Emerson X-STREAM Series Instruction Manual page 9

Instruction Manual
HASXENE-IM-EX
X-STREAM Non-Incendive
12/2014
Terms
Lower Explosion Limit (LEL)
Volume ratio of fl ammable gas in air below
which an explosive gas atmosphere will not
be formed: the mixture of gas and air lacks
suffi cient fuel (gas) to burn.
Non-Incendive (Ex n)
Within this manual "non-incendive" stands for
a protection method for equipment marked
Ex nA nC,intended to be installed in hazar-
dous areas, classifi ed Zone 2 or Division 2.
In the following, the term "non-incendive" is
abbreviated to "Ex n", the code used within
related standards.
Upper Explosion Limit (UEL)
Volume ratio of fl 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 (defi cient in oxygen) to burn.
Zone 1
Where ignitable concentrations of fl 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 times per year.)
Zone 2
Where ignitable concentrations of fl ammable
gases are not likely to exist under normal
operating conditions.
(A guideline value [not part of a standard ] is
less than 10 times per year.)
Emerson Process Management GmbH & Co. OHG S-3