CTA Report, Draft 1, ISP Review - US Chemical Safety and Hazard ...

5.0 Incident Description
5.1 Pre-Incident Events
5.1.1 Ventilation Study
In February 2002, CTA contracted with a heating, ventilating, and air conditioning engineering firm to
investigate ventilation improvements in the production and molding areas of the plant. One area of
concern was release of dust from the production lines; however, the investigation did not specifically
examine combustible dust hazards.
The engineering contractor concluded that the general flow of air inside the building was from south to
northeast. The contractor also found that airflow rates at the capture hoods were less than the design
intent. Filters had been placed over ventilation hoods but were not regularly cleaned, resulting in poor
collection of dust. The contractor also noted that the blend rooms were more dust laden than the rest of
the processing lines.
The contractor found that on line 405, the actual volume of air exhausted by the baghouse was only 35
percent of design capacity. The contractor attributed the diminished airflow to the poor condition of the
fans, overloading of the baghouse, and possible plugging of the ductwork. The contractor’s report also
noted that the area around the line 405 mat-former released large quantities of dust. Based on this
information, CSB concluded that phenolic resin dust and small fibers migrated from the blend rooms
through door and wall openings and settled onto flat surfaces throughout the facility.
To balance the plant airflow, the contractor recommended replacing the baghouses on lines 403 and 405,
modifying ventilation hoods on the processing lines to increase capture velocities, and installing four air-
handling units on the roof to provide additional makeup air to the plant.
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