Podcast
Questions and Answers
What term refers to the sensor's reaction to an interfering gas?
What term refers to the sensor's reaction to an interfering gas?
- Response Time
- Cross Sensitivity (correct)
- Noise/Drift
- Dynamic Range
Which factor describes the ability of a sensor to react to its specific gas in a specified time frame?
Which factor describes the ability of a sensor to react to its specific gas in a specified time frame?
- Precision
- Limit of Detection (LOD)
- Response Time (correct)
- Accuracy
What does 'Limit of Detection (LOD)' represent in gas detection equipment?
What does 'Limit of Detection (LOD)' represent in gas detection equipment?
- The accuracy in measurement
- The precision of measurement under unchanged conditions
- The ability to withstand electromagnetic fields
- The lowest quantity the instrument can detect with confidence (correct)
Which term represents the degree to which repeated measurements under unchanged conditions show consistent results?
Which term represents the degree to which repeated measurements under unchanged conditions show consistent results?
What does 'Dynamic Range' measure in gas detection equipment?
What does 'Dynamic Range' measure in gas detection equipment?
Which factor defines how much readings fluctuate when the concentration of a substance remains constant?
Which factor defines how much readings fluctuate when the concentration of a substance remains constant?
What is the purpose of Intrinsic Safety in gas detection?
What is the purpose of Intrinsic Safety in gas detection?
Which category of hazardous atmospheres includes oxygen deficiency and asphyxiating gases?
Which category of hazardous atmospheres includes oxygen deficiency and asphyxiating gases?
What type of instruments are commonly used in mine rescue gas detection?
What type of instruments are commonly used in mine rescue gas detection?
Why is it important to select gas detection equipment tailored to the specific incident's needs?
Why is it important to select gas detection equipment tailored to the specific incident's needs?
What is the primary purpose of direct-reading instruments in gas detection?
What is the primary purpose of direct-reading instruments in gas detection?
What should be considered before conducting any gas testing?
What should be considered before conducting any gas testing?
What is a key advantage of multi-gas detectors?
What is a key advantage of multi-gas detectors?
What is a limitation of using multi-gas detectors?
What is a limitation of using multi-gas detectors?
How can a multi-gas detector be more versatile in its usage?
How can a multi-gas detector be more versatile in its usage?
What is a characteristic of oxygen sensors in terms of lifespan?
What is a characteristic of oxygen sensors in terms of lifespan?
Which type of gas sensor has the longest lifespan according to the provided information?
Which type of gas sensor has the longest lifespan according to the provided information?
What is the responsibility of the operator when performing sample tests for gas detection?
What is the responsibility of the operator when performing sample tests for gas detection?
What is the purpose of the colorimetric (tube-style) gas detectors mentioned in the text?
What is the purpose of the colorimetric (tube-style) gas detectors mentioned in the text?
What should be done before using a colorimetric tube-style gas detector?
What should be done before using a colorimetric tube-style gas detector?
How are the readings from colorimetric tubes typically read?
How are the readings from colorimetric tubes typically read?
What consideration is important when using short-term indicator tubes?
What consideration is important when using short-term indicator tubes?
What is one of the advantages of colorimetric (tube-style) gas detectors mentioned in the text?
What is one of the advantages of colorimetric (tube-style) gas detectors mentioned in the text?
Why is it important to store colorimetric tubes properly?
Why is it important to store colorimetric tubes properly?
What is a major limitation of gas tube testers mentioned in the text?
What is a major limitation of gas tube testers mentioned in the text?
Which of the following is a characteristic of electronic gas detectors as described in the text?
Which of the following is a characteristic of electronic gas detectors as described in the text?
What distinguishes electronic gas detectors from gas tube testers according to the text?
What distinguishes electronic gas detectors from gas tube testers according to the text?
What is a common limitation of gas tube testers and electronic gas detectors mentioned in the text?
What is a common limitation of gas tube testers and electronic gas detectors mentioned in the text?
How do electronic gas detectors differ from gas tube testers in terms of the response time for results?
How do electronic gas detectors differ from gas tube testers in terms of the response time for results?
What distinguishes small tubes in plastic chips used by certain gas detectors as per the text?
What distinguishes small tubes in plastic chips used by certain gas detectors as per the text?
What is the primary purpose of Intrinsic Safety as mentioned in the text?
What is the primary purpose of Intrinsic Safety as mentioned in the text?
Why is it crucial to consider personal protective equipment before conducting any gas testing?
