- Estimate the ventilation rate required to ensure that the gasoline concentration in a close space is below its TLV during the fueling of a car ( 12gal tank). You will have to consider volume displacement AND evaporation rate. Be sure to note what assumptions you made. You can use example 3-9 as guide (004 industrial Hygiene Part 2 Evaluation pdf ) Railroad cars are being splash-filled with toluene. The 10,000 -gal cars are being filled at the rate of one every 8hr. The filling hole in the tank car is 4 in. in diameter. Estimate the concentration of toluene vapor as a result of this filling operation. The ventilation rate is estimated at 3000ft3/min. The temperature is 77F and the pressure is 1atm. Solution The concentration is estimated using Equation 3-24. From Example 3-8, K =0.949ft/min and psat=0.0371atm. The area of the filling hole is A=4d2=(4)(144in2/ft2)(3.14)(4in)2=0.0872ft2 Thus KA=(0.949ft/min)(0.0872ft2)=0.0827ft3/min. The filling rate rf, is rr=(8hr1)(60min1hr)=0.00208min1 For splash filling the nonideal filling factor is 1.0. The displacement term in Equation 324 is r1Vc=(1.0)(0.00208min1)(10,000gal)(7.48galft3)=2.78ft3/min As expected, the evaporation term is small compared to the displacement term. The concentration is computed from Equation 324, using k as a parameter: kCppen=QvPPatr1Vc=(3000ft3/min)(1atm)(0.0371atm)(2.78ft3/min)106