14 • 65-2301RKSS Toxic Detector
Calibration
This section describes how to calibrate the toxic detector. It includes procedures to prepare for
calibration, set the fresh air reading, set the response reading, and return to normal operation. It
describes calibration using a calibration kit that includes a calibration cup, calibration gas, sample
tubing, and a fixed flow regulator with an on/off knob. The required sample flow rate and calibration
cup depend on the detector being calibrated. Table 2 below lists the required calibration cups and
regulators for the various toxic detectors.
WARNING: RKI Instruments, Inc. recommends that you dedicate a regulator for use with chlorine
(Cl
2
) gas and that you do not use that dedicated regulator for any other gases,
particularly hydrogen sulfide (H
2
S).
WARNING: Not using the recommended calibration cup, sample flowrate, and specified flow
direction (for 81-1138RK calibration cup only) will result in an inaccurate calibration.
Make sure to use the calibration cup and sample flow rate listed in Table 2 for your
target gas when performing a calibration. Also make sure to connect the sample tubing
to the calibration cup port that results in the specified flow direction for the 81-1138RK
calibration cup.
Preparing for Calibration
1.
Unscrew the splashguard from the detector housing cap. Make sure the cap remains securely
screwed onto the housing body.
2.
Push the calibration cup onto the plug-in sensor that sticks through the housing cap. The
calibration cup seals to the sensor with an O-ring.
3.
Screw the regulator into the zero air calibration cylinder.
4.
Use the sample tubing to connect the regulator to the calibration cup. Make sure to connect the
tube to the inlet side of the calibration cup if using the 81-1138RK calibration cup which is marked
on the outside bottom to show the required flow direction through the cup.
Table 2: Required Calibration Cups and Flow Rates
Detector Type
Required
Calibration Cup
Required Regulator/
Flowrate for Calibration
Gas
Flow Direction
Specified on
Calibration Cup
Arsine (AsH
3
)
81-1138RK
81-1051RK, 0.5 LPM (liters
per minute)
Yes
Chlorine (Cl
2
), 0 - 3.00 ppm
and 0 - 10.0 ppm
81-1138RK-CL2
81-1051RK, 0.5 LPM
No
Hydrogen Cyanide (HCN)
81-1138RK
81-1051RK, 0.5 LPM
Yes
Ammonia (NH
3
)
81-1138RK-NH3
81-1051RK-25, 0.25 LPM
No
Phosphine (PH
3
)
81-1138RK
81-1051RK, 0.5 LPM
Yes
Sulphur Dioxide (SO
2
)
81-1138RK
81-1051RK, 0.5 LPM
Yes
