How long must you run a pump at 14 Lpm to collect 1250 liters?

To determine how long a pump must run at a rate of 14 liters per minute (Lpm) to collect 1250 liters, you can use the formula:

Time (in minutes) = Total volume (in liters) / Flow rate (in Lpm)

By substituting the given values into this formula, you would calculate:

Time = 1250 liters / 14 Lpm = approximately 89.29 minutes.

Since time is usually rounded up to the nearest whole minute, this suggests that running the pump for about 90 minutes would be sufficient to collect the desired volume of air. Therefore, the correct response, indicating the necessary duration for effective and accurate sampling at that flow rate, is indeed 90 minutes. This calculation highlights the importance of understanding flow rates in air monitoring scenarios, as it allows technicians to effectively plan their sampling times to ensure they collect adequate samples for analysis.