Employee Exposure Limits to Hexane
As the environmental health and safety (EHS) manager, you have been asked to evaluate an existing operation to determine employee’s current exposure to hexane, which is a chemical used in painting processes.
You are to complete an evaluation of the employee’s current exposure by determining the employee’s exposure to hexane (toxic contaminant) by calculating time-weighted average (TWA) and compare it to the permissible exposure limit (PEL) and modify the PEL, if necessary.
If it is necessary to modify the PEL, explain the reasoning why it is to be modified.
Once the Current exposure has been determined, select the appropriate ventilation system between dilution and local exhaust that is the best choice to control the concentration of the contamination.
Ensure that you provide the reasons why you think your Selection of ventilation system is the best choice. You are to provide the results in a three-page project report using the Unit
III Consulting Report template.
Scenario
An employee working in a room measuring 15 ft x 20 ft x 15 ft sprays paint assembly parts using a paint containing hexane.
The PEL for hexane is 500 ppm. The employee wears a half-face, air-purifying respirator, but management would like to
install engineering control measures to reduce or eliminate the employee’s exposure to hexane. The options are to:
(1) install a dilution ventilation system, or
(2) install a local exhaust ventilation system.
The employee works a 9-hour shift and has the following exposures:
Sample 1 – Concentration 550ppm – Sampling Time – 1.5 hours
Sample 2 – Concentration 400ppm – Sampling Time – 5.8 hours
Sample 3 – Concentration 375ppm – Sampling Time – 1.7 hours
For the general dilution ventilation system to work, there must be at least 20 room air changes per hour. The fan which supplies air to this area produces 1,500 cubic feet per minute (cfm) (Q).
In order for the local exhaust ventilation system to remove the contaminant to acceptable concentrations, the capture velocity must be at least 140 feet per minute (fpm).
The proposed local exhaust system ventilation system uses a 1.0 feet
diameter duct and a fan that provides a total volume of 1,275 cubic feet per minute (cfm). The source of the contamination is located 1.5 feet from the opening of the duct.
Determine the appropriate ventilation control and calculate the capture
velocity.
Complete your project by following the Unit III Consulting Report template linked above. Ensure you show your equations and all work for determining answers for all three scenarios in the project document. You may either formulate the scenario Equations using the Word equation formula toolbar or write out and solve your equations with answers on a separate paper.
Then, take a screenshot of your work for each scenario using your phone or similar device and insert it as an image in the Document. Make sure your image is clear and legible to read.
No references are required for this assignment; however, if outside sources are used, adhere to APA Style when
Creating citations and references for this assignment
