Bacharach GDC-150 Operation Manual - page 23
GDC-150 Operation Manual
5209-9000 Rev 0
17
NOTE:
It is recommended that a calibration label should be applied after
every calibration to confirm work performed and the date it was
confirmed. If a controller is involved, the alarm set points should be
indicated on a label on the front door of the enclosure so anyone
working in the environment will be aware.
NOTE:
For best performance and to ensure the sensor meets the
indicated specifications, all electrochemical sensors should be calibrated
every six months. The sensors may not perform to the listed
specifications if they are not maintained regularly.
5.2. Calibration Specifications – Gases
Calibration span gases should be at least ±5% accuracy and have a current date
stamp. Gas generators should have a current dated cell installed. Service personnel
should flow zero emissions air or oxygen before attempting to null adjust toxic gas
sensors.
NOTE:
For most electrolytic sensors, nitrogen (N
2
) can be substituted
for zero air. However, for solid-state and catalytic sensors, nitrogen (N
2
)
should not
be substituted for zero air because all solid-state and
catalytic sensors require at least a small volume of Oxygen to operate.
Calibration will be inaccurate.
5.3. Regulators and Flow – Solid-State and Catalytic Sensors
Calibration gases that are lighter than or the same weight as air (CH
4
, H
2
, etc.) should
be flowed at 0.5 LPM. Gases heavier than air (C
3
H
8
, etc.) should be flowed between
0.5 and 1.0 LPM. Fixed flow regulators provide more accuracy. Gases should be
flowed over the sensor for at least 3 minutes.
The proper calibration adapter should be utilized to allow the gas to properly diffuse
around the sensor. They are available from Bacharach (see table on page 21).
A humidification chamber must be utilized for all solid-state sensors. This is also
available from Bacharach (see table on page 21).
5.4. Regulators and Flow – Electrochemical Sensors
Calibration gases should be flowed at 0.5 LPM. Fixed flow regulators provide more
accuracy. Zero air and span gases should be flowed over the sensor for at least
3 minutes.
The proper calibration adapter should be utilized to allow the gas to properly diffuse
around the sensor. They are available from Bacharach (see table on page 21).
For best performance and to ensure the sensor meets the indicated specifications, all
electrochemical sensors should be calibrated every six months. The sensors may not
perform to the listed specifications if they are not maintained regularly.