Cross Interference To Other Gases And Vapours - Honeywell Searchpoint Optima Plus Operating Instructions Manual

MAN0905_Issue 7_07/17
Table Number Table Name
Standard Gases
D3240 Ethylene
Special Gases
D3227 Benzene
D3229 Buta-1,3-diene
Table Number Table Name
Standard Gases
D3228 Styrene
Note: For other gases, solvents and vapours, contact Honeywell Analytics.
Note: The choice of LEL value should be in accordance with local regulations.

15.3 Cross Interference to Other Gases and Vapours

Searchpoint Optima Plus is supplied pre-calibrated and ready for installation. The signal output
configuration, gas and range for which the unit is calibrated are indicated on a label attached to the main
housing.
Note: The following information is only applicable when detecting Hydrocarbons.
A Searchpoint Optima Plus calibrated for a particular hydrocarbon will have a response to most other
hydrocarbon gases. The cross-sensitivity figures below are approximate and are for guidance only.
The approximate amount of gas required to give an output equal to 50% LEL methane, on Searchpoint
Optima Plus calibrated for 100% LEL (LEL = 5 %v/v) methane is: -.
The following gases are known to produce a negative response from Searchpoint Optima Plus: -
• Ammonia
• Acetylene
• Propyne (Methyl Acetylene)
As a guide, the approximate concentrations that will create a Fault condition in a Searchpoint Optima Plus
calibrated for methane are: -
15. Specifications
Calibrated against EN60079-20-1:2010 LEL levels
CAS Number
74-85-1
71-43-2
106-99-0
Calibrated against EN61779 LEL levels
CAS Number
100-42-5
Methane
Propane
Butane
Hexane
Heptane
Propylene
Ammonia
Acetylene
Propyne (Methyl Acetylene)
79
Searchpoint Optima Plus with optional HART
Full Scale LEL (%V/V)
100%LEL 2.3
100%LEL 1.2
100%LEL 1.4
Full Scale LEL (%V/V)
100%LEL 1.1
2.5 %v/v
0.3 %v/v
0.2 %v/v
0.3 %v/v
0.3 %v/v
0.8 %v/v
~ 5500 ppm
~ 1000 ppm
~ 1000 ppm
output
®
Operating Instructions
2108M0550
ATEX Performance
Approved
Y
ATEX Performance
Approved