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Calibration

 

ABOUT CALIBRATION
Every gas monitoring system needs to be calibrated [except the Delphian infrared Determinator does not require span calibration (zero point adjustments are required infrequently)]. Each gas monitoring channel is calibrated separately.

HOW OFTEN DOES A GAS MONITORING SYSTEM NEED TO BE CALIBRATED?
Although some companies calibrate their systems only twice a year, we recommend that the system calibration (for all sensors except infrared) be checked at least every 90 days. Checking it every 30 days would be considerably safer. Our system can detect many fail conditions, but not every fail condition. For instance, if a sensor has become poisoned or access to it has been blocked, it may lose some or all of its sensitivity. Calibration is the only way to detect this condition. In addition, as sensors age, they begin to lose their calibration more quickly. Sensors older than one year need more frequent calibration to maintain their accuracy and to prevent false alarms. Calibration is also necessary whenever a sensor is replaced.
Initial Calibration: An initial calibration can be made within 30 minutes after system power is applied to the sensor. However, to achieve accuracy, a second calibration should be made no sooner than 24 hours after systems power is applied.

WHAT IS REQUIRED FOR CALIBRATION?
Calibration gases : Zero air and Span Gas
Calibration gas regulator & sensor connector assembly
and
for the Fuel Guard and SafeCAL a magnetic Calibrator
for the Sage Series III a walkie talkie
for the Remote Calibration System, a remote calibration meter
for a Micro Controller System without Remote Calibration - a

TWO TYPES OF CALIBRATION: FLOW and STATIC
A calibration system must be chosen for each gas to be monitored. Some gases can be calibrated by a flow method;others are considered too dangerous to use this method and a static system is provided for them. There is only one choice per gas.

FLOW CALIBRATION KITS for Combustible Gases
The kits which supply gas by flowing it over the sensor are of two types.
Type A includes everything (a sensor gas connector with tubing, a pressure and flow regulator assembly, a calibration adapter, and a calibration screwdriver), except the gas bottle, needed to calibrate a sensor and comes in a carrying case which can hold one or two bottles of cal. gas.
Type B does not include the carrying case. In each instance, A or B, the appropriate gas must be ordered with the Kit. These gases are offered in 3.6 cubic foot canisters.
Which gas to choose for combustible gas calibration
STATIC CALIBRATION KITS for Toxic Cases
Static calibration systems come in one kit form, Type C, which includes a Calibration Chamber, a gas calibration gauge and valve assembly, a calibration screwdriver, and a calibration adapter. You must select the gas to be used separately. These gas canisters are 36 liters and provide approximately 400 calibrations.
If there is a background gas, a canister of zero air and a calibration kit should be selected so that a true zero calibration can occur. This is especially important for toxic gases such as hydrogen sulfide where a large background can exist without the calibrator’s knowledge.

 

ZERO CALIBRATION
ZERO calibration requires that the sensor be exposed to clean air. The best way to assure accurate ZERO calibration is to apply a source of clean or Zero Air to the sensor. Once this is done, calibration with the sense gas can be initiated

SPAN CALIBRATION
Remove the clean air source and apply the span gas of the appropriate concentration to the sensor.
See Calibration Gases for Combustible Sensors

See Determinator Calibration (infrared)

 

 

Sensor Technology  |  Glossary of Gas Detection Terms
 

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