Bump Testing and Calibrating CL2 or CL2 and SO2 Sensors

Updated October 25, 2022

This article describes Blackline Safety’s equipment and device setting recommendations for bump testing and calibrating G7 and G7 EXO equipped with either a chlorine (Cl₂) gas sensor, or both Cl₂ and sulfur dioxide (SO₂) gas sensors.

ABOUT Chlorine (Cl₂) AND Sulfur Dioxide (SO₂)

Cl₂ is considered a sticky gas. Sticky gases are a group of toxic gases that tend to sorb (absorb or adsorb) with surfaces, such as sampling tubing or the exterior of gas detection devices. This means your device response time will be slower than normal when bump testing or calibrating with Cl₂ because of the tendency of the tubing material to interact with the gas flowing along it, slowing down the overall flow of gas to the sensor.

In addition, when calibrating or bump testing devices, the presence of SO₂ can inhibit CI₂ responses and lead to errors in calibration. For detailed information, refer to G7 and G7 EXO Gas Sensor Bump Testing and Calibration Order.

To reduce the impact of all these behaviors, Blackline recommends that you use the following equipment and device settings when bump testing or calibrating devices equipped with Cl₂ gas sensors, or Cl₂ and SO₂ gas sensors.

BUMP TESTING AND CALIBRATING G7 DEVICES USING G7 DOCK

Prior to bump testing or calibrating a G7 device equipped with either a Cl₂ gas sensor, or both Cl₂ and SO₂ gas sensors using G7 Dock, update G7 Dock's configuration settings in Blackline Live as follows:

• Configure inlet 1 to Cl₂.
  NOTE: Inlet 1 is optimized for Cl₂(and other highly reactive gases) based on order of gas calibration or bump testing.
• Configure the pump inlet speed for Cl₂ to 80%.

• If applicable, configure inlet 3 to SO₂.

Once G7 Dock is configured in Blackline Live, set up the dock as follows:

• Use Teflon lined tubing (ACC-FEP-T2) to connect the Cl₂ gas cylinder to inlet 1, making sure the tubing between the dock and gas cylinder is of the shortest length possible.
• Use a stainless-steel regulator, or a regulator with a Viton valve seat and seals (ACC‑DFR-V), on the Cl₂ gas cylinder.

Before placing a device into the configured G7 Dock, you should:

• Ensure that the device has been switched on, left in fresh air, and hasn’t been bump tested or calibrated in the last 15 - 20 minutes.
• Verify that the Cl₂ sensor and, if applicable, the SO₂ sensor, are reading zero ppm, and if they are not, complete a zero of the device in fresh air.

For detailed information on how to bump test or calibrate your device using G7 Dock, refer to the G7 Dock Technical User Manual.

IMPORTANT: For devices equipped with Cl₂ and SO₂ sensors, the Cl₂   sensor may display an under limit (UL) notification once G7 is removed from G7 Dock. This response is normal due to cross-sensitivity between Cl₂ and SO₂.

The notification can be muted but you should not attempt to fresh air zero the sensor. The Cl₂ reading should revert to zero within 20 minutes, depending on the device’s exposure to fresh air. Alternatively, use a single-gas calibration cap attached to a Cl₂ gas cylinder to apply a burst of Cl₂ gas directly to the Cl₂ sensor for 5 - 10 seconds.

MANUALLY BUMP TESTING AND CALIBRATING G7 and G7 EXO DEVICES

Prior to manually bump testing and calibrating a G7 or G7 EXO device equipped with either a Cl₂ gas sensor, or Cl₂ and SO₂ gas sensors, set up your equipment as follows:

• Ensure that a 1.0L/min stainless steel fixed flow regulator (ACC-REG-1.0L-SS) is used on the Cl₂ gas cylinder.
• Ensure that Teflon-lined tubing (ACC-FEP-T2) is used to connect the Cl₂ gas cylinder to the calibration cap, making sure the tubing between the device and gas cylinder is of the shortest length possible.
• If applicable, use two separate single-gas calibration caps (ACC-S-CAL) to bump test or calibrate the Cl₂ sensor and the SO_{2 sensor.}

_{Before applying gas to a device, you should:}

• Ensure that the device has been switched on, left in fresh air, and hasn’t been bump tested or calibrated in the last 15 – 20 minutes.
• Verify that the Cl₂ and if applicable, the SO₂ sensor, are reading zero ppm, and if not, complete a zero of the device in fresh air.

For detailed information on how to manually bump test or calibrate G7, refer to the G7 Technical User Manual. For detailed information on how to manually bump test or calibrate G7 EXO, refer to the G7 EXO Technical User Manual.

IMPORTANT: For devices equipped with Cl₂ and SO₂ sensors, the Cl₂   sensor may display an under limit (UL) notification after bump testing or calibrating SO₂. This response is normal due to cross-sensitivity between Cl₂ and SO₂.

The notification can be muted but you should not attempt to fresh air zero the sensor. The Cl₂ reading should revert to zero within 20 minutes, depending on the device’s exposure to fresh air. Alternatively, use the single-gas calibration cap attached to the Cl₂ gas cylinder to apply a burst of Cl₂ gas directly to the Cl₂ sensor for 5 - 10 seconds.

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