When testing for carbon monoxide, if there is no discolouration in the tube after the first depression of the bellows, how many more times should you depress the bellows?

When testing for carbon monoxide, if there is no discolouration in the tube after the first depression of the bellows, how many more times should you depress the bellows?

• A. Once
• B. Twice
• C. Three times
• D. Four times

Answer: (B)

When testing for carbon monoxide using a colorimetric tube, a specific protocol must be followed to ensure accurate measurements. If there is no discoloration in the tube after the initial depression of the bellows, it’s necessary to depress the bellows further to allow a sufficient volume of air to pass through the tube, as the first draw may not have captured enough air for a reliable reading. Depressing the bellows a second time typically provides an additional sample for the colorimetric reaction to occur, allowing for a better chance to detect any presence of carbon monoxide. The chemical reaction in the tube is dependent on the concentration of carbon monoxide in the sampled air, and subsequent depressions increase the exposure of the test material to the gas, thereby enhancing the likelihood of observable change, assuming carbon monoxide is present. Therefore, repeating the process once is commonly regarded as standard practice in such tests to ensure accuracy and reliability in the readings.

When testing for carbon monoxide using a colorimetric tube, a specific protocol must be followed to ensure accurate measurements. If there is no discoloration in the tube after the initial depression of the bellows, it’s necessary to depress the bellows further to allow a sufficient volume of air to pass through the tube, as the first draw may not have captured enough air for a reliable reading.

Depressing the bellows a second time typically provides an additional sample for the colorimetric reaction to occur, allowing for a better chance to detect any presence of carbon monoxide. The chemical reaction in the tube is dependent on the concentration of carbon monoxide in the sampled air, and subsequent depressions increase the exposure of the test material to the gas, thereby enhancing the likelihood of observable change, assuming carbon monoxide is present.

Therefore, repeating the process once is commonly regarded as standard practice in such tests to ensure accuracy and reliability in the readings.