THIS INSTRUCTION MANUAL
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
sufcient 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 (decient 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)
Cellssupplied withanintrinsically safepower
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-
quirementsfor pressurizedhousings: thusan
infallible containment can be characterized
by no intended leakage out of the gas paths
enabling gas to enter the inner compartment
of the analyzer housing.
NAMUR
NAMURisan internationaluserassociation of
automation technology in process industries.
This organisation has issued experience
reports and working documents, called re-
commendations (NE) and worksheets (NA).
Protection Class IP66 / NEMA 4X
Both terms are used to specify conditions for
equipment to be installed outdoor.
IP stands for Ingress Protection, the rst num-
ber species protection against solid objects
(6. = dust tight) while the second number
species the degree of protection against
liquids (.6 = heavy seas).
NEMA stands for National Electrical Manuf-
acturers Association. 4X species a degree
of protection to personnel against incidental
contact with the enclosed equipment; to pro-
videa degreeof protectionagainst fallingdirt,
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