Which method can be applied when measuring fumigants delivered from pressurized cylinders?

Calibration by weight is the most appropriate method for measuring fumigants delivered from pressurized cylinders. This approach involves weighing the cylinders before and after use, allowing for an accurate assessment of the amount of fumigant dispensed. Because fumigants are often released in varying conditions of temperature and pressure, directly correlating the weight of the gas in the cylinder to the actual quantity delivered provides a reliable measurement method.

Using weight ensures that the calculation accounts for any variations in gas density and behavior under pressure, ultimately leading to precise fumigation dosages. This is crucial for compliance with safety regulations and effectiveness in pest control measures.

In contrast, calibration by volume might not accurately reflect the actual quantity of fumigant due to gas expansion or contraction under differing temperatures. Calibration by time can also be unreliable, as it does not consider variations in flow rates and can lead to inaccuracies based on how the fumigant is dispensed. Calibration by pressure is generally not used as it can fluctuate due to changes in temperature and gas composition, which would not accurately indicate the quantity of fumigant released. Thus, using weight as a calibration standard provides the most accurate and practical means for measuring fumigants from pressurized cylinders.