How is required sample time calculated in an industrial hygiene context?

In the context of industrial hygiene, calculating the required sample time is essential for accurately measuring air contaminants or other substances in the environment. The correct formula for determining the required sample time is based on the relationship between volume and flow rate.

The required sample time is derived by taking the minimum sample volume desired and dividing it by the sample rate. This makes sense intuitively: if you know how much sample volume you need to collect (to ensure adequate representation of the hazard) and you also know the rate at which you are collecting the sample (flow rate), you can easily determine how long you need to run the sampling device to achieve that volume.

For instance, if you need to collect a minimum volume of 100 liters and you have a sample rate of 2 liters per minute, the calculation would be 100 liters divided by 2 liters per minute, resulting in a required sample time of 50 minutes.

This formula helps ensure that you obtain a representative sample of the air being tested, which is crucial for accurate monitoring and compliance with occupational health standards.