Why is it crucial to consider personal protective equipment before conducting any gas testing?
Which characteristic defines the ability of direct-reading instruments to provide information quickly?
Which characteristic defines the ability of direct-reading instruments to provide information quickly?
What distinguishes electronic gas detectors in terms of practical use compared to gas tube testers?
What distinguishes electronic gas detectors in terms of practical use compared to gas tube testers?
How does Intrinsic Safety contribute to the selection of gas detection equipment?
How does Intrinsic Safety contribute to the selection of gas detection equipment?
Which characteristic is most critical when selecting gas detection equipment tailored to a specific incident?
Which characteristic is most critical when selecting gas detection equipment tailored to a specific incident?
What factor plays a significant role in ensuring rapid decision-making during mine rescue gas detection?
What factor plays a significant role in ensuring rapid decision-making during mine rescue gas detection?
Why should gas detection equipment be selected based on the specific needs of an incident?
Why should gas detection equipment be selected based on the specific needs of an incident?
When bump testing a gas detector, what is the purpose of exposing the monitor to a known concentration of gas?
When bump testing a gas detector, what is the purpose of exposing the monitor to a known concentration of gas?
What should be done if an instrument fails to respond properly during a bump test?
What should be done if an instrument fails to respond properly during a bump test?
Which type of gases are lighter than air and need to be sampled at different levels within a space according to the text?
Which type of gases are lighter than air and need to be sampled at different levels within a space according to the text?
What is the recommended frequency for bump tests on gas detectors according to manufacturers?
What is the recommended frequency for bump tests on gas detectors according to manufacturers?
What should be visually inspected before using a gas detector as per the 7-5 Steps for Gas Detector Operation?
What should be visually inspected before using a gas detector as per the 7-5 Steps for Gas Detector Operation?
What does 'zeroing the instrument' refer to in gas detector operation?
What does 'zeroing the instrument' refer to in gas detector operation?
What is the main purpose of gas detector bump tests?
What is the main purpose of gas detector bump tests?
What should an operator do if a gas detector fails a bump test?
What should an operator do if a gas detector fails a bump test?
What factor in gas detection equipment measures the ratio between the largest and smallest possible signals?
What factor in gas detection equipment measures the ratio between the largest and smallest possible signals?
Which gas can interfere with gas detection equipment sensors and mask the presence of sulphur dioxide?
Which gas can interfere with gas detection equipment sensors and mask the presence of sulphur dioxide?
What term is used to define the degree to which the measurement of a substance's quantity matches its actual value in gas detection instruments?
What term is used to define the degree to which the measurement of a substance's quantity matches its actual value in gas detection instruments?
What is the primary purpose of considering performance criteria/specifications when selecting gas detection equipment?
What is the primary purpose of considering performance criteria/specifications when selecting gas detection equipment?
Which of the following could interfere with gas detection equipment and potentially mask the presence of certain gases?
Which of the following could interfere with gas detection equipment and potentially mask the presence of certain gases?
What is a significant advantage of multi-gas detectors over colorimetric tubes?
What is a significant advantage of multi-gas detectors over colorimetric tubes?
What does 'Cross Sensitivity' refer to in relation to gas detection equipment sensors?
What does 'Cross Sensitivity' refer to in relation to gas detection equipment sensors?
Why is it important for operators to continuously sample the atmosphere while work is being completed?
Why is it important for operators to continuously sample the atmosphere while work is being completed?
Which characteristic of gas detection equipment describes how much readings fluctuate when the concentration of a substance remains constant?
Which characteristic of gas detection equipment describes how much readings fluctuate when the concentration of a substance remains constant?
What factor contributes to premature sensor degradation in gas detectors?
What factor contributes to premature sensor degradation in gas detectors?
What is the purpose of following all manufacturer’s specifications for application and use when selecting gas detection equipment?
What is the purpose of following all manufacturer’s specifications for application and use when selecting gas detection equipment?
How do portable field docking stations enhance the usability of some gas detectors?
How do portable field docking stations enhance the usability of some gas detectors?
Which gas sensor type has the shortest typical life span according to the information provided?
Which gas sensor type has the shortest typical life span according to the information provided?
What is an essential requirement before using a multi-gas detector in confined spaces?
What is an essential requirement before using a multi-gas detector in confined spaces?
What is an advantage of multi-gas detectors over gas tube testers in terms of alarms?
