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# Examples PowerPoint PPT Presentation

Examples. Review for first exam. Learning Objectives for 1 st Exam. Be able to define accident and loss statistics (OSHA Incident rate, FAR, Fatality rate) and be able to calculate FAR and Fatality rates List the various responses of humans to toxic exposure and whether they are reversible.

Examples

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## Examples

Review for first exam

### Learning Objectives for 1st Exam

• Be able to define accident and loss statistics (OSHA Incident rate, FAR, Fatality rate) and be able to calculate FAR and Fatality rates

• List the various responses of humans to toxic exposure and whether they are reversible.

### Learning Objectives for 1st Exam

• Be able to explain the difference between ED, TD and LD.

• Be able to determine the predicted response to various exposures using probit analysis.

• Be able to calculate Threshold Limit Values (TLV) and time weighted TLV’s.

### Learning Objectives for 1st Exam

• Be able to estimate the vaporization rate of a liquid and the expected ambient concentration.

• Be able to calculate the flow rate of liquids through a) a hole with constant back pressure; b) a hole in a tank; and c) through a broken pipe.

### Learning Objectives for 1st Exam

• Be able to calculate the flow rate of vapors/gases through a hole, adiabatic flow through a pipe and isothermal flow through a pipe.

• Be able to calculate the rate of release for a flashing and boiling liquid

### In Class Homework Team Problem

• A gasoline filling station has an underground gasoline storage tank with a volume of 5000 gallons. The tank has a 1.0 inch diameter vent. The tank must be filled every week with 4000 gallons of gasoline through an 8 inch diameter opening from a tank truck. The tank is never emptied completely. It takes one hour to fill the tank from the truck.

• Vapor Pressure @77°F=4.6 psia, Approximate molecular weight=94

• What is the gasoline concentration in ppm assuming an effective ventilation rate for outside exposures of 3000 ft3/min during the filling operation?

### In Class Homework Team ProblemSolution to Part A

• Cppm during filling (modified 3.24)

• Eq. 3.18

### In Class Homework Team ProblemSolution to Part A

Assume ½ of fill pipe “open” for evaporation Afill~0.175ft2

### In Class Homework Team ProblemSolution to Part A

• Assume worst case conditions

• Φ=1 Splash Filling

• k=0.1 Poor Mixing

• Vapors escape through ½ of 8” hole during filling

• Qv =3000 ft3/min

• P=atmospheric=14.7 psia

• Psat=4.6 psia

### In Class Homework Team ProblemSolution to Part A

• Cppm=9474 ppm

• If no evaporation through fill pipe 9302 ppm

• If neglect evaporation entirely 9297ppm

### In Class Homework Team Problem

• A gasoline filling station has an underground gasoline storage tank with a volume of 5000 gallons. The tank has a 1.0 inch diameter vent. The tank must be filled every week with 4000 gallons of gasoline through an 8 inch diameter opening from a tank truck. The tank is never emptied completely. It takes one hour to fill the tank from the truck.

• Vapor Pressure @77°F=4.6 psia, Approximate molecular weight=94

• What is the gasoline concentration in ppm assuming that the tank is vented with an effective ventilation rate of 3000 ft3/min when the tank is not being filled?

### In Class Homework Team ProblemSolution for Part B

• Modified Eq 3.14

Assume no gasoline in venting air and ideal gas

### In Class Homework Team ProblemSolution for Part B

• Eq. simplifies for evaporation through 1” vent

• Cppm = 5.4 ppm

### In Class Homework Team Problem

• A gasoline filling station has an underground gasoline storage tank with a volume of 5000 gallons. The tank has a 1.0 inch diameter vent. The tank must be filled every week with 4000 gallons of gasoline through an 8 inch diameter opening from a tank truck. The tank is never emptied completely. It takes one hour to fill the tank from the truck.

• TLV for gasoline is 300 ppm

• What is the time weighted average exposure for a worker on a 10 hour shift during which the tank is filled?

• What is the time weighted average exposure for a worker on a 10 hour shift during which the tank is not filled?

### In Class Homework Team Problem

• Determine the average time-weighted concentration, CTWA, of hydrogen sulfide in ppm that would be estimated to cause 10% fatalities if exposed for 15 minutes.

• How many times greater is this compared to the TLVTWA, i.e., what is the Safety Factor?

### In Class Homework Team ProblemSolution for Problem 2

• TLVTWA = 10 ppm (Table 2.8)

• From Handout in class

• C in ppm, t in min

• For H2S

• a=-11.5

• b=1.0

• n=1.9

### In Class Homework Team ProblemSolution for Problem 2

• From Table 2.4

10% corresponds to Y=3.72

Some algebra

• More Algebra

• More algebra

### In Class Homework Team ProblemSolution for Problem 2

The concentration that would kill 10% of the people is nearly twice the threshold limit value