28
Appendicies
Appendix A: How to calibrate your
Ex Chek in contaminated air
Calibration of the Ex Chek
is a two-step
process. The first step is to expose the
sensors to contaminate-free fresh air and
perform a fresh air calibration.
Unfortunately some locations are never
completely free of contaminants. To make
calibration easy in this case, it is necessary
to use special calibration "Zero
Contaminant" gas. This gas cylinder,
Biosystems part number 9039, is used in
conjunction with the sample draw
calibration adapter.
Flow the zero contaminant gas across the
sensors for a minute, just as if you were
doing a span calibration. Then do the fresh
air calibration steps described in Chapter 3
of the reference manual.Appendix B:
Suggested Calibration Gases
Use of non-standard
calibration gas and/or calibration kit
components when calibrating the Ex
Chek can lead to dangerously inaccurate
readings and may void the standard
Biosystems warranty.
Biosystems offers calibration kits and
long lasting cylinders of test gas
specifically developed for easy Ex Chek
calibration. Customers are strongly
urged to use only Biosystems
calibration materials when calibrating
their Ex Chek.
Part
Number
Calibration
gas mixture
Comments
54-9031
Methane
(CH
4
) (2.5%
by volume =
50% LEL in
air)
Use when
monitoring for
presence of
methane or
natural gas only.
54-9032E Propane
Equivalent
(50% LEL, in
air)
Recommended
for general
purpose
combustible gas
monitoring.
54-9068E Pentane
Equivalent
(50% LEL, in
air)
Use when
monitoring for
presence of
pentane or
gasses with
similar response
ratios only.
54-9039
Zero air
(20.9 %
oxygen in
nitrogen)
Use for fresh air
calibration in
contaminated
areas.
