Asbestos Contractor/Supervisor Practice Exam

If an employee averages breathing 10 liters of air per minute containing 0.01 fibers per cubic centimeter, how many fibers will the employee breathe during an 8-hour shift?

1. 0.48 fibers

2. 2.88 fibers

3. 4,800 fibers

4. 2,400 fibers

The correct answer is: 4,800 fibers

To determine how many fibers an employee will breathe during an 8-hour shift given the breathing rate and concentration of fibers in the air, you start by calculating the total volume of air inhaled over the shift. First, the employee breathes 10 liters of air per minute. Over an 8-hour shift, the total minutes worked is 8 hours multiplied by 60 minutes per hour, equaling 480 minutes. Therefore, the total volume of air inhaled is calculated as follows: Total air inhaled (in liters) = Breathing rate (liters/minute) × Total time (minutes) Total air inhaled = 10 liters/minute × 480 minutes = 4,800 liters Next, to find out how many fibers this volume corresponds to, you need to consider the fiber concentration in the air, which is given as 0.01 fibers per cubic centimeter. Since 1 liter is equivalent to 1,000 cubic centimeters, you can convert the total air inhaled into cubic centimeters: Total air inhaled (in cubic centimeters) = 4,800 liters × 1,000 cubic centimeters/liter = 4,800,000 cubic centimeters. Finally, you calculate the total number of