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Exam 2 Sample Problems 1. Using an inverted buret for pump calibration, the industrial hygienist timed the movement of a

soap bubble from 200 to 0 mL. The following are the obtained results:

Time 1: 7.45 sec Time 2: 7.39 sec Time 3: 7.49 sec Time 4: 7.41 sec Time 5: 7.44 sec Calculate the flow rate (in LPM) of the sampling train.

2. A diffuser opening measures 24 x 12 inches and has an anemometer reading of 25 fpm. Calculate the volumetric rate of airflow, Q (in cfm).

3. The indoor CO2 concentrations in a work space during the workday were measured as follows.

The outdoor CO2 concentration is 500 ppm. Nine (9) employees occupy the space.

Time of Day Indoor CO2 Concentration (ppm) 8 AM 330 1 PM 970 8 PM 540

a) Calculate the volume of outside air per person (cfm/person) flowing into the work space.

b) Is the resulting volume of outside air acceptable based on the minimum flow of 20

cfm/person as recommended in the ASHRAE Standard? 4. Pitot traverse measurements in a duct resulted to an average velocity pressure of 0.05 inches of

water. a) Calculate the duct velocity.

b) The LEV system should be operating at a minimum velocity of 800 fpm. Is the measured

duct velocity acceptable? 5. Calculate the required dilution flow rate if 20 pounds of toluene are evaporated from a process

during an 4-hour work shift. The acceptable airborne concentration of toluene is set at 10 ppm. Assume that Kmix=1.5, d = 1 and MW = 92.1. (4 points)