RKI Instruments 71-0191RK - Manual (Page 31)

Obtaining a Relative Response Factor • 28
correct, transmit the new data to the connected instrument by
pressing “Transmit New Data”.
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 reasponse 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 4 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 4 below has 4 columns:
• Gas/VOC-The most common name for the VOC (volatile organic