The calibration of gas detectors is essential in ensuring their accuracy and reliability, which is critical for safety in various industries. Gas detectors are used to detect and monitor the presence of gases and vapors, including flammable gases, toxic gases, and oxygen deficiency, in workplaces and other environments. Here are some examples of how the calibration of gas detectors is important in various industries:
- Chemical and petrochemical industry: In the chemical and petrochemical industry, gas detectors are used to monitor the presence of toxic and flammable gases, such as hydrogen sulfide and methane, which can be released during the production process. Accurate calibration of gas detectors is essential in ensuring that workers are alerted in case of a gas leak or buildup, preventing accidents, and ensuring workplace safety.
- Oil and gas industry: Gas detectors are used extensively in the oil and gas industry to monitor the presence of flammable and toxic gases in drilling rigs, refineries, and pipelines. Calibration of gas detectors is critical in ensuring that workers are protected from the risks associated with gas leaks and spills, such as explosions and fires.
- Mining industry: Gas detectors are used in the mining industry to monitor the presence of gases, such as carbon monoxide and methane, which can accumulate in underground mines and pose a serious threat to workers. Calibration of gas detectors is essential in ensuring that workers are alerted to the presence of dangerous gases and can take appropriate action to avoid exposure.
- Education and research: Gas detectors are also used in educational and research settings to teach students and researchers about the properties and behavior of various gases. Calibration of gas detectors is important in ensuring that accurate data is collected and analyzed, enabling students and researchers to develop a better understanding of gas behavior and safety protocols.
- Flammable gas storage and handling: Gas detectors are used in facilities where flammable gases are stored or handled, such as in laboratories, chemical plants, and refineries. Calibration of gas detectors is critical in ensuring that workers are alerted to the presence of flammable gases, preventing accidents, and ensuring workplace safety.
In summary, calibration of gas detectors is critical in ensuring accurate and reliable detection of gases and vapors in various industries, including chemical and petrochemical, oil and gas, mining, education and research, and flammable gas storage and handling. Accurate detection and monitoring of gases are essential for maintaining workplace safety and preventing accidents.
Calibration of Gas Detectors is important as a gas detector is a device that detects the presence of gases in an area, often as part of a safety system. This type of equipment is used to detect a gas leak and interface with a control system so a process can be automatically shut down. A gas detector can sound an alarm to operators in the area where the leak is occurring, giving them the opportunity to leave. This type of device is important because there are many gases that can be harmful to organic life, such as humans or animals.
Gas detectors can be used to detect combustible, flammable, and toxic gases and oxygen depletion. This type of device is used widely in industry and can be found in locations, such as on oil rigs, to monitor manufacturing processes and emerging technologies such as photovoltaic. They may be used in firefighting.
Gas leak detection is the process of identifying potentially hazardous gas leaks by sensors. These sensors usually employ an audible alarm to alert people when a dangerous gas has been detected. Common sensors include infrared point sensors, ultrasonic sensors, electrochemical gas sensors, and semiconductor sensors. More recently, infrared imaging sensors have come into use. All these sensors are used for a wide range of applications and can be found in industrial plants, refineries, waste-water treatment facilities, vehicles, and homes.
Calibration of Gas Detectors:
When the Gas detector powers up, it will take an initial power-up period of 1 minute approximately and is observed during which it displays “PU”. This is to allow the sensor to stabilize, then the display should read ‘0’ if there is no gas present at the sensor. If this doesn’t occur then refer to the manual book, in the section troubleshoot.
Calibration of Gas Monitors:
Ensure that the Gas Sensor has stabilized for at least 1 hour, and there is no combustible gas present at the sensor. A true zero reading will be obtained when the reading stabilized at the lower value.
Place the magnet over the General Monitors logo at the surface body. ‘–‘ will appear on the display first to indicate that the magnet has been positioned correctly. Then the display will begin to flash. After a total of 9 seconds ‘AC’ will be displayed, indicating that the unit is in the auto-calibration, then remove the magnet.
Use a General Monitors Portable Purge or Calibration Chamber to apply gas at 50% LEL (+/-5%) to the sensor. When the gas sensor detects this gas it will display ‘CP’, which means ‘CP’ = CALIBRATION IN PROGRESS
Wait until ‘CC’ is displayed before removing gas. This will normally take less than 2 minutes, ‘CC’ = CALIBRATION COMPLETE
When the gas disperses from the sensor the gas sensor will leave CALIBRATION MODE and return to a normal monitoring condition. The display should read ‘0’ when the gas has dispersed.
If the above does not occur as described and a different code is displayed. go to the TROUBLESHOOTING section.
Calibration Check:
After performing calibration on the Gas detector then will continue to perform calibration checks:
Position the magnet over the General Monitors logo, the symbol ‘–‘ will be displayed for three seconds and then will begin to flash
Remove the magnet and the display will now flash the gas concentration at the sensor. The analog output will be held at 1.5mA regardless of the gas concentration at the sensor.
If gas is not applied within 6 minutes the analog output will fall to 0mA and the display will read ‘F2’. To recover from this position, replace the magnet over the General Monitors Logo, repeat steps 1 and 2 then proceed to step 4 within the timeout period
Apply gas at 50% LEL to the sensor. Observe that the gas reading settles at 50+/-5%. Should the final response fall outside this limit, a full calibration is required.
Note: The sensor should be exposed to clean air conditions for at least two minutes prior to entering calibration mode.
The display will be continued to flash and the analog output will remain at 1.5mA until the gas has been removed and the level at the sensor drops below 3% LEL approx. Normal monitoring will then be resumed (i.e the display will give a steady reading and the analog output will follow the gas concentration at the sensor)
Calibration of Gas Detectors:
Calibration of Gas Point can be executed at any time during normal operation except the self-test period (from 10 minutes before the self-test until the self-test is complete) BW Technologies recommends a premium grade calibration gas, Gases with NIST (National Institute of Standards and Technology)
Start Calibration:
Press and hold the external button down while the LCD displays the alarm setpoints, continue to hold the button until the display reads CAL (approx. 5 seconds), and then release the button.
– The 4-20 mA output will be 3 mA throughout calibration. Calibration of the Gas Point will not cause false alarms at the controller
– on this step: first LCD monitor will display low and high alarms (approx. 8 sec), next the CAL icon lights for 3 sec, gas type is constantly displayed, and the backlight is activated.
Auto Zero:
The Gas Point will then take a zero-level reading, combustible and toxic sensors; if background gas is present, apply zero the sensor, and restart the calibration sequence will take 30 to 60 seconds.
– On display, the numeric display will read 00, auto zero advice flashes, and the gas monitor is constantly displayed.
Auto Span:
Insert cal cap and apply gas to the sensor for approx. 2 minutes (ammonia 5 minutes)
When the countdown (300 to 00) begins, the span is complete, disconnect the gas
– If the span falls: check the calibration gas cylinder used and the concentration expected. Replace the cylinder and/or change the cal gas expected value, if required, re-calibrate
– Oxygen sensor, use pure air calibration gas (20.9% O2) in case of deficiency to the enriched atmosphere.
– on display: the numeric display will show the calibration gas value expected, gas cylinder icon flashes, span advice lights, and gas type is constantly displayed, after a successful calibration, the gas point automatically returns to normal operation and displays the current reading (ppm or %) present.
Note: Gas Detectors Calibration Procedure may change from vendor to vendor