February I

Noise:
Determine the total percent dose for the following noise measurements:

1 hour @ 85 dB
3 hours @95 dB
0.5 hours @ 105 dB
3.5 hours @ 80 dB

Ventilation:
What is the airflow rate given the following conditions:

Hood Entry Coefficient = 0.90
Hood Static Pressure = -2.5 “w.g.
Duct Diameter = 12”

Heat Stress:
What is the amount of radiant heat gain for a worker exposed to a radiant heat source with a temperature of 134 ˚F?

General Sciences:
How many moles of acetone are there in 250 mL of vapor at NTP (760 mm Hg, 25 ˚C)?

Ventilation:
What is the steady state concentration for acetone (MW = 58.08) given an emission rate of 1.0 pints per hour and a ventilation rate of 1200 cfm (assume NTP)?

General Sciences:
How many milliliters of carbon disulfide (MW = 76.14, SG = 1.261) must be placed in a room (volume = 800 ft³) to result in a concentration of 100 ppm (assume NTP)?

Radiation:
What is the final activity for a 2.5 millicurie radioactive source after 45 days (T1/2 = 12 days)?

General Sciences:
Solve for X:

10^x = 123.985

Radiation:
The half value layer for a shield is 1.5 cm. If you want to reduce the radiation source by a factor of 200 using this shielding material, what thickness should you use?

Radiation:
If the measured exposure to UV for a worker is 12 • 10^-6 W/cm², what is the allowable exposure time for the worker over an 8-hour shift?

Noise:
If a fan is operating at 400 Hz and has 12 blades, what is it's speed?

Ventilation:
How long will it take to reduce the concentration of acetone in a room (volume = 22.656 m³) from 1500 ppm to 400 ppm if the effective ventilation rate is 400 cfm?

Ventilation:
If the total pressure in a duct is -0.6 “w.g. and the static pressure is -1.2 “w.g., what is the velocity of the air moving through the duct?

Noise:
The sound pressure of a noise is 0.44 N/m². What is the sound level?

General Sciences:
100 milliliters of CO2 are mixed into a 40 gallon tank containing air. What is the resultant concentration of CO2 in the tank?

Ventilation:
Air enters a 6” round plain duct hood. What is the required volumetric flow rate for capture 9” in front of the hood if we need a capture velocity of 150 fpm?

General Sciences:
Convert 55.0 mg/m³ of acetone (MW = 58.08) to ppm (assume NTP).

General Sciences:
Convert 55.0 mg/m³ of acetone (MW = 58.08) to ppm (T = 82 ˚F, P = 745 mm Hg)

Heat Stress:
Determine the WBGT in an indoor setting given the following information:

NWB = 32.3 ˚C
Globe = 30.1 ˚C
DB = 27.4 ˚C

Ventilation:
What is a hood’s static pressure loss when the duct velocity pressure = 0.56 “w.g. and the hood entry loss = 0.72 “w.g.?

Ventilation:
What is a hood’s coefficient of entry when the duct velocity pressure = 0.56 “w.g. and the hood entry loss = 0.72 “w.g.?

Radiation:
A worker is exposed to an alpha emitter at a rate of 0.25 mrad/hr for 8 hours. What is the dose equivalent in rem?

Radiation:
Given a radioactivity measurement of 500 mrem at 12 feet, at what distance would 5 mrem be measured?

General IH:
What is the minimum sampling time for sampling lead in air if the LOQ is 2.0 µg, the target concentration is 30 µg/m³ and the flow rate is 2 liters per minute?

General Sciences:
Determine the density correction factor at T = 35 ˚C, and P = 28.85 mm Hg