RKI Instruments Eagle 2 - Manual (Page 105)

Detail Settings Button • 101
Obtaining a Relative Response Factor
If the gas that you want to monitor on the catalytic combustible
or PID channel is not included in the catalytic or PID relative
response lists, you may define up to 5 gases for the catalytic
combustible channel using the Conversion Table tab and 1 gas
for the PID channel using the PID Sensor tab. Testing must be
done using the desired target gas in order to obtain the
response factor value for the catalytic combustible channel. To
determine the relative response factor value for the PID
channel, first look in Table 5 for the desired gas. If the desired
gas does not appear in the table, you must obtain the response
factor through the testing procedure described below.
To determine the relative response factor value for the catalytic
or PID channels, do the following:
1. For determining the catalytic combustible channel relative
response factor, calibrate the catalytic combustible channel
to methane. For determining the PID channel relative
response factor, calibrate the PID channel to isobutylene.
2. Obtain a gas sample of known concentration for the target
gas you wish to define. The sample needs to be at least 10%
of the full scale but RKI Instruments, Inc. recommends using
50% of the full scale. If the concentration tested results in an
overscale reading, test a lower concentration.
3. Apply the gas sample to the EAGLE 2 and take note of the
reading. If the gas sample is of 50 %LEL concentration and
the EAGLE 2 display shows a reading of 25 %LEL, then the
factor for that gas is 2. Conversely, if the gas sample is of 50
%LEL concentration and the EAGLE 2 display shows a
reading of 100 %LEL, then the factor for that gas is 0.5. This
conversion factor value is what you will enter in the Factor
column of the gas you are defining.
Table 5 below has 4 columns:
• Gas/VOC-The most common name for the VOC (volatile
organic compound)
• CAS No.-Sometimes it is easier to identify a VOC from the
internationally recognized CAS (Chemical Abstracts Service)