What is an advantage of multi-gas detectors over gas tube testers in terms of alarms?
Why do many multi-gas detectors have interchangeable-sensor capabilities?
Why do many multi-gas detectors have interchangeable-sensor capabilities?
What is a significant difference between small tubes in plastic chips used by certain gas detectors and traditional gas tube testers?
What is a significant difference between small tubes in plastic chips used by certain gas detectors and traditional gas tube testers?
Which factor plays a significant role in determining the accuracy of colorimetric tube-style gas detectors?
Which factor plays a significant role in determining the accuracy of colorimetric tube-style gas detectors?
What distinguishes electronic gas detectors from gas tube testers in terms of their portability?
What distinguishes electronic gas detectors from gas tube testers in terms of their portability?
Which aspect is crucial for the proper functioning of electronic gas detectors?
Which aspect is crucial for the proper functioning of electronic gas detectors?
Why is it important for electronic gas detectors to have alarms (visual, audible, vibrating)?
Why is it important for electronic gas detectors to have alarms (visual, audible, vibrating)?
Which statement accurately describes the uniqueness of Drager CMS among common types of detectors mentioned?
Which statement accurately describes the uniqueness of Drager CMS among common types of detectors mentioned?
Study Notes
Gas Detection Instruments
- Four categories of hazardous atmospheres:
- Toxic
- Oxygen deficiency/Asphyxiating gases
- Explosive/flammable gases or vapours
- Smoke, aerosols, fumes (particulate contaminants)
Selecting Gas Detection Equipment
- Select equipment that fits specific needs of the incident
- Consider performance criteria/specifications of the instrument:
- Response Time
- Noise/Drift
- Limit of Detection (LOD)
- Accuracy
- Precision
- Dynamic Range
- Check for conditions that could interfere with the equipment:
- Cross Sensitivity
- Electromagnetic fields
- Humidity
- Atmospheric pressure/altitude
- Low temperatures
- Saturation and high concentrations
Colorimetric (Tube-style) Indicators
- Measure more than 200 organic and inorganic gases and vapours in the air
- Advantages:
- Operation with one hand
- Low weight and simple operation
- Always ready for use (no batteries)
- Tubes for more than 200 different gases and vapours
- Printed measuring scale on the tubes provides immediate reading of the result
- Low maintenance
- Limitations:
- Tubes and pumps are manufacturer-specific
- No alarm system, therefore not recommended for continuous monitoring
- Dependent upon operator’s interpretation of results
- Application can require longer periods of time in atmospheres for results to appear (up to several minutes)
- Limited shelf-life
- Only accurate within +/- 20%
- Many cross-sensitivities
Electronic Gas Detectors
- Complex system including a sensor(s) surrounded by sensitive electronics, alarms, battery, and display
- Advantages:
- Multi-gas detectors use separate sensors for oxygen and combustible atmospheres
- Can register multiple toxic gases in the same hand-held monitor
- Many models have interchangeable-sensor capabilities
- Will provide low-level and high-level alarms
- Accidental power-off protection
- Many are capable of internal data-logging
- Portable field docking stations are also available for several models
- Can have an internal motorized pump or a diffusion monitor with attachable pump
- More accurate than colorimetric tubes – accurate within +/- 10%
- Limitations:
- Sensor sensitivity and response to gas will degrade over time; Limited shelf life
- Gases recognized are sensor-specific
- Requires time to perform a pre-use procedure
- Sensors and batteries have a finite life
- Environmental conditions contribute to premature sensor degradation
Practical Skills for Gas Detection
- Atmospheric sampling:
- Follow all manufacturer’s specifications and guidelines
- Proper sampling techniques due to the stratification of gases that may be present
- Sample prior to entry, prior to re-entry, and continuously while work is being completed
- Relative Density:
- Sample at the top, middle, and bottom of a space
- Sample every 1–2 metres (3–7 ft) due to the weights of gases
Bump Testing and Calibration
- Function (“bump”) testing involves a brief exposure of the monitor to a known concentration of gas(es) for the purpose of verifying sensor and alarm operation
- Calibration involves adjusting the instrument to ensure accuracy
- Important elements of gas detector maintenance include:
- Function (“bump”) testing
- Calibration
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Description
Learn about colorimetric (tube-style) gas detectors which measure over 200 organic and inorganic gases and vapors in the air. Understand the pre-use steps, such as performing pump leak tests and ensuring the correct orientation of the detector. Explore how a portable pump draws air for operation.
