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 listed in attachement (1)
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 attached Report template. 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.
